深部大变形回采巷道围岩拉压分区变形破坏的模拟研究

为研究深部回采巷道围岩大变形破坏规律，在地质力学评估及矿压显现特征实测的基础上，采用真三轴相似模拟方法，模拟了不同加载梯度下巷道围岩应变特征。结果显示，在浅埋静水压力条件下，巷道围岩呈现“浅部拉应变、深部零应变”的特征；深埋静水压力及初掘采动应力下巷道围岩出现“径向应变拉压交替分布”现象；当采动应力集中系数大于2时，深埋巷道围岩应变进入非线性大应变状态。采用FLAC3D的应变软化模型与摩尔-库仑模型，对比研究了深部回采巷道围岩位移、塑性区分布规律。结果表明，应变软化条件下，巷道围岩产生拉、压分区破坏且软化后的围岩位移与实测结果更吻合。综合研究结果，揭示了深部回采巷道围岩拉、压分区的产生机制，初步提出了注浆、喷层等措施，防止过度应变软化引起深部回采巷道围岩大变形，为类似巷道稳定性控制提供了一定的参考。

Simulation of zonal tensile and compressive deformation and failure of surrounding rock in deep large deformation mining gateway

This paper aims to investigate the laws of large deformations of surrounding rock around a deep mining roadway. A true triaxial model experimental device is applied to simulate the strain characteristics of surrounding rock under different loading gradients based on geomechanical estimation and strata behavior test. The results show that, under shallow hydrostatic pressure conditions, surrounding rocks express a characteristic of tensile strain at shallow depth and zero strain at deep level. The tensile and compressive zonal regions alternately appear under deep hydrostatic pressure and initial excavation stress conditions. The nonlinear large strain phenomenon of surrounding rocks is observed when mining stress concentration factor is greater than 2. A comparative simulating of the displacement and distribution of plastic zonal regions in surrounding rock is conducted using the Mohr-Coulomb constitutive model and the Mohr-strain-softening constitutive model in FLAC3Dsoftware. It is found that under strain softening condition, the zonal disintegration of surrounding rock occurs due to tensile and compressive effects, and displacement after softening agrees with the observation. Based on aforementioned results, the zoning mechanism of surrounding rock induced by deeply mining are revealed. Some preliminary measures including grouting and shotcreting are suggested to control large deformation of surrounding rocks induced by immoderate strain softening.