Investigation of scale effects of rock bridges based on Multi-Physical field monitoring

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2024-11-01 DOI:10.1016/j.tafmec.2024.104744

Tong Jiang, Li Wan, Zangnan Yu, Chao Xu, Zhanhui Li, Kun Huang, Fanke Meng

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Abstract

The presence of rock bridges is crucial for ensuring the stability of rock slopes. However, evaluating the mechanical properties of rock bridges solely based on the joint persistence coefficient (K) raises doubts due to potential variations in the scales of rock bridges within a rock mass with a constant K value. In this study, direct shear tests with different scales were carried out on sandstone specimens. Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques were utilized to monitor the damage procession of the specimens. The evolution process of the specimen was divided into stages and three threshold points were determined based on AE parameters. As the scale decreased, the Joint Roughness Coefficient (JRC) increased, the tensile failure increased, and the shear failure decreased. As the normal stress increased, the JRC with the same scale decreased, the tensile failure decreased, and the shear failure increased. The change of fracture mechanism was the primary reason for the strength deterioration with decreasing scales. The decrease of the scale was not conducive to the failure prediction. By improving the rock bridge failure potential (RBP) index, the proposed RBP_n index could appropriately characterize scale effects under different normal stresses.

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基于多物理场监测的岩石桥梁规模效应调查

岩桥的存在对于确保岩石斜坡的稳定性至关重要。然而，仅根据节理持续系数（K）来评估岩桥的力学性能会引起怀疑，因为在 K 值不变的岩体中，岩桥的尺度可能存在变化。本研究对砂岩试样进行了不同尺度的直接剪切试验。利用声发射（AE）和数字图像相关（DIC）技术监测试样的损坏过程。试样的演变过程被分为几个阶段，并根据声发射参数确定了三个阈值点。随着刻度的减小，接头粗糙度系数（JRC）增大，拉伸破坏增加，剪切破坏减少。随着法向应力的增加，相同尺度的接合粗糙度系数降低，拉伸破坏减少，剪切破坏增加。断裂机制的变化是强度随鳞片减小而降低的主要原因。尺度的减小不利于破坏预测。通过改进岩桥破坏潜势（RBP）指数，所提出的 RBPn 指数可以恰当地描述不同法向应力下的鳞片效应。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.