隧道锚原位缩尺模型试验的施力方式研究  

Loading Mechanism Research on In-situ Reduced Scale Model Test of Tunnel Anchorage

作　　者：李维树[1] 王帅[1] 吴相超[1] 周火明[1] 

机构地区：[1]长江水利委员会长江科学院重庆分院,重庆400026

出　　处：《地下空间与工程学报》2017年第2期453-458,共6页Chinese Journal of Underground Space and Engineering

基　　金：国家青年科学基金(51409013)

摘　　要：介绍了隧道锚原位缩尺模型试验两种施力方法的原理及方法,剖析了不同施力方式对缩尺模型锚试验的影响。缩尺后模型尺寸变小,前拉法的散索难以可靠实施,直接影响拉拨效果,同时,拉拨中需要设置巨大的反力梁,不仅大大增加试验成本,而且对围岩变形测量影响大。为此研究了一种替代方法——后推法。以实例为基础剖析了前拉法的优缺点,介绍了后推法的原理、方法及实施要点,并以重庆几江长江大桥为例,采用有限差分法对模型锚不同施力方式作用后的塑性区分布、变形特征及破坏特征进行了比较分析,两种施力方法作用于模型锚后的塑性区分布和变形分布上有细微差别,通过重庆几江长江大桥1∶10缩尺模型试验验证,其破坏模式基本吻合,表明后推法可以替代前拉法。目前该方法得到了推广应用。Two loading methods and mechanisms were compared in in-situ reduced scale model test of tunnel anchorage,influence of different loading methods on reduced scale tunnel model was analyzed. Reducing the size of model,it is unreliable to apply anchorage cables in front-pull method and directly effects the pull-out result,and huge anti-force beam has to be set up to fix it,increasing the cost of test and affecting the monitor of surrounding rock deformation. Therefore,back-stepping method was put forward as a substituted way. The case was analyzed to elaborate the merits and drawbacks of front-pull method. At the same time,Jijiang yangtze river bridge in Chongqing was analyzed as an example to introduce the mechanism,the way and the taking points of back-stepping method.Finite difference method was taken to study the distribution of plastic zone in different loading conditions of model cable,to compare with the deformation characteristic and failure behavior. Finally,it concludes that there is a few distinctions between plastic zone distribution and deformation of model cable under two forcing conditions. The Jijiang yangtze river bridge model test in scale 1： 10 proves that the failure mechanism of front-pull method and back-stepping method basically tallies,which indicates front-pull method can been substituted by back-stepping method.

关 键 词：隧道锚原位模型试验 施力方式 前拉法 后推法 重庆几江长江大桥 

分 类 号：TD325[矿业工程—矿井建设]