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Peak shear strength model considering the dilation and shear failure effect of actual contact joint asperities
Abstract To consider joint asperities degradation effect during the shear process, the average effective dip angle of the actual contact joint surface is taken as the expansion angle before wear under certain normal stress. A modified shear area ratio is proposed to reflect the degradation of the dilation angle. A method for calculating the contribution of the joint dilation effect to peak shear strength (PSS) considering the degradation of the dilation angle is proposed. Based on the effect of the sheared area in the actual contact joint, a calculation method for the contribution of the sheared asperities to PSS is proposed. Combining the joint dilation and sheared asperities effect, a PSS model considering the dilation and shear failure of actual contact joints is proposed. The results of 76 sets of tests show that the new model has the highest accuracy compared with four existing models. The prediction effect is discussed when the ratio of transition stress to compressive strength (RTSCS) ranges from 0.2 to 1. The value of RTSCS in this model is 0.5, which is within the stable range. Six sets of test data with σn/σc around 0.1 represent the shear test with high normal stress. The results show that the model is the best when the normal stress is large. The physical meaning of the new model is the combination of the shear stress provided by the dilation and shear failure of asperities, which contributes to explain the mechanism of the shear failure of rock joints.
Peak shear strength model considering the dilation and shear failure effect of actual contact joint asperities
Abstract To consider joint asperities degradation effect during the shear process, the average effective dip angle of the actual contact joint surface is taken as the expansion angle before wear under certain normal stress. A modified shear area ratio is proposed to reflect the degradation of the dilation angle. A method for calculating the contribution of the joint dilation effect to peak shear strength (PSS) considering the degradation of the dilation angle is proposed. Based on the effect of the sheared area in the actual contact joint, a calculation method for the contribution of the sheared asperities to PSS is proposed. Combining the joint dilation and sheared asperities effect, a PSS model considering the dilation and shear failure of actual contact joints is proposed. The results of 76 sets of tests show that the new model has the highest accuracy compared with four existing models. The prediction effect is discussed when the ratio of transition stress to compressive strength (RTSCS) ranges from 0.2 to 1. The value of RTSCS in this model is 0.5, which is within the stable range. Six sets of test data with σn/σc around 0.1 represent the shear test with high normal stress. The results show that the model is the best when the normal stress is large. The physical meaning of the new model is the combination of the shear stress provided by the dilation and shear failure of asperities, which contributes to explain the mechanism of the shear failure of rock joints.
Peak shear strength model considering the dilation and shear failure effect of actual contact joint asperities
Xue, Yaodong (author) / Ban, Liren (author) / Du, Weisheng (author) / Qi, Chengzhi (author) / Wang, Zefan (author) / Jin, Tianwei (author)
2023
Article (Journal)
Electronic Resource
English
BKL:
56.00$jBauwesen: Allgemeines
/
38.58
Geomechanik
/
38.58$jGeomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
56.00
Bauwesen: Allgemeines
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB18
Shear behaviour of joint roughness with two types of asperities
| British Library Conference Proceedings | 1996
Non-Linear Hoek-Brown Shear Strength Reduction Technique Considering the Effect of Dilation
| British Library Conference Proceedings | 2012