Anisotropy of Shear Strength of Layered Rocks and Determination of Shear Failure Plane

2017 ◽  
pp. 649-653
Author(s):  
Zhang Yujun ◽  
Liu Yiping ◽  
Xiong chuanyi
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Bo Meng ◽  
Hongwen Jing ◽  
Shengqi Yang ◽  
Yingchao Wang ◽  
Biao Li

The shear behavior of concrete blocks reinforced by fully grouted bolts with different diameters was studied in this paper. More than 90 intact cubic samples (100 mm × 100 mm × 100 mm) with bolts ranging from 2 mm to 5 mm in diameter were tested at a constant stain rate of 0.5 mm/min. An oblique shear apparatus, which could simultaneously apply shear and normal force on tested samples at three slope angles (53°, 58°, and 63°) of a predetermined shear plane, was employed. The results indicate that the bolt has no evident influence on the shear behavior of intact concrete blocks at the prepeak shear strength stage. The bolt could significantly reduce the shear strength drop in the peak shear strength of the concrete block and contribute to reserving the residual shear strength of concrete blocks, especially at steep slope angles of the shear failure plane. The shear resistance provided by the bolt to the concrete block at the residual shear slip stage has a positive relationship with the diameter. The bolt with a larger diameter inflected in the vicinity of the shear failure plane of concrete block at the postpeak shear strength stage; additional normal force and direct shear resistance could still be persistently provided. Two empirical equations of the apparent cohesion and apparent internal angle of the bolted concrete block were obtained by linear regression considering rb, which is the ratio of the cross-sectional area of the bolt to that of the bolted concrete block.


2015 ◽  
Vol 825-826 ◽  
pp. 806-813 ◽  
Author(s):  
Kay André Weidenmann ◽  
Lisa Baumgärtner ◽  
Benedikt Haspel

The interlaminar shear strength is a characteristic value describing the mechanical behavior of composite materials such as laminates. Several methods for the determination of the interlaminar shear strength are described in open literature by several authors. Among these methods, the ILSS test (DIN EN ISO 14130) measuring the apparent interlaminar shear strength by using a modified bending test is the state of the art technique, as both the necessary testing equipment and the sample geometry are quite common. However, the ILSS tests implements shear loads indirectly by bending often leading to sample failure which is then not solely initiated by shear loads. Particularly for ductile matrices or those showing pronounced elastic behavior under bending, no interlaminar shear failure can be implemented and the interlaminar shear strength can not been determined or – if the user is not sensitized to the identification of non-shear failure behavior – the determined value is not correct.Up to now, alternative methods for determining the interlaminar shear strength implementing a shear load directly to the sample are quite elaborate regarding the test equipment to be used or the specimen preparation and geometry. In this contribution the authors present a novel test setup for an edge shear test which allows both a direct shear load and at the same time a reduced complexity of the specimen geometry which is comparable to those used in the ILSS test. The authors present results based on this novel testing method in comparison to conventional ILSS tests.


1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck

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.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jianhang Chen ◽  
Fan Zhang ◽  
Hongbao Zhao ◽  
Junwen Zhang

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.


1983 ◽  
Vol 29 (103) ◽  
pp. 485-491 ◽  
Author(s):  
R. Perla ◽  
T. M. H. Beck

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.


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