scholarly journals Non-cohesive Soil Direct Shear Strength Affected with Hydrostatic Pressure

2017 ◽  
Vol 9 (5) ◽  
pp. 520-523
Author(s):  
Tadas Tamošiūnas ◽  
Šarūnas Skuodis
Keyword(s):  
Hydrostatic Pressure ◽  
Baltic Sea ◽  
Research Work ◽  
Cohesive Soil ◽  
Pressure Change ◽  
Direct Shear ◽  
Angle Of Internal Friction ◽  
Testing Procedures ◽  
Direct Shear Tests ◽  
Shearing Strength

This paper presents first results of non­cohesive soil direct shear tests with hydrostatic pressure. To reach this aim, it was chosen the Baltic Sea Klaipėda sand, due to granulometry composition and particles shape. According to this, investigated Baltic Sea sand can be called Lithuanian standard sand for scientific testing. Analysis of results revealed, that when it is increased hydrostatic pressure, the shearing strength is also increasing. Comparing air­ dry sand results with fully saturated sand and affected with 100 kPa of hydrostatic pressure, the angle of internal friction increased for 21,24%. Meanwhile, the cohesion was not changing so dramatically according to hydrostatic pressure change. Obtained results allows to proceed this research work more detailed with different loading types, testing procedures and hydrostatic pressures.

scholarly journals Reconstruction of Holocene marine sand natural hydrostatic pressure and its relation with shearing strength

Baltica ◽  
2019 ◽  
Vol 32 (2) ◽  
pp. 182-189
Author(s):  
Šarūnas Skuodis ◽  
Gintaras Žaržojus ◽  
Tadas Tamošiūnas ◽  
Neringa Dirgėlienė
Keyword(s):  
Hydrostatic Pressure ◽  
Experimental Testing ◽  
Sand Sample ◽  
Direct Shear ◽  
Angle Of Internal Friction ◽  
Direct Shear Tests ◽  
Marine Sand ◽  
Shearing Strength

This research paper represents interpretation of engineering geological and geotechnical conditions by using a direct shear device with a possibility to apply hydrostatic pressure during the experimental testing. In the authors’ opinion, the evaluation of in-situ hydrostatic pressure and reconstruction of it in the laboratory tests is a very important step in the determination of the engineering geological and geotechnical properties of the sand strength and its behaviour. To understand the influence of hydrostatic pressure on shearing strength results, there were performed direct shear tests with and without hydrostatic pressure. Obtained results clearly show the differences in the shearing strength analysed during this study. When the investigated sand sample was loaded with maximum hydrostatic pressure (σH = 100 kPa), the peak value of the angle of internal friction (ϕ’mean) was 21.24% higher compared to that of dry soil. No tendencies were found for cohesion.

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 DIRECT SHEAR TESTS WITH EVALUATION OF VARIABLE SHEARING AREA / TIESIOGINIO KIRPIMO BANDYMAI ĮVERTINANT KINTAMĄ KERPAMĄJĮ PLOTĄ

2014 ◽  
Vol 6 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Šarūnas Skuodis ◽  
Tadas Tamošiūnas
Keyword(s):  
Test Procedure ◽  
Horizontal Displacement ◽  
Strength Properties ◽  
Direct Shear ◽  
Shear Tests ◽  
Angle Of Internal Friction ◽  
Testing Procedures ◽  
Direct Shear Tests ◽  
Tangential Stresses ◽  
Soil Shear Strength

Investigations of soil shear strength properties for Baltic Sea shore sand along Klaipėda city are 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 A0. Second test procedure is different because shearing area according to horizontal displacement each test second is recalculated. This recalculated shearing area author’s call corrected shearing area A. Obtained normal and tangential stresses’ difference via two different testing procedures was 10%. Šiame straipsnyje yra pristatyta idėja, kaip įvertinti grunto kerpamojo stiprumo parametrus, t. y. vidinės trinties kampą (φ) ir sankibą (c). Eksperimentiniams bandymams atlikti buvo naudotas Baltijos jūros pakrantės smėlinis gruntas ties Klaipėda. Grunto tiesioginio kirpimo bandymai atlikti dviem skirtingomis kirpimo metodikomis. Pirmoji metodika yra standartizuota ir įprasta atliekant geotechninius tyrimus, kai kerpamasis plotas yra vertinamas kaip pastovus plotas A. Antroji kirpimo metodika skiriasi nuo pirmosios grunto kirpimo ploto įvertinimu. Antrojoje metodikoje grunto kerpamasis plotas yra perskaičiuojamas tiesiogiai pagal horizontalųjį poslinkį. Horizontaliojo poslinkio indikatoriaus rodmenys yra registruojami kiekvieną sekundę, todėl kas sekundę yra perskaičiuojamas vis naujas grunto kerpamasis plotas. Atliekant bandymus skirtingomis metodikomis, nustatytas vertikalaus normalinio ir tangentinio įtempių skirtumas, kuris apytiksliai lygus 10 %.

Study on the Effect of Water Content on Shearing Strength Parameters of Unsaturated Loess

2014 ◽  
Vol 638-640 ◽  
pp. 585-588 ◽  
Author(s):  
Si Zhong Qian
Keyword(s):  
Internal Friction ◽  
Water Content ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Micro Particles ◽  
Shearing Strength ◽  
Unsaturated Loess

This paper experiments on typical Malan loess, performs consolidated quick direct shear tests under different water contents by conventional direct shear apparatus, then analyzes the effects of water content on shearing strength parameters, namely cohesion and internal friction angle. The results show that cohesion decreases linearly as the water content increasing, and the relation could be obtained by data fitting. However, internal friction angle keeps basically stable with the increase of water content. Finally, based on the force analysis for micro particles, the changing rules of cohesion and internal friction angle with water content were deeply explained.

scholarly journals Permeability and Direct Shear Tests Characteristics of Railway Subballast

2015 ◽  
Vol 9 (1) ◽  
pp. 388-393 ◽  
Author(s):  
Guoqing Jing ◽  
Zijie Wang ◽  
Hongmei Huang ◽  
Yan Wang
Keyword(s):  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Large Size ◽  
Shearing Strength ◽  
Coefficient Of Uniformity ◽  
Drainage Capacity ◽  
Constant Head ◽  
Highly Correlated ◽  
Good Drainage

Permeability, filtration and shearing strength were widely considered to be the key properties in evaluating the performance of railway subballast. An investigation on these key properties of railway subballast was presented in this paper. A constant head permeability test and a middle scale direct shear test of railway subballast were conducted in the research, aiming to investigate the subballast permeability and shear direct tests characteristics. Four different designed gradations within the standards were subjected to the investigation in order to study the particle size distribution effect on permeability performance of subballast. Lab results showed that drainage capacity and shearing strength of subballast highly correlated with each other. Subballast with more large-size particles and a low coefficient of uniformity were proved to acquire good drainage of water and strong resistance ability to shear.

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.

scholarly journals Study on the Effects of Grouting and Roughness on the Shear Behavior of Cohesive Soil–Concrete Interfaces

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3043
Author(s):  
You-Bao Wang ◽  
Chunfeng Zhao ◽  
Yue Wu
Keyword(s):  
Shear Band ◽  
Friction Angle ◽  
Cohesive Soil ◽  
Shear Behavior ◽  
Direct Shear ◽  
Direct Shear Tests ◽  
Apparent Cohesion ◽  
Post Grouting ◽  
Vertical Bearing ◽  
Direct Shear Apparatus

Grouted soil–concrete interfaces exist in bored piles with post-grouting in pile tip or sides and they have a substantial influence on pile skin friction. To study the effect of grouting volume on the shearing characteristics of the interface between cohesive soil and concrete piles with different roughness, grouting equipment and a direct shear apparatus were combined to carry out a total of 48 groups of direct shear tests on cohesive soil–concrete interfaces incorporating the grouting process. The test results showed that the shear behavior of the grouted cohesive soil–concrete interface was improved mainly because increasing the grouting volume and roughness increased the interfacial apparent cohesion. In contrast, increasing the grouting volume and roughness had no obvious increasing effects on the interfacial friction angle. Interfacial grouting contributed to the transition in the grouted cohesive soil from shrinkage to dilation: as the grouting volume increased, the shrinkage became weaker and the dilation became more obvious. The shear band exhibited a parabolic distribution rather than a uniform distribution along the shearing direction and that the shear band thickness was greater in the shearing direction, and it will become thicker with increasing grouting volume or roughness. The analysis can help to understand the shear characteristics of soil–pile interface in studying the vertical bearing properties of pile with post-grouting in tip or sides.

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.

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