基于黄土工程特性的隧道围岩空间位移分析  

Analysis on spatial displacement of surrounding rock based on engineering properties of loess

作　　者：扈世民[1] 

机构地区：[1]北京城建设计研究总院有限责任公司,北京100037

出　　处：《土木工程学报》2013年第9期117-122,共6页China Civil Engineering Journal

基　　金：铁道部科技研究开发计划重大项目(2009G005)

摘　　要：以兰渝高铁黄土隧道为工程背景,采用室内试验与三维数值模拟等措施,基于黄土工程特性研究隧道围岩空间位移的变形特征,可得结论:①黄土工程特性表现为结构性与垂直节理发育,结构性黄土仍服从Mohr-Coulomb准则且破坏包线为双线性折线;②大量存在的孔隙结构与较小抗拉强度造成黄土围岩垂直节理普遍发育;③拱部竖向位移衰减较慢,边墙水平位移衰减较快,垂直节理的存在破坏了围岩的完整性,开挖扰动引起的围岩变形逐渐向深部转移;④考虑黄土工程特性,开挖扰动引起的塑性区面积增幅较大且表现为较大范围张拉破坏;⑤与既有理论相比,模型计算充分考虑了黄土工程特型,由于垂直节理的普遍存在,开挖引起的掌子面挤出变形较大,故更符合黄土围岩工程实际。For the loess tunnel in Lanzhou-Chongqing high-speed railway, the spatial deformation characteristics of surrounding rock is studied based on the loess engineering properties. The results show that： （1） The engineering properties of loess are characterized by its structure and well developed vertical joints, and structural loess may be modeled by the Mohr-Coulomh criterion with the bilinear failure envelope ; （2） The well developed vertical joints may be caused by a large quantity of pore structure and small tensile strength; （3） The vertical displacement of the crown attenuates slowly, while the horizontal displacement of the side wall attenuates rapidly. The integrity of surrounding rock may be impaired due to the vertical joints, the deformation of surrounding rock caused by the excavation disturbance is gradually transferred to the deep; （4） In view of the engineering properties of loess, the plastic zone caused by excavation disturbance increases quickly and leads to tension damage in a wide range; （5） Compared to the existing theories, the computational model may fully consider the engineering properties. Due to the widespread vertical joints, the extrusion deformation at tunnel face induced by tunnel excavation is large, and hence the simulated results accord with the practical surrounding rock in loess.

关 键 词：工程特性 结构性 垂直节理 空间位移 先期位移 

分 类 号：TU443[建筑科学—岩土工程] U451[建筑科学—土工工程]