地下洞室围岩与支护损伤演化的微震释放研究

发布时间：2018-07-28 19:03

【摘要】：岩石和混凝土是两种常见的工程材料,它们有着不同的力学性能及破坏机制。在地下洞室中,与岩石和混凝土相对应的是围岩和支护结构,而围岩和支护结构的稳定性又直接关系到地下洞室整体的稳定性,因此研究围岩与支护结构的损伤破坏机制以及它们之间共同作用的微震释放规律对于地下洞室有重要意义。主要开展的工作和取得的成果如下：(1)通过室内声发射试验对岩石和混凝土破坏过程的微震释放机制的研究,进行了混凝土的压缩、拉伸试验,进行了岩石的压缩试验。研究发现花岗岩与混凝土的压缩破坏过程都分为四个发展阶段；混凝土拉伸变形过程较受压过程简单,只经历一个微裂纹稳定发展阶段；同强度等级的混凝土抗拉强度比抗压强度小；抗拉强度受骨料粒径的影响更大。(2)对围岩-支护共同作用的微震释放进行了数值模拟研究,就支护体系、开挖方式、不同倾角断层等三个方面进行了模拟。从剪应力和微震事件的分布情况来看,支护体系之于地下洞室的稳定性有不可或缺的作用,支护体系和围岩共同承担了来自岩体的重分布应力；台阶法开挖过程中可能会出现裂缝,因此,当岩体中应力较大时,要注意及时对围岩进行临时支护或初期支护；在水平断层、30°倾角断层、45°倾角断层等三种情况下,含有水平断层的洞室在同样的工况下较晚才出现失稳破坏,可见水平断层对洞室稳定性的破坏作用更小。(3)通过对大岗山地下厂房微震监测数据的处理,在分析围岩与支护结构的微震事件时空分布规律的基础上,从微震事件的分布规律、断层微震分布以及微震影响因素等三个角度来分析厂房的稳定性。分析发现厂房周围出现的微震事件大都与施工活动密切相关,震源离厂房主体结构较远,整个分析过程中出现的事件震级较小且没有大事件发生,微震所产生的变形位移也很小,因此判定该厂房基本稳定。对断层引起的塌空区进行支护以后,从微震事件的空间、震级以及位移分布等角度分析,发现塌空区域在围岩与支护的共同作用下无再次发生失稳破坏的趋势,厂房是稳定的。
[Abstract]:Rock and concrete are two common engineering materials, which have different mechanical properties and failure mechanisms. In the underground cavern, the surrounding rock and the supporting structure correspond to the rock and concrete, and the stability of the surrounding rock and the supporting structure is directly related to the stability of the underground cavern as a whole. Therefore, it is important for underground caverns to study the damage and failure mechanism of surrounding rock and supporting structure and the microseismic release law of the interaction between them. The main works and achievements are as follows: (1) through indoor acoustic emission test, the mechanism of microshock release of rock and concrete failure process is studied, the compression and tensile tests of concrete are carried out, and the compression test of rock is carried out. It is found that the compressive failure process of granite and concrete is divided into four stages, the tensile deformation process of concrete is simpler than that of compression process, and it only goes through a stable development stage of microcracks. The tensile strength of concrete with the same strength grade is smaller than that of the compressive strength, and the tensile strength is more affected by the particle size of aggregate. (2) numerical simulation of the microseismic release of the interaction between surrounding rock and support is carried out. Three aspects of the fault with different dip angles are simulated. According to the distribution of shear stress and microseismic events, the supporting system plays an indispensable role in the stability of underground cavern, and the supporting system and surrounding rock bear the redistribution stress from rock mass. Cracks may appear in the excavation process of step method. Therefore, when the stress in the rock mass is large, we should pay attention to the temporary or initial support for the surrounding rock in time, and in the case of the horizontal fault with 30 掳inclined angle fault and 45 掳dip fault, The caverns with horizontal faults appear instability failure only later under the same working conditions, which shows that horizontal faults have less effect on the stability of caverns. (3) through the processing of monitoring data of microearthquakes in underground powerhouse of Dagangshan, Based on the analysis of the temporal and spatial distribution of microseismic events in surrounding rock and support structure, the stability of the powerhouse is analyzed from three aspects: the distribution of microseismic events, the distribution of fault microearthquakes and the influencing factors of microearthquakes. It is found that most of the microseismic events around the factory building are closely related to the construction activities, the focal is far from the main structure of the building, and the magnitude of the events in the whole analysis process is small and no major events occur. The deformation displacement caused by the microearthquake is also very small, so it is determined that the plant is basically stable. Based on the analysis of the space, magnitude and displacement distribution of the microseismic events, it is found that there is no tendency of instability and failure in the caving area under the joint action of surrounding rock and support, and the workshop is stable.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU91

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