施工方法对黄土隧道围岩结构相互作用的影响

Influence of Construction Method on Interaction of Surrounding Rock Structure of Loess Tunnel

研究目的:因黄土自身特性,以致于黄土隧道施工时往往会出现围岩变形较大且支护结构受力情况复杂的现象,因而黄土隧道施工时一般采用分部开挖法。为了探明不同的分部开挖法对黄土隧道围岩结构相互作用的影响,现以某富水黄土隧道为工程背景,采用有限元软件Midas GTS分别对CRD法、CD法及三台阶七步开挖法进行数值模拟,分析比较三种施工方法下的围岩位移、应力及弹性反力系数k,并通过实测数据与既有理论对数值计算结果进行检验。研究结论:(1)不同的施工方法对富水黄土隧道的围岩位移、应力以及弹性反力系数k值大小确有一定的影响;(2)通过实测数据与既有理论的检验,证明了数值模拟计算结果的合理性,因此,表2中的围岩弹性反力系数k的取值,可为今后类似工程设计、施工等提供参考;(3)本研究成果有助于理解富水黄土隧道围岩结构相互作用的特点,并可应用于富水黄土隧道计算分析相关领域。

Research purposes: Because of the characteristics of loess itself, the phenomenon of large deformation of surrounding rock and complex stress of supporting structure often occurs in the construction of loess tunnel. Therefore, the partial excavation method is generally used in the construction of loess tunnels. In order to find out the influence of different partial excavation methods on the interaction of loess tunnel surrounding rock structure, a water-rich loess tunnel is taken as the engineering background. The finite element software Midas GTS is used to simulate the CRD method, CD method and three-stage seven-step excavation method respectively. The displacement, stress and elastic reaction coefficient k of surrounding rock of three construction methods are analyzed and compared, and the numerical calculation results are verified through measured data and existing theories. Research conclusions:(1) Different construction methods have certain influence on the displacement, stress and elastic reaction coefficient k of surrounding rock of water-rich loess tunnel.(2) The rationality of the numerical simulation results is verified by the measured data and the existing theory, Therefore, the value of elastic reaction coefficient k of surrounding rock in Table 2, it can provide reference for the design and construction of similar projects in the future.(3) The research results are helpful to understand the characteristics of the surrounding rock structural interaction of water-rich loess tunnel, and it can be applied to the related fields of calculation and analysis of water-rich loess tunnel.