普速铁路单线直墙式隧道衬砌厚度不足评价标准

Evaluation Criteria for Insufficient Thickness of Single⁃track Straight⁃wall Lining of Conventional Railway Tunnel

采用衬砌加载数值模拟和层次分析法,分析了普速铁路单线直墙式隧道衬砌厚度不足对衬砌抗裂和抗压极限承载力的影响。结果表明:衬砌厚度不足对衬砌抗裂极限承载力的影响小于对抗压极限承载力的影响,且厚度不足并不一定会导致衬砌抗裂极限承载力降低,宜采用抗压极限承载力作为衬砌极限承载力;衬砌厚度不足时极限承载力降至无缺陷时的40%时,结构缺陷极严重。基于此构建两种评定方法,综合考虑两种方法的评定结果确定衬砌厚度不足等级。根据衬砌厚度不足缺陷长度和有效厚度比对极限承载力的影响,结合两种评定方法,建立了基于衬砌厚度不足缺陷长度比和有效厚度比的评价标准。

The influence of insufficient lining thickness on the ultimate bearing capacity of crack resistance and compressive of lining was analyzed by numerical simulation of lining loading and Analytic Hierarchy Process.The results show that the influence of insufficient lining thickness on the ultimate bearing capacity of crack resistance is less than that on the ultimate compressive bearing capacity,and the insufficient thickness does not necessarily lead to the reduction of the ultimate bearing capacity of crack resistance.It is advisable to use ultimate compressive bearing capacity as the ultimate bearing capacity of lining.When the lining thickness is insufficient and the ultimate bearing capacity drops to 40%of the one under no defect,the structural defect is extremely serious.Based on this,two evaluation methods are constructed,the insufficient lining thickness level is determined by considering the evaluation results of the two methods.According to the influence of the defect length and effective thickness ratio of insufficient lining thickness on the ultimate bearing capacity,the evaluation criteria based on the defect length ratio and effective thickness ratio of insufficient lining thickness was established.