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.

scholarly journals Experience with Shear Frames

1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Shear Failure ◽  
Statistical Data ◽  
Failure Plane ◽  
Shear Frame ◽  
Strength Distributions

AbstractThe shear frame is a simple in situ device for indexing the shear strength of thin weak layers. The index is sensitive to shear-frame geometry, rate-of-pull, and shear-frame mass. It is time-consuming to carefully align the device on the Gleitschicht (shear failure plane) in a slab avalanche zone. The ratio shear frame index/shear stress of the Gleitschicht has a high variance, and may not be a fundamental measure of slab avalanche stability. Corrections for the normal stress on the Gleitschicht reduce the variance only slightly. Despite these limitations, the shear frame is a useful tool for gathering statistical data on strength distributions and anisotropies of the Gleitschicht until a more fundamental technique is developed.

scholarly journals Experience with Shear Frames

1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Shear Failure ◽  
Statistical Data ◽  
Failure Plane ◽  
Shear Frame ◽  
Strength Distributions

AbstractThe shear frame is a simplein situdevice for indexing the shear strength of thin weak layers. The index is sensitive to shear-frame geometry, rate-of-pull, and shear-frame mass. It is time-consuming to carefully align the device on theGleitschicht(shear failure plane) in a slab avalanche zone. The ratioshear frame index/shear stressof theGleitschichthas a high variance, and may not be a fundamental measure of slab avalanche stability. Corrections for the normal stress on theGleitschichtreduce the variance only slightly. Despite these limitations, the shear frame is a useful tool for gathering statistical data on strength distributions and anisotropies of theGleitschichtuntil a more fundamental technique is developed.

scholarly journals Effect of Particle-Size Gradation on Coarse Sand-Geotextile Interface Response in Cyclic and Postcyclic Direct Shear Test

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jun Wang ◽  
Meng-Jie Ying ◽  
Fei-Yu Liu ◽  
Hong-Tao Fu ◽  
Jun-Feng Ni ◽  
...  
Keyword(s):  
Particle Size ◽  
Shear Stress ◽  
Shear Strength ◽  
Shear Behaviour ◽  
Direct Shear ◽  
Interface Shear ◽  
Cycle Number ◽  
Cyclic Shear ◽  
Stress Degradation ◽  
Particle Size Gradation

In order to investigate the influence of sand particle-size gradation on cyclic and postcyclic shear strength behaviour on sand-geotextile interfaces, a series of monotonic direct shear (MDS), cyclic direct shear (CDS), and postcyclic direct shear (PCDS) tests were performed using a large-scale direct shear apparatus. The influence of cyclic shear history on the direct shear behaviour of the interface was studied. The results indicated that cyclic shear stress degradation occurred at the sand-geotextile interface. Shear volumetric contraction induced by the cyclic direct shear increased with the increase in cycle number. The lowest final contraction value was observed in discontinuously graded sand. In the MDS tests, there were great differences in interface shear strength due to the different particle-size gradations, whereas the differences between shear volumes were negligible. In the PCDS tests, the shear stress-displacement curves exhibited postpeak stress hardening behaviour for different particle-size gradations, and differences in shear volumes were detected. The well-graded sand-geotextile interface had a higher value of shear stiffness and a higher damping ratio relative to the other interfaces. Postcyclic shear stress degradation was observed for the discontinuously graded sand-geotextile interface.

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.

Measurement of unsaturated soil – geomembrane interface shear-strength parameters

2007 ◽  
Vol 44 (1) ◽  
pp. 78-88 ◽  
Author(s):  
J S Sharma ◽  
I R Fleming ◽  
M B Jogi
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Pore Pressure ◽  
Unsaturated Soil ◽  
Pressure Transducer ◽  
Shear Behaviour ◽  
Direct Shear ◽  
Shear Tests ◽  
Interface Shear Strength ◽  
Interface Shear

Laboratory tests of soil–geomembrane interface shear strength are typically carried out with no provision for the measurement of pore pressures at the soil–geomembrane interface. This paper describes a series of soil–geomembrane interface shear tests carried out with continuous measurement of suction close to the interface during the shearing process. The tests were conducted using a modified direct shear box with a miniature pore-pressure transducer installed adjacent to the surface of the geomembrane. Results of the interface shear tests conducted using this method show that it is quite effective in evaluating shear behaviour at the interface between a geomembrane and an unsaturated soil at low matric suction values. The results suggest that soil suction contributes to shearing resistance at low normal stress values. At higher normal stress values, the interface shear behaviour appears to be governed only by the magnitude of total normal stress.Key words: geomembrane, interface shear strength, suction, direct shear test, pore-pressure transducer.

scholarly journals Experimental study on shear mechanical properties of through-step joints under direct shear

2021 ◽  
Author(s):  
Liangxiao Xiong ◽  
Haijun Chen ◽  
Zhongyuan Xu ◽  
Shu Zhou ◽  
Xiaohua Huang
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Normal Stress ◽  
Shear Failure ◽  
Major Influence ◽  
Initial Increase ◽  
Direct Shear ◽  
Small Length ◽  
Rock Bridge ◽  
Large Length

Abstract In this study, direct shear tests were carried out on artificial rock mass specimens with single-ladder, single-rectangular, and double-rectangular step joints. Consequently, the shear strength, cohesive force (c), internal friction angle (φ), and crack shape of specimens with these through-step joints were analyzed, in order to understand the influence of the shape of the through-step joint on their direct shear mechanical properties. The results of the investigation were as follows: (1) Under the same normal stress, any increases in the height h of the step joint caused an initial-increase–decrease in the shear strengths of specimens with single-ladder and double-rectangular step joints, with a type-W variation pattern for the specimens with single-rectangular step joint. More essentially, when normal stress and h were constant, the shear strength of specimens with a single-ladder step joint was the greatest, followed by specimens with a double-rectangular step joint, whereas that for specimens with a single-rectangular step joint was the least. (2) For specimens with a single-ladder step joint, a small length of the bottom of the step joint with a large length of the rock bridge allowed c to dominantly influence the specimen shear strength. Conversely, a large length of the bottom of the step joint with a small length of the rock bridge caused φ to play a key role in the specimen shear strength. For specimens with a single-rectangular step joint, when the length of the top of the step joint and that of the rock bridge were large, c had the dominant influence on the specimen. Otherwise, when the length of the top of the step joint and that of the rock bridge were small, φ had the major influence on the specimen shear strength. (3) Furthermore, given a small h and low normal stress, specimens with a single-ladder step joint mainly experienced shear failure, whereas specimens with single-rectangular and double-rectangular step joints mainly generated extrusion milling in the step joints. Any increases in h caused specimens with the three types of step joints to have oblique cracks at the bottom and apex points of the step joint. The number of oblique cracks was expected to increase with greater normal stress.

scholarly journals Assessing Machine Learning versus a Mathematical Model to Estimate the Transverse Shear Stress Distribution in a Rectangular Channel

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 596
Author(s):  
Babak Lashkar-Ara ◽  
Niloofar Kalantari ◽  
Zohreh Sheikh Khozani ◽  
Amir Mosavi
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Fuzzy Inference ◽  
Rectangular Channel ◽  
Tsallis Entropy ◽  
Shear Stress Distribution ◽  
Data Series ◽  
Shear Stresses ◽  
Inference System ◽  
Aspect Ratios

One of the most important subjects of hydraulic engineering is the reliable estimation of the transverse distribution in the rectangular channel of bed and wall shear stresses. This study makes use of the Tsallis entropy, genetic programming (GP) and adaptive neuro-fuzzy inference system (ANFIS) methods to assess the shear stress distribution (SSD) in the rectangular channel. To evaluate the results of the Tsallis entropy, GP and ANFIS models, laboratory observations were used in which shear stress was measured using an optimized Preston tube. This is then used to measure the SSD in various aspect ratios in the rectangular channel. To investigate the shear stress percentage, 10 data series with a total of 112 different data for were used. The results of the sensitivity analysis show that the most influential parameter for the SSD in smooth rectangular channel is the dimensionless parameter B/H, Where the transverse coordinate is B, and the flow depth is H. With the parameters (b/B), (B/H) for the bed and (z/H), (B/H) for the wall as inputs, the modeling of the GP was better than the other one. Based on the analysis, it can be concluded that the use of GP and ANFIS algorithms is more effective in estimating shear stress in smooth rectangular channels than the Tsallis entropy-based equations.

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