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

摘要

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.%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。