scholarly journals Experimental Study on the Shearing Behaviour on the Interface between Coarse Sand and Concrete under High Stress

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Junkun Tan ◽  
Jiaqi Guo ◽  
Shifan Qiao ◽  
Changrui Dong ◽  
Ziyong Cai ◽  
...  
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Normal Stress ◽  
High Stress ◽  
Shear Stiffness ◽  
Coarse Sand ◽  
Shear Behaviour ◽  
Hyperbolic Model ◽  
Displacement Curve ◽  
Ultimate Shear Strength

The shear behaviour on the interface between soil and structure is a research hot point. Based on the RMT-150B rock mechanics test system, a series of high-stress direct tests were performed on the coarse sand under the condition of different moisture contents and concrete substrates with different rough and hardness. The results showed that the shear stress-displacement curve and volumetric strain-displacement curve of the interface under high stress could be fitted by a hyperbolic model; the ultimate shear strength and initial shear stiffness of the interface both increased with the normal stress while the shear stiffness decreased with the shear displacement. The crushing rate of the coarse sand particles on the interface increased with the normal stress. After the range analysis for the influencing factors of the interface’s shearing behaviour, it was shown that for the ultimate shear strength, their sequence of influencing degree was normal stress, the roughness of interface, moisture content, and hardness of concrete base; for the initial shear strength, the sequence was normal stress, moisture content, interface roughness, and basal hardness. As for dry sand, the possibility of relative particle crushing was higher than that of sand with a moisture content of 8%, and a peak of crushing occurred when the moisture content was 16%.

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

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.

Numerical Simulation for Shear Characteristics of Rock-Mass Structural Plane

2013 ◽  
Vol 734-737 ◽  
pp. 574-578
Author(s):  
Bao Yuan Yuan ◽  
Qi Wang ◽  
Hai Feng Lu
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Friction Angle ◽  
Normal Displacement ◽  
Displacement Curve ◽  
Peak Shear Strength ◽  
Structural Plane ◽  
Linear Feature ◽  
Stress And Deformation ◽  
The Stability

The characteristics of structural plane are very important to the stability of rock mass.In this paper,the stress and deformation characteristics of structural plane under direct shear conditions are analyzed based on FLAC3D code.And the influence of structural plane inhomogeneity to shear test was discussed.The results obtained in this paper indicate that, with the increase of normal stress, the shear strength of structural plane is constantly increasing,and the tow of them presents linear feature significantly. The normal displacement and shear displacement increase with the rise of the normal stress too. The peak shear strength increases gradually on the condition of uneven friction angle in the interface. This situation changes smaller when the discrete degree of friction angle is small. The peak shear strength increases significantly when the discrete degree of friction angle is big,and the stress-displacement curve exhibits a nonlinear characteristics before yield.

scholarly journals Shear strength of bonded concrete-granite joints under constant normal stress conditions

2019 ◽  
Vol 92 ◽  
pp. 13014
Author(s):  
Matthieu Briffaut ◽  
Bassel El Merabi ◽  
Frédéric Dufour ◽  
Grégory Coubard
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Roughness Parameter ◽  
Stress Conditions ◽  
Shear Behaviour ◽  
Bonded Joints ◽  
Test Results ◽  
Direct Shear Tests ◽  
Joint Surfaces ◽  
Granite Samples

The shear behaviour of bonded concrete-granite joints under constant normal stress conditions is experimentally investigated in this paper. Concrete was prepared following standard mix used in pre-existing dams in France and poured on granite samples with a natural surface roughness. Before the direct shear tests, the joint surfaces were scanned by a laser profilometer to obtain the 3D morphology features. By analysing the shear test results, no direct correlations were found between the shear strength of bonded joints and classical roughness parameter.

scholarly journals Numerical Analysis on Shear Behavior of Joints under Low Confining and Eccentric Loads

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Gongfa Chen ◽  
Zhuangcheng Fang ◽  
Shaodi Wang ◽  
Haibo Jiang ◽  
Hualian Liang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Precast Concrete ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Displacement Curve ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Ultimate Shear Strength ◽  
Eccentric Load

The joints of precast concrete segmental beams (PCSBs), which are in complex stress status and susceptible to failure, are very important parts of the structure. In this paper, a finite element model was established to study the shear performance of single-keyed joints. The plastic damage model was used to simulate the cracking of specimens. Three types of single-keyed joints were investigated, including the dry joint with normal concrete (NC), dry joint with steel fiber-reinforced concrete (SFRC), and epoxied joint with NC. The cracking pattern, ultimate shear strength, and load-displacement curve for these specimens were obtained. Based on these numerical simulation models, extended analyses in terms of low confining pressures and eccentric loads were performed. It has been found that the influence of fiber-reinforced concrete should be considered. The ultimate shear strength of specimens reduced with the reduction of confining pressure. When an eccentric load was applied, a lower shear capacity would be obtained. Under the low confining stress, the AASHTO LRFD 2014 provision underestimated the shear strength of single-keyed dry joints with both NC and SFRC, while the shear capacity of single-keyed dry joints with both NC and SFRC has been overestimated under the eccentric loads.

scholarly journals Laboratory pullout resistance of a new screw soil nail in residual soil

2018 ◽  
Vol 55 (5) ◽  
pp. 609-619 ◽  
Author(s):  
H. Tokhi ◽  
G. Ren ◽  
J. Li
Keyword(s):  
Shear Strength ◽  
Practical Importance ◽  
Shear Behaviour ◽  
Residual Soil ◽  
Ultimate Shear Strength ◽  
Interface Shear ◽  
Soil Nail ◽  
Testing Procedures ◽  
Pullout Load ◽  
And Performance

The ultimate shear strength at the interface between the soil nail and surrounding soil is of practical importance in the design and performance of a soil nail system. The most commonly adopted method of measuring this interface shear strength is by soil nail pullout testing. This study introduces a novel soil nail system in the form of a screw nail and compares its performance with a conventional grouted soil nail. Both types of soil nails are tested in a controlled laboratory setting using residual soil in a large purpose-made pullout box. The development of the screw nail and the laboratory testing procedures are briefly discussed first, followed by presentation and discussion of the results of the interface shear behaviour measured from pullout tests. It is shown that the screw nail offers many advantages in terms of pullout load–displacement behaviour and the interface shear mechanism than that of the conventional grouted soil nail.

Triaxial Compression of a Cohesive Soil with Effective Octahedral Normal Stress Control

1965 ◽  
Vol 2 (1) ◽  
pp. 40-52 ◽  
Author(s):  
R L Kondner ◽  
J M Horner
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Triaxial Compression ◽  
Cohesive Soil ◽  
Deviatoric Stress ◽  
Strain Response ◽  
Compression Tests ◽  
Ultimate Shear Strength ◽  
Stress Strain ◽  
Stress Control

The influence of the first invariant of the effective stress tensor upon the deviatoric response of a cohesive soil is investigated. Triaxial compression tests with effective octahedral normal stress control show the deviatoric stress-strain response to be definitely affected by the value of the effective octahedral stress, [Formula: see text]. The values of [Formula: see text] range from 7.5 psi to 30.0 psi. For a constant value of strain, the deviatoric stress increases with an increase in [Formula: see text]. The ultimate shear strength can be approximated as a linear function of [Formula: see text]. Hyperbolic representation of the stress-strain response provides a convenient method for obtaining a measure of the ultimate shear strength using the response of stress states other than failure. The deviatoric stress-strain response as a function of the effective octahedral stress, [Formula: see text], can be expressed in the normalized form[Formula: see text]where ε is the strain, [Formula: see text] is a measure of the shear strength expressed in terms of [Formula: see text] , and A as well as B are numerical coefficients.

Experimental Study on Shear Mechanical Characteristics of Soil-Structure Interface under Different Normal Stress

2011 ◽  
Vol 243-249 ◽  
pp. 2332-2337 ◽  
Author(s):  
Hong Chun Xia ◽  
Guo Qing Zhou ◽  
Ze Chao Du
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Soil Structure ◽  
Mechanical Characteristics ◽  
Shear Displacement ◽  
Interface Roughness ◽  
Displacement Curve ◽  
Direct Shear ◽  
High Normal Stress

The direct shear mechanical characteristics of soil-structure interface under different experimental condition were studied systematically using the DRS-1 high normal stress direct and residual shear apparatus. The results show that the normal stress is an important factor which determines the mechanical characteristics of soil-structure interface. The curve of shear stress-shear displacement presents strain softening when the normal stress<3MPa, linear hardening when =3~5MPa and strain hardening when12MPa, separately. At the same time, the volume of the soil expands when <3MPa and contracts when >3MPa. But the volume of the soil expands and contracts simultaneously during the process of direct shear when =3MPa.The roughness of the interface influences not only the shape of the shear stress-shear displacement curve but also the shear strength of the interface. Under same normal stress condition，the shear strength of interface increases with the roughness but the influence degree of interface roughness reduces gradually with the increase of normal stress. The grain breakage degree is different under different normal stress. It increases evidently with the increase of normal stress.

scholarly journals Effect of Cobble Content on the Shear Behaviour of Sand-Cobble Mixtures

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Chuang Wang ◽  
Jinyu Dong ◽  
Zhiquan Huang ◽  
Jianjun Zhou ◽  
Jihong Yang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Large Scale ◽  
Shear Displacement ◽  
Shear Behaviour ◽  
Normal Displacement ◽  
Displacement Curve ◽  
Control Effect ◽  
Angle Of Internal Friction

The sand and cobble stratum is a kind of mechanically unstable stratum. Shield machine often encounter problems such as difficulty in excavation, cutterhead wear, and poor slag discharge of the spiral dumper while constructing in this kind of stratum. Considering the complexly and variety of the material composition and structure of this stratum, the sand and cobble stratum in China, Chengdu Subway Line 7, Chadianzi-Yipintianxia Station, was selected to conduct indoor large-scale direct shear tests to systematically study the effects of cobble content (CC) on the shear strength and shear properties of sand and cobble soil. The test results showed that the shear strength and angle of internal friction of sand and cobble soil nonlinearly increased with CC, and the shear strength and angle of internal friction slightly increased when CC was less than 40%. The shear strength and angle of internal friction of sand and cobble soil significantly increased after CC reaching 40%. The shear stress-shear displacement curve has three stages, including the elastic deformation stage, yield stage, and hardening stage. The CC had a control effect on the strength and deformation characteristics of sand and cobble soil. The shear stress-displacement curve of sand and cobble soils with CCs of 20% and 80% can be fitted as an exponential model, while the shear stress shear displacement curves of sand and cobble soils with CCs of 40% and 60% are hyperbolic. For sand and cobble soil with same CC, the larger the vertical stress is, the larger the normal displacement is.

scholarly journals Numerical Simulation of the Shear Behaviour of Cement Grout

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jianhang Chen ◽  
Fan Zhang ◽  
Hongbao Zhao ◽  
Junwen Zhang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Stress Distribution ◽  
Normal Stress ◽  
Shear Failure ◽  
Cement Grout ◽  
Shear Stress Distribution ◽  
Shear Behaviour ◽  
Direct Shear ◽  
Failure Plane

Cement grout is widely used in civil engineering and mining engineering. The shear behaviour of the cement grout plays an important role in determining the stability of the systems. To better understand the shear behaviour of the cement grout, numerical direct shear tests were conducted. Cylindrical cement grout samples with two different strengths were created and simulated. The numerical results were compared and validated with experimental results. It was found that, in the direct shear process, although the applied normal stress was constant, the normal stress on the contacted shear failure plane was variable. Before the shear strength point, the normal stress increased slightly. Then, it decreased gradually. Moreover, there was a nonuniform distribution of the normal stress on the contacted shear failure plane. This nonuniform distribution was more apparent when the shear displacement reached the shear strength point. Additionally, there was a shear stress distribution on the contacted shear failure plane. However, at the beginning of the direct shear test, the relative difference of the shear stresses was quite small. In this stage, the shear stress distribution can be assumed uniform on the contacted shear failure plane. However, once the shear displacement increased to around the shear strength point, the relative difference of the shear stresses was obvious. In this stage, there was an apparent nonuniform shear stress distribution on the contacted shear failure plane.

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