浅埋大跨度隧道施工方法的比选与应用

Comparative Analysis and Application of The Construction Method in Shallow Large Span Tunnel

结合京珠复线长湘高速公路三车道隧道工程,采用数值模拟对双侧壁导坑法、三台阶法施工隧道围岩和支护系统变形及受力特点进行对比分析,并结合现场施工应用情况,对比分析两种工法的优缺点。研究结果表明,双侧壁导坑法施工在控制围岩变形及地面沉降方面优于三台阶法,且产生的围岩塑性区较小,但两种工法施工均能满足围岩及支护稳定性的要求;三台阶法在施工进度、资源利用、造价、工序转化及施工难度方面具有优势,长沙地区浅埋大跨度隧道采用三台阶法施工,可以保证施工的安全、快速、高效。

The thesis takes a three-lane tunnel construction of a double track from Beijing-Zhuhai Expressway, the Changsha-Xiangtan highway as an example. It carry out comparative analysis of deformation and stress situation in the tunnel surrounding rocks and the support system through numerical modeling of double side drift method and three bench method, and compares the advantages and disadvantages between the two construction methods with a consideration of the real application on the construction site. The study shows that, double side drift method is better than three bench method in the way of con- trolling surrounding rocks deformation and ground subsidence, and produces less surrounding rock mass plastic zone, while both two methods can meet the requirements of stability of surrounding rock and support stability. The three bench method is more advantageous in construction schedule, resource utilization, cost, process transformation and the construction difficuhy. Therefore, as far as the project is con- cerned, the three bench method should be adopted in the shallow large span tunnel construction in the city of Changsha, which can ensure the safety, speed and efficiency of the construction. The research results provide a further exploration about reasonable construction method in the shallow large span tunnel constructions, and offers useful references for the design and monitoring of the tunnel engineering.