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在黏结颗粒模型中引入强度弱化因子生成弱化介质材料,进行弱化模型试件的单轴抗压强度试验。结果表明,弱化作用在降低试件单轴抗压强度的同时,还将导致试件弹性模量逐步下降。这一结果符合相关室内试验的研究成果。为进一步对岩石强度弱化模拟方法进行效果检验,利用颗粒流程序内置的FISH语言建立弱化岩石节理直剪试验模型,进行不同法向应力条件下弱化岩石节理的直剪试验。结果表明:弱化节理模型试件表现出类似于真实节理的一系列宏观剪切力学特征;不同壁面弱化程度条件下,节理模型试件的抗剪强度及剪切峰值膨胀角的试验结果与法向应力的依存关系均符合经典的JRC-JCS模型。由此表明,所采用的岩石强度弱化模拟方法可以较好地再现岩石介质的强度弱化效应。通过模型试件内微裂纹发展演化特征的研究表明,壁面弱化作用可导致试件内裂纹发育数目的快速增长、微裂纹分布范围的迅速扩大,以及剪切裂纹发育比例的迅速提高,由此从细观角度揭示了弱化节理面更易于产生宏观剪切破坏的原因。研究成果可以为弱化岩石节理的抗剪强度及大型岩质边坡的稳定性研究提供参考。
The weakening factor was introduced into the bonded particle model to produce the weakening medium material, and the uniaxial compressive strength test of the weakened model specimen was carried out. The results show that the weakening effect can reduce the uniaxial compressive strength of the specimen and decrease the elastic modulus of the specimen at the same time. This result is in line with the research results of related indoor tests. In order to further verify the effect of weakening rock strength simulation method, a direct shear test model of weakened rock joints was established by using the FISH language built in the particle flow program, and the direct shear tests of weakened rock joints under different normal stress conditions were carried out. The results show that the weakened joint model specimens show a series of macroscopic shear mechanics characteristics similar to the real joints. The test results of the shear strength and the shear peak expansion angle of the joint model specimen under the weakening degree of different wall are similar to those of the normal The dependence of stress is in line with the classic JRC-JCS model. It shows that the rock strength weakened simulation method can reproduce the strength weakening effect of rock media well. The study on the evolution and development of microcracks in the model specimen shows that the weakening of the wall can lead to the rapid growth of the number of cracks in the specimen, the rapid expansion of the distribution range of microcracks and the rapid increase of the ratio of the development of shear cracks, The microscopic view reveals the reason why the weakened joint surface is more prone to macro-shear failure. The research results can provide reference for weakening the shear strength of rock joints and the stability of large-scale rock slopes.