双层叠合初支拱盖法支护结构安全性评价方法  

Safety assessment method for support structure of double-layered and primary-supported arch cover method

作　　者：王安东[1,3] 邓昆 童建军 Wang Andong;Deng Kun;Tong Jianjun

机构地区：[1]中铁二院工程集团有限责任公司地下铁道设计研究院,四川成都610031 [2]湖南省交通规划勘察设计院有限公司轨道磁浮设计研究院,湖南长沙410200 [3]西南交通大学土木工程学院,四川成都610031

出　　处：《现代城市轨道交通》2023年第6期61-67,共7页Modern Urban Transit

摘　　要：文章通过分析双层叠合初支拱盖法围岩破坏特征,提出双层叠合初支拱盖法分为拱部结构和整体结构2次安全性评价的思路,并推导加强初支荷载分配系数计算公式和边墙附加水平压力计算公式,提出拱部结构、整体结构计算模型和安全性评价流程。最后将此安全性评价方法应用于重庆市轨道交通5号线凤西路车站工程。研究表明,双层叠合初支中的加强初支荷载分配系数与一次及加强初支的厚度、弹性模量和泊松比等因素有关;拱部结构拱脚底面竖向应力与围岩物理力学性质、拱脚竖向应力和宽度等因素有关;拱部结构安全性评价可分为一次初支模型和双层叠合初支模型,评价的关键分别是所承受围岩荷载依据加强初支荷载分配系数进行分配,整体结构安全性评价须考虑边墙附加应力作用。This study analyzes the failure characteristics of the surrounding rock failure in the double-layered and primary-supported arch cover method and proposes a two-step safety assessment approach for this method.The assessment is divided into the arch structure and the overall structure.The derivation of the calculation formula for the reinforced primary-support load distribution coeffi cient and the calculation formula for additional horizontal pressure on side walls is presented.Calculation models and a safety evaluation process are proposed for both the arch structure and the overall structure.Finally,this safety evaluation method is applied to the Fengxi Road Station project of Chongqing rail transit line 5.The research fi ndings indicate that the reinforced primary-support load distribution coeffi cient in the double-layered and primary-support is infl uenced by factors such as the thickness,elastic modulus,and Poisson's ratio of the primary-support and the reinforced primary-support.The vertical stress on the arch foot surface of the arch structure is related to the physical and mechanical properties of the surrounding rock,the vertical stress of the arch foot,and the width.The safety assessment of the arch structure involves both the primary-support model and the double-layered and primary-support model,where the rock load is distributed based on the reinforced primary-support load distribution coeffi cient.The safety evaluation of the overall structure needs to consider the additional stress on the side walls.

关 键 词：双层叠合初支拱盖法 围岩破坏 安全性评价 加强初支荷载分配系数 边墙附加水平压力 

分 类 号：U231.3[交通运输工程—道路与铁道工程]