Automated Shear Test on Reinforced Clayey Sand

2011 ◽  
Vol 261-263 ◽  
pp. 1019-1023 ◽  
Author(s):  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Shear Stress ◽  
Fiber Length ◽  
Shear Test ◽  
Natural Fiber ◽  
Fiber Content ◽  
Embankment Dam ◽  
Shear Tests ◽  
Clayey Sand ◽  
Direct Shear Tests ◽  
Strength Behavior

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on shear stress of composite soil (i.e. sand composite). A series of laboratory direct shear tests carried out to evaluate fiber effect on strength behavior of composite sand. Clayey sand was selected as soil part of the composite and natural fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length were changed from 20 mm to 50 mm and fiber content were varied from 0.5% and 6%.Normal stress kept constant at 200 kpa. For each test, stress_ displacement graph derived and the results were compared. The results proved that inclusion of fiber affected strength behaviour of sand composite so that increasing in fiber content and length caused increasing in shear stress.

scholarly journals Shear Test on Reinforced Clay

2011 ◽  
Vol 250-253 ◽  
pp. 3223-3227 ◽  
Author(s):  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Shear Stress ◽  
Fiber Length ◽  
Shear Test ◽  
Fiber Content ◽  
Embankment Dam ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Strength Behavior ◽  
Stress Behaviour ◽  
Reinforced Clay

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on shear stress of composite soil (i.e. clay composite). A series of laboratory direct shear tests carried out to evaluate fiber effect on strength behavior of composite clay. Clay was selected as soil part of the composite and plastic fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length were changed from 20 mm to 65 mm and fiber content were varied from 0.7% and 2%.Normal stress kept constant at 150 kpa. For each test, stress_ displacement graph derived and the results were compared. The results proved that inclusion of fiber affected shear stress behaviour of clay composite so that increasing in fiber content and length caused increasing in shear stress.

Composite Clayey Sand and Short Fiber

2011 ◽  
Vol 383-390 ◽  
pp. 2764-2769 ◽  
Author(s):  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Shear Stress ◽  
Fiber Length ◽  
Short Fiber ◽  
Fiber Content ◽  
Direct Shear ◽  
Embankment Dam ◽  
Shear Tests ◽  
Clayey Sand ◽  
Direct Shear Tests ◽  
Strength Behavior

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on shear stress of composite soil (i.e. sand composite). A series of laboratory direct shear tests carried out to evaluate fiber effect on strength behavior of composite sand. Clayey sand was selected as soil part of the composite and glass fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length were changed from 10 mm to 35 mm and fiber content were varied from 0.6% and 3%.Normal stress kept constant at 150 kpa. For each test, stress_ displacement graph derived and the results were compared. The results proved that inclusion of fiber affected strength behaviour of sand composite so that increasing in fiber content and length caused increasing in shear stress.

Waste Paper Application in Geotechnical Project

2012 ◽  
Vol 535-537 ◽  
pp. 2148-2153
Author(s):  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Shear Stress ◽  
Kaolin Clay ◽  
Direct Shear ◽  
Reinforcement Effect ◽  
Embankment Dam ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Reinforcement Content ◽  
Strength Behavior ◽  
Clay Kaolin

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on shear stress of composite soil (i.e. clay composite). A series of laboratory direct shear tests carried out to evaluate paper reinforcement effect on strength behavior of composite clay. Kaolin clay was selected as soil part of the composite and paper was used as reinforcement. The paper reinforcement parameters differed from one test to another, the paper length was changed from 10 mm to 30 mm and paper content were varied from 5% to 15%. Normal stress kept constant at 150 kPa. For each test, stress_ displacement graph derived and the results were compared. The results proved that inclusion of paper reinforcement affected strength behaviour of clay composite so that increasing in paper reinforcement content and length caused increasing in shear stress.

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 Using Post-Harvest Waste to Improve Shearing Behaviour of Loess and Its Validation by Multiscale Direct Shear Tests

2019 ◽  
Vol 9 (23) ◽  
pp. 5206 ◽  
Author(s):  
Wen-Chieh Cheng ◽  
Zhong-Fei Xue ◽  
Lin Wang ◽  
Jian Xu
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Strain Hardening ◽  
Gradual Increase ◽  
Small Scale ◽  
Optimal Dosage ◽  
Direct Shear ◽  
Shear Tests ◽  
Post Harvest ◽  
Direct Shear Tests

Loess and PHW (post-harvest waste) are easily accessible in the Chinese Loess Plateau and have been widely applied to construction of residential houses that have been inhabited for decades under the effect of freeze-thaw cycles. Although many researchers have recognised that the addition of fibers to loess soil is effective in preventing soil erosion and stabilising slopes, a consensus on this claim has not been reached yet. This study investigates the shearing behaviour of the loess-PHW mixture using small-scale and large-scale direct shear (SSDS and LSDS) tests. Four typical shear stress versus horizontal displacement curves from the multiscale direct shear tests are recognised where one is featured with strain-softening shape and the other three with a strain-hardening shape. Two out of the three curves with strain-hardening shape show a gradual increase in the shear stress at additional and larger displacements, respectively, in which some factor starts to have an influence on the shearing behaviour. Comparisons of the shear strength measured in SSDS and LSDS are made, indicating that there are differences between SSDS and LSDS. The effect of PHW addition on shear strength is assessed in order to determine the optimal dosage. The improvement of shear strength is attributed to the effect of particle inter-locking, resulting from the addition of PHW to loess specimens, and takes effect as the water content surpassed a threshold, i.e., >14%, that facilitates particle rearrangement. Particle-box interaction behaviour is assessed at the same time, and the findings satisfactorily address the main cause of the gradual increase in shear stress following the curve inflection point. The improved shearing behaviour proves the ability of the loess-PHW mixture to resist the seepage force and consequently stratum erosion.

Geotechnical Parameters of Composite Soil

2011 ◽  
Vol 308-310 ◽  
pp. 1651-1655 ◽  
Author(s):  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Natural Fiber ◽  
Fiber Content ◽  
Unit Weight ◽  
Embankment Dam ◽  
Geotechnical Parameters ◽  
Dry Unit Weight ◽  
Optimum Water Content ◽  
Compaction Characteristic ◽  
Optimum Water ◽  
Compaction Behaviour

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on compaction characteristic of composite soil (i.e. clay composite). A series of laboratory tests carried out to evaluate fiber effect on optimum water content and maximum dry unit weight of composite soils. Clay was selected as soil part of the composite and natural fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length varied from 10 mm to 25mm and fiber content were selected as 0.1% and 0.3%. For each test, compaction curved derived and the results were compared. The results proved that inclusion of fiber affected compaction behaviour of samples so that increasing in fiber content and length caused increasing in Optimum Moisture Content (OMC) and slightly decreased maximum dry unit weight.

scholarly journals Pile Side Resistance in Sands for the Unloading Effect and Modulus Degradation

2019 ◽  
Vol 69 (334) ◽  
pp. 185 ◽  
Author(s):  
C. F. Zhao ◽  
Y. Wu ◽  
C. Zhao ◽  
Q. Z. Zhang ◽  
F. M. Liu ◽  
...  
Keyword(s):  
Shear Stress ◽  
Maximum Amount ◽  
Interface Roughness ◽  
Direct Shear ◽  
Shear Tests ◽  
Interface Shear ◽  
Direct Shear Tests ◽  
Side Resistance ◽  
Unloading Effect ◽  
Concrete Interface

A total of 36 groups of sand-concrete interface loading and unloading direct shear tests were used to analyze the mechanical properties of the pile side-soil interface. The test results show that the interface residual shear stress for the same applied normal stress tends to be constant for the rough sand-concrete interface. The initial shear modulus and peak shear stress of the interface both decrease with the degree of unloading and increase with the interface roughness. The maximum amount of interface shear dilatancy increases with the degree of unloading, and the maximum amount of interface shear shrinkage decreases with unloading for the same interface roughness. A pile side resistance-displacement model is established using the shear displacement method. The proposed function considers both the radial unloading effect and modulus degradation of soil around the pile. The effect of radial unloading and interface roughness on the degradation of the equivalent shear modulus is analyzed using a single fitting parameter b. Good agreement of the proposed model is confirmed by applying the direct shear tests of the 36 groups.

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.

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