论文部分内容阅读
随着地下工程开挖深度的增加,深部洞室围岩中将出现与浅埋洞室破坏模式迥异的分区破裂现象。为进一步研究分区破裂现象的形成机制,基于应变梯度理论和连续损伤力学建立分区破裂弹性损伤软化模型,推导考虑平面外应力影响的准平面应变问题的平衡方程和边界条件,应用Matlab求得深部洞室围岩中径向位移、径向应变和应力的波峰和波谷交替出现的振荡型变化规律。理论计算值与地质力学模型试验实测值在量值与变化规律两方面均符合较好,这证实了分区破裂弹性损伤软化模型在解释深部岩体分区破裂问题中的适用性。深部洞室围岩中应力场的波峰和波谷交替出现的振荡型变化规律是导致分区破裂现象出现的关键原因。
With the increase of the excavation depth of underground engineering, there will be subdivision and rupture in the surrounding rock of deep caverns with different modes of destruction in shallow caverns. In order to further study the formation mechanism of zonal disintegration, the elastic damage softening model of zonal disintegration is established based on strain gradient theory and continuous damage mechanics. The balance equation and boundary conditions of quasi-plane strain problem considering the effect of out-of-plane stress are deduced. Variations of the oscillation modes alternating with the radial displacements, radial strains and stress peaks and troughs in the surrounding rock. The theoretical calculation value and the measured value of the geomechanical model test are in good agreement with both the magnitude and the variation rule, which confirms the applicability of the elastic damage softening model of zonal disintegration to explain the zonal breakage of deep rock mass. The variation of oscillation type in which the crests and troughs of the stress field in the deep cavern surrounding rock alternate is the key reason for the phenomenon of zonal disintegration.