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1
Gong, Fei, Bangrang Di, Lianbo Zeng, Jianxin Wei, Jiwei Cheng e Liangliang Gao. "The elastic properties and anisotropy of artificial compacted clay samples". GEOPHYSICS 86, n. 1 (1 gennaio 2021): MR1—MR15. http://dx.doi.org/10.1190/geo2019-0608.1.
Abstract (sommario):
Clay minerals are a major component of hydrocarbon reservoir rocks, and they are known to play important roles in the physical and elastic properties of rocks. However, it is difficult to directly measure these properties of single-crystal clays due to their small particle size. Therefore, we have constructed three sets of artificial clay samples with different compaction stresses to investigate the effect of the compaction stress and clay mineralogy on their elastic properties and anisotropy. All of the dry samples are measured by the pulse-transmission method. The results indicate that the compaction stress and clay mineralogy have a significant influence on the physical and elastic properties of the clay samples. The microstructures of clay samples indicate that the clay platelets are aligned almost perpendicularly to the direction of compaction stress, and the ultrasonic velocity analysis validates the assumption of transverse isotropy of our clay samples. The velocities increase with the compaction stress, especially at low stress, which corresponds to the rapid porosity reduction at low stress levels. Velocity anisotropy parameters increase with increasing of compaction stress due to the increase of texture sharpness for clay minerals during the compaction process. The elastic moduli of the clay samples display a significant stress sensitivity and a strong directional dependence, with the Young’s moduli increasing and the Poisson’s ratios decreasing with the compaction stress. A simple theoretical template is used to quantify the orientation distribution functions (ODFs) of clay platelets, and the generalized Legendre coefficients of ODF increase with the increase of compaction stress, especially at low stress. Further, the compressional-wave (P-wave) and shear-wave anisotropy increase with the ODF coefficients [Formula: see text] and [Formula: see text], especially P-wave anisotropy.
2
de Freitas Neto, Osvaldo, Olavo Francisco dos Santos Jr., Fagner Alexandre Nunes de França e Ricardo Nascimento Flores Severo. "Influence of Compaction Energy and Bentonite Clay Content in the Soil Hydraulic Conductivity". Applied Mechanics and Materials 851 (agosto 2016): 858–63. http://dx.doi.org/10.4028/www.scientific.net/amm.851.858.
Abstract (sommario):
This paper intends to evaluate changes in permeability of a soil sample from Formação Barreiras, in Natal, the capital city of Rio Grande do Norte State, related to the degree of compaction and the adding of clay to the soil sample. In field works, samples were collected and permeability and density tests were performed. In laboratory, grain size distribution, Attemberg limits and particle density tests were conducted. Afterwards, compaction and permeability tests fulfilled the set of laboratory tests, with changes in compactive energy and sample clay content. The results from field and laboratory tests were compared and the relationship between compaction energy and sample clay content were portrayed. The soil was classified as silty sand. Field and laboratory test results were quite similar. As expected, the tests indicated that permeability is inversely proportional to both compaction energy and sample clay content in the soil tested.
3
Grocholski, Brent. "Clay-driven compaction". Science 372, n. 6539 (15 aprile 2021): 251.4–252. http://dx.doi.org/10.1126/science.372.6539.251-d.
4
Voltolini, Marco, Hans-Rudolf Wenk, Nazmul Haque Mondol, Knut Bjørlykke e Jens Jahren. "Anisotropy of experimentally compressed kaolinite-illite-quartz mixtures". GEOPHYSICS 74, n. 1 (gennaio 2009): D13—D23. http://dx.doi.org/10.1190/1.3002557.
Abstract (sommario):
The anisotropy of physical properties is a well-known characteristic of many clay-bearing rocks. This anisotropy has important implications for elastic properties of rocks and must be considered in seismic modeling. Preferred orientation of clay minerals is an important factor causing anisotropy in clay-bearing rocks such as shales and mudstones that are the main cap rocks of oil reservoirs. The preferred orientation of clays depends mostly on the amount of clays and the degree of compaction. To study the effect of these parameters, we prepared several samples compressing (at two effective vertical stresses) a mixture of clays (illite and kaolinite) and quartz (silt) with different clay/quartz ratios. The preferred orientation of the phases was quantified with Rietveld analysis on synchrotron hard X-ray images. Pole figures for kaolinite and illite display a preferred orientationof clay platelets perpendicular to the compaction direction, increasing in strength with clay content and compaction pressure. Quartz particles have a random orientation distribution. Aggregate elastic properties can be estimated by averaging the single-crystal properties over the orientation distribution obtained from the diffraction data analysis. Calculated P-wave velocity anisotropy ranges from 0% (pure quartz sample) to 44% (pure clay sample, highly compacted), but calculated velocities are much higher than measured velocities. This is attributed to uncertainties about single-crystal elastic properties and oriented micropores and limited grain contacts that are not accounted for in the model. In this work, we present an effective method to obtain quantitative data, helping to evaluate the role of clay percentage and compaction pressure on the anisotropy of elastic properties of clay-bearing rocks.
5
Masujima, T., Y. Xie, Q. Zhang, G. L. Ye e J. Leng. "A new method for rapid preparing high-strength saturated clay samples in large-scale model tests". IOP Conference Series: Earth and Environmental Science 1330, n. 1 (1 maggio 2024): 012029. http://dx.doi.org/10.1088/1755-1315/1330/1/012029.
Abstract (sommario):
Abstract The preparation of high-strength saturated clay samples for large-scale model tests presents a significant challenge in geotechnical engineering. The slurry consolidation method has been conventionally employed to prepare saturated clay, despite its time-consuming and labor-intensive nature. Therefore, this study proposes a rapid preparation technique for clayey soils utilizing the dynamic compaction method, enabling the facile preparation of saturated clay samples by compacting the soils from an unsaturated state. During compaction, the void ratio decreases, thereby increasing the degree of saturation and enhancing the soil strength. Critical to this method are two variables: the moisture water content and the soil density, which are determined through bench-scale compaction tests using the Proctor compaction test apparatus. These tests establish the relationships between moisture content and density, degree of saturation, and soil strength. The moisture content aligning with the target soil strength is selected as the target moisture content for model-scale soil preparation, whereas the moisture content-density relationship sets the target density value. The laboratory tests validate that the soil strength of the saturated model-size clay samples prepared using the proposed method fulfills the requisite criteria, indicating its effectiveness for rapid preparation of high-strength saturated clay samples in large-scale model tests.
6
Tarantino, A., e E. De Col. "Compaction behaviour of clay". Géotechnique 58, n. 3 (aprile 2008): 199–213. http://dx.doi.org/10.1680/geot.2008.58.3.199.
7
Ponomaryov, Andrey, e Evgenia Sychkina. "Effect of clay compaction around driven pile and prediction of pile settlement". E3S Web of Conferences 363 (2022): 02016. http://dx.doi.org/10.1051/e3sconf/202236302016.
Abstract (sommario):
In the article the problem of geotechnical application of clay nd claystone as a base of driven pile foundations has been considered. When using these foundations, a compaction zone is formed in the clay space around the pile. The purpose of this research is to analyze the influence of compaction zones on the results of analytical and numerical calculations for predicting the settlement of a driven pile in layered clay soils. The following tasks were solved: 1) The existing investigations of pile settlement in layered clay soils were analyzed; 2) The characteristics of experimental sites and the parameters of numerical modeling were, methods for testing single field piles in layered clay soils were described; 3) Calculation of single pile settlement was performed carried out by numerical methods with the use of Plaxis 2D software package and by an analytical method; 4) The experimental data were compared with the results of calculations by analytical and numerical methods. The developed calculation scheme with two compaction zones around driven piles can provides reasonable estimates of vertical displacements of the clay base. Based on the results obtained, the authors recommend using the analytical method with due regard for compaction zones in clays and claystones around the driven pile.
8
Lakho, Nawab Ali, Muhammad Auchar Zardari e Naeem Aziz Memon. "Reduction of Cracking and Shrinkage in Compressed Clay Beams during Drying". July 2016 35, n. 3 (1 luglio 2016): 395–400. http://dx.doi.org/10.22581/muet1982.1603.09.
Abstract (sommario):
Uncontrolled evaporation of moisture from compressed clay beams can cause surface cracks, resulting in reduction of strength. This paper presents various treatments applied to clay beams during the process of casting, compacting and drying in order to curtail the possibility of cracking and to decrease percentage of drying shrinkage. Following treatments were applied to the beams during casting and drying: (i) a steel plate and double layer of plastic sheet was provided between the beam and the plank, (ii) the beam was enveloped with a propylene fabric sheet during casting and (iii) beams were covered with plastic sheet during drying. Using these treatments, the clay beams were cast and compacted at various intensities of compaction. The results show that the drying shrinkage was reduced to minimum and the cracks were curtailed. The rate of drying shrinkage was decreased depending upon the level of compaction. Thus at the higher degree of compaction, more density of clay beams was achieved, which resulted in higher degree of compressive strength in baked and unbaked state.
9
Clayton, C. R. I., I. F. Symons e J. C. Hiedra-Cobo. "The pressure of clay backfill against retaining structures". Canadian Geotechnical Journal 28, n. 2 (1 aprile 1991): 282–97. http://dx.doi.org/10.1139/t91-034.
Abstract (sommario):
This paper investigates the pressures exerted by clay backfills against retaining structures. The lateral pressures are developed during three main phases: placement, compaction, and burial; horizontal total stress reduction at constant moisture content; and swelling or consolidation under approximately constant vertical stress. Experimental data from laboratory and pilot-scale studies, using clays of intermediate and high plasticity, are presented and used to assess the magnitude of the pressure changes in each phase. The process of compaction is examined and it is concluded that previously developed theories for assessing the pressures on retaining walls developed by compaction of granular soils are inapplicable for cohesive soils. The factors controlling the swelling of cohesive backfill are reviewed and results from a preliminary numerical study are used to provide an indication of the likely effects of plasticity and placement moisture content. Key words: earth pressure, retaining walls, clay, compaction, swelling.
10
Cabot, Louis, e Jean-Pierre Le Bihan. "Quelques propriétés d'une argile sur la « ligne optimale de compactage »". Canadian Geotechnical Journal 30, n. 6 (1 dicembre 1993): 1033–40. http://dx.doi.org/10.1139/t93-100.
Abstract (sommario):
This paper deals with the evolution of the texture of the clay during compaction and with the importance of maintaining a close correlation between the degree of compaction and the water content to obtain a sealed fill with a homogeneous texture. The results of laboratory tests show the orderly evolution of some physical and mechanical properties of the compacted clay along this optimal correlation of compaction. Finally, the results of the control tests on the clay of the core of Kompienga dam compacted according to these specifications are presented. Key words : compacted clay, texture, macroporosity, optimal line of compaction, evolution of properties, specifications of compaction.
11
Kolmogorov, S. G., P. L. Klemyatsionok e S. S. Kolmogorova. "Toward compaction of overmoistured clay soil". Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. JOURNAL of Construction and Architecture 24, n. 5 (27 ottobre 2022): 145–50. http://dx.doi.org/10.31675/1607-1859-2022-24-5-145-150.
Abstract (sommario):
Various complicated processes, including physical and chemical, occur in clay soils, which finally determine their strength and stress-and-strain properties. In order to use clay soils as a subgrade, it is necessary to increase their strength primarily through a compaction. In clay soil compaction, the main role belongs to physically bound water, which gathers around soil particles forming water envelopes and making the compaction difficult. The paper considers compaction of overmoistured clay soils along with vibration, that provides an intensive transition of bound water to a free state. In this case, the envelopes of physically bound water become smaller, thereby increasing the possibility of the particle bonding under pressure. This improves the contact between the soil particles and the soil compaction.
12
Kolmogorov, S. G., P. L. Klemyatsionok e S. S. Kolmogorova. "Relationship between consistency and compaction of clay soils (Saint-Petersburg)". Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. JOURNAL of Construction and Architecture 25, n. 5 (26 ottobre 2023): 156–63. http://dx.doi.org/10.31675/1607-1859-2023-25-5-156-163.
Abstract (sommario):
Clay soils are often found under building foundations, construction properties of which depend on many factors. One of them is the natural soil compaction, which is relevant in the construction classification of soils. This paper analyzes the relationship between the consistency and compaction of clay soils of different genesis and consistency using the Priklonskii soil compaction index. Water saturation of clay soil affects the relative discrepancy between the consistency coefficient and compaction index for soils of different genesis and consistency. It is noted that for soils with the water saturation coefficient lower than one, the consistency coefficient differs from the compaction index. This difference increases with decreasing water saturation coefficient. It is essential that significant differences can also appear when the water saturation coefficient is equal to 0.95 or more, approaching to unity. It is shown that the assessment of the natural compaction of clay soils should be based on their formation conditions. A study of various genetic types of clay soils affecting natural densification and consistency provides a reasonable approach to use of soil densification in the construction classification of soils.
13
Gong, Fei, Bangrang Di, Jianxin Wei, Pinbo Ding, He Li e Dingyuan Li. "Experimental investigation of the effects of clay content and compaction stress on the elastic properties and anisotropy of dry and saturated synthetic shale". GEOPHYSICS 83, n. 5 (1 settembre 2018): C195—C208. http://dx.doi.org/10.1190/geo2017-0555.1.
Abstract (sommario):
Anisotropy in shales is an important issue in exploration and reservoir geophysics, and it has been proven extremely difficult to correlate anisotropy in natural shale by means of a single variable (in this case, clay content or compaction stress) because of the influence of multiple factors, such as water content, total organic carbon content, and complex mineral compositions. Thus, we used quartz, kaolinite, calcite, and kerogen extract as the primary materials to construct two sets of synthetic shale samples, each with a different clay content by weight and a different compaction stress. Ultrasonic experiments were conducted to investigate the anisotropy of velocity and mechanical properties in dry and saturated samples of our synthetic shales. The results reveal that the velocities decrease with clay content by weight and increase with compaction stress and that these changes are significant at low compaction stress. The velocity anisotropy of the samples increases with clay content and compaction stress due to the increasing alignment of the clay platelets. S-wave anisotropy is more sensitive to the clay content or compaction stress than P-wave anisotropy. The dynamic Young’s modulus [Formula: see text] of the samples decreases with clay content and increases with compaction stress, whereas Poisson’s ratio [Formula: see text] increases with clay content and decreases with compaction stress. Young’s modulus perpendicular to the symmetry axis is always larger than that parallel to the symmetry axis, but Poisson’s ratio perpendicular to the symmetry axis may be larger or smaller than that parallel to the symmetry axis, which indicates that mechanical properties have obvious anisotropic behavior. The elastic properties and anisotropy are also affected by fluids; the values of elastic and mechanical anisotropy parameters in saturated samples are significantly lower than those in dry samples.
14
Tan, Feng Yi, Rong Hua Zou, Han Bing Hu e Zu Kai Lin. "Construction Technology of Treatment Measure of Swelling Rock Slope Replaced Backfilling Clay". Advanced Materials Research 168-170 (dicembre 2010): 2334–39. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.2334.
Abstract (sommario):
Replaced backfilling clay is one of the treatment measures in the Luwangfen swelling rock test Region of middle-route of South-to-North Water Division Project. First, by using 18 tons vibration roller compaction mechanism, on the condition of 3 different thicknesss and 5 different compaction times, settlement, dry density, water content and permeability coefficient are studied before and after the compaction test to find out the optimal thickness and compaction times. Then, by using different compaction mechanisms, the compaction effect is studied on the condition of the optimal thickness and compaction times. Results show that the compaction degree of replaced backfilling clay is 100.0% on the condition that the quantity of vibration bumping roller is above 18 tons, thickness of replaced backfilling clay is no more than 35.0cm and at least it is compacted at least 12 times. Finally, the construction parameters of compaction and related quality controlling index is proposed, which is provided as a reference for design, mechanism’s choice, compaction parameter and quality control index.
15
V., Giridhar, G. Jagadeesh e P. Rajendra Kumar. "Regression Analysis on Compaction Characteristics of Sand Clay Soils". ECS Transactions 107, n. 1 (24 aprile 2022): 19265–77. http://dx.doi.org/10.1149/10701.19265ecst.
Abstract (sommario):
Soil compaction is one of the major geo technical engineering applications in infrastructure development of the nation. Large volumes of soil are used in the construction of flyovers, earth dams, and railways. There is a need to understand comprehensively in a unified and coherent manner. Thus the knowledge of compaction behavior and its characteristics of fine grained soils at different compaction energies assume great importance from they viewpoint of practical significant. In the present work, compaction parameters such as (MDD) (max) and optimum moisture content (OMC) care determined at various compaction energies by conducting the laboratory compaction tests. In the field, the compaction of soils usually involves using different compaction energies. A limited experimental investigation has been taken up in the present study. The cardinal aim of the present study is to focus on effect of compaction energy on the behavior and compaction characteristics and unconfined compressive strength (qu) of soils.
16
Basu, Saibal. "Clay mineralogy and pressure analysis from seismic information in Krishna‐Godavari basin, India". GEOPHYSICS 55, n. 11 (novembre 1990): 1447–54. http://dx.doi.org/10.1190/1.1442792.
Abstract (sommario):
Interval transit time data derived from seismic velocities have been analyzed to predict clay mineralogy and overpressures from compaction trends in the offshore areas of Krishna‐Godavari basin located on the east coast of India. Compaction trends from rms velocity fairly well match the trends obtained from sonic logs. This study has been extended to the undrilled part of the basin with the help of seismic information. Areal distribution of clay mineral types has been determined from the compaction trends. Prospective areas are identified on the basis of clay mineral distribution and overpressure zones related to the areas of different clay mineral associations.
17
Zeng, Biao, Lin-feng Wang, Yun Tian, Tao-rui Zeng e Bing Li. "Study on Compaction Characteristics and Construction Control of Mixtures of Red Clay and Gravel". Advances in Civil Engineering 2018 (4 novembre 2018): 1–8. http://dx.doi.org/10.1155/2018/8079379.
Abstract (sommario):
Red clay cannot be used as embankment filler directly due to its water-sensitive property. Gravel is usually added into red clay to enhance its performance in engineering practice. In order to investigate the influence of mixtures of red clay and gravel on the road performance, gravitational compaction experiment of red clay and vibratory compaction experiment of mixtures of red clay and gravel were conducted, respectively. The results indicate that compaction curves of red clay have double peak; the second peak is the real maximum dry density, and its corresponding moisture content is the optimal moisture content. The dry density of mixtures of red clay and gravel is influenced by the content of gravel, vibration frequency, and vibration time. The optimal content of gravel is 30%, the best vibration frequency is 45 Hz, and the optimal vibration time is 5 minutes for the mixtures of red clay and gravel in this study. The effectiveness of optimal content of gravel and optimum vibration parameters was confirmed by a CBR test. According to the compaction experiment results and actual situation in the field, a suitable construction method of subgrade using the mixtures of red clay and gravel was put forward. The feasibility of this method was also confirmed by postconstruction deformation data of the field test embankment.
18
Zhang, Junhui, Qingping Jiang, Yuqing Zhang, Liangliang Dai e Houxuan Wu. "Nondestructive Measurement of Water Content and Moisture Migration of Unsaturated Red Clays in South China". Advances in Materials Science and Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/542538.
Abstract (sommario):
To reveal the moisture migration mechanism of the unsaturated red clays, which are sensitive to water content change and widely distributed in South China, and then rationally use them as a filling material for highway embankments, a method to measure the water content of red clay cylinders using X-ray computed tomography (CT) was proposed and verified. Then, studies on the moisture migrations in the red clays under the rainfall and ground water level were performed at different degrees of compaction. The results show that the relationship between dry density, water content, and CT value determined from X-ray CT tests can be used to nondestructively measure the water content of red clay cylinders at different migration time, which avoids the error reduced by the sample-to-sample variation. The rainfall, ground water level, and degree of compaction are factors that can significantly affect the moisture migration distance and migration rate. Some techniques, such as lowering groundwater table and increasing degree of compaction of the red clays, can be used to prevent or delay the moisture migration in highway embankments filled with red clays.
19
Alhaji, Mustapha Mohammed, Musa Alhassan, Taiye Waheed Adejumo e Ramatu Jibrin. "Effect of Density on Consolidation and Creep Parameters of Clay". Indonesian Journal of Science and Technology 5, n. 1 (21 gennaio 2020): 31–44. http://dx.doi.org/10.17509/ijost.v5i1.16819.
Abstract (sommario):
Effect of density on consolidation and creep parameters of a clay soil was investigated using a soil classified according to Unified Soil Classification System (USCS) as Clay of High plasticity (CH) and composing majorly of secondary minerals, including montmorillonite. The air-dried soil was compacted at five different compaction energy levels (Reduced Standard Proctor compaction energy, Standard Proctor compaction energy, West African compaction energy, Reduced Modified Proctor compaction energy, and Modified Proctor compaction energy). Specimens for consolidation tests were molded at the five different compaction energy levels (densities). The consolidation parameters (initial void ratio, compression index, and preconsolidation pressure) were observed to be empirically related to the compaction energy. The creep parameters (i.e. primary compression index, secondary compression index, and magnitude of creep) were observed to increase with increases in loading to 387kN/m2, after which the values decreased. Curves resulting from these relationships were observed to increase with increases in compaction energy level and tent towards straight line at Modified Proctor compaction energy. Maximum magnitude of creep estimated for three years was observed to reduce from 455.5 mm at Reduced Standard Proctor compaction energy through 268 mm at West African compaction energy to 247.4 mm at Modified Proctor compaction energy levels.
20
Strydom, Jessica, Hans Eggenkamp, Jérôme Sterpenich, Pierre Agrinier, Antonin Richard, Dragan Grgic, Patrick Gaire, Régine Mosser-Ruck e Eric C. Gaucher. "Cl/Br and δ37Cl evolution in seawater expelled during the compaction of MX-80 smectite". E3S Web of Conferences 98 (2019): 12022. http://dx.doi.org/10.1051/e3sconf/20199812022.
Abstract (sommario):
During a high pressure (up to 150 MPa) high temperature (up to 150°C) compaction experiment of MX-80 smectite equilibrated with ocean water, it was found that the Cl and Br concentrations in the expelled solution are progressively being decreased while simultaneously being increased in the compacted clay. This significant retention of Cl and Br in the pore water of the compacted clay is indicative of ultrafiltration by the clay. Despite the size difference between the two anions no significant chemical partitioning between Cl and Br is observed in the expelled water. The δ37Cl value of the expelled water shows a sharp decrease (from -0.1 ‰ down to -0.5‰) during the first steps of compactions (between 45MPa – 21°C and 65MPa – 30°C) and then remains stable until 125MPa – 120°C. The largest impact on anion and stable isotope composition is seen during the earlier phases of the compaction. It is supposed that the surface chemistry of the clay in combination with decreasing porosity result in re-equilibration of compressed and overlapping diffuse double layers which in part, drive the anion and δ37Cl evolution.
21
Yang, Shu Rong, Wei Hsing Huang e Shao Hung Chung. "Temperature Effects on Soil Suction for Compacted Clay Soils". Advanced Materials Research 723 (agosto 2013): 527–34. http://dx.doi.org/10.4028/www.scientific.net/amr.723.527.
Abstract (sommario):
An investigation was conducted to determine the effects of temperature, compaction water content, and compaction efforts on soil suction of two expansive subgrade soils. For this purpose, two expansive soils were statically compacted at target water contents ranging from 5% to 20%. This made it possible to explore a broad spectrum of compaction conditions. Filter paper method and thermocouple psychrometer were used to measure soil suction at temperatures ranging from 10°C to 60°C. Experimental results show that compaction water content, compaction effort, and temperature have influences on soil suction. As water content increases, the influences of compaction effort and temperature on suction become less significant. Finally multiple regression formulations for predicting the soil suction of as-compacted clayey soil were established.
22
Lvovska, Tetyana, Tetyana Lytvynenko e Alla Kariuk. "Soil Compaction Methods Development". International Journal of Engineering & Technology 7, n. 3.2 (20 giugno 2018): 636. http://dx.doi.org/10.14419/ijet.v7i3.2.14605.
Abstract (sommario):
A process of soil compaction methods development including new authors’ methodology is described. The importance of soil compaction for engineering purposes is substantiated. Preconditions for Proctor compaction test appearance are highlighted. Proctor’s approach and suggestions for the degree of soil compaction assessing are analyzed. Soviet version of Proctor’s equipment and Modified Proctor compaction test are given. Principal differences between Proctor test, Standard compaction test and Modified Proctor test are presented. The problems and disadvantages of existent soil compaction tests are revealed. New authors’ physical experiment methodology for patterns establishment of water migration in subgrade embankment depth, in the capacity factors of what it is accepted: clay soil type (its number plasticity); moisture, at what the soil was compacted; soil skeleton density; embankment height; «rest» time after subgrade erection and before it’s operation is developed and realized. By laboratory and field tests water migration patterns in compacted subgrade soils depth are established. As a result of statistical processing of research results, the empirical dependence of compacted clay soil stabilized moisture is obtained. Empirical dependence parameter corresponds to maximum molecular moisture capacity at what it is advisable to do the subgrade clay soils multilayer consolidation for their long-term strength ensuring.
23
Benhamida, A., I. Djeran-Maigre, H. Dumontet e S. Smaoui. "Clay compaction modelling by homogenization theory". International Journal of Rock Mechanics and Mining Sciences 42, n. 7-8 (ottobre 2005): 996–1005. http://dx.doi.org/10.1016/j.ijrmms.2005.05.021.
24
Revil, A., D. Grauls e O. Brévart. "Mechanical compaction of sand/clay mixtures". Journal of Geophysical Research: Solid Earth 107, B11 (novembre 2002): ECV 11–1—ECV 11–15. http://dx.doi.org/10.1029/2001jb000318.
25
Lahiri, Sivaji, Kitty L. Milliken, Peter Vrolijk, Guillaume Desbois e Janos L. Urai. "Mechanical compaction mechanisms in the input sediments of the Sumatra subduction complex – insights from microstructural analysis of cores from IODP Expedition 362". Solid Earth 13, n. 10 (10 ottobre 2022): 1513–39. http://dx.doi.org/10.5194/se-13-1513-2022.
Abstract (sommario):
Abstract. The input sediments of the North Sumatra subduction zone margin, drilled during IODP Expedition 362, exhibit remarkable uniformity in composition and grain size over the entire thickness of the rapidly deposited Nicobar Fan succession (seafloor to 1500 m b.s.f.), providing a unique opportunity to study the micromechanisms of compaction. Samples were prepared from dried core samples (from Sites U1480 and U1481) by both Ar-ion cross-section polishing and broad ion beam cutting and imaged with a field-emission scanning electron microscope (SEM). The shallowest samples (seafloor to 28 m b.s.f.) display a sharp reduction in porosity from 80 % to 52 % due to collapse of large clay-domain surrounding matrix pores associated with rotation and realignment of clay platelets parallel to the bedding plane. The deeper succession (28 to 1500 m b.s.f.) exhibits less rapid reduction in porosity from 52 % to 30 % by the progressive collapse of silt-adjacent larger pores through bending as well as subsequent sliding and/or fracturing of clay particles. In addition, there is a correlated loss of porosity in the pores too small to be resolved by SEM. Clastic particles show no evidence of deformation or fracturing with increasing compaction. In the phyllosilicates, there is no evidence for pressure solution or recrystallization: thus, compaction proceeds by micromechanical processes. An increase in effective stress up to 18 MPa (∼ 1500 m b.s.f.) causes the development of a weakly aligned phyllosilicate fabric mainly defined by illite clay particles and mica grains, while the roundness of inter-particle pores decreases as the pores become more elongated. We propose that bending of the phyllosilicates by inter-particle slip may be the rate-controlling mechanism. Pore size distributions show that all pores within the compactional force chain deform, irrespective of size, with increasing compactional strain. This arises because the force chain driving pore collapse is localized primarily within the volumetrically dominant and weaker clay-rich domains; pores associated with packing around isolated silt particles enter into the force chain asynchronously and do not contribute preferentially to pore loss over the depth range studied.
26
Pijnenburg, Ronald P. J., e Christopher J. Spiers. "Microphysics of Inelastic Deformation in Reservoir Sandstones from the Seismogenic Center of the Groningen Gas Field". Rock Mechanics and Rock Engineering 53, n. 12 (14 agosto 2020): 5301–28. http://dx.doi.org/10.1007/s00603-020-02215-y.
Abstract (sommario):
AbstractPhysics-based assessment of the effects of hydrocarbon production from sandstone reservoirs on induced subsidence and seismicity hinges on understanding the processes governing compaction of the reservoir. Compaction strains are typically small (ε < 1%) and may be elastic (recoverable), or partly inelastic (permanent), as implied by recent experiments. To describe the inelastic contribution in the seismogenic Groningen gas field, a Cam–clay-type plasticity model was recently developed, based on the triaxial test data obtained for sandstones from the Groningen reservoir (strain rate ~ 10−5 s−1). To underpin the applicability of this model at production-driven strain rates (10−12 s−1), we develop a simplified microphysical model, based on the deformation mechanisms observed in triaxial experiments at in situ conditions and compaction strains (ε < 1%). These mechanisms include consolidation of and slip on µm-thick clay films within sandstone grain contacts, plus intragranular cracking. The mechanical behavior implied by this model agrees favourably with the experimental data and Cam–clay description of the sandstone behavior. At reservoir-relevant strains, the observed behavior is largely accounted for by consolidation of and slip on the intergranular clay films. A simple analysis shows that such clay film deformation is virtually time insensitive at current stresses in the Groningen reservoir, so that reservoir compaction by these mechanisms is also expected to be time insensitive. The Cam–clay model is accordingly anticipated to describe the main trends in compaction behavior at the decade time scales relevant to the field, although compaction strains and lateral stresses may be slightly underestimated due to other, smaller creep effects seen in experiments.
27
GRANT, C. A. "THE EFFECT OF K AND Cl FERTILIZER ADDITIONS ON BARLEY HERBAGE YIELD AND NUTRIENT CONTENT IN UNDISTURBED AND ARTIFICIALLY COMPACTED SOIL CORES". Canadian Journal of Plant Science 69, n. 3 (1 luglio 1989): 729–39. http://dx.doi.org/10.4141/cjps89-089.
Abstract (sommario):
Disturbed soil cores, at two bulk densities, and undisturbed soil cores were collected from two fields which had been maintained under reduced tillage management. Dry matter yield of growth chamber-grown barley in the disturbed soil cores was equal to or lower than that produced in the undisturbed cores but was unaffected by degree of soil compaction. Increase in dry matter yield in response to K or Cl fertilization was greater in disturbed than undisturbed soils. Compaction did not generally influence response to KCl fertilization. Soil disturbance did not consistently influence concentration of N, K or Cl in barley tissue. Tissue content of Zn was increased by soil disturbance in the clay loam soil and decreased by soil disturbance in the sandy loam soil. Compaction did not influence tissue content of N or Cl. Compaction did not influence K content of plants grown on the clay loam soil, which initially had high levels of plant-available K, but reduced K content of plants grown on K-deficient sandy loam soil. Increased compaction also reduced the Zn content of plants in the sandy loam soil but increased Zn content of plants in the clay loam soil. Application of KCl or CaCl2 increased Cl content of barley tissue and tended to reduce the N content of the tissue, particularly in the clay loam soil. Application of KCl or KNO3 increased K concentration in barley tissue grown on the K-deficient sandy loam soil but not on the higher K clay loam soil.Key words: Potassium, chloride, zinc, compaction, bulk density, barley
28
Nooraiepour, Mohammad. "Clay Mineral Type and Content Control Properties of Fine-Grained CO2 Caprocks—Laboratory Insights from Strongly Swelling and Non-Swelling Clay–Quartz Mixtures". Energies 15, n. 14 (15 luglio 2022): 5149. http://dx.doi.org/10.3390/en15145149.
Abstract (sommario):
Understanding and predicting sealing characteristics and containment efficiency as a function of burial depth across sedimentary basins is a prerequisite for safe and secure subsurface storage. Instead of estimators and empirical relationships, this study aimed to delineate data-driven variability domains for non-cemented fine-grained clastic caprocks. Constant rate-of-strain uniaxial compression experiments were performed to measure changes in properties of brine-saturated quartz–clay mixtures. The binary mixtures were prepared by mixing quartz with strongly swelling (smectite) and non-swelling (kaolinite) clays representing end-member clay mineral characteristics. The primary objective was to evaluate the evolution of mudstone properties in the first 2.5 km of burial depth before chemical compaction and cementation. By conducting systematic laboratory tests, variability domains, normal compaction trends, and the boundaries in which characteristics of fine-grained argillaceous caprocks may vary were identified, quantified, and mathematically described. The results showed distinct domains of properties, where kaolinite-rich samples showed higher compressibility, lower total porosity, higher vertical permeability, and higher Vp and Vs. Two discrepancies were discovered in the literature and resolved regarding the compaction of pure kaolinite and the ultimate lowest porosity for quartz–clay mixtures. The present experimental study can provide inputs for numerical simulation and geological modeling of candidate CO2 storage sites.
29
Marins, Araceli Ciotti de, José Miguel Reichert, Deonir Secco, Doglas Bassegio e Daniela Trentin Nava. "Crambe grain yield affected by compaction degrees of an Oxisol". Research, Society and Development 11, n. 3 (15 febbraio 2022): e12111326500. http://dx.doi.org/10.33448/rsd-v11i3.26500.
Abstract (sommario):
Crambe is a new crop that produces oil used for biodiesel production. Soil compaction in a no-tillage (NT) system is one of the main challenges for sustainable grain production in soil clay. The objective of this study was to evaluate the effect of compaction degree on crambe grain yield over two years. The levels of artificial compaction were generated using a roller compactor (0, 1, 3, and 5 passes) under a NT system. The experimental design was a strip block, and soil density and crambe grain yield were evaluated. The passes of the roller increased the density from 0.98 to 1.24 Mg m−3 in the 0–0.1 m layer, and 1.03 to 1.15 Mg m−3 in the 0.1–0.2 m layer. As a result, the compaction degree increased from 53% to 66% in the 0–0.1 m layer and 54% to 61% in the 0.1–0.2 m layer. Five passes of the roller compactor reduced the crambe grain yield by 41% and 9% in the first and second years, respectively, compared to the NT system without additional compaction. The crambe grain yield was reduced when the compaction degree reached 53%; therefore, crambe is not suitable for compacted soils.
30
Yang, Hong Xia. "Experimental Study on Compaction Characteristics of High Liquid Limit Clay of the Yellow River Alluvial Plain and its Subgrades Filling Technology". Advanced Materials Research 368-373 (ottobre 2011): 2558–61. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2558.
Abstract (sommario):
Based on the geologic exploration materials and indoor test of Ji-He expressway,analysed the compaction characteristics of high liquid limit clay of the Yellow River alluvial plain,the relationship among compaction work and moisture content and dry unit weight,and the changing rules of the CBR value in different compaction works with the change of moisture content.Demonstrated that high liquid limit clay of the Yellow River alluvial plain can be used in expressway subgrades filling. Moreover, through the experimental sections of subgrades filling,the reasonable construction technology and quality controlling measures is put forward, and provides reference of subgrades filling with high liquid limit clay of the Yellow River alluvial plain.
31
Tirado-Corbalá, Rebecca, e Brian Slater. "Soil Compaction Effects on the Establishment of Three Tropical Tree Species". Arboriculture & Urban Forestry 36, n. 4 (1 luglio 2010): 164–70. http://dx.doi.org/10.48044/jauf.2010.022.
Abstract (sommario):
Tree seedlings planted in containers along sidewalks in urban environments show restricted growth and development over time. This is the result of limited soil volume and soil compaction that hampers nutrient availability and water movement. Using tree species commonly used in urban forestry in Puerto Rico, this study was conducted to determine their growth response when planted in compacted soils. Seedlings of three ornamental tropical tree species, trumpet bush [Tecoma stans (L.) Juss. ex Kunth], bottle brush [Callistemon citrinus (Curtis) Skeels], and pink trumpet (Tabebuia rosea dc.) were transplanted into pots of sandy clay loam or clay soils at three levels of compaction: control (no compaction), 1.2 g/cm3 and 1.4 g/cm3 bulk density, respectively. Plant height, shoot diameter, leaf number and color, foliar area, and root, shoot, and leaf dry weights were measured on two plants every two months for six months. All species exhibited better growth in sandy clay loam at 1.2 g/cm3; after six months, all species showed a reduced root-shoot ratio. When planted in clay at 1.4 g/cm3, all trumpet bush seedlings died within two months. No leaf color differences were observed between species at different compaction levels. Bottle brush showed less growth suppression by increasing compaction level in both soils.
32
Matteson, A., J. P. Tomanic, M. M. Herron, D. F. Allen e W. E. Kenyon. "NMR Relaxation of Clay/Brine Mixtures". SPE Reservoir Evaluation & Engineering 3, n. 05 (1 ottobre 2000): 408–13. http://dx.doi.org/10.2118/66185-pa.
Abstract (sommario):
Summary Effective interpretation of nuclear magnetic resonance (NMR) logs in shaly sands requires an understanding of the NMR contribution of clays. Of particular importance is the role of clays in the rapidly relaxing part of the NMR signal. In this study we measured the transverse relaxation time spectrum T2 of brine mixed with four clays (illite, smectite, kaolinite and glauconite) as a function of compaction. The Larmor frequency was 2 MHz and the echo spacing 0.16 ms. Mild compaction was achieved by centrifuging the clay slurry at three successive pressures ranging from 1 to 125 psi. Highly compacted samples were produced in a uniaxial press at six sequential pressures ranging from 500 to 16,000 psi. Each clay/brine slurry and its associated compacted sample showed a single peak in the T2 distribution spectrum. A second peak, which could be interpreted as the "clay-bound water," was never observed. The T2 peak position shifted to faster relaxation times as compaction increased, in proportion to the pore volume-to-surface ratio, Vp/As. The single peak and Vp/As proportionality are consistent with fast diffusion between the pore water and the monolayer of water on the clay surface. Surface relaxivity varied among the four clay minerals; glauconite, the clay with the highest magnetic susceptibility and iron content had the largest surface relaxivity. These results have important implications for the interpretation of NMR logs in shaly sands. Because of the effects of compaction and to a lesser extent the iron content on a clay's T2 peak position, it is not possible to independently determine clay type from some characteristic relaxation time. These data also imply that it is not feasible to estimate the cation exchange capacity from a single time cutoff of the T2 distribution without additional information such as laboratory measurements or other log data. Introduction Nuclear magnetic resonance logging has become an important tool in evaluating a formation's petrophysical properties. The unique and valuable advantage that NMR provides is pore size distribution information. No other logging method provides these data, which are the key component of log-based estimates of capillary-bound water volume, and permeability to flow.1 It has been proposed that NMR logging can be extended to estimate clay-bound water volumes, and identify clay minerals. Clay-bound water volume, important in determining water saturation from resistivity, has been correlated with the short-T2 less than 3 ms, porosity of 45 oilfield sandstones.2 Prammer et al.'s3 NMR clay/brine study found that the T2 distribution of clay-bound water associated with kaolinite and chlorite was greater than 3 ms, for illite it ranged between 1 and 2 ms and for smectite it was less than 1 ms. Observed T2 's were then used as an indicator of cation exchange capacity (CEC) because the number of available exchange sites is proportional to a clay's specific surface area. CEC is fundamental to converting bulk resistivity measurements into water saturation. The ability to estimate clay-bound water, and to identify the clay type, from NMR T2 distributions is not compatible with the ability to determine pore size distribution from the same data. In the first two cases the molecular diffusion rate of water in the pores must be slow, whereas in the latter case it is assumed to be fast. For example, consider a monolayer of water on the surface of room-dry clay. The monolayer has a short relaxation time, less than a millisecond, because of its interaction with the solid rock. Now fill the void space between the clay particles with water and consider the two extreme cases. In the first case, there is no molecular diffusion (exchange) between the surface-monolayer water and bulk water. Thus, the T2 spectrum will contain two separate peaks, one associated with the surface-monolayer water at less than a millisecond and one associated with the bulk water. In the opposite case, molecular diffusion is highly effective, and both the surface monolayer and bulk water have a common relaxation time, a single peak in the T2 spectrum with time constant: 1 T 2 = ρ s ( A s V p ) . ( 1 ) In this equation, which provides the fundamental connection between T2 and pore size, the term ?2 is the surface relaxivity parameter that indicates the capacity of the rock to cause the decay of magnetization in the water. Fig. 1 is a conceptual drawing of a T2 distribution for a sandstone that includes fluid in small pores that are typically associated with clays, capillary-bound and producible fluid. The objective of this study was to determine whether it is possible to infer a clay-bound water volume (peak or T2 cutoff), or clay type, and a pore size distribution from a NMR distribution spectrum. To achieve this goal we designed a set of experiments that examined the NMR relaxation of clay/brine mixtures at various compaction states. In contrast to shaly sands, the clay/brine mixtures provided the means to minimize the pore volume-to-surface ratio, so that any water-monolayer-related signal might be detected. The pore volume-to-surface ratio was easily varied through compaction, and the monomineralic samples enable the NMR response of individual clay types to be evaluated. We chose to study four clays commonly found in oil-bearing sedimentary environments: kaolinite, illite, smectite and glauconite. Experimental Procedures Samples of illite and glauconite were obtained from Wards Natural Science Establishment. Kaolinite and smectite (Ca Montmorillonite) were procured from ECC Intl., Georgia Kaolin Co. and the Source Clay Minerals Repository, respectively. Various physical properties of the clays were measured. Prior to the surface area and magnetic susceptibility measurements, the clays were dried overnight in a vacuum oven at 100°C. Surface area measurements were collected using the Micromeritics Gemini 2360 with nitrogen gas as adsorbate, and magnetic susceptibilities were measured on a Johnson Matthey MSB-AUTO magnetic susceptibility balance. CEC measurements were taken using the ammonium acetate/ammonium ion-specific electrode method by David K. Davies & Assoc., Inc. Table 1 is a summary of clay type, clay origin and clay physical properties. The samples were analyzed for mineralogy using dual-range Fourier transform infrared (FTIR) spectroscopy.4 In addition, the samples were sent to X-Ray Assay Laboratories for chemical analyses (Table 2). The mineralogy data indicate the presence of quartz in the illite sample. Consequently, a <2 ?m fraction of the sample was extracted by centrifuging the illite and drying the supernatant. The physical properties for these clays are in good agreement with those in the literature.5 The clay samples used for the room-dry and clay/brine mixture NMR experiments were kept at room temperature and at typical laboratory humidity conditions of 50%. To evaluate whether clay samples have a measurable NMR signal at room-dry conditions, samples were prepared by placing the clay in a test tube and sealing it off with a stopper and Teflon tape.
33
Zhemchuzhnikov, Alexandr, Khosrow Ghavami e Michéle dal Toé Casagrande. "Static Compaction of Soils with Varying Clay Content". Key Engineering Materials 668 (ottobre 2015): 238–46. http://dx.doi.org/10.4028/www.scientific.net/kem.668.238.
Abstract (sommario):
The use of compressed earth blocks (CEBs) is widespread in the field of earth construction. They present better mechanical performance than adobe and the equipment for their production is simple. Laboratory testing of compressed earth blocks requires large amounts of material. There are variations of unconfined strength testing procedures such as testing halves of the blocks with layers of mortar between them or testing whole blocks in diverse directions. This complicates the interpretation of test results as the shape factor and mortar characteristics influence the results significantly. Static compaction test can be used to produce cylindrical samples representative of CEBs. The water content of soil used for the production of CEBs is often determined in standard Proctor test while experimental data indicate that the optimum moisture content for static and dynamic compaction is different. The present article addresses the behavior of four soil mixes with varying clay content compacted statically with a constant rate of strain. Static compaction curves were compared with those obtained in standard Proctor test. For all the soil mixes the static optimum moisture content was found to correspond to the start of consolidation. The compaction curve presented no wet side of optimum in contrast to Proctor test. The energy needed to achieve a desired density by static compaction was analyzed for soils with varying clay contents. Static compaction was found to be more efficient than dynamic for clayey soils. An increase in water content was observed to help achieving higher densities at low pressures, which can improve the performance of manual CEB presses.
34
Li, Fu Rong, Hou Chao Sun e Zhao Yu Wang. "Mechanism Analysis and Experimental Study of Soil-Compacting by Silent Piling". Applied Mechanics and Materials 170-173 (maggio 2012): 457–60. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.457.
Abstract (sommario):
The mechanism of soil-compacting effect by silent piling is analyzed, and based on large-scale model box test, using soft clay of typical sites in Yancheng District, taking the single pile as the study objects respectively, and studying the soil compaction effects with the process of sinking into the single pile, analyzing the variation law of the soil deformation and pore water pressure while sinking into the single pile. The results shows that the greater the radial distance, the smaller of soil compaction effect, the influence scope of soil compaction effects on the displacement and pore water pressure reaches 0.6 times and 0.5 times the pile length sinking the single pile, which is accord to the actual engineering. The results could guide the pile foundation construction on soft soil.
35
Chao, Li, Luo Xiaorong, Zhang Likuan, Lei Yuhong, Chen Ming e Yu Lan. "Chemical compaction of deep buried mudstone and its influence on pressure prediction". IOP Conference Series: Earth and Environmental Science 600, n. 1 (1 novembre 2020): 012012. http://dx.doi.org/10.1088/1755-1315/600/1/012012.
Abstract (sommario):
Abstract The chemical compaction of mudstones which is dominated by the transformation of clay minerals leads to significant changes in the mineral composition and microstructure of mudstone during process of deep burial. In particular, the transformation of smectite to illite in mudstones results in noticeable impact on the pore pressure formation and the overpressure logging responses. At present, the study about the pressurization mechanism of chemical compaction and the impact on overpressure logging responses is really weak, which made it hard to pore pressure identification and pressure prediction for deep buried formations. Taking the Paleogene Shahejie Formation in the Dongying depression of the Bohai Bay Basin in eastern China as typical case, this paper analyses the characteristics of clay mineral transformation of the Shahejie Formation in the Dongying depression, the logging responses of overpressures, and the influence of chemical compaction on the prediction of pore pressure. The results showed that the chemical compaction of mudstones changes the relationship between the petrophysical properties of mudstone and vertical effective stress and the logging responses of overpressure. The typical characteristic of chemical compaction manifested as density increase continuous with the depth. The normal compaction trends of the different compaction stages are the basis for overpressure mechanisms identification and pore pressure prediction. The depth of the rapid transformation of clay minerals has a good consistency with the top of overpressure zone (2000–2800 m) in Dongying depression, which indicates that the overpressure and its logging responses may be related to the chemical compaction of mudstones. The measured pressure in intervals deeper than 3000 m is closer to the predicted pressure based on the normal compaction trend of chemical compaction.
36
Yang, Xiao-Guang, e Shao-Bin Guo. "Porosity model and pore evolution of transitional shales: an example from the Southern North China Basin". Petroleum Science 17, n. 6 (23 luglio 2020): 1512–26. http://dx.doi.org/10.1007/s12182-020-00481-7.
Abstract (sommario):
AbstractThe evolution of shale reservoirs is mainly related to two functions: mechanical compaction controlled by ground stress and chemical compaction controlled by thermal effect. Thermal simulation experiments were conducted to simulate the chemical compaction of marine-continental transitional shale, and X-ray diffraction (XRD), CO2 adsorption, N2 adsorption and high-pressure mercury injection (MIP) were then used to characterize shale diagenesis and porosity. Moreover, simulations of mechanical compaction adhering to mathematical models were performed, and a shale compaction model was proposed considering clay content and kaolinite proportions. The advantage of this model is that the change in shale compressibility, which is caused by the transformation of clay minerals during thermal evolution, may be considered. The combination of the thermal simulation and compaction model may depict the interactions between chemical and mechanical compaction. Such interactions may then express the pore evolution of shale in actual conditions of formation. Accordingly, the obtained results demonstrated that shales having low kaolinite possess higher porosity at the same burial depth and clay mineral content, proving that other clay minerals such as illite–smectite mixed layers (I/S) and illite are conducive to the development of pores. Shales possessing a high clay mineral content have a higher porosity in shallow layers (< 3500 m) and a lower porosity in deep layers (> 3500 m). Both the amount and location of the increase in porosity differ at different geothermal gradients. High geothermal gradients favor the preservation of high porosity in shale at an appropriate Ro. The pore evolution of the marine-continental transitional shale is divided into five stages. Stage 2 possesses an Ro of 1.0%–1.6% and has high porosity along with a high specific surface area. Stage 3 has an Ro of 1.6%–2.0% and contains a higher porosity with a low specific surface area. Finally, Stage 4 has an Ro of 2.0%–2.9% with a low porosity and high specific surface area.
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Eberemu, Adrian O. "Desiccation Induced Shrinkage of Compacted Tropical Clay Treated with Rice Husk Ash". International Journal of Engineering Research in Africa 6 (novembre 2011): 45–64. http://dx.doi.org/10.4028/www.scientific.net/jera.6.45.
Abstract (sommario):
Desiccation studies are an integral part of material selection for waste containment systems. Laboratory studies on compacted tropical clay (with illite as the dominant clay mineral sourced from an excavation site) treated with up to 16% rice husk ash (RHA); an agro-industrial waste to evaluate its desiccation induced shrinkage and hence its suitability as a cover material in waste containment systems were carried out. Soil-RHA mixtures were compacted using three compactive efforts at -2, 0, 2 and 4% of optimum moisture content (OMC). Compacted samples, extruded from the compaction mould were allowed to air dry in the laboratory for a 30 day period after which they were subjected to two cycles of wetting and drying. Results show that changes in mass and volumetric shrinkage strain (VSS) were large within the first five days of drying and were affected by the compactive effort. VSS increased with higher moulding water content, water content relative to optimum and RHA treatments. VSS were affected by the compactive effort. Acceptable compaction planes were obtained for up to 12% RHA treatment. After two cycles of wetting and drying, it was observed that the rate of capillary rise within the compacted soil increased with lower compactive effort and higher rice husk ash treatment. Lower amount of cracking was observed in soil specimen with higher rice husk ash treatment and higher cracking in soils with lower rice husk ash content. Increased compactive effort reduced the effect of swelling during wetting; showing the suitability of the material as a cover in municipal waste containment facility and beneficial reuse of this agro waste product.
38
Yang, Yong Shou, e Bin Xin Li. "Application Research on Dynamic Compaction Replacement Pier Foundation Treatment Methods". Applied Mechanics and Materials 353-356 (agosto 2013): 482–85. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.482.
Abstract (sommario):
The dynamic compacted replacement pier technique is a new ground-treatment technology, which developed from the dynamic consolidation method. It can be used for the improvement in high-saturated silts and soft plastic to flow plastic clays, which cannot be treated using dynamic compaction method. T his new approach has many advantages, such as its simple equipment, significant reinforcing effects, construction time-saving, low-cost, no requirement of dewatering, and etc. In this paper, combined with engineering examples, according to analysis and evaluation of the monitoring results, it is feasible to adopt dynamic compaction replacement pier in uneven thickness hard plastic silt-clay foundation. Concrete-gravel dynamic compaction replacement pie can enhance the bearing capacity of pier and compound foundation. It provides a practical basis to expand the application scope of dynamic compaction replacement foundation treatment and enrich this technology.
39
Ogundare, Damilola Ayodele, Oyetunde Oluwafemi Adeleke e Ayodeji Theophilus Akinbuluma. "Chemical and Mechanical Characterisation of Clay Soil Stabilised with Steel Slag and Calcium Carbide Waste". Civil and Sustainable Urban Engineering 4, n. 1 (14 maggio 2024): 55–64. http://dx.doi.org/10.53623/csue.v4i1.427.
Abstract (sommario):
Problematic subgrade soil such as clay is expansive by nature and is challenging to work with during pavement construction. In an effort to combat this issue and lower the rate of pavement failure on highway construction projects, cementitious industrial waste materials should be used. This study thus examined the influence of steel slag (SS) and calcium carbide waste (CCW) as stabilisers for clay soil. Chemical and mineralogical analyses of clay soil, SS and CCW were assessed while the stabilised soil were subjugated to Atterberg limit, compaction and california bearing ratio (CBR) tests. The existence of calcium oxide, iron oxide and calcium hydroxide in both the chemical and mineralogical constituents of SS and CCW indicate that they are binding materials which notably influences hardness and contributes more to the strength of the clay soil. With varied amounts of the additives (SS and CCR), the clay soil's liquid limit and plasticity index dropped from 54.0% and 13.8% to 43.5% and 9.2%, respectively. This significantly lowers the clay soil’s swell potential, increases its resilience, and decreases its infiltration capacity. The compaction characteristics revealed that SS and CCW enhanced the compactness of the clay soil signifying enhancement of the soil compaction properties. The CBR value of all the stabilised clay soils improve significantly with 40%SS + 60%CCW acquiring the maximum CBR of 17.3% and 29.0% compared with clay soil having CBR of 4.7% and 6.9% in soaked and unsoaked states respectively.
40
Nguyen, M. D., K. H. Yang e W. M. Yalew. "Compaction behavior of nonwoven geotextile-reinforced clay". Geosynthetics International 27, n. 1 (febbraio 2020): 16–33. http://dx.doi.org/10.1680/jgein.19.00053.
41
Mitchell, R. J., e M. A. Knight. "Compaction control of clay barriers by centrifugation". International Journal of Physical Modelling in Geotechnics 1, n. 3 (settembre 2001): 27–33. http://dx.doi.org/10.1680/ijpmg.2001.010303.
42
Lyashenko, P. A., V. V. Denisenko, V. S. Kovalenko e N. S. Kolomiets. "The conditions of bulk clay soil compaction". IOP Conference Series: Materials Science and Engineering 698 (18 dicembre 2019): 022036. http://dx.doi.org/10.1088/1757-899x/698/2/022036.
43
Chaney, RC, KR Demars, JL Howell, CD Shackelford, NH Amer e RT Stern. "Compaction of Sand-Processed Clay Soil Mixtures". Geotechnical Testing Journal 20, n. 4 (1997): 443. http://dx.doi.org/10.1520/gtj10411j.
44
Radhakrishna, H. S., H. T. Chan, A. M. Crawford e K. C. Lau. "Thermal and physical properties of candidate buffer–backfill materials for a nuclear fuel waste disposal vault". Canadian Geotechnical Journal 26, n. 4 (1 novembre 1989): 629–39. http://dx.doi.org/10.1139/t89-076.
Abstract (sommario):
As part of the Canadian Nuclear Fuel Waste Management Program, Ontario Hydro has, over several years, conducted research into the behaviour and performance of buffer–backfill for the proposed nuclear fuel waste disposal vault. In this paper, a review has been made of laboratory studies made at Ontario Hydro on the thermal properties, strength, hydraulic conductivity, and compactability of clay-based buffer materials. The results of this work have enabled the formulation of selection criteria for the buffer material mix for the prototype Canadian nuclear fuel waste disposal scheme. Key words: bentonites, buffer, backfill, nuclear waste disposal, thermal conductivity, clays, hydraulic conductivity, compaction, clay barriers, clay seals, shrinkage.
45
Zhao, Rong Fei, Yong Ning Mi e Wei Gao. "Testing Study on Soil’s Moisture Content of Geogrid-Reinforced Clay under Freezing-Thawing Cycles". Applied Mechanics and Materials 256-259 (dicembre 2012): 139–44. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.139.
Abstract (sommario):
A series of moisture content tests were carried out to study the changes in geogrid-reinforced clay moisture content under freezing-thawing cycles, the influences of compaction degree, reinforcement layers and initial moisture content of the soil on the soil moisture content under freezing-thawing cycles were discussed. We can see that the soil compaction degree is the first important factor to the moisture content, the change of upper lay clay moisture content is positive for the low compaction degree and negative for a high one; the reinforcement layers is the second important factor to moisture content, the upper lay moisture content reduces with the increasing of reinforcement layers, it is significant in the high compaction soil; the initial moisture content is the weakest factor, a big change of upper lay moisture content only appears when the initial moisture content is large and the soil compaction is low.
46
Woldeyohannis, Yared Seifu, Someshakher S. Hiremath, Simie Tola e Amana Wako. "Investigation of Soil Physiochemical Properties Effects on Soil Compaction for a Long Year Tilled Farmland". Applied and Environmental Soil Science 2022 (17 ottobre 2022): 1–9. http://dx.doi.org/10.1155/2022/8626200.
Abstract (sommario):
In many parts of the world, the earth has been heavily compacted as a result of large farm equipment. For soil compaction, the main constituent factors were soil physiochemical properties such as soil texture, moisture content, electrical conductivity, cation exchange capacity, total organic carbon, organic matter, total nitrogen, and soil pH directly and indirectly. This article addressed the causes and effects of soil compaction, operating parameters, and soil physicochemical properties in the Bishoftu long year tilled farmland of Ethiopia. For the experimental test, 5 different depths (5, 10, 15, 20, and 25 cm) and fifteen sample points were selected in 0.6 ha of 60 m by 100 m farmland for taking soil compaction data. Soil samples are taken from three depth ranges (0–10, 10–20, and 20–30 cm) from farmlands for investigation of soil physicochemical properties. The maximum and minimum values of the cone index of this study were 1918.133 kPa and 864.733 kPa, respectively, by taking the average of all sample points. The soil laboratory result shows that Bishoftu farmland soil is a mixture of loam, clay loam, and sandy clay loam with 47.33% of sand, 25.67% of clay, and 27% of silt. The maximum and minimum percentages of soil moisture values were 27.02 and 21.46 at 0–10 cm and 20–30 cm depth, respectively. Total organic carbon, organic matter, and total nitrogen exhibit positive relationships with depth and soil compaction. The correlation analysis indicates soil pH, electric conductivity, percentage of sand, cation exchange capacity, organic matter, and total nitrogen were among soil physiochemical parameters that are positively correlated with soil compaction. Furthermore, the percentage of clay, percentage of silt, and total organic carbon ( p ≤ 0.05 ) are negatively correlated with soil compaction in soil samples.
47
Nihei, Kurt T., Seiji Nakagawa, Frederic Reverdy, Larry R. Myer, Luca Duranti e Greg Ball. "Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments". GEOPHYSICS 76, n. 3 (maggio 2011): WA113—WA123. http://dx.doi.org/10.1190/1.3567160.
Abstract (sommario):
Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.
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Kwon, Hyug Moon, e Le Anh Tuan. "The Influence of Soil Grading and Compaction Pressure on Characteristics of Compressed Cement-Soil Materials". Applied Mechanics and Materials 284-287 (gennaio 2013): 1368–72. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.1368.
Abstract (sommario):
The relationships among soil, sand, cement binder and compaction pressure were considered in this paper. The soil grading was investigated with particle sizes which are, in particular order, finer than 5, 1.18, 0.6, 0.3 and 0.15 mm. Corresponding to each of soil grades, the compaction pressure was applied in the range from low to high level. The influence of soil grading and compaction pressure could be determined by value of compressive strength, dry density and water absorption. The experimental results reported in term of the optimal proportion for mixture, which gave the best strength in each level of compaction pressure and size of soil particles. In addition, the conclusion about the influence of clay content on characteristics of compressed cement-soil materials was also figured out so that the suitable clay content in the optimal mix proportion for practical application could be determined.
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Jin, Chang Ning, e Yu Hong Zhang. "Influences of Change of Plasma on CBR of Eolian Sand". Advanced Materials Research 250-253 (maggio 2011): 3120–27. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.3120.
Abstract (sommario):
The plasma in the eolian sand, included silt particle and clay particle, change easily and hugely. For studying their influences on the strength property of eolian sand, mixed silt particles and clay particles in different proportion into the eolian sand to carry out CBR test. The test result indicates that, along with the increase of silt particle and clay particle content the CBR value also increases within a certain range, which indicates the increase of silt particle and clay particle content can firstly improve the gradation of eolian sand; after the gradation is improved can obtain large compaction dry density, and at the same time also can enhance the earth strength, included the CBR value. The range of silt particle and clay particle content made the CBR value increase is also very large: ≤40% when formed under dry state, and ≤45% when formed under optimum or saturated water content; if the water content in forming could be retained at all times, the former could be ≤55% and the latter still ≤45%. The mechanism analysis further indicates that, when there were no excessive silt particles and clay particles, in the large range of silt particles and clay particles changing from small to large, the engineering nature of eolian sand will be improved due to the improvement of gradation, which is advantageous to the extensive application of dry compaction process; but the eolian sand formed by dry compaction is defective on microstructure, and so the requirements for silt particle and clay particle content should be more strict in practical works.
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Oliveira, Pedro D. de, Michel K. Sato, Sueli Rodrigues e Herdjania V. de Lima. "S-index and soybean root growth in different soil textural classes". Revista Brasileira de Engenharia Agrícola e Ambiental 20, n. 4 (aprile 2016): 329–36. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n4p329-336.
Abstract (sommario):
ABSTRACT This study tested the hypothesis that the limiting values of S-index, proposed in the literature can not be used to determine the degradation condition of soils under soybean cultivation in the state of Pará, Brazil. The objective was to determine limiting values of S-index using soil physical attributes and validate it with soybean root growth, in soils with different textural classes. For the experimental design, the following treatments were established: five compaction levels for sandy loam and sandy clay loam soils and three levels for clayey and very clayey soils. The following physical parameters were analysed: particle-size distribution, soil bulk density, critical soil bulk density, degree of compaction, soil-water retention curve, S-index and relative root length of soybean. The limiting values of S-index varied according to soil textural class and were equal to 0.037, 0.020 and 0.056 for sandy loam, sandy clay loam and clay, respectively. The S-index does not apply to soils with clay content > 71%, because it does not vary with the degree of compaction of the soil or the root growth of the evaluated crop.