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1
Zarraq, Ghazi. "Slope Stability Analysis of the Southwestern Limb of Kosret Anticline in Dokan, Northeastern Iraq". Iraqi Geological Journal 54, n. 2A (31 luglio 2021): 34–48. http://dx.doi.org/10.46717/igj.54.2a.3ms-2021-07-24.
Testo completoAbstract (sommario):
The stability of the rock slopes was studied on the southwestern limb of the Kosret Anticline in the Dokan Area in northeastern Iraq to analyze and indicate the danger of rock mass failures along the public street linking Dokan and Quesangaq, Erbil and the road which link between the city and the residential neighborhood of Dokan Lake, as well as the revealing and the analysis of the risk of landslides in the slopes and rocks detectors of exposed rocks of the formations in the study area. The stereographic projection was used in the analysis and classification of the rock slopes. This study has shown that the failures of rocks are fall and day lighting bedding plane. The factors that affect the stability of the slopes were assessed. This research mainly focuses on identifying the types of collapses along the rocky slopes and the factor that affects the instability of the studied slopes. It was found that it is the direction slopes and the interruption geometry. Different treatment methods have been proposed for the studied rock base on the rock slope analysis. The expected failure types that may occur along the road are plane sliding, rock fall, toppling, and probably the failure type in the future may be planner sliding due to the angle of the friction comes to zero degree. The rocky slopes along the road require constant monitoring due to their hazardous conditions. Where it was found that the attitude of the joints and their frequency with the relation between the attitude of the slopes and the rock beds played an important role in the failures, as well as the weak rocks of the Marl layers of the Shiranish, Kometan and Tanjero formations play a key role in responding to weathering and erosion factors that increase the failures of rock slopes.
2
Pegu, Ajanta. "Hydrocarbon Source Rock Analysis of Barail & Disang group". International Journal for Research in Applied Science and Engineering Technology 10, n. 5 (31 maggio 2022): 2305–12. http://dx.doi.org/10.22214/ijraset.2022.42814.
Testo completoAbstract (sommario):
Abstract: Petroleum source rocks are those which has sufficient amount of organic matter to generate and expel hydrocarbons to form a commercial accumulation of oil or gas. The objective of this project is to analyze the principal learning on the application of the formation of petroleum source rocks and hydrocarbon generation to exploration activities along with evaluation of petroleum source rocks and hydrocarbon generation. In this project, samples of Barail Group and Disang Group of rocks of Naga-Schuppen Belt were analyzed to determine their source rock characteristics and petroleum generative potentials Keywords: source rock, van Krevelen, Rock Eval pyrolysis, Hydrogen Index, Total organic Carbon content
3
Lee, Dong-Keun, Duk-Ho Chung, Woong-Hyeon Jeon e Chul-Min Lee. "Analysis of igneous rock classification process by earth science teachers using eye trackers". Korean Association For Learner-Centered Curriculum And Instruction 22, n. 15 (15 agosto 2022): 461–77. http://dx.doi.org/10.22251/jlcci.2022.22.15.461.
Testo completoAbstract (sommario):
Objectives The purpose of this study is to find out the characteristics that earth science teachers show in the process of classifying igneous rocks and the difficulties in classifying igneous rocks.
Methods To this end, the researchers collected gaze data and language data in the process of classifying igneous rocks by using a Eyetracker(Tobii Ⅱ) and a think-aloud method from five high school earth science teachers in Jeollabuk-do. Then, the collected data were analyzed using the gaze analysis program and the semantic network analysis, respectively.
Results First, in the process of classifying igneous rocks, earth science teacher’s gaze fixation duration was long in the order of diorite, andesite, rhyolite, gabbro, basalt, and granite. Second, in the semantic network for the classification of igneous rocks by earth science teachers, the eigenvector centrality of words related to the apparent characteristics of rocks such as “particles” and “rock color” was high. Third, in the process of classifying igneous rocks, earth science teachers found it difficult to determine the range of characteristics that determine each igneous rock, that is, the range of rock colors, particle sizes, stripes, etc. In other words, earth science teachers found it most difficult to distinguish diorite, and granite was the easiest to distinguish. In the process of classifying igneous rocks, they classified igneous rocks mainly based on the size of the particles that make up the rocks and the color shown by the rocks rather than the minerals that make up the rocks. In addition, earth science teachers were unclear about the scope of the criteria for classification of igneous rocks.
Conclusions Earth science teachers need to clearly establish personal standards for the classification of igneous rocks. And personal standard for rock classification can be established through various observation experiences as well as the geological knowledge they perceive. Therefore, earth science teachers should be provided with various types of rocks and typical rocks for extensive observation experiences, such as activities to observe rocks and various types of rocks.
4
Ahrari-Roudi, Mohyeddin, e Mojtaba Zaresefat. "Armourstone Quality Analysis for Coastal Construction in Chabahar, Southeast Iran". Water 15, n. 1 (30 dicembre 2022): 151. http://dx.doi.org/10.3390/w15010151.
Testo completoAbstract (sommario):
Natural stones (armourstones) of varying sizes and qualities are frequently used to construct breakwaters to protect coastal engineering structures from wave actions for economic reasons. Time-related armourstone deterioration in the form of abrasion and disintegration may result in structural damage. Therefore, it is necessary to investigate the performance and quality of the armourstones, which should be robust and long-lasting. The study aimed to examine the quality of two distinct types of rocks from three breakwaters used as armourstones in the Chabahar region and compare the results to the observed field performance. This study aimed to illustrate why it is crucial to characterise rocks thoroughly before deciding which ones to use in a particular project and to evaluate how well current classification techniques account for the observed field performance of stones that may have complex geological compositions. The physical and mechanical properties of the rock were evaluated through both on-site observation and laboratory testing. The results indicated that the class of rocks used in the breakwater had a wide range of suitability ratings. It was discovered that sedimentary rocks have the best water absorption and porosity properties. In addition, age is a positive factor, as the rate of destruction decreases with age. Component and particle size can also play a role in lithology, which is a significant factor in the rock’s durability. Also, the findings demonstrated that the marine organisms in the rock component play an important role in the stability of these structures, even though rock mass breakwaters are less qualified for breakwater construction as per international coastal engineering standards. According to the findings, a breakwater made of lumachel rock boulders, or alternatively sandstone boulders, will last the longest.
5
Almisned, Omar A., e Naif B. Alqahtani. "Rock analysis to characterize Saudi soft sandstone rock". Journal of Petroleum Exploration and Production Technology 11, n. 6 (10 maggio 2021): 2381–87. http://dx.doi.org/10.1007/s13202-021-01160-y.
Testo completoAbstract (sommario):
AbstractAs more engineering projects and activities are taking place on and around weak rocks, it is becoming more important to study and characterize them. Since regular practices of rock mechanical testing are not effective for weak rocks, special laboratory tests and measurements were performed to characterize the Alkharj Saudi weak sandstone rock which is a clastic rock dominantly sandy limestone and sandstone. Test results are presented in this paper. Porosity, permeability, and mechanical properties (stress, strain, Poisson's ratio, confined compressive strength and unconfined compressive strength) were obtained and then used to characterize the proposed weak rock. This paper provides a mean of classifying weak soft rocks despite encountered problems in handling and testing such materials.
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Rajapaksha, G. K. M., J. K. Clegg, K. S. A. Arachchige, A. V. R. S. Coswaththa, G. D. N. H. Gunarathna, K. M. E. P. Fernando, H. M. R. Premasiri, N. M. S. Sirimuthu, C. N. K. Patabendige e N. M. S. Sirimuthu. "Detailed Chemical Analysis of Unusually Weathered Rocks". Indian Journal of Science and Technology 15, n. 24 (27 giugno 2022): 1213–23. http://dx.doi.org/10.17485/ijst/v15i24.367.
Testo completo
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Custer, Jay F. "Experimental analysis of fire-cracked rocks from varied use contexts". North American Archaeologist 38, n. 3 (7 marzo 2017): 237–91. http://dx.doi.org/10.1177/0197693117696533.
Testo completoAbstract (sommario):
This experimental study of fire-cracked rocks sought to determine if varied rock fracture attributes could be correlated with specific past uses of heated stones. A total of 864 rocks were heated in 41 fires that replicated hearth, stone boiling, sweat lodge, and earth oven uses of quartz, quartzite, and sandstone cobbles as heating elements. Analysis of experimental results considered three fire-cracked rock attributes (fracture rate, fragment type, and fragment shape) which can be correlated with some of the specific uses of rocks as heating elements. These attributes can be applied to fire-cracked rock assemblages from archaeological contexts to determine their past uses with relatively consistent results as long as the archaeological context of the fire-cracked rocks is carefully considered.
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Safira, Amanda, Dina Yulianita e Widya Utama. "Fluid Substitution Analysis Using Gassmann’s Equation Modification on Carbonate Environment". Pakistan Journal of Scientific Research 1, n. 2 (30 dicembre 2021): 8–12. http://dx.doi.org/10.57041/pjosr.v1i2.6.
Testo completoAbstract (sommario):
Gassmann’s equation can be used to determine the velocity of compressional waves that pass through rocks with various pore fluid contents, using fluid substitution concept, but is generally applied to certain conditions only (physical rock properties). Carbonate rock has properties in contrary of Gassmann’s assumption; is a heterogenic, anisotropic rock and does not have a well-interconnected pores. In this research, secondary data from laboratory measurements are used, consisting of carbonate rocks (limestone and dolomite) to test modified Gassmann’s equation on carbonate rocks. Two approaches of Gassmann’s equation are used by using k-dry and k-1 components, which are the value of compressional modulus bulk of saturated rocks. The result of both approaches shows that the usage of k-1 component is more optimal to be applied to carbonate rocks because it does not use k-dry component, which should only be used on field measurements, as there is a difference in the environment condition (air, temperature, and pressure) on reservoir and laboratory.
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Ren, Jia Guo, e Qian Qian Wu. "Discussion on Geological Experiment Technology in Geological Work". Advanced Materials Research 616-618 (dicembre 2012): 60–63. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.60.
Testo completoAbstract (sommario):
This essay puts silicate rocks test as example on the basic of the analysis of new technology and method of geological experiment. This essay analyses the experimental principal and process of silicate rock’s total iron content, and it based on geology experimental operation process. The essay tries to probe into silicate rock’s mineral chemical composition, rock structure and tectonics through the research of the iron content and other chemical components of silicate rocks. Furthermore, this essay also estimates the optional mineral’s component content of sandstone ore, and then evaluates mining products and industrial and economic value. It is very important to guide the development of the mine.
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Zhang, Ke, Zi Nan Wang, Hong Sun, Jian Sun e Yu Hou Wu. "ANSYS-Based Finite Element Analysis on TBM Disc Cutter". Advanced Materials Research 889-890 (febbraio 2014): 66–73. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.66.
Testo completoAbstract (sommario):
The purpose of the essay is to know the rock fragmentation mechanism of TBM and improve the efficiency of disc cutter. The method of simulation is applied. The cutter ring and cutter axis surface stress distribution are studied under different rocks and the change of them is analyzed under different penetrations. Under different rocks conditions, the cutter ring surface stress is affected due to the change of rock load; the same rock condition, it is changed along with the change of penetrations. But the cutter axis surface stress changes little. In different rocks conditions, the change of stress on the cutter ring surface is proportional to rock ultimate stress; the same rock condition, it is proportional to the penetration of the cutter ring. The results are significant in improving the working efficiency of disc cutter.
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Liu, Shunqing, Xianwen Huang, Aizhao Zhou, Jun Hu e Wei Wang. "Soil-Rock Slope Stability Analysis by Considering the Nonuniformity of Rocks". Mathematical Problems in Engineering 2018 (8 novembre 2018): 1–15. http://dx.doi.org/10.1155/2018/3121604.
Testo completoAbstract (sommario):
Soil-rock slopes are widely distributed around the world, while the commonly adopted method by simplifying it as a uniform media tends to be excessively conservative. In this study, a slope stability analysis method considering the nonuniform characteristics of rocks was proposed. It was found that the distribution, relative position, and shape of rock have significant effect on slope stability. For the influence of distribution, large rocks at the foot of slope have the most significant effect on slope stability while the effect is insignificant when the rocks are on the slope surface. In terms of the relative position of rocks, four plastic expansion modes of bypass, diversion, inclusion, and penetration were put forward through the analysis on the expansion mode of the plastic zone. Moreover, rock shape also has influence on slope stability.
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Li, Hai Feng, Guo Xing Zhang, Tao Huang e Qiu Jing Zhou. "Stability Analysis of Dangerous Rocks on the Slope of a Hydropower Station". Applied Mechanics and Materials 405-408 (settembre 2013): 621–29. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.621.
Testo completoAbstract (sommario):
Dangerous rocks are among the most significant factors in analyzing the stability of high slopes, and are the main geological hazards on such slopes. These rocks are typical spatial blocks. The unstable failure of dangerous rocks poses evident spatial features. Consequently, their stability should be calculated by considering it as a three-dimensional (3-D) problem. In this research, the general block method of fractured rock mass and 3-D discontinuous deformation analysis (DDA) are used to study the stability of dangerous rocks on the slope of a hydropower station. The general block method of fractured rock mass is used to generate dangerous rocks and to assess the geometric mobility of blocks. The progressive unstable failure of dangerous rocks is also analyzed. Moreover, 3-D DDA is implemented to examine the stability of dangerous rocks, including the regularity of their unstable failure. The failure sequence of each batch of blocks estimated by general block theory is the same as that in the results of 3-D DDA. The decrease in the shear parameters of the structural plane shortens the time interval of failures, but increases the number and capacity of blocks.
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Sabri, Mohammed M. "Chemical and Structural Analysis of Rocks Using X-ray Fluorescence and X-ray Diffraction Techniques". ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY 8, n. 1 (17 giugno 2020): 79–87. http://dx.doi.org/10.14500/aro.10643.
Testo completoAbstract (sommario):
Rock examinations for mining and commercial use are a vital process to save money and time. A variety of methods and approaches have been used to analyze rocks and among them, X-ray fluorescence (XRF), and X-ray diffraction (XRD) techniques proved to be an accurate method. This research was conducted to evaluate the utility and reliability of XRF and XRD to analyze the major and trace elements of rocks as well as their crystalline structures. Results showed that XRF and XRD techniques are fast and reliable, nondestructive and non-invasive analytical tools for mineral analysis, particularly for rocks. For this purpose, the analysis of 28 samples of rocks, which collected from three different places of Kurdistan region-Iraq, is reported. These places are Haybat Sultan (HS) region in Koya city as well as TaqTaq (TA) and Garmuk (GT) district nearby Koya city. Throughout this analysis, 34 major and trace elements were detected in the rocks collected from HS region, whereas forty major and trace elements were detected in the rocks collected from TA district and GT district. In addition, it was found that the structures of these rocks were crystalline in nature. This was proved through the value of diffracted angle and it was found that the majority of these rocks are oxides. The external view (the appearance) of all collected rocks was also discussed and it was found that each rock consists of a variety of minerals which will be the reason that each rock has a specific color.
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Ye, Dayu, Guannan Liu, Ning Luo, Feng Gao, Xinmin Zhu e Fengtian Yue. "Quantitative Analysis of the Topological Structure of Rock Pore Network". Geofluids 2021 (13 giugno 2021): 1–11. http://dx.doi.org/10.1155/2021/5517489.
Testo completoAbstract (sommario):
As the most significant nonlinear reservoir, the rocks have complex structural characteristic. The pore structure of the rock is varied in shape and complex in connectivity. However, the prevailing methods for characterising the microstructure of rocks, such as the coordination number method and fractal theory, are still difficult to quantify the structural properties. In this study, based on the CT-scan method and a new complex network theory, the topological characteristics of rocks such as seepage path selection, degree of pore aggregation, pore importance, and pore module structure are analysed. The results show that the scale-free network model is more reliable in characterising the rock pore network than previously published structural models, and a small number of pores are the “key” to the seepage process. Besides, we proposed a new method to quantify the importance of rock pores and present the distribution characteristics and connectivity laws of the rock-pore network. This provides a new method to study the seepage process of the nonlinear reservoirs.
15
Jahidin, LO Ngkoimani, LM Iradat Salihin, Hasria, Erzam S. Hasan, Irfan Ido e Suryawan Asfar. "Analysis of Ultramafic Rocks Weathering Level in Konawe Regency, Southeast Sulawesi, Indonesia Using the Magnetic Susceptibility Parameter". Journal of Geoscience, Engineering, Environment, and Technology 5, n. 2 (24 giugno 2020): 73–81. http://dx.doi.org/10.25299/jgeet.2020.5.2.4247.
Testo completoAbstract (sommario):
The Konawe region is part of the Sulawesi Southeast Arm ophiolite belt where ultramafic rocks are exposed in the form of dunite and peridotite. The formation of nickel deposits is closely related to the weathering process of ultramafic rocks as a source rock. Ultramafic rocks exposed to the surface will experience weathering which is influenced by many factors, including in the form of climate change, topography, and existing geological structures.
The weathering process in the source rock can influence variations in chemical elements and magnetic properties in laterite soil profiles. For example, the chemical weathering might affect magnetic mineralogy and the physical weathering could affect granulometry as well as the quantity of magnetic minerals in the soil. Condition of weathering of ultramafic rocks (initial, moderate and advanced) can affect nickel content in laterite sediments. The weathering profile study of serpentine mineral is an indication of the lateralization process that occurs in ultramafic rocks and is carried out through petrographic analysis of thin cuts and polish cuts. Determination of weathering level like this is based on the level of weathering of the mineral serpentine.
In this study, the determination of the weathering level of ultramafic rocks (initial, moderate, and continued) uses magnetic susceptibility parameter. A total of 232 ultramafic rock core samples obtained from 34 hand samples were taken from different places and weathered levels were analyzed. The results of the research have shown that the magnetic susceptibility of ultramafic rocks in the study area varies, from 580 x 10-6 SI to 4.724 x 10-6 SI. Based on the value of magnetic susceptibility, magnetic minerals contained in ultramafic rock samples are hematite and geotite minerals. This means that the weathering level of ultramafic rock samples is the continued weathering level. The level of continued weathering that occurs in ultramafic rocks in the study area produces nickel laterite deposits with a nickel content of 1.65 - 2.40% in the saprolite zone, 0.42% in the saprock zone, and 0.20 - 0.51% in the basic rock zone (bedrock).
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Liu, Kouqi, e Mehdi Ostadhassan. "Estimation of the Permeability of Rock Samples Obtained from the Mercury Intrusion Method Using the New Fractal Method". Fractal and Fractional 6, n. 9 (24 agosto 2022): 463. http://dx.doi.org/10.3390/fractalfract6090463.
Testo completoAbstract (sommario):
Rock permeability, defined as the ability of fluid to flow through the rocks, is one of the most important properties of rock. Many researchers have developed models to predict the permeability of rock from the porosity and pore size based on the mercury intrusion. However, these existing models still have some limitations. In this study, based on data regarding the fractal nature of the mercury intrusion of the rocks, we built a new model to predict the permeability of the rocks. In order to verify the new model, we extracted data regarding different kinds of samples from the literature and estimated the permeability using the new model. The results showed that the model could predict various types of rocks, such as tight sandstone, carbonates, and shale. The comparison of the calculated permeability using the new model is closer to the measured value than the value estimated from the existing models, indicating that the new model is better in predicting the permeability of rock samples.
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Xian-Wen, Huang, Zhi-Shu Yao, Wang Bing-Hui, Zhou Ai-Zhao e Peng-Ming Jiang. "Soil-Rock Slope Stability Analysis under Top Loading considering the Nonuniformity of Rocks". Advances in Civil Engineering 2020 (16 dicembre 2020): 1–15. http://dx.doi.org/10.1155/2020/9575307.
Testo completoAbstract (sommario):
Soil-rock slopes are widely distributed in central or western China. With the development of transportation, many subgrades are being built on mountainsides and therefore, slope stability has to be estimated under high loadings. To obtain better estimation results, a new rock contour establishing algorithm was developed, capable of considering interlock effect between rocks. Then, computed tomography (CT) and unconfined triaxial tests with ring top loadings were conducted. Based on rock distribution characteristics (obtained by CT photos) and the appearance of shear failure surfaces in slopes under ring top loadings, four rock skeleton status and five shear failure surface developing models were introduced. Based on the developed rock contour establishing algorithm, ten groups (twelve models per group) were established and calculated by finite element method (FEM). After this, normalized ultimate loading increasing multiple N, which was the ultimate loading ratio of rock-containing slope to uniform soil slope, was introduced to evaluate the influence of rock distributions on slope stability. The value of N was increased with the increase of rock content due to rock skeleton status. The values of N in slopes with angular rocks were about three times higher than those with round rocks which was due to complex geometric shape and distribution characteristics of angular rocks. Then, considering different slope angles (50°–60°), rock contents (0%–60%), and rock shapes (round and angular), the ultimate loading increasing multiple N of soil-rock slopes under high loadings was calculated and suggested for engineering designs. Finally, based on the failure surfaces of numerical modes, three typical failure modes were developed, which could be reference for designers to deal with slopes.
18
Zhang, Ruofei, Guangming Zhao, Xiangrui Meng, Jian Sun, Wensong Xu, Yingming Li, Zenghui Liu e Siming Kao. "Analysis on Characteristics of Surrounding Rocks of Roadway and Bearing Structure Based on Stress Regulation". Advances in Civil Engineering 2021 (20 marzo 2021): 1–18. http://dx.doi.org/10.1155/2021/6621961.
Testo completoAbstract (sommario):
To address the prominent status of great deformation and difficult maintenance of the roadway under high stresses, this study investigated the mechanical characteristics of surrounding rocks and bearing structural stability in a roadway under adjustment and redistribution of stresses through theoretical analysis, numerical simulation, and engineering field test. Stability forms of the bearing structure of roadway surrounding rocks were analyzed by using the axis-changing theory from the perspectives of surrounding rock, mechanical properties of roadways, surrounding rock stress distribution, and mechanical mechanism of the bearing structure. It is suggested that the surrounding rock stress distribution state is improved and the bearing structure is optimized through unloading and reinforcement construction. A mechanical model of roadway excavation was constructed to analyze the influences of excavation spatial effect on the stress releasing and bearing structure of surrounding rocks. A rock postpeak strain softening and dilatation model was introduced to investigate the mechanical characteristics of the surrounding rock mass in the rupture residual zone and plastic softening zone in a roadway. Moreover, we analyzed the influences of unloading and reinforcement construction on the stress path and mechanical characteristics of the rock unit model, which disclosed the adjustment mechanism of the bearing structure of surrounding rocks by the failure development status of rocks. A numerical simulation on the distribution of surrounding rock stress fields and adjustment features of the bearing structure after roadway excavation and unloading and reinforcement construction was carried out by using the FLAC3D program. Results demonstrate that the unloading construction optimizes the axial ratio of spatial excavation in a roadway and the reinforcement zones on both sides are the supporting zones of the bearing structure. Moreover, the ratio between the distance from two side peaks to the roadway sides and the distance from the roof and floor peaks to the excavation space is equal to the coefficient of horizontal pressure. In other words, the final collapse failure mode of surrounding rock is that the long axis of the excavation unloading space points to the same direction with the maximum principal stress of the primary rock. Reinforcement forces the surrounding rocks to form a “Ω-shaped” bearing structure, which is in favor of the long-term maintenance of the roadway.
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Tawil, Sukardan, Muh Imran Syam e Irianto Uno. "Analysis of Rock Mass Rating Classification with Using RMR Method". European Journal of Engineering and Technology Research 6, n. 1 (26 gennaio 2021): 133–36. http://dx.doi.org/10.24018/ejers.2021.6.1.2342.
Testo completoAbstract (sommario):
The looseness that occurs on the road along Tawaeli-Toboli is a very important issue to be examined because the road is the most important axis road in Central Sulawesi - Indonesia. The goal to be achieved is to know the value of the quality of the rocks and their relation to the size of the slope angle on the road, especially at km 16 to km 26 from Palu City, using the Rock Mass Rating (RMR) method. From the analysis of RMR obtained one slope whose description of rocks is poor, namely on slope 3 with a value of RMR of 28 and a medium description with a value of 51 is on slope 1, for the other six slopes the description of the rock is still a good rock state with values ranging from 63-73. It is concluded that the lowest RMR value requires special attention to be on slope 3. Thus, the friction angle in small rocks, the value of RMR is also small, and the type of soil indicated is bad.
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Tawil, Sukardan, Muh Imran Syam e Irianto Uno. "Analysis of Rock Mass Rating Classification with Using RMR Method". European Journal of Engineering and Technology Research 6, n. 1 (26 gennaio 2021): 133–36. http://dx.doi.org/10.24018/ejeng.2021.6.1.2342.
Testo completoAbstract (sommario):
The looseness that occurs on the road along Tawaeli-Toboli is a very important issue to be examined because the road is the most important axis road in Central Sulawesi - Indonesia. The goal to be achieved is to know the value of the quality of the rocks and their relation to the size of the slope angle on the road, especially at km 16 to km 26 from Palu City, using the Rock Mass Rating (RMR) method. From the analysis of RMR obtained one slope whose description of rocks is poor, namely on slope 3 with a value of RMR of 28 and a medium description with a value of 51 is on slope 1, for the other six slopes the description of the rock is still a good rock state with values ranging from 63-73. It is concluded that the lowest RMR value requires special attention to be on slope 3. Thus, the friction angle in small rocks, the value of RMR is also small, and the type of soil indicated is bad.
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Andayany, Helda, e Josephus Ronny Kelibulin. "Characteristics Of Minerals With Spectroskopic IR At The Gold Mining Area Of Botak Mountain". Jurnal Fisika Indonesia 22, n. 2 (16 aprile 2020): 7. http://dx.doi.org/10.22146/jfi.v22i2.41529.
Testo completoAbstract (sommario):
There are three rock samples that have been taken from the gold mining area of Botak mountain. The rock samples were then analyzed with spectroscopic IR to estimate the characteristic of mineral in the area. Analysis results indicate that the type of mineral found in rock samples 2 is dominated by Kaolinite, Organic Carbon, Palygorskite and Quartz. So it can be estimate the type of rock contained in that area is Quartzite. The analysis result of mineral type analysis on rock samples 1 dan 3 have similarities that is Kaolinite, Organic Carbon, Palygorskite, and Albite. So it can be estimate that the other types of rock in the area are Andesite and Limestone. The existence of Andesit and Limestone shows that there has been alteration and hydrothermal mineralization from volcanic origin rock. So it can be estimate that these rocks are the bearing rocks and hosted rocks of base metals and gold. Whereas the quartzite is a bond mineral from gold carrying rocks
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Guo, Jian, e Qi Cai Wang. "The Numerical Simulation Analysis of Excavation Process of Loess Tunnel". Advanced Materials Research 383-390 (novembre 2011): 6594–600. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.6594.
Testo completoAbstract (sommario):
The bench method dynamic construction process of Xin Baotashan tunnel which located in the grade IV surrounding rock is simulated by using the finite element method. The variation of displacement and stress field of the surrounding rocks and the internal force of the lining structures during every excavation step is calculated. The state of the surrounding rocks can be predicted by the numerical simulation results, and the construction plan and construction sequences can be guided by the analysis results. At the same time the reasonability and feasibility of the design parameters can be judged by analyzing the internal forces of the lining structures. Analysis and experimental results showed that the stability of the surrounding rocks is good by using the bench method construction to the IV grade surrounding rocks and the design parameters of the lining structures are feasible.
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Hall, Lisa, Emmanuelle Grosjean, Irina Borissova, Chris Southby, Ryan Owens, George Bernardel e Cameron Mitchell. "Petroleum systems analysis of the northern Houtman Sub-basin". APPEA Journal 57, n. 2 (2017): 755. http://dx.doi.org/10.1071/aj16026.
Testo completoAbstract (sommario):
Interpretation of newly acquired seismic data in the northern Houtman Sub-basin (Perth Basin) suggests the region contains potential source rocks similar to those in the producing Abrolhos Sub-basin. The regionally extensive late Permian–Early Triassic Kockatea Shale has the potential to contain the oil-prone Hovea Member source interval. Large Permian syn-rift half-graben, up to 10 km thick, are likely to contain a range of gas-prone source rocks. Further potential source rocks may be found in the Jurassic–Early Cretaceous succession, including the Cattamarra Coal Measures, Cadda shales and mixed sources within the Yarragadee Formation. This study investigated the possible maturity and charge history of these different source rocks. A regional pseudo-3D petroleum systems model was constructed using new seismic interpretations. Heat flow was modelled using crustal structure and possible basement composition determined from potential field modelling, and subsidence analysis was used to investigate lithospheric extension through time. The model was calibrated using temperature and maturity data from nine wells in the Houtman and Abrolhos sub-basins. Source rock properties are assigned based on an extensive review of total organic carbon, Rock Eval and kinetic data for the offshore northern Perth Basin. Petroleum systems analysis results show that Permian, Triassic and Early Jurassic source rocks may have generated large cumulative volumes of hydrocarbons across the northern Houtman Sub-basin, whereas the Middle Jurassic–Cretaceous sources remain largely immature. However, the timing of hydrocarbon generation and expulsion with respect to trap formation and structural reactivation is critical for the successful development and preservation of hydrocarbon accumulations.
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Troup, Alison, e Justin Gorton. "Analysis and characterisation of petroleum source rocks in Queensland". APPEA Journal 57, n. 2 (2017): 806. http://dx.doi.org/10.1071/aj16170.
Testo completoAbstract (sommario):
A project to improve the understanding of petroleum source rocks across Queensland’s basins was proposed through the Industry Priorities Initiative. The study has identified new source rocks, improved characterisation of known source rocks, and examined their potential as unconventional reservoirs. Round 2 of the project sampled known source rock formations in the Adavale, Bowen, Cooper and Eromanga basins, all with proven petroleum potential. Forty-eight samples from these basins were screened through Rock-Eval and total organic carbon by LECO to determine candidates for further analysis. Pyrolysis gas chromatography was conducted on selected samples (n = 15) to understand the bulk chemical signatures of kerogens with fluids extracted to derive isotopic and biomarker signatures. Organic petrology (n = 11) examined kerogen components and reflectance. Immature samples were analysed for bulk kinetics (n = 10) to determine the stability of kerogens while some were sent for compositional kinetics (n = 7), to predict the gas to oil ratio (GOR) and saturation pressure. Some more mature samples were sent for late gas analysis (n = 6) to understand hydrocarbon generation at later stages of thermal maturation. The results indicate that the marls in the Bury Limestone may have promising potential, that the Permian coals are the principal source rocks in the Cooper and Bowen basins and that the coals and mudstones of the Birkhead Formation have potential to generate. High production index values were noted in the Bury Limestone, as well as coal and mudstone samples from the Cooper and Bowen basins, suggesting that some of these source rocks also have good retention capabilities.
25
Wang, Jian Hua. "Study on Random Reliability Analysis of Dam Abutment". Advanced Materials Research 214 (febbraio 2011): 218–23. http://dx.doi.org/10.4028/www.scientific.net/amr.214.218.
Testo completoAbstract (sommario):
Stability reliability analysis of abutment rock of arch dam is a very complicated problem which must be studied and solved. Generally, entirely sliding stability reliability analysis should be made when abutment rock bounded by structure planes like fault, joints and fissures, and layers is possible to slide. Due to the complex causes and structures, diverse litholigy, different rocks have different mechanics attributes. While the physical and mechanical parameters of the same rocks are of obvious dispersion and uncertainty. And it is also complex to calculate the pushing force at arch abutment on dam abutment rock, because the uncertain factors as water pressure, sediment, variable temperatures and materials parameters are contained. In this essay, based on Stochastic Finite Element Method, the formula of sliding stability reliability analysis of dam abutment rock is given. The formula can be used for entirely stability reliability analysis of dam abutment.
26
Asadova, G. Sh. "Analysis of cases associated with occurrence of elastic behavior of subsurface rocks while estimation of wellbore stability". Azerbaijan Oil Industry, n. 02 (15 febbraio 2022): 22–26. http://dx.doi.org/10.37474/0365-8554/2022-02-22-26.
Testo completoAbstract (sommario):
Due to the generalization of the studies on the interaction of elastic behavior of subsurface rocks and carried out static analysis, the dependence of the speed of longitudinal waves on the subsurface rocks’ density has been obtained. The dependence of Poisson coefficient on the lithologic features of the rocks has been specified. The poor interaction by the well in a whole in the dependence of Poisson coefficient on the rock density is observed. Moreover, analogical dependences developed on the data of specific rocks are characterized with the closely connected correlation.
27
Wang, Guohua, Jun Tan e Chengxiao Li. "Analysis of rock cracking characteristics during pyrolysis drilling". Thermal Science, n. 00 (2020): 322. http://dx.doi.org/10.2298/tsci200629322w.
Testo completoAbstract (sommario):
Thermal jet rock breaking technology refers to the use of high temperature medium such as supercritical water for a rapid local heating of rocks to break the rocks. Because of the low thermal conductivity of the rock matrix, thermal stress will only form on the rock surface. When the temperature stress exceeds the strength of the rock, micro-cracks will appear in the rock, and continue to expand, resulting in the thermal cracking on the rock surface, which will cause the rock surface to fall off from the body and break the rock. Based on thermal-solid coupling theory, a pyrolysis drilling model was established, and the distribution law of temperature field and temperature stress of bottom hole rock during pyrolysis was obtained by using a finite element method. The results show that during the pyrolysis drilling process, the temperature of the heated part of the rock increases rapidly, producing temperature gradients in radial and axial directions. The expansion of the heated volume is affected by compressive stress in the radial direction, buckling in the axial direction and shear stress. This is very important to the field application of pyrolysis drilling.
28
Kılınçarslan, Şemsettin, Ebru Yılmaz İnce, Ebru Başpınar Tuncay e Fuzuli Yağmurlu. "Clustering Analysis of Normal Strength Concretes Produced with Different Aggregate Types". Open Chemistry 16, n. 1 (22 ottobre 2018): 918–22. http://dx.doi.org/10.1515/chem-2018-0100.
Testo completoAbstract (sommario):
AbstractConcrete is the most commonly used structural material, which is composed of individual base materials. The compressive strength of concrete is important to understand for activities like construction arrangement, prestressing operations, proportioning new mixtures and quality assurance. Concrete has a problem known as Clustering, which is the unsupervised classification of patterns into clusters. The clustering problem has been addressed by several researchers in many contexts and various disciplines; this shows that clustering uses many areas and is an important step in data analysis. In this study, concrete samples with different aggregate types and normal strength were produced. Clustering analysis was performed on the effect of aggregate species for its mechanical strength. According to the result of clustering analysis, it was found that there were three different groups, the study predicts that clustering is not related to the origins of the rocks but is clustered between the strength of the rocks and the mechanical strengths of the concretes produced within these rocks. The common feature of L, RL and SG aggregates in the first cluster is that it is a sedimentary rock. The aggregate of the concrete in the second cluster is that it is a volcanic superficial rock. The common feature of DO and TB rocks in the third cluster is that it has high density. As a result, it was determined that the clay made in normal class concrete is related to the mechanical strength of rocks.
29
Liang, Zhi Lin, e Ze Li. "Study of Lower Bound Method for Plastic Limit Analysis of Wedge on Consideration of Anchor Bolt". Applied Mechanics and Materials 444-445 (ottobre 2013): 966–70. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.966.
Testo completoAbstract (sommario):
The massive rock slope is made up of rocks and structural surface. The existence and strength of the structural surface decides the stability of the rock mass. By adopting the lower bound method for the plastic limit analysis of wedge slope, we can easily calculate the stability of the rocky slope under various circumstances. To apply this method, we first took the wedge-shaped slide block as a complex of rigid block and structural surface for the analysis of the slope stress under the function of anchor bolts, the integrated function of rocks and structural surfaces being considered. Then, on the basis of the lower bound theory for the plastic limit analysis, a mathematical programming model which takes safety factor of slope stability as the object function is established. This model has to meet the equilibrium condition of the bolt, the Mohr-Coulomb yield condition and the boundary condition of slope. In the end, a classic model of wedge is analyzed and its lower bound solution is worked out. This result is compared to the result worked out by limiting equilibrium to test the validity of the measure and procedure used in this paper.
30
Luo, Junhui, Yong Wu, Decai Mi, Qiongyao Ye, Haifeng Huang, Zhenchao Chang, Qinglin Chen et al. "Analysis of the Distribution and Microscopic Characteristics and Disintegration Characteristics of Carbonaceous Rocks: A Case Study of the Middle Devonian Luofu Formation in Western Guangxi of China". Advances in Civil Engineering 2020 (30 agosto 2020): 1–15. http://dx.doi.org/10.1155/2020/8810648.
Testo completoAbstract (sommario):
Carbonaceous rock is a special soft rock containing TOC organic carbon 6%∼40%. In order to reveal the influence of engineering characteristics of carbonaceous rock on the engineering construction, firstly the stratigraphic distribution of carbonaceous Rocks in Guangxi is investigated, and the genetic mechanism and tectonic environment of carbonaceous rocks are discussed. Secondly, the influence of pore microstructure on the disintegration characteristics of carbonaceous rocks is analyzed. The role of geochemical characteristics of carbonaceous rocks (mineral composition, TOC total organic matter content, and type) on engineering properties is revealed. Finally, combined with the distribution, structure, microstructure, and microscopic characteristics of the previous studies, the disintegration mechanism of carbonaceous rocks in water swelling and heat dehydration is discussed. The results are as follows. (1) Carbonaceous rocks in Guangxi are mainly distributed in Devonian, Carboniferous, and Cambrian systems. It is mainly formed in anoxic and reductive deep water basins, slopes, and relatively confined coastal lagoons and swamps. The carbonaceous rocks in the Devonian Luofu formation are most typical. (2) The pores of carbonaceous rocks are divided into mineral pores, organic matter pores, and microfracture, which are mainly mineral pores. The more developed pores in mineral pores are intragranular dissolved pores. Secondly, mineral intergranular pores and a small amount of intergranular dissolution pores and less inner pores. Organic matter porosity increases with the increase of shale organic carbon content and maturity, but the shale porosity and adsorption capacity decrease when shale maturity reaches more than 2.4%. (3) Clay minerals in carbonaceous shale mainly consist of illite and illite/montmorillonite layer, which have water swelling and heat dehydration. The total average value of TOC (total organic matter content) is more than 1%, which belongs to carbonaceous rocks of medium high grade hydrocarbon source rocks. Organic matter is mainly dominated by type I and II1-II2 type with large hydrocarbon generating potential, which is prone to oxidation-reduction reaction and cause rock disintegration.
31
Dias, Gilmar Pauli, e Emílio Velloso Barroso. "Determinação experimental do coeficiente de restituição normal de rochas: aplicação na previsão do alcance de blocos em encostas". Anuário do Instituto de Geociências 29, n. 2 (1 gennaio 2006): 149–67. http://dx.doi.org/10.11137/2006_2_149-167.
Testo completoAbstract (sommario):
Among the several parameters involved in rock fall analisys, the restitution coefficient, which is related to the kinetic energy wasted after repeated impacts of a rocky body against the ground, is probably the most important and most difficult to acquire. There is the necessity of in situ tests where blocks of rocks are thrown down on the slopes. However these tests cannot be performed in places where people or urban equipments could be in risk. In this paper an acoustic method is used for the measurement of the normal restitution coefficient of rocks. This method is very well known by physicists but it has not been applied in the geosciences and engineering areas. It consists in the sound recording of successive impacts of a rock sphere against a smooth rocky surface. The gravity acceleration was back calculated from data obtained in order to verify if precision of the method is suitable. A sensibility analysis of the coefficient of restitution was already carried out simulating real rock fall problems.
32
Wang, Teng Yue, Ke Zhang, Hong Sun, Yu Hou Wu e Kai Jun Zhao. "Analysis on the Stress and Failures of Disc Cutter of Full Face Rock Tunnel Boring Machine". Advanced Materials Research 102-104 (marzo 2010): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amr.102-104.223.
Testo completoAbstract (sommario):
Full face rock tunnel boring machine (TBM) plays an important role in boring rock of tunnel. The failure of disc cutter is the main reason leading to low efficiency of TBM. In this paper, analysis of force and motion for disc cutter are carried by using ABAQUS to study stress distribution and concentration in disc cutter and rocks. Influence of different rocks on stress in disc cutter is analyzed. By combination the failure modes of disc cutter and its stress distribution, methods of decreasing failures of disc cutter are presented. Wear resistance and service life of disc cutter are improved by matching the materials of disc cutters with rocks. The results are useful for structural optimization and strengthening treatment of material of disc cutter.
33
Zhang, Qiu Mei, Jin Tao Tang e Hao Ma. "Analysis between Water Contain and Lithology". Applied Mechanics and Materials 744-746 (marzo 2015): 422–25. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.422.
Testo completoAbstract (sommario):
Water content has a great influence on the rock mechanics properties. Four kinds of rock samples have been tested in the MTS Electro hydraulic Tri-axial Servo Test System. The result shows that with the increase of water content, the rock uniaxial compressive strength and elastic modulus value are declining. We get the fitting equation between water content and rock mechanical properties with four kind of rocks, provide a new basis for slope stability analysis and landslide prevention and control measures.
34
Anderson, John G., e James N. Brune. "Methodology for using precarious rocks in Nevada to test seismic hazard models". Bulletin of the Seismological Society of America 89, n. 2 (1 aprile 1999): 456–67. http://dx.doi.org/10.1785/bssa0890020456.
Testo completoAbstract (sommario):
Abstract Fields of precariously balanced rocks indicate that strong earthquake motions have not occurred at that site since the precarious rocks developed. These fields can be characterized with an estimate of the peak acceleration that would be sufficient to topple the rocks and an estimate of how long the rocks have been precarious. This article uses this information to test the input to probabilistic seismic hazard analysis. The fundamental assumption is that the probability of exceeding a ground motion capable of toppling a precarious rock during a time period equal to the age of the rock is equal to the confidence level at which the inputs to the probabilistic seismic hazard analysis can be rejected. We performed a probabilistic seismic hazard analysis for 26 sites of observed precarious rocks in Nevada, using preliminary estimates of the toppling acceleration and the age of the features. Two standard models are rejected with over 95% confidence by most of the precarious rock observations. We consider several possible explanations for the inconsistency. A probabilistic seismic hazard analysis that eliminates the area sources and only includes faults is consistent with the precarious rock observations at most of the sites. Spatial clustering of small-magnitude events could maintain this effect without contradicting the precarious rock observations. However, it may not be necessary to completely reject the area sources from our probabilistic seismic hazard analysis. The physics of rock stability may allow increasing the minimum magnitude to 6.0 in the area sources, because the short duration of high-frequency accelerations in smaller events may not topple all precarious rocks. The precarious rocks could generally have small site effects. Attenuation models may overestimate ground motions on the foot wall of normal faults, and a different attenuation model in general might decrease the ground-motion predictions. The ergodic assumption that is made in estimating the uncertainty in attenuation models may be contributing to overestimate the hazard. Individually, each of these effects might allow more of the precarious rock sites to be consistent with the area source zones.
35
Chen, Yit-Jin, Cheng-Chieh Hsiao e Anjerick Topacio. "Side Resistance of Drilled Shafts Socketed into Rocks for Serviceability and Ultimate Limit States". Advances in Technology Innovation 5, n. 3 (1 luglio 2020): 156–65. http://dx.doi.org/10.46604/aiti.2020.4155.
Testo completoAbstract (sommario):
This study evaluates the analysis models of side resistance in rock sections by utilizing a wide variety of load test data. Available analytical models including the empirical adhesion factor versus the rock’s uniaxial compressive strength and its root are analyzed and compared statistically to determine the optimum relationships. The interpretation criteria for the L1 and L2 methods are used to analyze the load test results for serviceability and ultimate limit states, respectively. The analysis results show that the relationship model with the empirical adhesion factor versus the root of the rock’s uniaxial compressive strength exhibits better correlation than the one with the rock’s uniaxial compressive strength. Moreover, the general coordinate axes regression equation demonstrates better reliability than the semi-logarithmic and full logarithmic axes equations for both limit states. Based on these analyses, specific design recommendations for the side resistance of drilled shafts socketed into rocks are developed and provided with the appropriate statistics to verify their reliability.
36
Xiu, Li Jun, He Ping Pan e Hao Xiu. "The Logging Evaluation of the Relationship between Source Rock and Oil Layer Distribution in Southern Songliao Basin". Advanced Materials Research 962-965 (giugno 2014): 574–77. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.574.
Testo completoAbstract (sommario):
At present, Most of the studies on source rocks is above the effective source rock identification and quality evaluation. But the spatial distribution of the high quality source rocks do not necessarily reflect the position of the layer. So, logging evaluation of the relationship between source rock and layer distributed in a region is necessary. In this paper 70 cores have selected from 4 wells in the first period of Qingshankou (q1), Songliao Basin, then get the experimental TOC value after core analysis. On the basis of source rock geochemical analysis, the author estimated the source rock TOC value with the ∆lgR method. As the distribution of high quality source rocks are clarified,the author draw a conclusion by researching on the relationship between the distribution of source rocks and layers which based on the "Source Control Theory" theory. Finally, it is found that the quality of the source rocks and layer distribution match well in both horizontal and vertical in this paper. This discovery is important for layer prediction and researches.
37
Premalatha, K., S. Angammal e K. Raja. "Behaviour of Precariously Balanced Rocks under Seismic Excitation". Disaster Advances 16, n. 2 (15 gennaio 2023): 7–12. http://dx.doi.org/10.25303/1602da07012.
Testo completoAbstract (sommario):
A naturally occurring geological formation is precariously balanced rocks (PBRs) which might easily topple by an earthquake with severe ground motion. These rocks have been at the same place for many years. Strong ground accelerations have not occurred in the area for thousands of years as shown by the zone of unstable rocks. So, they are significant in both the engineering and seismological domains since they provide source of data for the maximum earthquake ground motion occurring at a site over the rock’s life time. The precariously balanced rock taken for this study is Krishna Butter Ball which is in Mahabalipuram, Chengalpattu district. In the numerical analysis, the peak ground acceleration at which the Krishna butter ball may topple is obtained. To identify the possible future earthquake, deterministic seismic hazard analysis has been carried out for Chengalpattu district. For this analysis, fault details have been obtained from Geological Survey of India. Arc map 10.1 version in Geographical Information System (GIS) platform is used for the interpretation of data like fault length, source (fault) to site (Mahabalipuram) distance from the fault details given by GSI. From the results of Deterministic Seismic Hazard Analysis (DSHA), it is observed that the possible future earthquake may have the magnitude in the range of 6.03 to 7.9. The computed peak ground acceleration (PGA) value corresponding to those magnitude ranges from 0.027g to 0.49g. The maximum PGA value 0.49g corresponds to the Palar river fault which is just 28.53 km away from the Krishna butter ball. From the results of numerical analysis, the behavior of Krishna butter ball for three different PGA i.e. 0.05g, 0.1g, 0.15g has been observed. Newmark sliding block analysis said that the rock may topple at the PGA of 0.35g. From this it can be concluded that the toppling acceleration of Krishna butter ball is relatively low.
38
Shine, Richard, Jonathan K. Webb, Mark Fitzgerald e Joanna Sumner. "The impact of bush-rock removal on an endangered snake species, Hoplocephalus bungaroides (Serpentes : Elapidae)". Wildlife Research 25, n. 3 (1998): 285. http://dx.doi.org/10.1071/wr97022.
Testo completoAbstract (sommario):
We examined the impact of habitat degradation (removal of surface rocks) on an endangered snake species (Hoplocephalus bungaroides, Elapidae) at 23 sites in south-eastern Australia, by quantifying the impact of rock removal on (i) the availability of suitable shelter-sites for the snakes and their major prey species (the velvet gecko, Oedura lesueurii), and (ii) the numbers of snakes and geckos. Our survey showed that both the snakes and the geckos prefer rocks lying on other rocks, rather than on soil, and select rocks of particular sizes. The rocks removed by bush-rock collectors overlap considerably in size (diameter and thickness) and substrate (rock on rock) with those used by broad-headed snakes and velvet geckos. Multivariate path analysis suggests that population densities of broad-headed snakes (as measured by capture rates) may be determined primarily by gecko numbers, which in turn depend upon availability of suitable rocks. In some sites, rock numbers were substantially reduced by anthropogenic disturbance. Thus, our survey data suggest that bush-rock removal has contributed to the endangerment of H. bungaroides.
39
Thandar Phyu, Hnin, Heru Hendrayana, I. Gde Budi Indrawan e Toshitaka Kamai. "Simulation of Kalirejo Road Side Slope based on Altered Andesite Characters, Kulon Progo Regency, Indonesia". Journal of Applied Geology 5, n. 2 (18 gennaio 2021): 101. http://dx.doi.org/10.22146/jag.56916.
Testo completoAbstract (sommario):
ABSTRACT. This study is performed to investigate the characteristics of intrusive andesite rock consisting of Kalirejo Road Side Slope located in Kulon Progo Mountains. The rocks consisting the slope are identified by visual observation of hand specimens in the field, petrographic and X-ray Diffraction (XRD) analyses of the rock samples in the laboratory, upon which genetic rock classification is determined. The altered rock types are determined by the presence of specific minerals identified in the petrographic and XRD analyses. The alteration intensity is examined by comparing the amount of secondary minerals to the primary minerals observed in the petrographic and XRD analyses. The developments of rock weathering are determined in the field GSI classification based on the visual characteristics and in the laboratory-based on the Chemical Index of Alteration (CIA) and engineering properties of the altered rocks. The results show that the rocks typically consisted of 33.2 to 59.2% plagioclase, 1.4 to 5.1% quartz, therefore, are classified as andesite. The presence of halloysite, montmorillonite, and kaolinite as secondary minerals in the altered andesite indicated that the parent andesite rocks have undergone argillic alteration. Meanwhile, the percentages of primary minerals to secondary minerals indicate that the andesite rocks have undergone moderate to high alteration intensity. Based on the visual characteristics, the research area consisted of fresh, slight weathered andesite rocks and complete weathered residual soil. The CIA values of the samples are increased with the increase in rock weathering. Identification of visual characteristics of rock weathering appeared to be in good agreement with those classified based on the CIA and engineering properties analysis results. The uniaxial compressive strength (UCS) of rocks and soils is determined by point load tests. Engineering properties of the residual soils are performed by using ASTM standard procedures. In the lower part of the roadside, slope consists of fresh and slightly weathered andesite rocks, which have relatively high strength and are classified as medium strong rocks. Meanwhile, the upper part of the slope profile contained completely weathered residual soil, which had very low compressive strength, are classified as very weak soil.Keywords: andesite, argillic alteration, Geological Strength Index (GSI), hydrothermal alteration, roadside slope, weathering
40
Al-Jawadi, Azealdeen. "Theoretical Models of Slope Stability Analysis in The Maqlub Mountain Rock Cut Routes, North Iraq". Iraqi Geological Journal 54, n. 1A (31 gennaio 2020): 55–68. http://dx.doi.org/10.46717/igj.54.1a.6ms-2021-01-27.
Testo completoAbstract (sommario):
In many sections, the road leading up to the top of Maqlub Mountain is dangerous due to the fall of several rocks. There were six locations recognized for this dynamic geological process, rockfalls of varying sizes, with very large measurements up to 230 x 120 x 110 cm are falling on the road. The study suggested three theoretical models explain the causes of rockfall, through a comprehensive study in the area. The first model showed that the cause of rockfall was the presence of rocky slopes with a reverse slope. The second model has shown that the rockfall is caused by weak engineering properties of marl beds and it can be squeezed under thick and fractured beds of hard and fractured limestone rocks. The third model determined the small area of the rock base at the rocky slope surface and its large height that reduced their stability. A field survey was performed to study an area that included measuring the height and inclination of the slope surface and measuring the attitude of all discontinuities and their engineering characteristics to classify the slope stability, as well as the technical parameters of the road that determine the risk and consequence factors. Two computer programs were designed to evaluate slope stability, one used to classify risk and consequence (Rockfall Hazard Rating System Program) and the other to classify slope stability based on its geotechnical properties (Slope Mass Rating System Program) in addition to the areas where a rock climb previously occurred, the study concluded that dangerous sites have been recognized along the road to Maqloub Mountain. The size of the falling rock cuttings was classified between small and medium size. The study indicated that this road requires support in hazardous locations to prevent accidents causing losses of property and humans.
41
Palu, Tehani, Lisa Hall, Emmanuelle Grosjean, Dianne Edwards, Nadege Rollet, Karen Higgins, Christopher Boreham et al. "Integrated petroleum systems analysis to understand the source of fluids in the Browse Basin, Australia". APPEA Journal 57, n. 2 (2017): 781. http://dx.doi.org/10.1071/aj16191.
Testo completoAbstract (sommario):
The Browse Basin is located offshore on Australia’s North West Shelf and is a proven hydrocarbon province, hosting gas with associated condensate in an area where oil reserves are typically small. The assessment of a basin’s oil potential traditionally focuses on the presence or absence of oil-prone source rocks. However, light oil can be found in basins where source rocks are gas-prone and the primary hydrocarbon type is gas-condensate. Oil rims form whenever such fluids migrate into reservoirs at pressures less than their dew point (saturation) pressure. By combining petroleum systems analysis with geochemical studies of source rocks and fluids (gases and liquids), four Mesozoic petroleum systems have been identified in the basin. This study applies petroleum systems analysis to understand the source of fluids and their phase behaviour in the Browse Basin. Source rock richness, thickness and quality are mapped from well control. Petroleum systems modelling that integrates source rock property maps, basin-specific kinetics, 1D burial history models and regional 3D surfaces, provides new insights into source rock maturity, generation and expelled fluid composition. The principal source rocks are Early–Middle Jurassic fluvio-deltaic coaly shales and shales within the J10–J20 supersequences (Plover Formation), Middle–Late Jurassic to Early Cretaceous sub-oxic marine shales within the J30–K10 supersequences (Vulcan and Montara formations) and K20–K30 supersequences (Echuca Shoals Formation). These source rocks contain significant contributions of terrestrial organic matter, and within the Caswell Sub-basin, have reached sufficient maturities to have transformed most of the kerogen into hydrocarbons, with the majority of expulsion occurring from the Late Cretaceous until present.
42
Park, Keunbo, Kiju Kim, Kichoel Lee e Dongwook Kim. "Analysis of Effects of Rock Physical Properties Changes from Freeze-Thaw Weathering in Ny-Ålesund Region: Part 1—Experimental Study". Applied Sciences 10, n. 5 (2 marzo 2020): 1707. http://dx.doi.org/10.3390/app10051707.
Testo completoAbstract (sommario):
In order to investigate the weathering characteristics of rocks in response to freeze-thaw conditions in northern latitudes, we analysed meteorological data from the Ny-Ålesund region in Norway, and observed changes in the physical and mechanical properties of rocks of dolomite and quartzite. To assess the effects of freeze-thaw weathering on these rock properties, 900 cycles of long-term freeze-thaw tests were conducted for the sampled rocks in two locations. P-wave velocity, absorption, shore hardness, and the uniaxial compressive strength of the sampled rocks were measured at every 150 cycles in order to analyse physical and mechanical mediator variables of freeze-thaw weathering. It was found that an increasing number of freeze-thaw cycle on the sampled rocks decreases uniaxial compressive strength, shore hardness, and P-wave velocity and increases absorption.
43
Seoung, Donghoon, Pyosang Kim, Hyeonsu Kim, Hyunseung Lee, Min Huh, Hyunwoo Lee e Yongmoon Lee. "Mineralogy of the Mudeungsan Tuff (Republic of Korea) Using Synchrotron X-ray Powder Diffraction and Rietveld Quantitative Analysis". Applied Sciences 11, n. 22 (15 novembre 2021): 10796. http://dx.doi.org/10.3390/app112210796.
Testo completoAbstract (sommario):
Mudeungsan (Mount Mudeung) is an extinct volcano located in the southwestern part of South Korea that was formed in the Late Cretaceous period. This mountain, 1187 m above sea level, is adjacent to Gwangju Metropolitan City, which has a large population (about 1.4 million) and volcanic rocks, including columnar joints, which form various types of outcrops. Although this mountain was listed as a national geopark in 2014 and a UNESCO Global Geopark in 2018, much basic research has yet to be carried out. In particular, there are no mineralogical studies of volcanic rock samples despite the well-preserved variety of volcanic rocks. For this study, X-ray diffraction analysis was conducted using rock samples from Mudeungsan columnar joints known as tuff. We report that the rocks are mostly dacite, mainly composed of quartz, plagioclase, and sanidine through Rietveld quantitative analysis. In particular, α-cristobalite, a crystalline polymorph of silica, appears in the columnar joint rocks, indicating that Mudeungsan experienced an explosive eruption during the formation of the mountain.
44
Shu, Jiaming, Lishuai Jiang, Peng Kong e Qingbiao Wang. "Numerical Analysis of the Mechanical Behaviors of Various Jointed Rocks under Uniaxial Tension Loading". Applied Sciences 9, n. 9 (1 maggio 2019): 1824. http://dx.doi.org/10.3390/app9091824.
Testo completoAbstract (sommario):
In a complex stress field of underground mining or geotechnical practice, tension damage/failure in rock masses is easily triggered and dominant. Unlike metals, rocks are generally bi-modularity materials with different mechanical properties (Young’s modulus, etc.) in compression and tension. It is well established that the Young’s modulus of a rock mass is directly related to the presence of the fracture or joint, and the Young’s modulus estimation for jointed rocks and rock masses is essential for stability analysis. In this paper, the tensile properties in joint rocks were investigated by using numerical simulations based on the discrete element method. Four influencing parameters relating to the tensile properties (joint dip angle, joint spacing, joint intersection angle, and joint density) were studied. The numerical results show that there is an approximately linear relationship between the joint dip angle (α) and the joint intersection angle (β) with the tensile strength (σt), however, the changes in α and β have less influence on the Young’s modulus in tension (Et). With respect to joint spacing, the simulations show that the effects of joint spacing on σt and Et are negligible. In relation to the joint density, the numerical results reveal that the joint intensity of rock mass has great effect on Et but insignificant effect on σt.
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Khaustova, Nadezhda, Elena Kozlova, Polina Maglevannaia, Andrey Voropaev, Evgenia Leushina e Mikhail Spasennykh. "Uranium in Source Rocks: Role of Redox Conditions and Correlation with Productivity in the Example of the Bazhenov Formation". Minerals 12, n. 8 (31 luglio 2022): 976. http://dx.doi.org/10.3390/min12080976.
Testo completoAbstract (sommario):
The paper reports comprehensive analysis of different factors affecting uranium content in oil source rocks and the relationship between uranium content and productivity of source rocks. The analysis of data for 13 wells of the Bazhenov Formation (Western Siberia, Russia) was carried out. The uranium content of the rocks was measured by gamma-ray spectrometry on core samples. In order to analyze factors affecting uranium accumulation in source rocks, we studied content and characteristics of organic matter (Rock-Eval pyrolysis), and also mineral, element, and isotope composition of rocks. We have shown that redox conditions at the sedimentation stage have the most pronounced impact on the uranium accumulation in the rocks of the Bazhenov Formation. It was also shown that productive intervals, containing increased amounts of mobile hydrocarbons, are characterized by low (<20 ppm) concentration of uranium. However, the intervals, containing phosphorite minerals may show better reservoir properties and oil saturation at higher concentration of uranium. The analysis of correlations and relationships between uranium content and Rock-Eval pyrolysis indexes (oil saturation index and productivity index) enabled formulation of criteria for selection of oil-saturated intervals using the spectral gamma and pulsed neutron spectroscopy log data.
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Hasria, Febiyanti, Masri, Ali Okto, Erzam S. Hasan, La Hamimu, Sawaludin, La Ode Muhammad Iradat Salihin e Wahab. "Serpentinization Study On Ultramafic Rock at Morombo Area, Lasolo Islands District, North Konawe Regency, Southeast Sulawesi, Indonesia". Journal of Geoscience, Engineering, Environment, and Technology 7, n. 1 (30 marzo 2022): 15–20. http://dx.doi.org/10.25299/jgeet.2022.7.1.6643.
Testo completoAbstract (sommario):
The research is in Morombo area, North Konawe Regency, Southeast Sulawesi. The purpose of this study was to determine the characteristics of serpentinized ultramafic rock and serpentine paragenesis. Research was conducted using field observations and laboratory analysis consisting of petrographic and geochemical analysis in the form of X-Ray Fluorosence (XRF). Petrographic analysis was carried out to identify the mineral content and textures in the rock and to determine the percentage of serpentine mineral presence. Both of these rocks are petrographically dominated by primary minerals olivine and clinopyroxine and secondary minerals namely lizardite, chrysotile, antiorite and opaque minerals. The XRF analysis was to determine the elements of Ni, Fe, Co, MgO, SiO2, CaO, Al2O3 and P in ultramafic rocks. The results of petrographic analysis show that serpentinized ultramafic rocks in the study area consist of serpentinized dunite and serpentinized peridotite. The formation of clay minerals in rocks does not occur because of the low serpentinization process in the rock. The results of XRF analysis showed that all samples in the bedrock showed Ni content above 0.2%. This is caused by the enrichment of Ni which is interpreted as a result of the serpentinization process along with the formation of lizardite in the rock. The serpentinization sub-processes in the study area comprised by hydration, serpentine recrystallization, and deserpentinization. Serpentine paragenesis is formed from the mid-oceanic ridge ocean floor, the orogenic phase to weathering. Substitution of Mg by Ni in ultramafic rocks will produce Ni-Serpentin. It is estimated that in the research area lizardite and chrysotile lizardite and chrysotile are the causes of Ni enrichment in bedrocks. The serpentinization characteristics of ultramafic rocks in the study area show a low to moderate level of serpentinization.
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Matsitsi, S. M., J. M. Linturi, J. M. Kebwaro e L. M. Kirago. "RADIOMETRIC SURVEY OF THE TYAA RIVER SAND MINE IN KITUI, KENYA". Radiation Protection Dosimetry 188, n. 4 (14 gennaio 2020): 405–12. http://dx.doi.org/10.1093/rpd/ncz300.
Testo completoAbstract (sommario):
Abstract Gamma spectroscopic analyses of sand and rock samples from Tyaa River report an average activity concentration of 33 ± 1, 55 ± 2.8 and 812 ± 40.46 Bqkg−1 for 226Ra, 232Th and 40K, respectively in the sand. A similar analysis of rock samples reveals a mean of 21 ± 2.47, 49 ± 2.47 and 782 ± 39.13 Bqkg−1 for 226Ra, 232Th and 40K, respectively. The absorbed dose rate in rocks averaged 75 ± 3.78 nGyh−1, while in the sand was 86.2 ± 4.31 nGyh−1. The ranges and mean radiological hazard indices (radium equivalent, internal and external) were within the permissible limits and the use of sand and rocks from this mine as construction material pose no health risks. Correlation analysis between the radioactivity in the sand and rocks reveals weak non-linear positive relationships suggesting that they might be from different bedrocks.
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HIRABAYASHI, Kenji. "Characteristics of Rock-Eval Analysis of Carbonates Source Rocks and of Petroleum Derived from Carbonate Source Rocks." Journal of the Japanese Association for Petroleum Technology 56, n. 3 (1991): 222–31. http://dx.doi.org/10.3720/japt.56.222.
Testo completo
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Tsibaev, Sergey, Alexey Renev, Rinat Zainulin e Alexander Kucherenko. "Analysis of rock mass and anchor support elements deformations during the long-term maintenance of mine workings". E3S Web of Conferences 174 (2020): 01001. http://dx.doi.org/10.1051/e3sconf/202017401001.
Testo completoAbstract (sommario):
The results of instrumental and visual assessment of near-rock massif and anchor support elements state in the conditions of long-term maintenance of mine workings has been presented. Particular attention is paid to underground mines in a flooded state. The result of various profiles fixing bolts strength tests of in the roof and sides of the workings has been presented. It has been established that the probability distribution of the anchoring bolts force in the holes in roof of the workings obeys the normal distribution tendency. The result of a radar survey of roof rocks using the Georadar OKO-2 has been analyzed. It was revealed that the height of the stratification of rocks in the mine workings roof varies from 0.2 m to 2.25 m, a comparison is made with the theoretical height of the collapse arch. The propensity of the near rock massif to water saturation has been estimated, the height of the water saturation of the roof rocks has been established. It has been established that the height of moisture depends on the arch of rock stability formed during the survey period. It has been found that water saturation of the rocks leads to a decrease in the specific cohesion of the resin capsules bonding composition with the walls of the hole by 55-67% in roof and by 72% in walls of mine workings.
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Demarco, Larissa Felicidade Werkhauser, Antonio Henrique da Fontoura Klein e Jorge Antonio Guimarães de Souza. "Marine substrate response from the analysis of seismic attributes in CHIRP sub-bottom profiles". Brazilian Journal of Oceanography 65, n. 3 (settembre 2017): 332–45. http://dx.doi.org/10.1590/s1679-87592017124306503.
Testo completoAbstract (sommario):
Abstract This paper presents an evaluation of the response of seismic reflection attributes in different types of marine substrate (rock, shallow gas, sediments) using seafloor samples for ground-truth statistical comparisons. The data analyzed include seismic reflection profiles collected using two CHIRP subbottom profilers (Edgetech Model 3100 SB-216S), with frequency ranging between 2 and 16 kHz, and a number (38) of sediment samples collected from the seafloor. The statistical method used to discriminate between different substratum responses was the non-parametric Kruskal-Wallis analysis, carried out in two steps: 1) comparison of Seismic Attributes between different marine substrates (unconsolidated sediments, rock and shallow gas); 2) comparison of Seismic Attributes between different sediment classes in seafloors characterized by unconsolidated sediments (subdivided according to sorting). These analyses suggest that amplitude-related attributes were effective in discriminating between sediment and gassy/rocky substratum, but did not differentiate between rocks and shallow gas. On the other hand, the Instantaneous Frequency attribute was effective in differentiating sediments, rocks and shallow gas, with sediment showing higher frequency range, rock an intermediate range, and shallow gas the lowest response. Regarding grain-size classes and sorting, statistical analysis discriminated between two distinct groups of samples, the SVFS (silt and very fine sand) and the SFMC (fine, medium and coarse sand) groups. Using a Spearman coefficient, it was found that the Instantaneous Amplitude was more efficient in distinguishing between the two groups. None of the attributes was able to distinguish between the closest grain size classes such as those of silt and very fine sand.