scholarly journals Effects of Clay and Moisture Content on Direct Shear Tests for Clay-Sand Mixtures

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Muawia A. Dafalla
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Direct Shear Test ◽  
Shear Test ◽  
Horizontal Displacement ◽  
Direct Shear ◽  
Shear Tests ◽  
Angle Of Internal Friction ◽  
Direct Shear Tests ◽  
Moisture Contents

The direct shear test using shear box is commonly recommended by practicing geotechnical engineers to obtain the cohesion and angle of internal friction for granular soils. The clay liners involve sand as a main constituent with added clay of variable proportions. This research aims at investigating the reliability of using the direct shear test for different clay contents and different moisture contents using an adequate shearing strain. These factors were found to affect the bilinear trends of shear force versus horizontal displacement profile as well as vertical displacement versus horizontal displacement curves. The cohesion of the mixture was found to increase consistently with the increase of clay content. Increase in moisture content was found to cause a drop in both cohesion and angle of internal friction. These changes are not independent of the density state of clay-sand mixtures. Standard compaction properties for a range of clay-sand mixtures were investigated. This work provides the general trends expected in direct shear tests for clay-sand mixtures of variable clay and moisture contents.

scholarly journals Direct Shear Test: Normal and Tangential Stresses Evaluation According to Constant and Variable Shearing Area

2016 ◽  
Author(s):  
Šarūnas Skuodis ◽  
Arnoldas Norkus
Keyword(s):  
Direct Shear Test ◽  
Shear Test ◽  
Test Procedure ◽  
Horizontal Displacement ◽  
Strength Properties ◽  
Direct Shear ◽  
Angle Of Internal Friction ◽  
Testing Procedures ◽  
Direct Shear Tests ◽  
Tangential Stresses

Investigations of soil shear strength properties for Baltic Sea shore sand along Klaipėda city is presented. Investigated sand angle of internal friction (φ) and cohesion (c) is determined via two different direct shear tests procedures. First procedure is standard and ordinary in geotechnical practice, when direct shear test is provided using constant shearing area. Second test procedure is different because shearing area according to horizontal displacement each test second is recalculated and reducing during horizontal movement. According to these two different testing procedures provided comparison of normal and tangential stresses.

scholarly journals Shear strength characteristics of Jerash expansive soil

2021 ◽  
Vol 3 (2) ◽  
pp. 74-80
Author(s):  
Talal Masoud
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Water Content ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soil ◽  
Content Increase ◽  
Direct Shear ◽  
Initial Water ◽  
Angle Of Internal Friction

The results of the direct shear test on Jerash expansive soil show the effect of the initial water content on the cohesion (c) and on the angel of internal friction ( ) [shear strength parameters].it show that, as the initial water increase, the cohesion (c) of Jerash expansive soil also increase up to the shrinkage limit, after that increase of water even small amount, decrease the cohesion of the soil. On the other hand, the results of direct shear test show also  that as the water content increase, the angle of internal friction ( )remain unchanged up to shrinkage limit , any increase of water cause a large decrease on the angle of internal friction of Jerash expansive soil.

Numerical Simulation of Interface Softening for Large Size Direct Shear Test

2011 ◽  
Vol 368-373 ◽  
pp. 3230-3235
Author(s):  
Zhao Yun Xiao ◽  
Wei Xu ◽  
Yan Sheng Deng ◽  
Fan Tu
Keyword(s):  
Numerical Simulation ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Model ◽  
Secondary Development ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Softening Behavior ◽  
Large Size

The interface of non-woven geotextile and HDPE geomembrane based on direct shear test has an obvious softening behavior. This paper adopts displacement-softening model that proposed by Esterhuizen and conducts secondary development by using ABAQUS and its embedded FRIC subroutine, making further efforts to conduct numerical simulation of interface of non-woven geotextile and HDPE geomembrane based on large-size direct shear tests. Results show that the developed interface friction model can simulate the characteristics of interface softening of certain materials better, thus providing a method when study the interface softening characteristic of materials.

scholarly journals Reliability Analysis of a Direct Shear Test of Modified Iron Tailings Based on the Monte Carlo Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ping Jiang ◽  
Jian Qian ◽  
Na Li
Keyword(s):  
Monte Carlo ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Direct Shear ◽  
Shear Tests ◽  
Type Curve ◽  
Direct Shear Tests ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

The resource utilization of iron tailings is of great significance for all countries in the world. Considering the particle composition and physicochemical characteristics of iron tailings, fiber and lime were used to modify iron tailings. The fiber content was 0%, 0.25%, 0.5%, 0.75%, and 1%, and the lime content was 0%, 2%, 4%, 8%, and 10%, respectively. Through a direct shear test, the shear stress displacement (τ-δ) curves and shear strength of modified iron tailings, under the action of a 0 freeze-thaw cycle and 1 freeze-thaw cycle, were tested. As statistics have shown that there are uncertainty factors associated with direct shear tests, the shear strength index cohesion c and internal friction angle φ of the modified iron tailings were analyzed using the Monte Carlo method. The results show that the τ-δ curve of the fiber-modified iron tailings is a hardening-type curve and that of the lime-modified iron tailings is a softening-type curve. In the direct shear tests, the main uncertain factors are the specimen diameter, vertical force, and horizontal force. The diameter of the sample obeys a normal distribution, and the vertical and horizontal forces obey a uniform distribution. The results of the Monte Carlo simulation show that both c and φ obey a normal distribution. Under a 95% confidence condition, the effect of fiber on the cohesion on iron tailings is obvious, but the effect on the internal friction angle is not obvious. However, the values of c and φ of the iron tailings are clearly improved by lime. Additionally, the iron tailings modified by a fiber content of 1% and those modified by a lime content of 8% have the best frost resistance.

scholarly journals Determination of the Effect of Soil Particle Size Distribution on the Shear Behavior of Sand

2021 ◽  
Vol 5 (2) ◽  
pp. 125
Author(s):  
Mohammad Afrazi ◽  
Mahmoud Yazdani
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Particle Sizes ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests

Many geotechnical problems require the determination of soil engineering properties such as shear strength. Therefore, the determination of the reliable values for this parameter is essential. For this purpose, the direct shear test, as one of the oldest tests to examine the shear strength of soils, is the most common way in laboratories to determine the shear parameters of soil. There are far too many variables that influence the results of a direct shear test. In this paper, a series of 10 × 10 cm direct shear tests were carried out on four different poorly graded sands with different particle size distributions to determine their shear behaviors. Four different poorly graded sands with a different median diameter or medium value of particle size distribution (D50) (0.2, 0.53, 1.3, and 2.3 mm) has been selected, and about 40 direct shear tests were conducted. It was concluded that a soil’s friction angle is affected by coarse-grained material. Accordingly, sandy soils with bigger particle sizes record a higher friction angle than soils containing small particles. The investigations also showed that sand with bigger particle sizes has a higher dilation angle. In addition, a non-linear regression analysis was performed to establish the exact relationship between the friction angle of the soil and the characteristics of the soil particles. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

scholarly journals Discrete Element Modelling of Rubber-Protected Ballast Performance Subjected to Direct Shear Test and Cyclic Loading

2020 ◽  
Vol 12 (7) ◽  
pp. 2836
Author(s):  
Yunlong Guo ◽  
Yameng Ji ◽  
Qiang Zhou ◽  
Valeri Markine ◽  
Guoqing Jing
Keyword(s):  
Direct Shear Test ◽  
Shear Test ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Discrete Element ◽  
Crumb Rubber ◽  
Discrete Element Modelling ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests

The rubber-protected ballast (RPB) is made from natural ballast particles and crumb rubber particles. The crumb rubber is shredded waste tires. RPB was chosen to replace the ballast as it has higher resistance to breakage and abrasion. However, the static and dynamic performance of the RPB has not been confirmed yet. Towards this end, experimental tests and numerical simulations were utilized to study the feasibility of RPB application. Direct shear tests (DSTs) were performed and a DST model and three-sleeper track model with the discrete element method (DEM) were built. The shear strength, settlement, displacement, and acceleration of the RPB were studied. The results show that the RPB has the advantage of increasing the force (stress) distribution and that the smaller crumb rubber size was more suitable for replacing the ballast particles.

The Determination of Young's Modulus from the Direct Shear Test

1972 ◽  
Vol 9 (4) ◽  
pp. 504-507 ◽  
Author(s):  
D. K. J. Noonan ◽  
J. F. Nixon
Keyword(s):  
Young’S Modulus ◽  
Direct Shear Test ◽  
Shear Test ◽  
Young's Modulus ◽  
Horizontal Displacement ◽  
Direct Shear ◽  
The Finite Element Method ◽  
Direct Shear Tests ◽  
The Relationship

A method is developed for determining Young's Modulus from a direct shear test. The finite element method is employed to compute stresses in a sample of rock subjected to direct shear. From the results of the analysis, the relationship between the shear load, horizontal displacement and the Young's Modulus is established for different sample geometries. The use of the solution is illustrated. Since direct shear tests are often used for strength testing the necessity for conducting alternative tests to determine the deformability characteristics of a rock mass is reduced.

Experimental Study on Shear Strength of Expansive Soil Improved by Lime - Weathered Sand

2013 ◽  
Vol 446-447 ◽  
pp. 1441-1447
Author(s):  
Meng Yun Huang ◽  
Jun Lai Xiong ◽  
Ji Bing Tang ◽  
Chi Long
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soil ◽  
Dry Density ◽  
Direct Shear ◽  
Mass Ratio ◽  
Angle Of Internal Friction ◽  
The Impact

This paper ananlyzes and contrasts the direct shear test of the expansive soil with different weathered sand dosage (mass ratio) and different lime dosage (mass ratio) in the case of the expansive soil with some water content and dry density .And try to analyzes and researches the impact of expansive soil improved by weathered sand and lime shear strength index . The direct shear test by the expansive soil mixed with different proportions of weathered sand and lime can be concluded that: mixing the weathered sand to improve the shear strength of expansive soil is effective, and cohesion gradually decreases with the increase of doped proportion of sand and the angle of internal friction first increases with the increase of doped proportion of sand and then decreases ;mixing of lime is effective to improve the shear strength of expansive soil, and cohesion gradually decreases with the increase of doped proportion of lime and angle of internal friction first increases and then decreases with the increase of doped proportion of lime. The shear strength of improved expansive soil can meet the subgrade filling with soil standards and at the same time the expansive soil improved by weathered sand and lime reduces the amount of lime and reduce project cost when to achieve the same shear strength standards.

Effect of Sample Size on TDA Shear Strength Parameters in Direct Shear Tests

2020 ◽  
Vol 2674 (9) ◽  
pp. 1110-1119 ◽  
Author(s):  
Khaled Zahran ◽  
Hany El Naggar
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Shear Tests ◽  
Strength Parameters ◽  
Angle Of Internal Friction ◽  
Direct Shear Tests ◽  
Shear Box ◽  
Box Dimensions

Tire-derived aggregate (TDA), a relatively new construction material, has been gaining acceptance as a backfill material for embankments, trenches, and earth-retaining structures because of its lightweight and excellent geotechnical properties. Type A TDA has a basic geometric shape, with particles approximately 12 to 100 mm in size. As a result of the simplicity and accuracy of the direct shear test, most laboratories choose this test in preference to more complex tests. However, TDA requires large-scale direct shear apparatus because of the consistently large size of its particles, and few facilities own this type of apparatus. Depending on the shear box dimensions, the aspect ratio of the particle size to the box dimensions may lead to variations in the shear strength results of the sample being evaluated. This research focuses on studying the effect of TDA sample size on the shear strength results of direct shear tests by using five different shear box sizes. The findings show that the angle of internal friction increases slightly as the dimensions of the shear box decrease. It was found that the maximum variation in the angle of internal friction and the cohesion results of the different shear boxes was only 1.9° and 2.4 kPa, respectively. These differences should be taken into consideration when TDA shear test results are used in the geotechnical design. It is recommended that a shear box with an aspect ratio (W/Dmax) greater than or equal to 4 should be used when evaluating the shear strength parameters of TDA.

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