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Published in J. Russell Boulding, Epa Environmental Engineering Sourcebook, 2019
The major engineering soil properties that must be defined are shear strength and hydraulic conductivity. Shear strength may be determined with the unconfined compression test (ASTM D2166), direct shear test (ASTM D3080), or triaxial compression test (ASTM D2850). Hydraulic conductivity of soils may be measured in the laboratory with either ASTM D2434 or D5083. Field hydraulic conductivity tests are generally recommended and may be performed, prior to actual cover construction on test pads to ensure that the low-permeability requirements can actually be met under construction conditions. EPA strongly encourages the use of test pads [3; 4].
Offshore site investigation
Published in White David, Cassidy Mark, Offshore Geotechnical Engineering, 2017
The direct shear test, also referred to as a shear-box test, is one of the simplest and most commonly used apparatus to investigate the shear strength and shear stress– strain behaviour of a soil sample. A low aspect ratio cylindrical or rectangular soil sample (typically 60 mm × 60 mm in plan and 20 mm thick) is placed inside a split box (Figure 3.62). A vertical stress is applied by dead-weights on a hanger and shearing is achieved by a motor driven ram acting on the bottom half of the box. The lateral force Fh required to hold the top half of the box stationary is measured by a load cell or proving ring.
Measuring stiffness of soils in situ
Published in Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto, Computer Methods and Recent Advances in Geomechanics, 2014
Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto
ASTM D3080, Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained Conditions, ASTM International, West Conshohocken, USA. Bajaj, I. B., Survase, S. A., Saudagar, P. S., and Singhal, R. S. (2007). Gellan Gum: Fermentative Production, Downstream Processing andA pplications. Food Technology and Biotechnology, 45(4), 341-354.
Characteristics, numerical analysis and countermeasures of mud inrush geohazards of Mountain tunnel in karst region
Published in Geomatics, Natural Hazards and Risk, 2023
Long-Long Chen, Zhi-Feng Wang, Wu Zhang, Ya-Qiong Wang
The soil parameters of clay failed in karst cave can obtained from in-situ and laboratory tests. The shear strength of the clay filled in the karst cave directly affects the stability of the filling in the karst cave. The direct shear test is a method to determine the shear strength of the soil. After the test, collate the derived data and draw the shear stress shear displacement curve. Draw the shear strength line of soil mass direct shear test with confining pressure as the horizontal axis and shear strength as the vertical axis, and obtain the cohesion of clay shear strength c = 34.4 kPa and internal friction angle φ = 16°. The water content in clay has a significant impact on the properties of clay and the characteristics of mud inrush geohazard (Yang and Juanes 2018; Yang et al. 2019; Li et al. 2022). The test and analysis of the samples of the clay in karst cave show that the average natural water content of the clay was 12.03%, and the average natural density was 2.19 g/cm3. Mechanical properties of clay in the karst cave are shown in Table 1.
A laboratory investigation on the effect of crushability on the interface parameters of Hormoz carbonated soil
Published in Marine Georesources & Geotechnology, 2022
Alireza Ahadi, Habib Shahnazari, Mehran Karimpour-Fard
The direct shear test is a suitable apparatus to determine the shear strength parameters of granular soils. The fixed location of the shearing plane in this test is an advantage in determining shear resistance along the predetermined planes and interfaces between dissimilar materials. The schematic shape of the interface shear test which is employed in this study is shown in Figures 1 and 2. The upper section of the shear box, filled with soil has the following dimensions: 10 × 10 × 3 cm. The lower part is filled with the materials to be studied. After applying the desired normal stress and before shearing is started, the top shear box is raised with respect to the bottom box by rotating the gap screws fitted in the corners of the upper shear box clockwise. This is continued until the gap thickness between the top and bottom boxes is equal to the diameter of the largest sand particle in the sample (ASTM 3080 2011). Then, the gap screws are removed before shearing is initiated.
Mechanical properties of calcareous silts in a hydraulic fill island-reef
Published in Marine Georesources & Geotechnology, 2021
Xing Wang, Jie Cui, Yang Wu, Changqi Zhu, Xinzhi Wang
Soil is a discrete material composed of solids, liquids, and gases. Under external loading, the stress state of the soil changes. When the soil is subjected to a shear stress exceeding its own shear strength, the soil undergoes shear failure, which is expressed as the movement of the soil along a sliding rupture surface at the macroscopic level. The direct shear test is a common method of measuring the shear strength of the soil in the laboratory. During the direct shear test, by applying a horizontal shear force to soil samples subjected to different normal stresses, the shear strength under the condition of a fixed shear plane is measured. In addition, based on the Mohr-Coulomb theory, the relationship between the shear strength and the normal stress of the soil sample is studied, and the strength parameters (c, φ) of the soil sample are calculated to determine its mechanical properties. These results provide the basic information required to estimate the bearing capacity of the foundation, to evaluate the stability of the foundation and slope, and to calculate the pressure on the retaining wall. Due to its clear theoretical basis and convenient operation, the direct shear test has been widely used in engineering practices (Wei 1999; Shen, Fang, and Chen 2010; Hu, Mei, and Wang 2013; Wang, Wang, Jin, et al. 2017; Wang, Wang, et al. 2019). In view of this, direct shear tests were conducted to explore the effects of water content and dry density on the strength characteristics of calcareous silt in this paper.