隔离桩对干砂地基中基坑侧方隧道影响的模型试验研究  

Model tests on the effect of isolation pile on existing tunnel with adjacent excavation in dry sand

作　　者：徐晓兵[1] 胡琦[1,2] 曾理彬 王金昌 王哲[1] XU Xiaobing;HU Qi;ZENG Libin;WANG Jinchang;WANG Zhe(Institute of Geotechnical Engineering,Zhejiang University of Technology,Hangzhou,Zhejiang 310023,China;Dongtong Geotechnical Technology Co.,Ltd.,Hangzhou,Zhejiang 310000,China;Institute of Transportation Engineering,Zhejiang University,Hangzhou,Zhejiang 310058,China)

机构地区：[1]浙江工业大学岩土工程研究所,浙江杭州310023 [2]东通岩土科技股份有限公司,浙江杭州310000 [3]浙江大学交通工程研究所,浙江杭州310058

出　　处：《岩石力学与工程学报》2020年第S01期3015-3022,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51478434);浙江省公路管理局科研项目(2018H18,2018H19)。

摘　　要：为研究基坑开挖过程中隔离桩对基坑侧方近接隧道整体位移和自身变形的控制机制,在干砂地基中开展室内1g模型试验。设计了无隔离桩、有埋深隔离桩和无埋深隔离桩共3组试验,对基坑分步开挖过程中的围护结构水平位移、隧道位移和隧道环向弯矩进行监测,研究有无隔离桩及桩顶埋深对围护结构水平位移、隧道位移和隧道环向弯矩的影响规律。研究结果表明:对于无隔离桩工况,隧道水平位移、竖向位移和环向弯矩均随坑深隧深比(基坑深度/隧顶埋深)的增加呈不断增大趋势;相对于无隔离桩工况,有埋深隔离桩工况对围护结构水平位移、隧道水平位移、隧道竖向位移、隧道环向正弯矩和隧道环向负弯矩的控制效果较明显;相对于无隔离桩工况,无埋深隔离桩工况对围护结构水平位移、隧道环向正弯矩和隧道环向负弯矩起到了控制作用,但是隧道水平位移和竖向位移的最大值反而分别增大了32.0%和123.8%;隧道保护效果受到隔离桩阻隔作用和牵引作用的共同影响。In order to study the effect of isolation pile on controlling the displacement and deformation of the tunnel with adjacent excavation,laboratory 1 g model tests were carried out in dry sand.Three groups of experiments including no isolation pile,isolation pile with embedment depth and isolation pile without embedment depth were designed and conducted.The horizontal displacement of retaining structure and the displacement and circumferential bending moment of tunnel were monitored and studied.The results showed that,without isolation pile,the horizontal displacement of retaining structure,the horizontal and vertical displacements and circumferential bending moment of tunnel all increased with excavation process(an increase of the ratio of excavation depth to the tunnel depth).In the case of isolation pile with embedment depth,compared to the case without isolation pile,the horizontal displacement of retaining structure,the horizontal and vertical displacements of tunnel,and the positive and negative circumferential bending moments of tunnel were all well controlled.In the case of isolation pile without embedment depth,compared to the case without isolation pile,the horizontal displacement of retaining structure,and the positive and negative circumferential bending moments of tunnel decreased.However,the horizontal and vertical displacements of tunnel increased by 32.0%and 123.8%,respectively.It was found that,the tunnel was mainly influenced by the isolation and drag effects of the isolation pile.

关 键 词：桩基础 隔离桩 基坑 围护结构 隧道 位移 弯矩 

分 类 号：TU47[建筑科学—结构工程]