兰渝高速铁路砂质围岩隧道初期支护结构安全度研究

以兰渝高速铁路某砂质围岩隧道为工程依托，针对砂质围岩的工程特性，施工中采用水平旋喷超前预加固措施，通过有限元数值模拟，结合围岩压力及拱架应力的监测资料，分析砂质隧道围岩压力的分布情况以及初期支护结构的受力特征。研究结果表明： 水平旋喷超前预加固后，初期支护结构的安全度能够满足要求，更有一定的富裕度，可为砂质围岩隧道的优化设计和施工提供理论依据。

Study on Safety Degree of Primary Support Structure of Tunnel in Sandy Rock Mass on Lanzhou-Chongqing High-speed Railway

In the construction of a tunnel in sandy rock mass on Lanzhou Chongqing high speed railway, advance reinforcement is made by means of horizontal jet grouting. The distribution of the pressure of the sandy rock mass and the loading characteristics of the primary support structure are analyzed by means of finite element numerical simulation and on basis of the monitoring data of the rock mass pressure and steel arch stress. The study results show that the safety degree of the primary support structure of the tunnel pre reinforced by horizontal jet grouting can meet relevant requirements and has some margin. The paper can provide theoretical reference for the optimization design and construction of tunnels in sandy rock mass in the future.