锚固裂隙岩体破坏过程中应变场演化规律及破坏前兆的数值模拟研究

Numerical simulation on strain field evolution and failure in fractured rock mass with anchoring

为探究锚固裂隙岩体的锚固作用,采用ABAQUS对裂隙岩体单轴加载破坏过程进行模拟,分析裂隙岩体的应变场演化规律,并讨论裂隙岩体破坏的前兆特征。模拟结果表明:裂隙岩体破裂前水平应变场演化过程可划分为理论弹性变形、裂隙萌发扩展、试件破坏3个阶段;未锚固和锚固裂隙岩体水平应变场标准差曲线表现出不同的分异阶段;与未锚固试件相比,锚固试件的峰值应力上涨了7.55%,且锚固岩体裂缝起裂预警大约发生在峰值应力的80%处。基于水平应变场演化规律进行前兆分析,将应变场分异速率的突变点作为破坏失稳前兆点。锚杆的锚固作用增强了裂隙岩体的强度和抗变形能力,提高了裂隙岩体的稳定性,模拟结果对裂隙岩体的监测和加固具有重要的参考意义。

In order to explore the anchoring action of fractured rock mass,ABAQUS is used to simulate the uniaxial loading failure process of fractured rock mass,analyze the strain field evolution law of fractured rock mass,and discuss the precursor characteristics of fractured rock mass failure.The simulation results show that the evolution process of horizontal strain field before fracture of fractured rock mass can be divided into three stages:theoretical elastic deformation,fracture germination and expansion,specimen failure.The standard deviation curves of horizontal strain field of unanchored and anchored fractured rock mass show different stages of differentiation.Compared with the unanchored specimen,the peak stress of the anchored specimen increased by 7.55%,and the early warning of fracture initiation of the anchored rock mass occurred at about 80%of the peak stress.Based on the evolution law of horizontal strain field,the precursory analysis is carried out and the mutation point of strain field differentiation rate is taken as the precursory point of failure and instability.The anchorage of bolt enhances the strength and deformation resistance of fractured rock mass and improves the stability of fractured rock mass.The simulation results have important reference significance for the monitoring and reinforcement of fractured rock mass.