隧道衬砌多点独立加载试验系统研发与应用

Development and Application of Multi-point Independent Loading Testing System for Tunnel Lining

隧道衬砌模型试验是一种研究衬砌力学性能和开裂行为、指导隧道衬砌结构设计优化与维修加固的重要试验手段。文章介绍了自主研发的隧道衬砌多点独立加载试验系统,该系统能够按照二次衬砌荷载的分布形态和量值,对大尺寸衬砌模型的15个关键位置进行低速高精度加载,实现复杂受力条件下衬砌结构受力变形和开裂行为的物理模拟。以某黄土隧道浅埋段衬砌断面为试验背景,基于二次衬砌受荷现场监测结果,利用该试验系统进行了相似比为1∶10的二次衬砌受力变形模型试验,归纳总结了二次衬砌的开裂特征与应变变化规律。结果表明,该系统加载效果良好,加载精度满足工程试验要求。其试验结果有助于预测二次衬砌裂缝病害发展,明确衬砌加固重点区域,可为衬砌的维修加固提供帮助。

Tunnel lining model test is an indispensable method to study the mechanical and cracking behaviors and guide the design optimization as well as maintenance and reinforcement of tunnel lining structure.This paper in⁃troduces a multi-point independent tunnel loading testing system which can apply load on the fifteen key positions of a large size lining model at a low speed and high precision based on the load distribution pattern and magnitude of secondary lining,realizing physical simulation of load induced deformation and cracking behaviors of lining struc⁃ture under complex loading conditions.Taking a lining section with shallow overburden of certain loess tunnel as the background,a model test of load induced deformation of secondary lining with 1∶10 similarity ratio is conducted on the basis of site monitoring results of load applied on the secondary lining,and the cracking characteristic and the law of strains changes of secondary lining are summarized.The results show the loading effect of this system is good and the loading accuracy meets the requirements of engineering test,and the test result is helpful to predict the cracking development and determine the key area of lining reinforcement.