裂纹长度对裂隙岩体力学特性及破坏模式的影响

采用伺服控制岩石力学试验机对水泥砂浆材料制备的类岩石试件进行单轴加载,利用颗粒流离散元软件对岩体进行单轴加载数值模拟试验,研究不同预制裂纹长度下裂隙试件的力学特征及破坏规律.结果表明:随着裂纹长度的增加,裂隙试件的峰值强度、峰值应变和弹性模量均减小,裂隙模型脆性减弱,延性增强,且随着裂纹长度的增加,弹性模量的降幅逐渐增大,敏感度增强;引入强度劣化系数来定量分析裂隙试件的劣化特征,当裂纹长度从10 mm增加到15 mm时,劣化系数增长迅速,试件强度下跌明显,强度敏感度最大;裂纹长度影响裂隙试件的最终破坏模式,在0°原生裂纹下,随着裂纹长度的增加,裂隙试件的破坏模式由剪切破坏为主变为剪切、张拉复合破坏再转化为出现宏观裂纹的张拉破坏.

Influence of Crack Length on Mechanics Characteristic andDamage Mode of Fractured Rock-mass

The rock specimen of cement mortar material was subjected to uniaxial loading by servo control rock mechanics testing machine.The numerical simulation of rock mass under uniaxial loading was carried out by using particle flow discrete element software to study the mechanical characteristics and failure law of fracture specimen under different prefabricated crack length.The results show that with the increase of the crack length,the peak strength,peak strain and elastic modulus of the fracture specimen are reduced,the brittleness of the fracture model is weakened and the ductility is enhanced,and the decrease of the elastic modulus increases with the increase of the crack length.The results show that the degradation coefficient increases rapidly,the strength of the specimen decreases obviously,and the strength is the most sensitive.The crack length affects the fracture specimen.When the crack length is increased from 10 mm to 15 mm,the strength of the specimen decreases.The failure mode of the fracture specimen is changed from shear failure to shear,and the tensile failure is converted into a tensile failure due to the occurrence of macroscopic cracks.