大断面黄土隧道不同试验工法下的力学特性及变形特征研究

针对大断面黄土隧道的工法适用性问题,依托郑西客运专线陕西境内秦东、潼洛川和高桥等隧道,开展大断面黄土隧道中的CRD、双侧壁导坑、CD、留核心土台阶法及双层支护台阶法5种试验工法的试验,通过现场试验测试及数据分析,研究不同试验工法下的力学特性和变形特征。总结其变形特征为垂直位移显著,变形受封闭距离与支护刚度影响明显;分析对地表沉降的控制效果,受力特征分析显示型钢受压明显而锚杆受力较小;得到不同埋深下的围岩压力特征曲线;接触压力测试显示刚度大的双层支护较单层支护小。最后对不同试验工法的适用性进行综合评价。

Study on Mechanical and Deformation Characteristics of Large Cross-section Loess Tunnels Constructed by Different Methods

Experimental study is made on 5 construction methods of large cross section loess tunnels, including CRD method, double side drift method, CD method, core reserved bench method and double layer support bench method, with Qindong tunnel, Tongluochuan tunnel and Gaoqiao tunnel on Zhengzhou Xi’an passenger dedicated line as examples. The mechanical and deformation characteristics of the tunnels constructed by different construction methods are analyzed on basis of site measurement and data analysis. Conclusions drawn are as follows: the deformation of the loess tunnel is featured with significant vertical displacement, and the deformation is significantly affected by the closure distance and the support rigidity; The analysis on the ground surface settlement control effect shows that the shaped steel is under significant pressure and the bolt is under small force; The characteristic curves of the pressure of the surrounding rock under different depths are gained; The measurement of the contact pressure indicates that the double layer support structure, which has larger rigidity, has smaller contact pressure than the single layer support. In the end, compressive evaluation is made on the applicability of the construction methods studied. 