Analisis Kestabilan Lereng Berdasarkan Kekuatan Geser Massa Batuan Terhadap Perubahan Kandungan Air Pada Tambang Batubara Di Area Blok Menyango

Mining activities is commonly to work with the problem of stability of rock mass, then befordesaining mine’s slope should know rock shear strength parameters, such as cohesion (c) andinternal friction angle value ( . Beside those parameters, also needed to know the impact ofwater content to the rocks. The water content will effect rock’s shear strength, proof by the rockcondition which is ductile when it is dry and soft when it is wet. Based on test results was doneusing sandstone with laboratory scale of direct shear test were analyzed using mohr – coulomband patton criteria (1966). It is known that the cohesion (c) of sandstone decreased from 510,35kPa at natural condition down to 133,75 kPa at wet condition. The internal friction angle ( ) alsodecreased from 54,56° at natural condition down to 48,45° at wet condition. The reduction of theshear strength is caused by fragments and clay minerals characteristics which are so reactiveand very easy to absorb water so that the cohesion of the sandstone reduce the active normalstress so that working the shear stress required to cause the shear failure becomeweaker. From the results, it is also known that the shear surface roughness had a lot ofinfluence on the shear strength the normal stresses applied on the direct shear tests werevery low under 20% of UCS.

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Comparison of Mechanical Properties of Fiber-Reinforced Sand under Triaxial Compression and Direct Shear

Open Geosciences ◽

10.1515/geo-2015-0041 ◽

2015 ◽

Vol 7 (1) ◽

Cited By ~ 7

Author(s):

Reza Noorzad ◽

Seyed Taher Ghoreyshi Zarinkolaei

Keyword(s):

Shear Strength ◽

Axial Strain ◽

Triaxial Compression ◽

Polypropylene Fiber ◽

Triaxial Tests ◽

Direct Shear ◽

Test Results ◽

Peak Reduction ◽

Shear Tests ◽

Direct Shear Tests

AbstractThis research investigates the behavior of sand reinforced with polypropylene fiber. To do this, 40 direct shear tests and 40 triaxial tests were performed on the coastal beaches of Babolsar, a city in the North of Iran. The effect of parameters such as fiber content, length of fiber and normal or confining pressure on the behavior of Babolsar sand have been studied. In this study, four various fiber contents (0, 0.25, 0.5 and 1 percent), three different lengths of fiber (6, 12 and 18 mm) and four normal or confining pressures (50, 100, 200 and 400 kPa) have been employed. The test results show that fiber inclusion has a significant effect on the behavior of sand. In both direct shear and triaxial tests, the addition of fibers improved shear strength parameters (C, '), increased peak shear strength and axial strain at failure, and also limited the amount of post-peak reduction in shear resistance. The comparison of the test results revealed that due to better fiber orientation toward the direction of principal tensile strain in triaxial test as compared to direct shear tests, the fiber efficiency and its effect on soil behavior is much more significant in triaxial specimens.

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Study on the Impact of Sand-Clay Bond in Geo-grid and Geo-Textile on Bearing Capacity

Journal of Sustainable Development ◽

10.5539/jsd.v9n6p83 ◽

2016 ◽

Vol 9 (6) ◽

pp. 83 ◽

Cited By ~ 1

Author(s):

Mohammadehsan Zarringol ◽

Mohammadreza Zarringol

Keyword(s):

Shear Strength ◽

Bearing Capacity ◽

Tensile Force ◽

Direct Shear ◽

Shear Tests ◽

Direct Shear Tests ◽

Increased Strength ◽

Reinforced Clay ◽

The Impact ◽

Total Shear

<p>This paper aims to determine the impact of sand-clay bond in geo-grid and geo-textile on bearing capacity. In doing so, we examined clay-geo-synthetics, sand-geo-synthetics and clay-sand-geo-synthetics samples using direct shear tests. The friction between clay and reinforcement was provided by encapsulated-sand system.</p><p>This method is used to transfer the tensile force mobilized in geo-synthetics from sand to clay and improve the strength parameters of clay. This study indicated that the provision of a thin layer of sand at both sides of the reinforcement significantly improved the shear strength of clay soil.</p>Bond coefficient computations indicated that the shear strength of clay-geo-synthetics samples was higher than non-reinforced clay. The increased strength was due to the impact of open meshes of geo-synthetics which provided some degree of resistance bearing. To determine the share of resistance bearing provided by geo-synthetic transverse members in the entire direct shear strength, we conducted a series of tests on geo-synthetics-reinforced samples with and without transverse members. The resistance bearing provided by geo-synthetic transverse members was almost 10% of total shear strength. The results indicated that encapsulated geo-grid and geo-textile sand system increased the bearing capacity of clay, with geo-grid being more efficient than geo-textile.

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Experimental Study on Shear Behavior of Short-Fill-Age MSW

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.479 ◽

2010 ◽

Vol 113-116 ◽

pp. 479-483

Author(s):

Li Sha Ma ◽

Huan Li Wang ◽

Wei Wang ◽

Zheng Wen Zhang

Keyword(s):

Shear Strength ◽

Shear Failure ◽

Friction Angle ◽

Exponential Model ◽

Hyperbolic Model ◽

Displacement Curve ◽

Shear Tests ◽

Direct Shear Tests ◽

Cohesion Force ◽

Coulomb Criterion

Mechanical behavior of municipal solid waste (MSW) is important to geo-environment engineering, and it is necessary to properly understand it. Laboratory direct shear tests were conducted on MSW with 3 short fill ages, namely 1d, 4d and 7d. Three different densities were taken into accounted in each fill age. Experimental data show that MSW’s shear failure still satisfies the Mohr-Coulomb criterion. As to bigger density, shear strength of MSW increases within 1-7d fill age. When density becomes smaller, its shear strength increases within 1-4d fill age but decreases within 4-7d fill age. With fill-age developing, friction angle of MSW increase monotonously, but cohesion force of it first increases and then decreases. Experimented shear stress-displacement curve of MSW can not be well fitted by either hyperbolic model or exponential model. This experimental research is helpful for design and numerical simulation of corresponding MSW landfill.

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Shear strength behaviour of sand-bentonite mixtures with pumice additivite under high temperature

E3S Web of Conferences ◽

10.1051/e3sconf/202020504004 ◽

2020 ◽

Vol 205 ◽

pp. 04004

Author(s):

Esra Güneri ◽

Yeliz Yükselen Aksoy

Keyword(s):

Shear Strength ◽

High Temperature ◽

Room Temperature ◽

Engineering Properties ◽

Direct Shear ◽

Test Results ◽

Soil Behavior ◽

Shear Tests ◽

Volume Deformation ◽

Direct Shear Tests

Depending on increase in the number and type of energy geostructures, studies on the change in soil behavior against heat increase becomes more important. The engineering properties such as permeability, volume deformation of surrounding soils around energy structures mustn’t alter in the presence of heat and thermal cycles. Pumice is a material used in many fields especially for thermal insulation. For that reason, pumice can be used for increasing the resistance of soils in the presence of heat. In this study, the shear strength behavior of sand-bentonite mixtures was investigated with pumice additive under high temperature. In the experiments, 10% and 20% pumice were added to 10% and 20% sand-bentonite mixtures and compaction, direct shear tests were conducted. The direct shear tests were performed both room temperature and under 80°C. The results have shown that the pumice additive increased the shear strength of sand-bentonite mixtures under high temperature when compared the test results under room temperature.

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

Journal of Advanced Engineering and Computation ◽

10.25073/jaec.202152.331 ◽

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.

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PEAT SOIL STABILIZATION IN RAWA PENING SALATIGA CENTRAL JAVA USING SYNTHETIC GYPSUM AND SALT

Jurnal Teknologi ◽

10.11113/jt.v81.12859 ◽

2019 ◽

Vol 81 (3) ◽

Author(s):

Niken Silmi Surjandari ◽

Noegroho Djarwanti ◽

Gunawan Prasetyo ◽

Febby Erianto

Keyword(s):

Shear Strength ◽

Soil Stabilization ◽

Soil Mechanics ◽

Peat Soil ◽

Dry Weight ◽

Friction Angle ◽

Soil Samples ◽

Direct Shear ◽

Shear Tests ◽

Direct Shear Tests

Peat is known as a problematic soil due to its low bearing capacity as well as its high and long settlement process. Necessary treatment is needed to improve peat soil capability. One of the methods to improve peat soil characteristics is by adding mixed materials. In this study the added materials are synthetic gypsum (CaSO4.2H20) and salt (NaCl). The research was conducted in a Soil Mechanics Laboratory using a consolidation test and direct shear tests. This research aims to find out the effect of CaSO4.2H20 and NaCl on consolidation and shear strength parameters. The soil samples taken for consolidation and direct shear tests were original and treated peat soil. The gypsum synthesis doses varied between 10%, 15%, and 20%, whereas the salt varied between 2%, 4%, and 6%, calculated from the dry weight of peat soil. The mixing of soil and the added materials was carried out under optimum water conditions of Standard Proctor compaction results. After the consolidation and direct shear tests were completed, the Scanning Electron Microscope (SEM) test was performed on the soil samples to determine the components of the peat soil on micron size. The addition of synthetic gypsum and salt resulted in the smallest Cc value of 0.0302 at 4% salt + 20% gypsum and the highest Cv value of 0.130 cm2/s at 6% salt + 20% gypsum. The addition of synthetic gypsum and salt mixture resulted in the highest cohesion, c value of 61,55 kPa at 6% salt + 15% gypsum and the greatest friction angle, ϕ value of 52.24° at 4% salt + 20% gypsum. NaCl gave better results than Gypsum in improving shear strength. A composition of 4%-6% of NaCl and 15%-20% of Gypsum is recommended, if NaCl and gypsum were to be applied simultaneously to improve shear strength.

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Experimental Study on the Reliability of Scaling Down Techniques Used in Direct Shear Tests to Determine the Shear Strength of Rockfill and Waste Rocks

CivilEng ◽

10.3390/civileng3010003 ◽

2022 ◽

Vol 3 (1) ◽

pp. 35-50

Author(s):

Akram Deiminiat ◽

Li Li

Keyword(s):

Experimental Study ◽

Particle Size ◽

Shear Strength ◽

Friction Angle ◽

Direct Shear ◽

Shear Tests ◽

Direct Shear Tests ◽

Field Samples ◽

Waste Rocks ◽

Scaling Down

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size (dmax) of tested samples for direct shear tests. To overcome this problem, a common practice is to prepare test samples by excluding the oversized particles. This method is called the scalping scaling down technique. Making further modifications on scalped samples to achieve a specific particle size distribution curve (PSDC) leads to other scaling down techniques. Until now, the parallel scaling down technique has been the most popular and most commonly applied, generally because it produces a PSDC parallel and similar to that of field material. Recently, a critical literature review performed by the authors revealed that the methodology used by previous researchers to validate or invalidate the scaling down techniques in estimating the shear strength of field materials is inappropriate. The validity of scaling down techniques remains unknown. In addition, the minimum required W/dmax ratio of 10, stipulated in ASTM D3080/D3080M-11 for direct shear tests, is not large enough to eliminate the specimen size effect (SSE). The authors’ recent experimental study showed that a minimum W/dmax ratio of 60 is necessary to avoid any SSE in direct shear tests. In this study, a series of direct shear tests were performed on samples with different dmax values, prepared by applying scalping and parallel scaling down techniques. All tested specimens had a W/dmax ratio equal to or larger than 60. The test results of the scaled down samples with dmax values smaller than those of field samples were used to establish a predictive equation between the effective internal friction angle (hereafter named “friction angle”) and dmax, which was then used to predict the friction angles of the field samples. Comparisons between the measured and predicted friction angles of field samples demonstrated that the equations based on scalping scaling down technique correctly predicted the friction angles of field samples, whereas the equations based on parallel scaling down technique failed to correctly predict the friction angles of field samples. The scalping down technique has been validated, whereas the parallel scaling down technique has been invalidated by the experimental results presented in this study.

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Analyses on the Differences of the Consolidated Quick Direct Shear Strength Index of the Silty Clay

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.1907 ◽

2011 ◽

Vol 71-78 ◽

pp. 1907-1910

Author(s):

Tian Yun Liu ◽

Ai Min Liu ◽

Zhi Fa Yu

Keyword(s):

Shear Strength ◽

Friction Angle ◽

Soil Samples ◽

Silty Clay ◽

Direct Shear ◽

Strength Index ◽

Shear Tests ◽

Direct Shear Tests ◽

Before And After ◽

Different Levels

It is found that great differences exist in the consolidated quick direct shear strength index of the silty clay based on several consolidated quick direct shear tests with different rate of shear. In this letter, the changes of the water-content coefficients of the soil samples before and after the tests are analyzed. The results indicate that the drain consolidation phenomenon exists during the consolidated quick direct shear tests. Different rates of shear are corresponding to different levels of drain consolidation, and then the strength index is different. Furthermore, the reason of the fact that the friction angle of the silty clay relatively increases with different rates of shear, while the cohesive strength decreases relatively is explained.

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Sand- and Clay-Photocured-Geomembrane Interface Shear Characteristics Using Direct Shear Test

Sustainability ◽

10.3390/su13158201 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8201

Author(s):

Lihua Li ◽

Han Yan ◽

Henglin Xiao ◽

Wentao Li ◽

Zhangshuai Geng

Keyword(s):

Soil Surface ◽

Friction Angle ◽

Direct Shear ◽

Tensile Crack ◽

Shear Tests ◽

Interface Shear ◽

Direct Shear Tests ◽

Carbon Black Powder ◽

Shear Characteristics ◽

Impermeable Layer

It is well known that geomembranes frequently and easily fail at the seams, which has been a ubiquitous problem in various applications. To avoid the failure of geomembrane at the seams, photocuring was carried out with 1~5% photoinitiator and 2% carbon black powder. This geomembrane can be sprayed and cured on the soil surface. The obtained geomembrane was then used as a barrier, separator, or reinforcement. In this study, the direct shear tests were carried out with the aim to investigate the interfacial characteristics of photocured geomembrane–clay/sand. The results show that a 2% photoinitiator has a significant effect on the impermeable layer for the photocured geomembrane–clay interface. As for the photocured geomembrane–sand interface, it is reasonable to choose a geomembrane made from a 4% photoinitiator at the boundary of the drainage layer and the impermeable layer in the landfill. In the cover system, it is reasonable to choose a 5% photoinitiator geomembrane. Moreover, as for the interface between the photocurable geomembrane and clay/sand, the friction coefficient increases initially and decreases afterward with the increase of normal stress. Furthermore, the friction angle of the interface between photocurable geomembrane and sand is larger than that of the photocurable geomembrane–clay interface. In other words, the interface between photocurable geomembrane and sand has better shear and tensile crack resistance.

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Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

Sustainability ◽

10.3390/su13147758 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7758

Author(s):

Biao Qian ◽

Wenjie Yu ◽

Beifeng Lv ◽

Haibo Kang ◽

Longxin Shu ◽

...

Keyword(s):

Shear Strength ◽

Void Ratio ◽

Soil Mass ◽

Direct Shear ◽

Test Results ◽

The Sustainable Development ◽

Direct Shear Tests ◽

Soil Cement ◽

Nano Clay ◽

New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

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