深埋硬岩隧道初期支护劣化过程衬砌力学特性试验研究

摘要

The study has developed a laboratory test to simulate the excavation,supporting and deterioration process of primary support of the deep hard rock tunnel. In the paper,variation rules of displacement,load and internal force of the secondary lining in the deterioration process of primary support are analyzed. The study proves that in the primary support deterioration period or even in the failure process,there are different effects between the shotcrete and the bolts. The effect of the bolts,which has step characteristics,is much more obvious than that of the shotcrete. The increasing trends of displacement,load and internal forces are all firstly rising up slowly and then accelerating,finally becoming steady. In the vault and side walls,such mechanical phenomenon is typical. After calculation of the lining security,we found that the safety extent is satisfied. The design is relatively conservatory.%　　通过室内相似模型试验对深埋硬岩隧道的开挖、支护及初期支护的劣化过程进行模拟，就初期支护劣化过程中的二次衬砌的荷载、位移及内力的变化规律进行深入研究。研究结果表明，二衬的内力随喷射混凝土的劣化呈现出相对稳定的增加，而随着锚杆的劣化呈现出明显的阶段性增加，而且锚杆的劣化相比较于喷射混凝土的劣化对二次衬砌的影响更为明显；总体上二次衬砌的荷载、位移及内力的增加都呈现出先缓慢增加，后快速增加，而后又趋于稳定的变化规律，拱顶及边墙是受力变化最为明显的区域，通过检算，衬砌的安全性是远远满足规范要求的，结构有较大的安全冗余度，可见当前的设计是偏于保守的。