基于结构安全的衬砌背后空洞评定标准优化研究

Study on Optimization of Evaluation Standard of Cavity behind Lining Based on Structural Safety

针对目前我国铁路隧道衬砌背后空洞评定标准及研究成果以经验为主的现状,采用资料调研、数值模拟等手段,对我国铁路隧道衬砌背后空洞评定标准进行了对比分析与优化研究,主要结论有:(1)日本对衬砌背后空洞的评定标准侧重于空洞范围围岩坍塌产生的冲击荷载对结构的影响,我国评定标准的制定主要侧重于和无损检测实施手段的结合;(2)拱顶部位出现空洞,且考虑围岩坍塌产生的冲击荷载时,对衬砌结构安全最为不利;(3)以空洞的纵向连续测线长度为特征参数,对铁路隧道衬砌背后空洞的评定标准进行了优化,优化后的评定标准更为严格。

In view of the current situation that the assessment criteria and research results of cavity deterioration behind railway tunnel lining in China are mainly based on experience,the assessment criteria were compared and optimized by numerical simulation and literature review.The main conclusions include:(1)The assessment criterion of cavity behind lining in Japan focuses on the impact load on the structure caused by the collapse of surrounding rock in the cavity range,and the formulation of evaluation standard in China mainly focuses on the implementation status of nondestructive testing.(2)The cavity is located at the vault of the lining,and when the impact load caused by the collapse of surrounding rock is considered,it is the most unfavorable to the safety of the lining structure.(3)With kLc as the characteristic parameter,the evaluation standard of cavity behind railway tunnel lining is optimized,and the optimized assessment criterion is more stringent.