不同埋深下地铁隧道围岩破坏的试验研究  

Model Test for Rock Failure During Metro Tunnelling at Different Overburden Depths

作　　者：李倩倩[1] 张顶立[1] 张成平[1] 房倩[1] 

机构地区：[1]北京交通大学城市地下工程教育部重点实验室,北京100044

出　　处：《现代隧道技术》2013年第6期85-93,共9页Modern Tunnelling Technology

基　　金：国家重点基础研究发展计划(973)项目(2010CB732102);教育部新世纪优秀人才支持计划(NCET-12-0770);国家自然科学基金项目(No.51108022)

摘　　要：文章采用模型试验对北京粘性地层中不同埋深条件下地铁区间隧道的围岩变形和破坏规律进行了研究。相似模型试验分析结果表明,随着埋深的增加,相应增大了地层变形传递到地表的距离,同时地层中拱结构的存在也在一定程度上阻隔了地层变形的发展,进而降低了地表沉降值;不同埋深下地铁隧道围岩的破坏过程是类似的,首先是起拱处的围岩发生剪切滑移破坏,然后是顶部围岩发生拉剪破坏。不同埋深下围岩破坏的特点是:埋深小于2.5D(D为隧道等效直径)时,隧道围岩塌落破坏可发展到地表,塌落形式类似椎体;埋深大于或等于2.5D时,隧道围岩的破坏程度相对较小,围岩能够形成拱结构,坍塌破坏未发展到地表,塌落形式类似拱形。在此基础上提出的相应控制措施是:对于埋深小于2.5D的隧道,建议在隧道起拱处双排或三排布置锁脚锚管,并且预先密排或双排布置顶部小导管注浆加固地层;对于埋深大于或等于2.5D的隧道,可采用单排布置锁脚锚管的辅助支护和均匀布置顶部小导管的预支护措施。The deformation and failure tnechanism of surrounding rock passed through by the running tunnel of the Beijing metro is studied by a model test regarding different depths of overburden in a clay stratum. Tje results show that overburden depth directly affects ground deformation and settlement, and that the rock failure process is similar no matter what the overburden depth is, which means that rock shear-slide failure initiates at the tunnel springing and develops upward gradually, uhimately causing tensile-shear failure at the tunnel crown. As for an overburden depth〈2.SD （D =tunnel diameter）, the rock collapse will develop to the ground surface in a conical shape, and for an overburden depth ≥2.5D, the rock collapse will not develop to the ground surface in the shape of an arch. It is recommended that, for the first case, two or three rows of locking anchors are installed at the tunnel springing and one row of dense grouting condulets or two rows of grouting condulets are installed at the tunnel roof to consolidate the ground. For the second case, the pre-support measures with one row of locking anchors and grouting condulets are proposed.

关 键 词：地铁隧道 埋深 模型试验 地层变形 围岩破坏 

分 类 号：U452.12[建筑科学—桥梁与隧道工程]