深部节理岩体分区破裂化机制数值研究

Numerical Study on Mechanism of Zonal Disintegration in Deep Rock Mass with Joints

基于深部地下工程围岩反复承受地质力作用和开挖扰动,其完整性和力学性能弱化的现实,认为其应力-应变关系服从峰后软化的遍布节理模型,然后考虑节理、原岩应力以及影响岩体性质的变形参数和强度参数等因素,设计模拟方案,利用FLAC3D数值软件,再现了围岩分区破裂化过程。模拟结果表明:节理的存在和分布对分区破裂化现象的形态和规模存在很大影响。岩体强度与原始应力场的相对关系是引发围岩分区破裂化的关键。当初始地应力超出岩体单轴抗压强度时,围岩将出现分区破裂现象,初始力相对于岩体强度、泊松比的增大与分区破裂的数目、破裂区延伸长度、破裂区范围等成近似的正比,而内摩擦角则呈现相反趋势。这一结果部分揭示了分区破裂发生的力学机制,为深部围岩支护设计理论的建立提供了有益参考。

Based on the reality that surrounding rocks of deep underground engineering repeatedly bear geological force and excavation disturbance, the integrity and mechanical properties were weakened, it is thought that the stress-strain relation submits to the post-peak softening joint model, and then considering other parameters like joints, original rock stress, strength and deformation parameters that affecting rock mass property, the simulation scheme is designed, and FLACD numerical software is used to reproduce the process of zonal disintegration. The simulation result shows that （ 1 ） the existence and distribution of joints have a great impact on the form and scale of zonal disintegration in jointed rock, the relative relation between rock mass strength and original stress field is the key to zonal disintegration; （2） when the initial geostress exceeds the rock uniaxial compressive strength, surrounding rock will be fractured; （3） initial geostress is approximately proportional to rock mass strength, increase of Poisson＇s ratio, number of zonal disintegration and extension length of rupture zone, etc., while friction angle reveals contrary trend. This result partly revealed the mechanical mechanism of zonal disintegration, provided a beneficial reference for the founding of deep surrounding rock supporting design theory.