XIAO Ming-qing, XU Chen, YANG Jian, et al. Study on the identification method of tunnel surrounding rock failure zone based on continuous discontinuous analysis theory[J]. 2023, 44(11): 3099-3108.
DOI:
XIAO Ming-qing, XU Chen, YANG Jian, et al. Study on the identification method of tunnel surrounding rock failure zone based on continuous discontinuous analysis theory[J]. 2023, 44(11): 3099-3108.DOI: 10.16285/j.rsm.2023.0652.
Study on the identification method of tunnel surrounding rock failure zone based on continuous discontinuous analysis theory
准确分析隧道挖破坏区的范围对合理确定支护参数有着重要的指导作用和工程意义,主要围绕连续介质分析方法和以有限元-离散元耦合方法(finiteelement-discrete element coupling method,简称FDEM)为代表的连续-非连续方法开展了隧道围岩破坏区判识方法研究。研究了连续介质分析方法与FDEM识别围岩破坏的判别标准;将岩体划分为弹性的岩石单元和弹塑性的界面单元,基于等效连续模型的思想,推导了界面单元力学参数与岩石单元及岩体单元力学参数的关系表达式,首次建立这两种方法参数取值的联系,解决了连续-非连续方法取值难的问题;对比了两种方法模拟不同岩性、断面铁路隧道开挖过程中围岩破坏区范围。基于规范中各级围岩的力学参数取值范围,给出了各级围岩下以FDEM中罚参数和断裂能等围岩主要破坏参数的取值范围;FLAC3D为代表的连续介质方法和FDEM两种方法对不同岩性、断面铁路隧道开挖过程模拟结果表明,连续介质方法得出的塑性区和以塑性极限应变得出的破坏区域和连续-非连续方法得出的裂纹扩展区和破坏区在分布范围、形态及破坏形式上基本一致,验证了提出的FDEM围岩破坏参数取值方法是合理可行的。Accurateanalyzing the scope of tunnel excavation failure zone has important guidanceand engineering significance in determining support parameters reasonably. Thisstudy focuses on the identification methods of tunnel surrounding rock failurezone
specifically the continuous medium analysis method and the continuous-discontinuousmethod represented by the finite element-discrete element coupling method(FDEM). Firstly
the continuous medium analysis method and FDEM identificationcriteria for surrounding rock failure are studied. Then the rock mass isdivided into elastic rock elements and elastic-plastic interface elements. Basedon the concept of equivalent continuous model
the relationship between themechanical parameters of interface elements and rock elements and rock masselement is mathematically derived. The connection between the parameter valuesof these two methods is established for the first time
resolving the challengeof determining values in the continuous-discontinuous method. Finally
theranges of surrounding rock failure zones simulated by these two methods duringthe excavation process of railway tunnels with different lithology andcross-sections are compared. According to the range of mechanical parametersfor each level of surrounding rock mass in the specification
the range ofvalues for the main failure parameters of surrounding rock
such as penaltyparameter and fracture energy
in FDEM
is given for each level of surroundingrock. The simulation results of railway tunnel excavation with differentlithology and cross sections using the continuous medium method represented by FLAC3D and FDEM method show that the plastic zone obtained by the continuous mediummethod
and the failure zone obtained by the plastic limit strain
as well as thecrack growth zone and failure zone obtained by the continuous-discontinuousmethod
are generally consistent in terms of distribution range
shape andfailure mode. The method proposed in this article for determining the failureparameters of surrounding rock in FDEM is verified as reasonable and feasible.