富水蚀变岩隧道施工稳定性分析

发布时间：2018-03-23 05:04

本文选题：富水　切入点：全风化花岗岩　出处：《石家庄铁道大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文以贵广高铁贺州段东科岭隧道为工程背景，研究富水、风化蚀变花岗岩地层的工程特性及隧道稳定性特点。饱和全风化花岗岩地层由于水的存在使得围岩软弱易流坍，，洞室自稳能力很弱。针对这种地层的隧道施工，非常有效的一种方法是先进行降水，再进行隧道开挖。通过采用流固耦合理论的计算方法，使用FLAC3D数值模拟手段，考虑降水前后CD法和核心土法，分析比较隧道施工引起的地表沉降、洞周位移和支护结构内力。降水前因为各项位移指标都较大，且变形速率也较大，不能使用核心土法施工，可以采用CD法施工，但是施工效率低下；采用降水井降水后CD法和核心土法的计算结果相差较小，且都能满足施工稳定性要求，考虑施工方便性应采用核心土法施工。在不降水的情况下，若要采用核心土法施工应对围岩进行加固，本文研究了合理的注浆加固圈厚度得出了合理的加固圈厚度为2.5m，再以2.5m合理的注浆加固圈厚度为基准研究合理的注浆加固范围，得出合理的注浆加固范围角为以隧道中心为圆心的拱顶240°范围，此时隧道的各项位移和应力指标都满足要求，且再增大注浆圈厚度和范围角后对控制位移以及应力的效果已经不明显。
[Abstract]:In this paper, the engineering characteristics and tunnel stability characteristics of water-rich and weathered altered granite strata are studied in the engineering background of Dongkeling Tunnel in Hezhou Section of Gui-Guang High Speed Railway. The saturated fully weathered granite strata are weak and prone to flow and collapse due to the presence of water. For tunnel construction in this kind of stratum, one of the most effective methods is to first dewatering and then to excavate the tunnel. The surface settlement caused by tunnel construction is analyzed and compared by using the fluid-solid coupling theory and the FLAC3D numerical simulation method, considering the CD method and the core soil method before and after precipitation. The displacement around the hole and the internal force of the supporting structure. Before precipitation, because of the large displacement index and the large deformation rate, the core soil method can not be used for construction, but the construction efficiency is low. The calculation results of CD method and core soil method after dewatering are small and can meet the requirements of construction stability. Considering the convenience of construction, the core soil method should be adopted. In the case of no precipitation, if the core soil construction should be used to strengthen the surrounding rock, In this paper, the reasonable thickness of grouting reinforcement ring is studied. The reasonable thickness of reinforcing ring is 2.5 m, and then the reasonable grouting reinforcement range is studied based on 2.5 m reasonable thickness of grouting reinforcement ring. It is concluded that the reasonable angle of grouting reinforcement range is 240 掳with the center of the tunnel as the center of the arch, and all the displacement and stress indexes of the tunnel meet the requirements. The effect of increasing the thickness and range angle of grouting ring on controlling displacement and stress is not obvious.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.49

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