论文部分内容阅读
针对地下洞室开挖扰动分析中常忽略应力主轴旋转以及应力扰动无法量化的现状,以大岗山水电站地下厂房为研究实例,根据主应力方向与洞室横断面及洞轴线之间的几何关系,定义了描述应力主轴旋转的特征角。研究表明,洞室开挖引起了顶拱和边墙不同程度的应力释放和主方向旋转,围岩主应力均在开挖当期卸荷强烈,主应力方向在开挖当期和后继一个开挖期中旋转强烈,且顶拱和边墙部位主应力方向调整具有一定的共性,表现为最小主应力方向最终近似垂直于洞室开挖面,而最大主应力与中主应力方向则近似在平行于开挖面的平面内调整。在此基础上,考虑应力主轴旋转影响,定义应力扰动指标SDI作为描述洞室围岩应力场扰动程度的力学表征量,研究了大岗山水电站地下厂房围岩应力场扰动的时间演化过程和空间分布特征,并将数值模拟得到的强应力扰动区与现场测试的开挖损伤区进行了对比分析,相关认识和结论具有一定理论和工程意义。
In view of the fact that the stress spindles rotate and the stress disturbance can not be quantified often, the underground powerhouse of Dagangshan Hydropower Station is taken as an example. According to the geometric relation between principal stress direction and cross-section and hole axis, A characteristic angle describing the rotation of the stress spindle is defined. The research shows that the excavation of the cavern causes different degrees of stress release and main direction rotation of roof arch and side wall. The main stress of surrounding rock is unloaded strongly during the excavation. The main stress direction is in the excavation period and the subsequent excavation period The rotation is strong and the direction of the principal stress of the roof arch and the side wall has some common features. The direction of the minimum principal stress is approximately perpendicular to the excavation face of the cavern, while the directions of the principal principal stress and the principal stress are approximately parallel to the open Digging plane adjustment. Based on this, considering the influence of stress spindle rotation, SDI is defined as the mechanical characterization describing the disturbance degree of stress field in the surrounding rock of the cavern. The time evolution process and space of the stress field perturbation of the surrounding rock of the underground powerhouse of Dagangshan Hydropower Station are studied. Distribution features and comparative analysis of the strong stress disturbance zone obtained by numerical simulation and the field excavation damage zone, the relevant understanding and conclusions have certain theoretical and engineering significance.