Exploring the clogging process in coarse soil deposits in a dam foundation

Author(s):  
Jianquan Ma ◽  
Xiaojie Zhao ◽  
Shibo Li ◽  
Hao Peng ◽  
Lele Xiao ◽  
...  
2021 ◽  
Author(s):  
Sylvestre M. Ntomba ◽  
Christelle R. Magnekou Takamte ◽  
Dieudonné Bisso ◽  
Joseph Mvondo Ondoa

This chapter mainly focuses on engineering geology for dam construction from the Memve’ele region in Cameroon. Here, it deals with geotechnical and geological proprieties of both construction and dam foundation materials. This study is done at the aim to ensure that these materials need to be improved and how they have been used during dam construction. Field investigations, borehole information, density and seismic velocity measurements have been used, and results indicate that soil deposits have slightly clay content, mechanically well for dam construction and display a weak thickness layer particularly on the dam site. These conditions suggest that soil materials can be used as construction (cushion, transition layers, etc.) and foundation materials after few amendments. Ntem Formations appear weathered and fractured sometimes, though their mechanical behaviors display a good character for civil applications. However, engineering processes have been used to improve it by GIN (Grouting Intensity Number) methods. These formations have been used as construction (rip rap crushing aggregate, etc.) and dam foundation materials. Thus, this chapter contributes to highlight materials and dam foundation conditions which are crucial criteria encountered in the dam with emphasis on both theoretical study and practical application during dam construction.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Jianquan Ma ◽  
Hao Peng ◽  
Shibo Li ◽  
Zhao Duan ◽  
Xinshe Zhang ◽  
...  

Leakage through the permeable coarse soils of dam foundations in Tibet, China, lessened over time without any additional antiseepage measures. In fact, clogging generated during the infiltration process is recognized as the major factor in reducing leakage. A laboratory study was conducted to understand clogging in highly permeable coarse soil of a dam foundation with the primary aim of determining the clogging patterns and optimum clogging particle size (PS). Seven replicate experiments were constructed using soil media with PS ranges of 32–64 mm, 16–32 mm, 8–16 mm, 4–8 mm, 2–4 mm, 1-2 mm, and 0.5–1 mm to observe clogging after feeding the soil media with sediments of different PSs. The experimental results showed that four clogging patterns were formed in different PSs of the coarse foundation soil. The ratio of the effective aperture of the soil Dea and the equivalent clogging particle size dede/Dea had a dominant effect on the four clogging patterns (surface clogging, de/Dea>1; surface-internal clogging, 0.5<de/Dea≤1; internal partial pore blockage, 0.25<de/Dea≤0.5; and unclogging, de/Dea≤0.25). The assessment criterion of the optimum clogging pattern was determined by 0.5<de/Dea≤1, and from that, the optimum clogging PS do was calculated.


1988 ◽  
Author(s):  
Richard D. Eckerlin ◽  
Dennis Larson
Keyword(s):  

Author(s):  
Richard D. Weir ◽  
Trevor A. Kinley ◽  
Richard W. Klafki ◽  
Clayton D. Apps

This chapter is based on ecological information on 82 radio-tagged badgers (39 F, 43 M) among three study populations in British Columbia, Canada between 1996 and 2010, data that were collected to learn more about the ecology of badgers and consider how variation in their ecology might inform regional conservation strategies. The widely spaced, lower density prey and distribution of soil deposits suitable for digging in British Columbia likely required badgers to use substantially larger areas, relative to the core range, in which to acquire sufficient energy to survive and reproduce. Strikes from automobiles were the primary cause of death among all radio-tagged badgers and this source of mortality is pervasive throughout the limited distribution of badgers in British Columbia. Despite their potential for high fecundity, populations of badgers in British Columbia likely remain at considerable risk compared to those in the core of the species’ range.


2021 ◽  
Vol 768 (1) ◽  
pp. 012084
Author(s):  
Tao Sun ◽  
Baoquan Yang ◽  
Yuan Chen ◽  
Jianye Chen ◽  
Chun Tan

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.


2020 ◽  
Vol 12 (13) ◽  
pp. 5426
Author(s):  
Donghui Chen ◽  
Huie Chen ◽  
Wen Zhang ◽  
Chun Tan ◽  
Zhifa Ma ◽  
...  

The failure mechanism analysis of dam foundations is key for designing hydropower stations. This study analyses the rock masses in a sluice section, which is an important part of the main dam of the Datengxia Hydropower Station currently built in China. The stability of the sluice rock masses is predominantly affected by gentle through-going soft interlayers and steep structural fractures. Its foundation failure mechanism is investigated by means of a numerical method, i.e., Universal Distinct Element Code (UDEC) and the geomechanical model method. The modeling principle and process, and results for the rock dam foundation are introduced and generated by using the abovementioned two methods. The results indicate that the failure mechanism of the foundation rock masses, as characterized by gentle through-going and steep structural discontinuities, is not a conventional type of shear failure mechanism but a buckling one. This type of failure mechanism is verified by analyzing the deformation features resulting from the overloading of both methods and strength reduction of the numerical method.


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