深部煤巷围岩碎胀大变形是一个从峰前损伤扩容到峰后破裂碎胀的连续-非连续渐进破坏演化过程。本文以数值流形方法为基本架构，发展了深部煤巷围岩破裂碎胀大变形模拟预测分析方法，主要进行了4个方面的研究:① 在数值流形方法中植入Voronoi随机多边形环路自动生成算法，基于该几何表征方法发展了能够考虑岩体非连续面黏聚力和张拉强度的界面接触计算模型，构建了基于界面接触模型的岩体破裂算法准则;② 构建了基于显式积分格式的数值流形算法，并引入Voronoi随机多边形环路自动生成算法和界面接触计算模型，搭建了基于Voronoi多边形环路构型的显式数值流形方法;③ 在上述算法改进的基础上，发展了基于软化单元法和删除单元法的煤巷开挖卸荷模拟算法;④ 基于上述改进的数值流形方法，对深部煤巷开挖卸荷作用下围岩渐进破坏演化规律与碎胀大变形力学行为特征、以及最终开挖损伤区的形成与分布特征等进行研究。研究结果表明，上述改进方法能够实现深部煤巷围岩复杂多裂纹扩展路径的模拟，并在同一架构下对围岩峰前损伤扩容连续变形-峰后破裂碎胀非连续变形进行仿真分析;通过该方法能够较好地对深部煤巷开挖卸荷作用下围岩破裂碎胀行为特征、围岩径向收敛变形特征以及最终形成的EDZ分布特征进行预测分析。

It is known that the fracturing expansion and squeezing deformation of the surrounding rock mass in the deep coal roadways is a continuum-discontinuum progressive failure evolution process which involves the pre-peak dilatancy damage and post-peak fracture expansion of rocks. However,this process cannot be well described and quantified by either traditional theoretical models,analytical solutions or laboratory experiments. Hence,it is essential to develop a numerical approach for the modelling of fracturing expansion in surrounding rock mass during deep coal roadway excavation. The numerical manifold method is a continuum-discontinuum coupling approach which has been widely adopted in the numerical simulations of geotechnical engineering. The most innovative feature of numerical manifold method is its two cover systems,which helps to solve both continuous and discontinuous problems flexibly and effectively in a unified framework. Besides,the interactions ( including squeezing,slipping and debonding) among discontinuous in- terfaces as well as large deformation (including translation and rotation) can be easily captured using the contact algo- rithm of numerical manifold method. In this study,a new modelling approach for the investigation of fracturing expan- sion and large squeezing deformation of surrounding rock mass in deep coal roadways is developed based on the origi- nal NMM approach. The main research work done is as follows:① A Voronoi tessellation technique is embedded into the original numerical manifold method to generate random polygonal loops,based on which an interface contact model considering the cohesion and tensile strength of discontinuities is developed accounting for the fracturing criterion of the rock mass;② An explicit integration version of numerical manifold method is developed,and the aforementioned Voronoi tessellation technique and interface contact model are embedded;③ Based on the above modifications,a road- way excavation modelling approach combining core softening and eliminating technique is developed for the simulation of unloading and spatial supporting effects during roadway digging;④ With the newly developed excavation modelling approach,the progressive failure process of the surrounding rock mass during a deep coal roadway excavation is simu- lated and the fracture evolution process as well as the formation mechanism of the excavation damaged zone (EDZ) is explored in details. Simulation results show that the continuum-discontinuum progressive failure evolution process which involves the pre-peak dilatancy damage,complex crack propagation and post-peak fracture expanding of rocks can be captured by the modified NMM approach. In addition,the fracturing expansion characteristics,convergence dis- placement and EDZ distribution of the surrounding rock mass is well predicted.