巷道开挖面抗剪承载结构形成和蠕变规律研究

Formation and Creep Characteristic of Shear Bearing Structure in Soft Roadway after Excavation

为掌握深部软岩巷道应力承载结构的形成机理和发生剪切蠕变失效规律,通过研究巷道抗剪力学承载结构划分方法和形成特征,掌握该承载结构的空间效应和蠕变效应。以开挖面附近围岩为研究对象,利用工程实测开挖面附近不同区段围岩应力场和裂隙场分布规律,探讨空间效应影响下围岩抗剪承载结构形成机制;通过理论分析方法,基于统一强度准则和岩石三线段力学模型,获得开挖后软岩巷道次生应力场、位移场的定量解析式,推导"弹塑性"位移释放后围岩蠕变定量解析解。由算例结果可知,不同区段围岩承载结构演化规律受空间效应影响较大。最后,根据围岩抗剪承载结构蠕变失效特征,提出动态补强支护方案。

To grasp the formation mechanism and the creep failure of stress-bearing structure in deep soft roadway occurring with the shear stress,the division method and formation characteristics of roadway shear bearing structure were analyzed,and space and creep effects of the bearing structure were mastered.Surrounding rock near the excavation surface was selected as the research object,in-situ measures were conducted on stress field and fracture distribution regularity in different extents of surrounding rock near the excavation face,the forming mechanism under the space effect of the shear bearing structure was analysed.Through the theoretical analysis method,based on the unified strength criterion and three line segments rock mechanics model,quantitative analytical equations of secondary stress field and elastic-plasticity displacement field are obtained,and the creep quantitative analytic solution of the soft roadway near the excavation face are deduced.The example results show that space and time effects have a great influence on the evolution law of bearing structure in different roadway sections.Finally,the dynamic support scheme is put forward according to the shear creep failure of the bearing structure of surrounding rock.