不同应力环境下巷道开挖卸荷岩爆模拟实验研究

摘要

采用Plaxis 3D数值模拟软件,以应力环境对巷道岩爆的影响问题为切入点,从位移云图、应力应变曲线和塑性点分布等方面开展不同应力对巷道岩爆问题的研究工作,为巷道岩爆预防及治理提供研究基础。研究结果表明,巷道开挖卸荷过程中,圆形巷道左右两侧同时出现了应力集中和位移集中,此部位最易发生岩爆。开挖过程中,根据周围岩体距巷道侧壁的厚度的关系,可将开挖操作对周围岩体的影响划分为“开始变大”、“明显增大”、“急剧增加”三个区域。巷道的左右两侧壁会产生高应力集中区和位移集中区,最大应力随着水平应力的增加呈线性增长,巷道发生位移集中区域的面积与水平应力呈指数型正相关关系变化。位移集中区域中心与巷道侧壁的距离是圆形巷道半径的2/5,随着应力的增加,位移集中区域向周围扩张,岩爆的程度及影响范围也随之增大。%Adopting Plaxis 3D simulation software,it takes a research about the rockburst in different stress environments,which puts the effects of different stress environments on rockburst as the breakthough point to analyze the rockburst in terms of cloud displacement,stress-strain curves and distribution of plastic points.And this research aims to provide basis for the prevention and control of rockburst.The results show that during the tunnel excavation,the rockburst tends to occur mostly when the stress concentration and displacement concentration are simultaneously present at both sides of the tunnel,according to the thickness relation between surrounding rock and side wall of the tunnel,the impact of the excavation on surrounding rock can be divided into three regions including “start larger”,“significantly increase”and “sharp increase”. Both sides of tunnel generate a high stress concentration and displacement concentration,the maximum stress increases linearly with the horizontal stress increasing,and the area of the displacement concentration takes an exponentially positive correlation with the horizontal stress.The distance between the displacement concentration and the side wall of the tunnel is about 2/5 of the tunnel radius.With the increase of stress,the displacement concentration is expanding to the surrounding area,and degree of rockburst is also increasing.