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1
Bullock, Paul R. "Seepage scald in southeastern Australia." Applied Geography 11, no. 1 (January 1991): 59–81. http://dx.doi.org/10.1016/0143-6228(91)90005-t.
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2
Conti, Stefano, Claudio Argentino, Chiara Fioroni, Aura Cecilia Salocchi, and Daniela Fontana. "Miocene Seep-Carbonates of the Northern Apennines (Emilia to Umbria, Italy): An Overview." Geosciences 11, no. 2 (January 28, 2021): 53. http://dx.doi.org/10.3390/geosciences11020053.
Повний текст джерелаАнотація:
The natural emission of methane-rich fluids from the seafloor, known as cold seepage, is a widespread process at modern continental margins. The studies on present-day cold seepages provide high-resolution datasets regarding the fluid plumbing system, biogeochemical processes in the sediment, seafloor seepage distribution and ecosystems. However, the long-term (hundreds of thousands to millions of years) evolution of cold seepage remains elusive. The identification and study of outcrop analogous now exposed on land represent a valuable method for better understanding the effects of geological processes and climate forcing on the development of cold seepage systems. Here, we provide an overview on Miocene seep-carbonate deposits of the northern Apennines (from Emilia to the Umbria-Marchean sector, Italy), based on decades of field research integrated with detailed sedimentological and geochemical investigations. We report a total of 13 seep-carbonate outcrops, which formed in three different structural settings of the paleo-accretionary wedge corresponding to wedge-top basins, outer slope and intrabasinal highs at the deformational front. We discuss the recurring lithostratigraphic occurrence of seep deposits and the main compositional features (carbonate facies, carbon and oxygen stable isotopes) in order to interpret the seepage dynamics, duration and infer the contribution of methane-rich fluids released by paleo-gas hydrates. The datasets presented in this study represent a valuable complete record of cold seepage spanning ~12 Myr, that can be used to better understand factors controlling the regional-scale spatial and temporal evolution of cold seepage systems at modern active continental margins.
3
Hojat, Azadeh, Maddalena Ferrario, Diego Arosio, Marco Brunero, Vladislav Ivov Ivanov, Laura Longoni, Andrea Madaschi, Monica Papini, Greta Tresoldi, and Luigi Zanzi. "Laboratory Studies Using Electrical Resistivity Tomography and Fiber Optic Techniques to Detect Seepage Zones in River Embankments." Geosciences 11, no. 2 (February 7, 2021): 69. http://dx.doi.org/10.3390/geosciences11020069.
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We present the results of laboratory experiments on a down-scaled river levee constructed with clayey material collected from a river embankment where a permanent resistivity instrument has operated since 2015. To create potential seepages through the levee, two zones (5 × 4 cm and 10 × 2 cm) were filled with sand during the levee construction. Electrical resistivity tomography (ERT) technique and Fiber Bragg Grating (FBG) technology were used to study time-lapse variations due to seepage. The ERT profile was spread on the levee crest and the Wenner array with unit electrode spacing a = 3 cm was used. Six organic modified ceramics (ORMOCER) coated 250 μm-diameter fibers were deployed in different parts of the levee. Time-lapse measurements were performed for both techniques from the beginning of each experiment when water was added to the river side until the water was continuously exiting from the seepage zones. The results showed that ERT images could detect seepages from the early stages. Although with a short delay compared to ERT, fiber optic sensors also showed their ability to detect water infiltrations by measuring temperature changes. Both technologies being successful, a discussion about respective peculiarities and pros and cons is proposed to suggest some criteria in choosing the proper technique according to the specific needs.
4
Wu, Yue, Yan-Zhi Li, Wei-Guo Qiao, Zhen-Wang Fan, Shuai Zhang, Kui Chen, and Lei Zhang. "Water Seepage in Rocks at Micro-Scale." Water 14, no. 18 (September 11, 2022): 2827. http://dx.doi.org/10.3390/w14182827.
Повний текст джерелаАнотація:
To complete groundwater diversion, the complex flow law of groundwater in rocks must be investigated so that groundwater diversion can be improved. This research uses the computer finite element method (FEM), CT scanning calculation method, Avizo method, and digital core technology combined with the Fluent calculation method (FCM) to reconstruct rocks with microscopic pore structures on a computer. The numerical simulation results under different conditions show that: the total pressure change gradually decreases under different pressure gradients. In a seepage channel, the seepage path does not change with the change in seepage pressure, and the seepage velocity is the largest in the center of the pore. The longer the seepage path is, the greater the decrease in seepage velocity. Different seepage directions have similar seepage laws. The research results provide effective guidance for the project to control groundwater.
5
Petrula, Lubomír, and Jaromír Říha. "A new small-scale experimental device for testing backward erosion piping." Journal of Hydrology and Hydromechanics 70, no. 3 (August 23, 2022): 376–84. http://dx.doi.org/10.2478/johh-2022-0023.
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Abstract Backward erosion piping is driven by seepage forces acting on the soil grains at the downstream end of the seepage path. A new device for the laboratory testing of backward erosion progression was developed and tested. The device consists of a plexiglass prism at which the seepage path has been predefined. The prism was equipped with an inflow consisting of gravel separated from tested sand by a strainer. The hydraulic gradient along the seepage pipe was observed by a set of piezometers and pressure cells, and the seepage discharge was measured volumetrically. The transported sediment was trapped in a vertical cone located downstream from the device. The progression of the seepage path, the piezometric heads and the trapped material was observed by two synchronous cameras. 15 trial tests have been carried out to date, and from these, the interim results are presented.
6
Ghafoori, Yaser, Matej Maček, Andrej Vidmar, Jaromír Říha, and Andrej Kryžanowski. "Analysis of Seepage in a Laboratory Scaled Model Using Passive Optical Fiber Distributed Temperature Sensor." Water 12, no. 2 (January 29, 2020): 367. http://dx.doi.org/10.3390/w12020367.
Повний текст джерелаАнотація:
Seepage is the key factor in the safety of dikes and earth-fill dams. It is crucial to identify and localize the seepage excesses at the early stages before it initiates the internal erosion process in the structure. A proper seepage monitoring system should ensure a continuous and wide area seepage measurement. Here, continuous monitoring of seepage at the laboratory-scale is achieved by a passive optical fiber Distributed Temperature Sensing (DTS) system. An experimental model was designed which consists of initially unsaturated sand model, water supply, seepage outflow, optical fiber DTS system, and water and air temperature measurement. Initially, the sand temperature was higher than the temperature of the seepage water. An optical fiber DTS system was employed with a high-temperature resolution, short sampling intervals and short time intervals for temperature monitoring in the sand model. In the system, the small variation in the temperature due to groundwater flow was detected. The numerical analysis was conducted for both the seepage process and the heat transfer progression in the sand model. The results of the heat flow simulation were evaluated and compared with the measured temperature by the optical fiber DTS. Obvious temperature reduction was obtained due to seepage propagation in the sand. The rate of temperature reduction was observed to be dependent on the seepage flow velocity.
7
Al-Madhlom, Qais, Nadhir Al-Ansari, Bashar Abid Hamza, Jan Laue, and Hussain Musa Hussain. "Seepage Velocity: Large Scale Mapping and the Evaluation of Two Different Aquifer Conditions (Silty Clayey and Sandy)." Hydrology 7, no. 3 (August 18, 2020): 60. http://dx.doi.org/10.3390/hydrology7030060.
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Seepage velocity is a very important criterion in infrastructure construction. The planning of numerous large infrastructure projects requires the mapping of seepage velocity at a large scale. To date, however, no reliable approach exists to determine seepage velocity at such a scale. This paper presents a tool within ArcMap/Geographic Information System (GIS) software that can be used to map the seepage velocity at a large scale. The resultant maps include both direction and magnitude mapping of the seepage velocity. To verify the GIS tool, this study considered two types of aquifer conditions in two regions in Iraq: silty clayey (Babylon province) and sandy (Dibdibba in Karbala province). The results indicate that, for Babylon province, the groundwater flows from the northwest to southeast with a seepage velocity no more than 0.19 m/d; for the Dibdibba region, the groundwater flows from the west to the east with a seepage velocity not exceeding 0.27 m/d. The effectiveness of the presented tool in depicting the seepage velocity was thus demonstrated. The accuracy of the resultant maps depends on the resolution of the four essential maps (groundwater elevation head, effective porosity, saturated thickness, and transmissivity) and locations of wells that are used to collect the data.
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Li, Linkai, Sheng Wang, Weijiang Jia, Jun Luo, Zhan Meng, Jingjing Gou, Hang Zhou, Deyan Zhong, Wenxin Xiu, and Xinlin Bai. "Mathematical Model of Shale Oil Seepage at Micro-Nano Pore Scale." Energies 15, no. 21 (October 28, 2022): 8041. http://dx.doi.org/10.3390/en15218041.
Повний текст джерелаАнотація:
Due to the unclear seepage mechanism for shale oil, it is hard to establish a reasonable mathematical model to describe the flowing law. In this study, a real shale pore structure was reconstructed with CT scanning and a numerical model of fluid flowing in the real shale pore is developed with COMSOL, based on the boundary slip at the micro-nano pore scale to study the causes of nonlinear seepage. A two-fluid model is employed to establish a simple mathematical model to describe the relationship between the flow rate and the pressure gradient using the effective slip length to account for the influence of pore structure and true slip, and the established model is verified with experimental data coming from Jiyang shale oil. The results indicated that the pore structure greatly affected the shape of the seepage curve. With the increase in displacement pressure, the percentage of fluid involved in the flow increased until it became stable, showing a changing trend from nonlinearity to linearity. The established model can fit the experimental data well and reasonably characterize the nonlinear seepage of shale oil.
9
Chavan, Rutuja, and Bimlesh Kumar. "Downward seepage effects on dynamics of scour depth and migrating dune-like bedforms at tandem piers." Canadian Journal of Civil Engineering 47, no. 1 (January 2020): 13–24. http://dx.doi.org/10.1139/cjce-2017-0640.
Повний текст джерелаАнотація:
The present study focuses on multi-scale statistical characterization of scour depth at tandem piers and migrating dune-like bedforms forming behind the piers in downward seepage affected alluvial channel, using an experimental approach. Experiments were conducted using two circular piers arranged in a tandem manner for no seepage, 10% seepage, and 15% seepage condition. The erosive capacity of reversal flow is hindered with downward seepage, which results in reducing velocity and Reynolds stress near the bed at upstream of piers in case of seepage runs. The bed elevation of the scoured region is decreasing with the increasing seepage percentage and the growth in scour depth is diminishing with time. The celerity of scour depth is decreasing with time as well as decreasing with increasing downward seepage. Probability density function of bedform elevation has positive tail slightly thicker than the Gaussian.
10
Cai, Wenya, Yan Wang, Fujun He, Pengyuan Zhang, and Shuo Sun. "The Seepage-Destruction Mechanism of Water Inrush Channel of Sandstone Fault Filling Using the EDEM-Fluent Method." Advances in Civil Engineering 2022 (October 5, 2022): 1–11. http://dx.doi.org/10.1155/2022/3313013.
Повний текст джерелаАнотація:
By the EDEM-Fluent coupling calculation method, the formation mechanism of the seepage failure water inrush channel and the migration of particles in the sandstone fault filling body are studied. Under the condition of variable hydraulic gradient, the whole seepage process can be divided into three stages: slow seepage stage, sudden seepage stage, and stable seepage stage. In the stage of slow seepage, the mass of lost particles is small. In the stage of sudden seepage, particles are lost on a large scale. In the stable seepage stage, the model is basically in a stable state. During the seepage process, the particles in the outlet zone will move before the particles in the inlet zone under the action of the seepage force. The overall movement trend of particles can be predicted, while the movement trajectory of a single particle is irregular. The change trend of the contact quantity between particles is basically consistent with the change in the quality of the lost particles. Moreover, the change in the contact quantity of particles is caused by the loss of the filler particles.
11
Taniguchi, M., M. Ono, and M. Takahashi. "Multi-scale evaluations of submarine groundwater discharge." Proceedings of the International Association of Hydrological Sciences 365 (March 2, 2015): 66–71. http://dx.doi.org/10.5194/piahs-365-66-2015.
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Abstract. Multi-scale evaluations of submarine groundwater discharge (SGD) have been made in Saijo, Ehime Prefecture, Shikoku Island, Japan, by using seepage meters for point scale, 222Rn tracer for point and coastal scales, and a numerical groundwater model (SEAWAT) for coastal and basin scales. Daily basis temporal changes in SGD are evaluated by continuous seepage meter and 222Rn mooring measurements, and depend on sea level changes. Spatial evaluations of SGD were also made by 222Rn along the coast in July 2010 and November 2011. The area with larger 222Rn concentration during both seasons agreed well with the area with larger SGD calculated by 3D groundwater numerical simulations.
12
Marques, José Couto. "A Sensitive Remote Experiment for Small Scale Groundwater Flow Problems." International Journal of Online and Biomedical Engineering (iJOE) 9, S8 (December 4, 2013): 71. http://dx.doi.org/10.3991/ijoe.v9is8.3397.
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Seepage or groundwater flow is an important topic in Civil and Mining Engineering curricula. A laboratory setup has been developed for small scale studies of seepage in embankment dams and other geotechnical structures for use in the context of a Soil Mechanics course. Numerical simulations have been prepared as a complement to the experimental setup. Remote access to the equipment has been made available via an IP camera. Student feedback about this sensitive remote experiment has been very positive.
13
Shi, Shaoshuai, Xiangxiang Zhu, Zhiguo Cao, Lin Bu, Zhijie Wen, Zongqing Zhou, Weidong Guo, and Ruijie Zhao. "Experimental Study of Seepage Characteristics of Filling Structures in Deep Roadway." Geofluids 2022 (March 14, 2022): 1–13. http://dx.doi.org/10.1155/2022/9517011.
Повний текст джерелаАнотація:
In order to study the seepage failure mechanism of roadway filling medium consisting of cohesive soil under complex hydrogeological conditions, a large-scale triaxial stress-seepage test system was utilized to investigate the influence of kaolin content and seepage loading rate on the seepage characteristics of filling medium. Through the analysis on the variation rules of sand loss and particle size distribution, the seepage characteristics and whole process of seepage instability of filling medium were explored in depth. It is concluded that (1) The seepage instability process of filling medium can be categorized into three stages: the initiation loss of fine clay, the accelerating loss of soil, and the stable status of soil loss. (2) The seepage failure process rate is proportional to the seepage loading rate and inversely proportional to the content of kaolin. (3) The kaolin and sand content of remaining mixture presented initial>bottom>middle>top status. The research results have guidance value for exploring the instability evolution mechanism of filling medium in deep roadway.
14
Grismer, Mark E. "Point- and reach-scale measurements are important for determining accurate seepage rates in controlled flow channels." California Agriculture 75, no. 2 (July 2021): 74–82. http://dx.doi.org/10.3733/ca.2021a0013.
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A critical component of water-resources management in the irrigated agriculture landscape, particularly those landscapes dependent on groundwater availability, is determining groundwater recharge rates from streams and other channels. In California, flows in many such channels are “controlled” by upstream reservoir releases to meet downstream urban, irrigation and environmental water requirements. Seepage volumes from these channels and how they might vary during controlled release periods is a key component of meeting downstream riparian and groundwater-pumping needs. Understanding annual seepage from streamflow channels is also important in developing water budgets as part of the management of groundwater resources under the Sustainable Groundwater Management Act (SGMA) in California. However, direct measurements of channel seepage rates are infrequent or unavailable, and these rates, or associated volumes, are most often only estimated. Here we describe direct point- and reach-scale field measurements of channel seepage rates in Lower Putah Creek (Solano County) and in distribution lateral channels of the Oakdale Irrigation District on the east side of the San Joaquin Valley (San Joaquin and Stanislaus counties). We measured overall average seepage rates of about 2 feet (610 mm) per day at both locations and determined how these rates varied spatially and temporally during the summer when channel flows are controlled for downstream requirements.
15
LI, FENGZHI. "SCALED BOUNDARY FINITE-ELEMENT AND SUBSTRUCTURE ANALYSIS ON THE SEEPAGE PROBLEMS." Modern Physics Letters B 24, no. 13 (May 30, 2010): 1491–94. http://dx.doi.org/10.1142/s0217984910023943.
Повний текст джерелаАнотація:
The scaled boundary finite element method is used to determine the seepage free surface of a dam with unbounded base. Two models for the bounded and the unbounded domains are established by using the mentioned method, and the numerical solutions are compared with the analytical results. Also, the free surface seepage of a dam with unbounded base is solved by combining the substructure and scaled boundary finite-element methods. The method has satisfactory accuracy and is quite efficient.
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Cheng, Y. M., Fu Chen, Zhen Zhu, Changfeng Yuan, and Liang Li. "Seepage Analysis for Construction, with Applications to Some Projects in Hong Kong." Geofluids 2021 (February 12, 2021): 1–18. http://dx.doi.org/10.1155/2021/6623816.
Повний текст джерелаАнотація:
Deep excavations are intensively carried out in many cities in China and other countries. One of the major loadings in such construction work is the water pressure, and great effort is required to assess the seepage problem and the corresponding water pressure on the retaining wall for a good design and construction. Different methods used for the seepage analysis are discussed in this paper through a series of projects in Hong Kong. Some interesting phenomena from the seepage analysis will also be discussed. Two large scale seepage field tests in Hong Kong are also used for the illustration of the back analysis in seepage problems which are seldom carried out. The comparative studies demonstrate that a realistic seepage analysis is very important for deep excavation works, but it was not seriously considered in the past.
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Chen, Chenghao, Shengshui Chen, Shiang Mei, Shaoyang Han, Xian Zhang, and Yi Tang. "An Improved Large-Scale Stress-Controlled Apparatus for Long-Term Seepage Study of Coarse-Grained Cohesive Soils." Sensors 21, no. 18 (September 18, 2021): 6280. http://dx.doi.org/10.3390/s21186280.
Повний текст джерелаАнотація:
Clay–gravel mixture has been widely used in high embankment dams and understanding its seepage characteristics is critical to dam safety. From the instrumental perspective, the realization of continuous pressurized water supply becomes a key technical challenge, significantly restricting the working conditions replicated in previous seepage apparatuses. To this end, a novel water provision system, relying on parallel-disposed sensor-based pressure devices, was introduced, so that the application of an existing large-scale stress-controlled apparatus can be expanded to long-term seepage tests regarding coarse-grained cohesive soils. Constant-head permeability tests were conducted on original-graded clay–gravel mixtures to investigate their hydraulic properties, incorporating the influence of stress relaxation. Test results show that with 35% gravel content, the clay–gravel mixture is suitable for dam construction as the core material. The stress relaxation holds a marginal effect on the hydraulic conductivity of soil. The functionality of this improved apparatus is verified, especially under long-term seepage conditions.
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Zhen, Zhixin, Xuewei Ma, and Bo Ma. "Exploration and Research on the Propagation Law of Seepage Risk Network in Tailings Storage Facility." Discrete Dynamics in Nature and Society 2021 (November 8, 2021): 1–14. http://dx.doi.org/10.1155/2021/8704259.
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The seepage accident of a tailings pond poses a serious threat to the stability of tailings dams and the surrounding environment. To reduce the occurrence of seepage accidents, this paper studies the identification of seepage hazards, the propagation law of seepage risk, the importance of hazards, and the priority of hazard treatment. To overcome the subjectivity and omission of hazard identification, according to the complexity and dynamics of tailings seepage, this paper proposes the evidence-based identification method of three-dimensional seepage hazards (EIMTSH) to identify the hazards of the tailings seepage system and the relationship between hazards. Then, on the basis of identifying the hazards of the tailings seepage system, the propagation network of seepage risk in tailing ponds (PNSRTP) is constructed based on the complex network theory. By analyzing the characteristics of the PNSRTP, it can be found that the propagation of seepage risk is scale-free and small-world. Through the node deletion method, this paper finds that the nodes with a higher degree value can reduce the network efficiency more quickly and should be governed first. By giving priority to the treatment of hazards with higher degree, the propagation of seepage risk can be reduced more quickly and the risk management level of tailings ponds can be improved, which is helpful to realize the sustainable development of mining production.
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Morel-Seytoux, Hubert J., Calvin D. Miller, Cinzia Miracapillo, and Steffen Mehl. "River Seepage Conductance in Large-Scale Regional Studies." Groundwater 55, no. 3 (December 20, 2016): 399–407. http://dx.doi.org/10.1111/gwat.12491.
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20
Taylor, Howard F., Catherine O'Sullivan, Way Way Sim, and Simon J. Carr. "Sub-particle-scale investigation of seepage in sands." Soils and Foundations 57, no. 3 (June 2017): 439–52. http://dx.doi.org/10.1016/j.sandf.2017.05.010.
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21
Wang, Yu, Xiangbao Duan, Yanchang Gu, and Shijun Wang. "Fractal Characteristics of the Seepage Erosion Process in Porous Soil." Geofluids 2022 (June 26, 2022): 1–12. http://dx.doi.org/10.1155/2022/3383773.
Повний текст джерелаАнотація:
Seepage-induced erosion in porous soil has always been a major concern in the field of geofluids. Various fractal models have been built to theoretically investigate the porosity and permeability coefficient. However, the seepage erosion process (i.e., incubation, formation, evolution, and destruction) in porous soil is not clearly demonstrated to clarify the seepage fractal characteristics. In this paper, a series of hydraulic tests were performed to reveal the mass fractal characteristics of sandy gravels, coarse-grained sands, and fine-grained sands in the seepage erosion process. The results show that the mass fractal dimension was appropriate to describe the cumulative mass distribution of particles, the complexity of pore networks, and the dynamic changes of the seepage erosion process. Moreover, the scale-invariant interval, as an essential precondition for the accurate calculation of the mass fractal dimension, was to some extent affected by the average grain size and the fine content of porous soil. In particular, the changing trend of porosity and permeability coefficient with the mass fractal dimension was demonstrated in the seepage erosion process. Both porosity and permeability coefficients indicated an increasing trend as the development of seepage erosion. However, the mass fractal dimension gradually decreased due to the removal of fine particles induced by seepage flow water. Research findings will not only provide a new perspective on the seepage erosion mechanism but also predict the development of the seepage erosion process in engineering practice.
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de Louw, P. G. B., S. Eeman, B. Siemon, B. R. Voortman, J. Gunnink, E. S. van Baaren, and G. H. P. Oude Essink. "Shallow rainwater lenses in deltaic areas with saline seepage." Hydrology and Earth System Sciences 15, no. 12 (December 7, 2011): 3659–78. http://dx.doi.org/10.5194/hess-15-3659-2011.
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Abstract. In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and size. Our findings are based on different types of field measurements and detailed numerical groundwater models applied in the south-western delta of the Netherlands. By combining the applied techniques we could extrapolate measurements at point scale (groundwater sampling, temperature and electrical soil conductivity (TEC)-probe measurements, electrical cone penetration tests (ECPT)) to field scale (continuous vertical electrical soundings (CVES), electromagnetic survey with EM31), and even to regional scale using helicopter-borne electromagnetic measurements (HEM). The measurements show a gradual mixing zone between infiltrating fresh rainwater and upward flowing saline groundwater. The mixing zone is best characterized by the depth of the centre of the mixing zone Dmix, where the salinity is half that of seepage water, and the bottom of the mixing zone Bmix, with a salinity equal to that of the seepage water (Cl-conc. 10 to 16 g l−1). Dmix is found at very shallow depth in the confining top layer, on average at 1.7 m below ground level (b.g.l.), while Bmix lies about 2.5 m b.g.l. The model results show that the constantly alternating upward and downward flow at low velocities in the confining layer is the main mechanism of mixing between rainwater and saline seepage and determines the position and extent of the mixing zone (Dmix and Bmix). Recharge, seepage flux, and drainage depth are the controlling factors.
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Yuan, Suxiang. "Discussion on Anti-Seepage Technologies in the Construction of Small-Scale Rural Water Conservancy Projects." Journal of World Architecture 6, no. 2 (March 21, 2022): 19–24. http://dx.doi.org/10.26689/jwa.v6i2.3791.
Повний текст джерелаАнотація:
In order to ensure the sustainable growth of rural economy, it is necessary to carry out further research on small-scale water conservancy projects and solve the seepage issue in rural areas. Based on the application significance of small-scale rural water conservancy projects and the analysis of anti-seepage technologies, along with specific examples, this paper specifically discusses the application of high-pressure jet technology, so as to provide reference for the development of engineering construction.
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de Louw, P. G. B., S. Eeman, B. Siemon, B. R. Voortman, J. Gunnink, E. S. van Baaren, and G. H. P. Oude Essink. "Shallow rainwater lenses in deltaic areas with saline seepage." Hydrology and Earth System Sciences Discussions 8, no. 4 (August 10, 2011): 7657–707. http://dx.doi.org/10.5194/hessd-8-7657-2011.
Повний текст джерелаАнотація:
Abstract. In deltaic areas with saline seepage, fresh water availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and size. Our findings are based on different types of field measurements and detailed numerical groundwater models applied in the south-western delta of The Netherlands. By combining the applied techniques we could extrapolate in situ measurements at point scale (groundwater sampling, TEC (temperature and electrical soil conductivity)-probe measurements, electrical cone penetration tests (ECPT)) to a field scale (continuous vertical electrical soundings (CVES), electromagnetic survey with EM31), and even to a regional scale using helicopter-borne electromagnetic measurements (HEM). The measurements show a gradual S-shaped mixing zone between infiltrating fresh rainwater and upward flowing saline groundwater. The mixing zone is best characterized by the depth of the centre of the mixing zone Dmix, where the salinity is half that of seepage water, and the bottom of the mixing zone Bmix, with a salinity equal to that of the seepage water (Cl-conc. 10 to 16 g l−1). Dmix manifests at very shallow depth in the confining top layer, on average at 1.7 m below ground level (b.g.l.), while Bmix lies about 2.5 m b.g.l. Head-driven forced convection is the main mechanism of rainwater lens formation in the saline seepage areas rather than free convection due to density differences. Our model results show that the sequence of alternating vertical flow directions in the confining layer caused by head gradients determines the position of the mixing zone (Dmix and Bmix and that these flow directions are controlled by seepage flux, recharge and drainage depth.
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Li, Hong, Hongyuan Tian, and Ke Ma. "Seepage Characteristics and Its Control Mechanism of Rock Mass in High-Steep Slopes." Processes 7, no. 2 (February 1, 2019): 71. http://dx.doi.org/10.3390/pr7020071.
Повний текст джерелаАнотація:
In Southwest China large-scale hydropower projects, the hydraulic conductivity and fracture aperture within the rock mass of a reservoir bank slope has dramatically undergone a time series of evolution during dam abutment excavation, reservoir impounding and fluctuation operation, and discharge atomization. Accordingly, seepage control measures by hydro-structures such as drainage or water insulation curtains should be guided by scientific foundation with a dynamic process covering life-cycle performance. In this paper, the up-to-date status of studying the evolution mechanism of seepage characteristics relating to fractured rock hydraulics from experimental samples to the engineering scale of the rock mass is reviewed for the first time. Then, the experimental findings and improved practice method on nonlinear seepage flow under intensive pressure drives are introduced. Finally, the scientific progress made in fractured rock seepage control theory and optimization of the design technology of high-steep slope engineering is outlined. The undertaken studies summarized herewith are expected to contribute to laying a foundation to guide the further development of effective geophysical means and integrated monitoring systems in hydropower station construction fields.
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Ye, Wei, Fuheng Ma, Jiang Hu, and Ziyang Li. "Seepage Behavior of an Inclined Wall Earth Dam under Fluctuating Drought and Flood Conditions." Geofluids 2018 (July 9, 2018): 1–11. http://dx.doi.org/10.1155/2018/4734138.
Повний текст джерелаАнотація:
Most dam seepage safety analyses evaluate a stable seepage field, infiltration line, and seepage flow. However, under fluctuating drought-flood conditions, the soil surface becomes cracked, making it too complicated to conduct a routine seepage analysis. In this paper, the seepage characteristics of an inclined wall dam under fluctuating drought-flood conditions were studied using a large-scale physical model. The results show that after drought, the permeability coefficient of clay with low crack development was smaller than that of the saturated permeability, but for cracked areas, with high permeability, permeability coefficients were much larger than those of the saturated permeability. As the water level rose, cracks could heal themselves, but this healing was superficial, and the soil could no longer return to its predrought state. After crack healing, the integrity of the dam slope was much less than its original state. In addition, the formation of cracks increased the porosity of the soil and changed the soil permeability, which permanently weakened the antiseepage performance of the clay soil. This study evaluated the seepage flow behavior of an inclined wall dam under fluctuating drought-flood conditions, and results can be used to monitor and protect the weak parts of seepage dams in practical engineering projects.
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Zhao, Xiaoming, Yulong Niu, Dongbin Cui, and Mingming Hu. "Random Characteristics of Hydraulic Gradient through Three-Dimensional Multilayer Embankment." Advances in Materials Science and Engineering 2022 (January 11, 2022): 1–8. http://dx.doi.org/10.1155/2022/7044267.
Повний текст джерелаАнотація:
The distribution characteristics of hydraulic gradient in embankment are closely related to seepage failure. Seepage failures such as flowing soil and piping will lead to serious damage and even the overall failure of embankment. The hydraulic conductivity has strong spatial variability, which changes the distribution of hydraulic gradient in embankment and increases the difficulty for predicting the embankment seepage instability. In this study, the distribution of soil hydraulic conductivity in a section of Shijiu Lake embankment was obtained by the permeability test. Based on Local Average Subdivision technique, a three-dimensional multilayer random field of embankment hydraulic conductivity was generated. Then, the mean and standard deviation of overflow point height and hydraulic gradient were calculated by the Monte Carlo method, which combined the generated three-dimensional random model and the deterministic analysis method of seepage field. Finally, the coefficient of variation (COV) of hydraulic conductivity (0.1, 0.3, 0.5, 0.7, 1.0, 2.0, and 3.0), the fluctuation scale in vertical direction (3 m) and the fluctuation scale in horizontal plane (3 m, 6 m, 12 m, 24 m, 36 m, and 48 m) were selected respectively for analyzing the random characteristics of embankment overflow point height and hydraulic gradient under the influence of different COV and fluctuation scale of embankment soil hydraulic conductivity.
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Peng, Peihuo. "Effect of matching relation of multi-scale, randomly distributed pores on geometric distribution of induced cracks in hydraulic fracturing." Energy Exploration & Exploitation 38, no. 6 (May 25, 2020): 2436–65. http://dx.doi.org/10.1177/0144598720928150.
Повний текст джерелаАнотація:
Reservoir rock contains many multi-scale, unevenly distributed pores, and the pore structures of shale in different reservoirs and geological environments vary greatly. Because the seepage velocity and pressure field are related to the pore spatial variations, the inhomogeneity of the seepage is superimposed on the anisotropy of the rock’s physical properties, which will affect the distribution of the induced cracks. A method for calculating the pore size in the bonded particle model, based on Delaunay triangulation, is proposed. A modeling approach capable of simulating the multi-scale pore distribution of actual rock is presented based on the proposed method. To understand how microcracks connect micropores in the process of fracturing, several bonded particle model samples with different pore structures were established, and numerical experiments were conducted based on the coupling calculation of the discrete seepage algorithm and discrete element method. The focus of this study was on the interactions between the distribution characteristics of multi-scale pores, the specific physical properties of the fracturing fluid, and the distribution differences of the induced cracks caused by the special seepage characteristics when using different fracturing fluids. The numerical results showed that the advantages of supercritical CO2 fracturing are maximized in deep reservoirs (high in-situ stress) and that a suitable in-situ stress condition is required (i.e. a stress ratio close to 1).
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Xiao, Qiong, and Ji-Peng Wang. "CFD–DEM Simulations of Seepage-Induced Erosion." Water 12, no. 3 (March 2, 2020): 678. http://dx.doi.org/10.3390/w12030678.
Повний текст джерелаАнотація:
Increases in seepage force reduce the effective stress of particles and result in the erosion of particles, producing heave failure and piping. Sheet piles/cutoff walls are often employed in dams to control the seepage. In this study, a computational fluid dynamics solver involving two fluid phases was developed and coupled with discrete element method software to simulate the piping process around a sheet pile/cutoff wall. Binary-sized particles were selected to study the impact of fine particles on the mechanisms of seepage. The seepage phenomenon mainly appeared among fine particles located in the downstream side, with the peak magnitudes of drag force and displacement occurring around the retaining wall. Based on the particle-scale observations, the impact of seepage produced a looser condition for the region concentrated around the retaining wall and resulted in an anisotropic condition in the soil skeleton. The results indicate that heave behavior occurs when the drag force located adjacent to the boundary on the downstream side is larger than the corresponding weight of the bulk soil.
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Ye, Zhenni, Xiaoli Liu, Qinxi Dong, Enzhi Wang, and Huan Sun. "Hydro-Damage Properties of Red-Bed Mudstone Failures Induced by Nonlinear Seepage and Diffusion Effect." Water 14, no. 3 (January 25, 2022): 351. http://dx.doi.org/10.3390/w14030351.
Повний текст джерелаАнотація:
Nonlinear catastrophes caused by geological fluids are a fundamental issue in rock mechanics and the geoengineering hazard field. For the consideration of hydrodynamic force on red-bed mudstone softening damage, X-ray visualization tests on the fissure flow in mudstone block failure under hydrodynamic force was performed in this study based on block scale, and the physical phenomena of fissure seepage and nonlinear diffusion were further explored. A new method for evaluating the hydro-damage degrees of rocks using an X-ray image analysis was proposed, and the quantitative relation of diffusion coefficients of hydro-damage and seepage was established. The research results revealed that the hydrodynamic force promoted the fluid-filled fissure behavior in mudstone specimen failure. Furthermore, the seepage and diffusion phenomena of fluid in rocks during failures were indicated using X-ray imaging. A dual mechanical behavior was presented in the nonlinear seepage and abnormal diffusion of a red mudstone geological body under hydrodynamic conditions. The damaged degree of mudstone was aggravated by the effect of hydrodynamic force, and the initial seepage–diffusion coefficient with respect to lower hydro-damage was larger than the final seepage–diffusion coefficient with respect to higher hydro-damage of rocks with a decreasing nonlinear trend.
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Ke, Xianmin, Wei Wang, Jinlong Li, Qiming Sun, Lulu Lian, Xiangdong Xu, and Qiaofen Lyu. "In-situ pumping tests and numerical simulations of seepage wells in the Yellow River valley, China." Water Supply 22, no. 2 (October 5, 2021): 1459–73. http://dx.doi.org/10.2166/ws.2021.340.
Повний текст джерелаАнотація:
Abstract Seepage wells that can convert surface water into groundwater are often constructed near river valleys to obtain more water and lead to smaller drawdown compared with traditional wells. Seepage wells have been widely used, whilst the groundwater and river-level variations caused by seepage wells are still unclear, and numerical models are rarely verified due to the lack of in-situ observational data, which may lead to results that are quite different from the actual conditions. To address those limitations, a large-scale pumping test was carried out near the Yellow River valley in China and a coupled seepage–pipe flow model was established using the exchange yield between the aquifer and pipe as the coupling key in this research. The coupled model was evaluated with in-situ measurement. The field observation showed that both the river and groundwater had a positive response to the pumping of the seepage wells. The simulation results indicated that our model can well estimate the pumping rate and drawdown with root-mean-square deviations of 158.235 m3/d and 0.766 m, respectively. Further, it is also found that the groundwater showed the obvious characteristics of three-dimensional flow under the influence of seepage wells and the maximum drawdown should be less than 15 m to ensure exploitation efficiency. These findings provide important information that can guide the design and construction of seepage wells to improve the rational exploitation of groundwater.
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Wu, Zhenkai, Feifei Fang, Xizhe Li, Hanmin Xiao, Xuewei Liu, Yuan Rao, Yang Li, Jie Wang, Yongcheng Luo, and Zhi Li. "Division Method and Seepage Law of Seepage Channels in a Tight Reservoir." Geofluids 2021 (October 29, 2021): 1–18. http://dx.doi.org/10.1155/2021/4804513.
Повний текст джерелаАнотація:
Tight oil reservoirs are characterized by a low porosity, low permeability, and strong heterogeneity. The macropores, throats, and microcracks in reservoirs are the main seepage channels, which affect the seepage law in the reservoirs. In particular, oil-water two-phase flow in different types of pores requires further study. In this study, two groups of online NMR displacement experiments were designed to study the seepage characteristics of tight oil reservoirs. It was found that the main seepage channels for oil-water two-phase flow are the microcracks, large pores, and throats in the reservoir. The large pores are mainly micron and submicron scale in size. The oil in the small pores is only transferred to the large pores through imbibition to participate in the flow, and there is no two-phase flow. Based on the influence of different pore structures on the seepage law of a tight reservoir, the pores were divided into seepage zones, and a multistage seepage model for tight reservoirs was established. Based on this model, the effects of the imbibition, stress sensitivity, threshold pressure gradient, and Jamin effect on model’s yield were studied. The results show that imbibition is no longer effective after a while. Owing to the stress sensitivity, the threshold pressure gradient, and the Jamin effect, oil production will be reduced. As the parameter value increases, the oil production decreases. The production decreases rapidly in the early stage of mining while decreases slowly in the later stage, exhibiting a trend of high yield in the early stage and stable yield in the later stage.
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Nie, Qingke, Huawei Li, Haipeng Yang, Tengfei Ni, and Sichen Jiang. "The Promotion/Inhibition of the Seepage Transport of Copper Ions by Suspension-Colloidal Particles with Wide Size Gradation." Geofluids 2021 (May 29, 2021): 1–12. http://dx.doi.org/10.1155/2021/9920415.
Повний текст джерелаАнотація:
Sand column tests were conducted to investigate the seepage transport of silicon powders (SPs) with two wide particle size ranges (30-2000 nm and 2-70 μm), including the cotransport of SPs and copper ions. The results show that the graded large-scale SP has an obvious inhibiting influence on the transport of copper ions. In contrast, in the presence of the graded small-scale SP, the concentration of copper ions in the effluent tends to increase; i.e., there appears to be a promoting effect. However, after a long transport distance, the presence of SPs, regardless of particle size, has an overall retarding effect on heavy metal pollutants (e.g., copper ions). The promoting effect of the increase in seepage velocity on the concentration of copper ions in the effluent is greater with the graded large-scale SPs than with the graded small-scale SPs. In terms of the microstructural characteristics by metallographic microscopy, the average particle size of the deposited graded small-scale SPs is almost constant at different transport distances, while that of the deposited graded large-scale SPs tend to decrease significantly with increasing transport distance; i.e., notable bed filtration is exhibited in the latter case. This physical mechanism also determines the sequence and rate of the retarding effect of SPs on heavy metal ions under seepage flow.
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Tong, Qiang, Dongbo He, Zhaohui Xia, Jixin Huang, Kaixiang Di, Fang Xu, and Songwei Guo. "Influence of Reservoir Pore-Throat Structure Heterogeneity on Water-Flooding Seepage: A Case Study of Yanchang Formation in Ordos Basin." Minerals 12, no. 10 (September 29, 2022): 1243. http://dx.doi.org/10.3390/min12101243.
Повний текст джерелаАнотація:
The microscopic pore-throat structure of low-porosity and ultralow permeability sandstone reservoirs controls the seepage characteristics, which directly affects the water injection development efficiency of oilfields. Different from typical tight sandstone reservoirs, macropores and mesopores are more developed in the pore-throat structure of this type of reservoir, which changes the dominance of micropores over seepage capacity. Based on the full-range pore-throat structure characterization method and fractal theory, many experimental methods are used to study the influence of the microscopic pore-throat structure over the seepage characteristics in the Chang 9 reservoir in the Yanchang Formation of the Ordos Basin. The results of 12 typical samples show that the pore-throat structure has multifractal characteristics, and the occurrence degree of movable fluid and seepage capacity vary greatly, showing strong microscopic heterogeneity. Following characterization of the full-range pore-throat structure, the relative proportion of macropores and mesopores determines the physical properties of the reservoir. The pore-throat scale and structural heterogeneity have a significant impact on porosity, while the pore-throat structure connectivity has a crucial impact on permeability. Quartz provides resistance to compaction and preserves more primary pores. Additionally, the relationship between clay minerals and physical properties is not significant. Only illite and I/S mixed layers have a slight effect on permeability reduction. Furthermore, laumontite cementation is the key factor in the destruction of the pore-throat structure. Porosity has a significant effect on movable fluid occurrence and is more closely related to the two-phase seepage. Permeability controls the oil displacement efficiency in the anhydrous period, and porosity controls the oil displacement efficiency in the final period. The fractal dimension has some significant controls on the pore-throat structure, which are reflected in the fact that the higher the homogeneity of macropores is and the higher the heterogeneity of mesopores and micropores is, the better the reservoir development will be. In particular, the degree of macropore development guarantees reservoir quality. The control of the fractal dimension on the seepage capacity is complex, especially for mesopores and micropores; the higher the degree of heterogeneity is, the stronger the seepage capacity will be. The occurrence of movable fluid is significantly affected by the scale and heterogeneity of the pore-throat structure, which is reflected as stronger heterogeneity of the pore-throat structure and poorer relative seepage capacity.
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Liu, Jianjun, Yao Wang, and Rui Song. "A Pore Scale Flow Simulation of Reconstructed Model Based on the Micro Seepage Experiment." Geofluids 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/7459346.
Повний текст джерелаАнотація:
Researches on microscopic seepage mechanism and fine description of reservoir pore structure play an important role in effective development of low and ultralow permeability reservoir. The typical micro pore structure model was established by two ways of the conventional model reconstruction method and the built-in graphics function method of Comsol® in this paper. A pore scale flow simulation was conducted on the reconstructed model established by two different ways using creeping flow interface and Brinkman equation interface, respectively. The results showed that the simulation of the two models agreed well in the distribution of velocity, pressure, Reynolds number, and so on. And it verified the feasibility of the direct reconstruction method from graphic file to geometric model, which provided a new way for diversifying the numerical study of micro seepage mechanism.
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Ding, Hao, Xinghong Jiang, and Ke Li. "Scale Model Study on Water Seepage from Cracked Lining Structure." IOP Conference Series: Materials Science and Engineering 741 (March 24, 2020): 012080. http://dx.doi.org/10.1088/1757-899x/741/1/012080.
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Liu, Lifeng, Yuxiang Xiao, Zhongbao Wu, and Xin Wang. "Hydro-mechanical coupling numerical simulation method of multi-scale pores and fractures in tight reservoir." IOP Conference Series: Earth and Environmental Science 983, no. 1 (February 1, 2022): 012060. http://dx.doi.org/10.1088/1755-1315/983/1/012060.
Повний текст джерелаАнотація:
Abstract In the fracturing, injection and production of unconventional tight reservoirs, the change of fluid pressure will cause significant changes in effective stress, which will greatly affect the dynamic characteristics of the reservoir. On the basis of the adaptive seepage numerical simulation method for different scale medium of tight oil in the early stage, through the study of the deformation mechanism and deformation law of natural / artificial fractures and matrix pores during the whole life cycle including hydraulic fracturing, production and fluid injection to supplement energy, the dynamic variation models of multi medium geometry, physical properties, conductivity and well index are established, and the multi medium fluid solid coupling dynamic simulation technology is formed. The integrated dynamic simulation of multi-media complex seepage and hydro-mechanical coupling is realized.
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Koteras, Aleksandra Katarzyna, and Lars Bo Ibsen. "Medium-scale laboratory model of mono-bucket foundation for installation tests in sand." Canadian Geotechnical Journal 56, no. 8 (August 2019): 1142–53. http://dx.doi.org/10.1139/cgj-2018-0134.
Повний текст джерелаАнотація:
Design implications of suction installation of bucket foundations are still not well understood. During suction installation, applied suction under the bucket lid results in seepage flow through the surrounding sand. Seepage flow plays a pivotal role in reducing the penetration resistance, allowing for full penetration despite the initial large soil resistance. However, loosening of the inside soil plug might be problematic when the soil approaches its failure stage, due to soil piping or extensive soil heave inside the bucket foundation. To better understand the interaction between the soil and bucket skirt during suction installation, this paper describes the results of medium-scale tests of bucket foundation installations in sand, comparing jacking and suction installations. Experimental measurements of the pore pressure around the bucket skirt are compared with the numerical simulation results, to validate the finite-element model and to enable analysis of the soil behavior around the skirt.
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Chen, Gang, Ling Ma, Hongsheng Gong, and Fengqiang Luo. "Numerical Calculation of Fracture Seepage in Rough Rock and Analysis of Local Pressure Drop." Geofluids 2021 (October 25, 2021): 1–14. http://dx.doi.org/10.1155/2021/1828175.
Повний текст джерелаАнотація:
The seepage performance of a rock mass mainly depends on the rock fractures developed in it. Numerical calculation method is a common method to study the permeability properties of fractures. Seepage in rock fractures is affected by various factors such as fracture aperture, roughness, and filling, among which aperture and roughness are the two most widely influenced factors. The Navier-Stokes (NS) equation can be solved directly for the seepage flow in rock fractures with good accuracy, but there are problems of large computational volume and slow solution speed. In this paper, the fracture aperture space data is substituted into the local cubic law as an aperture function to form a numerical calculation method for seepage in rough rock fractures, namely, the aperture function method (AFM). Comparing with the physical seepage experiments of rock fractures, the calculation results of AFM will produce a small amount of error under the low Reynolds number condition, but it can greatly improve the calculation efficiency. The high efficiency of calculation makes it possible to apply AFM to the calculation of large-scale 3D rough fracture network models. The pressure drop of fluid in the fracture has viscous pressure drop (VPD) and local pressure drop (LPD). VPD can be calculated using the AFM. After analyzing the results of solving the NS equation for fracture seepage, it is concluded that the LPD includes the pressure drop caused by area crowding in the recirculation zone (RZ), kinetic energy loss in the RZ, kinetic energy loss in the vortices, and other reasons.
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Rettinger, S., and W. Bischofsberger. "Subsoil Percolation of Sewage – Purification Efficiency of Unsaturated Zone and Mass Balance of Organic Load." Water Science and Technology 22, no. 7-8 (July 1, 1990): 313–15. http://dx.doi.org/10.2166/wst.1990.0275.
Повний текст джерелаАнотація:
The unsaturated zone is recently getting special attention because of its purification efficiency on discharges of septic tanks, leaking sewers, and seepage of agricultural lands. Since knowledge of quantitative effects and removal processes is poor, investigations are conducted by the use of lysime-ters and a full-scale soil disposal system. Results on variation of seepage water ingredients and mass balances are shown. These and further results give the possibility of upgrading soil disposal systems, in order to minimize pollution of soil and groundwater.
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MIELKE, ALEXANDER, and EDUARD ROHAN. "HOMOGENIZATION OF ELASTIC WAVES IN FLUID-SATURATED POROUS MEDIA USING THE BIOT MODEL." Mathematical Models and Methods in Applied Sciences 23, no. 05 (February 21, 2013): 873–916. http://dx.doi.org/10.1142/s0218202512500637.
Повний текст джерелаАнотація:
We consider periodically heterogeneous fluid-saturated poroelastic media described by the Biot model with inertia effects. The weak and semistrong formulations for displacement, seepage and pressure fields involve three equations expressing the momentum and mass balance and the Darcy law. Using the two-scale homogenization method, we obtain the limit two-scale problem and prove the existence and uniqueness of its weak solutions. The Laplace transformation in time is used to decouple the macroscopic and microscopic scales. It is shown that the seepage velocity is eliminated from the macroscopic equations involving strain and pressure fields only. The plane harmonic wave propagation is studied using an example of layered medium. Illustrations show some influence of the orthotropy on the dispersion phenomena.
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Luo, Yulong, Min Nie, and Ming Xiao. "Flume-scale experiments on suffusion at bottom of cutoff wall in sandy gravel alluvium." Canadian Geotechnical Journal 54, no. 12 (December 2017): 1716–27. http://dx.doi.org/10.1139/cgj-2016-0248.
Повний текст джерелаАнотація:
This paper presents a series of flume-scale experiments to investigate suffusion at the bottom of a cutoff wall in an internally unstable sandy gravel alluvium. The initiation, progression, and potential failure of suffusion and the interactive effects of geomechanical and hydraulic conditions with the evolution of suffusion were investigated in this particular application. Temporal and spatial development of pore pressure, earth pressure, and settlement demonstrated suffusion was a multi-phase (involving pore water, fine and coarse fractions) and multi-field (involving seepage, seepage-induced fine-fraction variation, and stress–deformation) coupling phenomenon. Suffusion initiated at the downstream side of the tip of the cutoff wall and then generally progressed backward to the upstream side. The monitored earth pressure provided an evidence of the heterogeneous stress distribution in internally unstable soil. Two linear empirical formulas for average hydraulic gradients at the initiation of suffusion and at blowout were derived based on the flume-scale model experiments.
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Jing, Wen, Luo Wei, Yin Qingguo, Wang Hongying, He Yongming, and Zhao Yarui. "PRODUCTIVITY PREDICTION OF FRACTURED HORIZONTAL WELLS WITH LOW PERMEABILITY FLOW CHARACTERISTICS." Journal of Environmental Engineering and Landscape Management 27, no. 2 (April 29, 2019): 82–92. http://dx.doi.org/10.3846/jeelm.2019.9803.
Повний текст джерелаАнотація:
Horizontal well and large-scale fracturing are revolutionary technologies in petroleum industry. The technologies bring obvious economic benefits to exploiting unconventional oil and gas reservoirs with low permeability, ultra-low permeability and shale gas. With the increasingly extensive application of these technologies, other correlated technologies have also gained great development. However, low-permeability reservoirs exhibit complicated features and horizontal well fractures have complex shape. The existing methods for the productivity prediction of fractured horizontal well in low-permeability reservoirs rarely consider the influencing factors in a comprehensive manner. In this paper, a horizontal well seepage model of casing fracturing completion was established according to the superposition principle of low-permeability reservoir and the relationship between potential and pressure, by which model the seepage characteristics of low-permeability reservoirs could be fully described. Based on the established new seepage model, a new targeted model with coupling seepage and wellbore flow was established for the productivity prediction of low-permeability fractured horizontal well. Finally, the new targeted model was verified through field experiment. The experimental results confirmed the reliability of productivity prediction by the proposed model. Sensitivity analysis was then performed on the parameters in the proposed model.
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Yang, Shengtao, Yan Lv, Yuanyuan He, Minggang Pang, and Xiaozhen Ma. "Mesoscale Numerical Analysis of Fiber-Reinforced Sand with Different Fiber Orientations Subjected to Seepage-Induced Erosion Based on DEM." Materials 16, no. 1 (December 29, 2022): 335. http://dx.doi.org/10.3390/ma16010335.
Повний текст джерелаАнотація:
This paper focuses on the effect of fiber orientation on the resistance of seepage-induced erosion in fiber-reinforced sand. To clarify the discrepancy and mechanism of different-oriented fibers improving the resistance of the sand matrix, a series of DEM-Darcy coupling simulations were conducted. The microscopic parameters of fiber-reinforced sand were confirmed by the rigorous calibration procedure. The fibers perpendicular to the seepage direction were found to increase the difficulty of moving fluid through the specimen and significantly reduce the erosion rate of the specimen. These macroscopic behaviors acquired corresponding explanations at the mesoscopic scale, including the evolution of fiber-sand contact orientation, coordination number, average normal contact force, tensile force, and energy dissipation. According to the simulation results, it is found that the highest proportion of tensile force in perpendicular fibers can reach 80%, while the parallel fibers are only 40%, which indicates that the perpendicular fibers have a significant netting effect. The mesoscopic behaviors reasonably revealed the role of the fibers with different orientations on the sand matrix during the seepage. This study is beneficial for further understanding the mechanical behaviors of fiber-reinforced sand under seepage-induced erosion in safety engineering.
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Boffo, Carolina H., Tiago A. de Oliveira, Daniel Bayer da Silva, Rafael Manica, and Ana Luiza de O. Borges. "Continental-slope instability triggered by seepage: An experimental approach." Journal of Sedimentary Research 90, no. 8 (August 19, 2020): 921–37. http://dx.doi.org/10.2110/jsr.2020.48.
Повний текст джерелаАнотація:
ABSTRACT Mass-transport complexes (MTCs), mass-transport deposits (MTDs), and associated facies and features are widely recognized in continental slopes around the world. In most current stratigraphic models of MTCs and MTDs, these submarine sediment failures are related to aquifer outflow (sapping, seepage) along continental slope fronts that originated during relative sea-level fall. We test a hypothetical scenario that is favored during early forced regression using reduced-scale physical simulation. A major underground subaerial hydraulic gradient is assumed to flow towards the basin depocenter as a function of relative sea-level fall. We developed an experimental apparatus with slope angles varying between 15 and 30° to test this concept. Hydraulic gradients, aquifer outflow velocities, and triggered collapses induced by the seepage effect were recorded at various positions of the slope. Analysis shows that steeper slope gradients require lower seepage velocities (and shear stresses) to trigger collapse, but gentler slopes remain unchanged. Experimental data are compatible with a seepage effect that could potentially trigger mass failure and the formation of MTCs during relative sea-level fall. The features produced in the experiment have geometries comparable to natural environments, and the experimental seepage velocities are of an order of magnitude similar to those monitored in submarine aquifers. The experimental results advance understanding of mass transport in continental slopes by introducing and testing new methods, and also provide new insights into potential submarine geohazard risks where tectonic uplift operates along some coastal regions.
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Xu, Zhijing, Guanghui Zhang, Xiaoming Chen, Liangxue Yao, Guangyao Chen, and Fei Wang. "Application of Optical Fiber Sensing Technology in Permeability Test of Three-Dimensional Physical Model of Medium and Long-Distance Diversion Tunnel." Wireless Communications and Mobile Computing 2022 (September 12, 2022): 1–10. http://dx.doi.org/10.1155/2022/7931914.
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In order to accurately simulate the dynamic change law of seepage field during construction, this paper proposes the application of optical fiber sensing technology in the permeability test of three-dimensional physical model of medium and long-distance headrace tunnel. This paper introduces the principle of optical fiber sensing, analyzes and compares the application advantages of optical fiber and general electrical signal sensing in the safety monitoring of long-distance diversion tunnel. Taking the safety monitoring of a 16# long tunnel of a diversion project as an example, the selection of monitoring sections, monitoring items, and the layout and networking of monitoring instruments are studied. In addition, combined with the tunnel project, the physical simulation of the construction process of the deep buried headrace tunnel under high seepage pressure is carried out, and the water pressure automatic control water supply system and the discrete flower tube seepage generation system are designed and manufactured to realize the high simulation of the seepage field. The seepage and evolution law in the surrounding rock of headrace tunnel during dynamic construction are calculated and analyzed. The test results show that the maximum external water pressure of the headrace tunnel is 15 MPa, which is equivalent to 1500 m head pressure, and the similar scale of head pressure is 100. Therefore, taking 15 m constant head water supply pressure for simulation calculation, the excavation of the tunnel is 120 cm, and the two-dimensional seepage of the vertical section of Z = 91 cm . The seepage flow of the two sides of the tunnel is large, and the contour of the hydraulic gradient is dense. The coordinates are 0.7 m, 2.090 m, and 0.9 m. This point in the original rock mass is located at the same elevation point of the four headrace tunnels and directly below the model exploratory tunnel. The head pressure is 1.40 m, and the corresponding prototype point pressure head is 140 M. During construction, such a high external water pressure is a great safety hazard. Conclusion. The test conclusion provides a theoretical basis for the seepage prevention construction technology design of the headrace tunnel and is of great significance to the long-term stability, safety evaluation, and prediction of the headrace tunnel.
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Park, Min-Cheol, Jong-Wook Lee, You-Seok Kim, and Heui-Soo Han. "Seepage Analysis of Large-Scale Embankment Model by Revised TDR Sensor." Journal of the Korean Geotechnical Society 28, no. 11 (November 28, 2012): 53–67. http://dx.doi.org/10.7843/kgs.2012.28.11.53.
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Liu, Jianhua, Zhonghua Yang, Da Li, Ming Li, and Fengpeng Bai. "Resistance coefficient for large-scale roughness with seepage through porous bed." Journal of Hydrology 590 (November 2020): 125498. http://dx.doi.org/10.1016/j.jhydrol.2020.125498.
Повний текст джерела
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Kim, Jinman, Heuisoo Han, and Yoonhwa Jin. "Analysis of Pore Water Pressure and Piping of Hydraulic Well." Water 13, no. 4 (February 15, 2021): 502. http://dx.doi.org/10.3390/w13040502.
Повний текст джерелаАнотація:
This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.
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Ye, Dayu, Guannan Liu, Ning Luo, Feng Gao, Xinmin Zhu, and Fengtian Yue. "Quantitative Analysis of the Topological Structure of Rock Pore Network." Geofluids 2021 (June 13, 2021): 1–11. http://dx.doi.org/10.1155/2021/5517489.
Повний текст джерелаАнотація:
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.