地下岩体工程顶板拉张破坏数值模拟研究

发布时间：2018-05-31 15:25

本文选题：覆岩离层 + 有限元程序　；参考：《西南科技大学》2015年硕士论文

【摘要】：在地下岩体工程中,顶板离层的产生、发育直至垮落是采空区灾害的一个重要成因。顶板离层是地应力、围岩力学性质、围岩体结构及巷道断面等因素综合作用的外在表现。因此,研究顶板离层破坏现象对优化巷道支护结构设计和施工等工程具有重要的理论意义和工程实用价值。本文研究地下岩体工程顶板离层发育过程,探讨发育离层现象的规律。主要介绍了离层产生的机理,张开型裂纹型尖端的应力场和位移场,裂纹失稳扩展等相关理论,以岩石受拉破坏理论和经典断裂力学理论为基础,结合岩石拉张破裂的判据,建立有限元模型,分析模拟顶板离层拉张破裂的结果。本文所建立的模拟方法是使裂纹从单元内部开裂,严格沿着破裂点主应力方向将周围相关单元裂开,增加新的单元和节点,并且对开裂后的网格能自动进行形状的优化处理。利用本文的程序模拟张开型裂纹尖端扩展过程和纯离层破坏无层内开裂过程,并且对纯层内开裂工程简例以及覆岩离层开裂工程简例进行数值模拟。模拟结果表明:采空区顶板离层的产生、发育直至垮落的过程是应力对岩层作用的表现形式,离层破坏形成不连续面后,离层周围应力状态发生改变,开裂点处应力被释放,应力重新分布,导致岩石裂纹进一步扩展形成二次破裂,这个过程不断反复。形成离层的过程就是形成新结构的过程,相应导致应力状态不断的调整和改变。利用本文所建立的程序可为地下工程顶板拉张破坏现象提供一种预测方法和手段。
[Abstract]:In the underground rock engineering, the roof separation is an important cause of the disaster in the goaf. The roof abscission layer is the external performance of the stress, the mechanical properties of the surrounding rock, the surrounding rock body structure and the roadway section. Therefore, the study of the roof separation failure phenomenon is the design and construction of the supporting structure of the optimized roadway. Engineering has important theoretical significance and practical value of engineering. In this paper, the development process of roof abscission layer of underground rock mass engineering is studied, and the law of development of separation phenomenon is discussed. The mechanism of abscission layer, stress field and displacement field of open type crack tip, crack propagation and other related theories are mainly introduced. Based on the theory of canonical fracture mechanics and combining the criterion of tensile fracture of rock, a finite element model is set up to analyze the result of the split tensile fracture of the simulated roof. The simulation method established in this paper is to crack the crack from the interior of the unit, to crack the surrounding phase unit strictly along the direction of the main stress of the fracture point, and to increase the new element and node. The mesh after the cracking can be automatically optimized for the shape of the crack. The program is used to simulate the expansion process of the open crack tip and the pure separation process, and the simple case of the crack engineering in the pure layer and the case of the overburden cracking engineering are numerically simulated. The simulation results show that the roof separation of the goaf is produced. The process of breeding or falling down is the form of stress on the rock formation. After the discontinuities are formed, the stress state around the separation layer changes, the stress is released at the cracking point and the stress is redistributed, which leads to the further expansion of the rock cracks to form two breaks and the process is repeated. The process of forming the separation layer is a new knot. The process of structure leads to the constant adjustment and change of stress state. The application of the program established in this paper can provide a prediction method and means for the tensile failure of the roof of the underground engineering.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD32

【参考文献】