摘要
成都地铁区间盾构隧道所处地层主要为典型富水砂卵石地层,盾构施工引起的地层损失在地下水、地面荷载等影响下很容易形成滞后沉降,导致地表发生塌陷。针对成都地铁1号线一期工程建设经验,总结了砂卵石地层滞后沉降形成的原因,同时,采用颗粒分析软件PFC2D,从细观层面对砂卵石地层中滞后沉降的发展形成过程进行模拟,分析隧道埋深、地层空洞位置等因素对滞后沉降的影响。研究表明,砂卵石地层的特殊工程地质性质是滞后沉降形成的根本原因,盾构施工工艺是关键影响因素。细观研究表明,地层损失导致在隧道两侧上方约45°方向出现两条破碎带,形成三角形的松散区域,洞周地层应力发生显著变化。隧道埋深直接影响滞后沉降是否发生,地层空洞方位对滞后沉降的发生区域有重要影响。
The Chengdu metro shield tunnel is mainly located in water-rich sandy cobble strata and the delayed settlement caused by ground loss will easily occur under the influence of groundwater and surface loading,making the ground surface collapse. The cause of delayed settlement in sandy cobble strata was summarized based on the construction experiences of Chengdu metro line 1. The particle analysis software PFC2 D,which would better reflect the discrete features of sandy cobble strata,was used to simulate the delayed settlement development process from the micro view,the impact of the buried depth and location of ground void on delayed settlement was also studied. The results show that the specific engineering geological properties of sandy cobble strata is the basic factor of delayed settlement,and shield construction technologies are the key influencing factors. Microscopic studies show that,there are two broken belts located at both sides above the tunnel with an angle about 45° caused by ground loss,forming a triangle loose region,meanwhile the ground stresses around the tunnel change significantly. Tunnel buried depth affects the occurrence of delayed settlement and the ground void location has important impact on the settlement condition.
出处
《地下空间与工程学报》
CSCD
北大核心
2015年第1期171-177,265,共8页
Chinese Journal of Underground Space and Engineering
基金
国家重点基础研究发展计划(973计划)(2010CB732105)
高铁联合基金重点项目(U1134208)
国家自然科学基金项目(50925830
50908193)
关键词
盾构施工
砂卵石地层
滞后沉降
颗粒离散元
shield tunneling
sandy cobble strata
delayed settlement
particle distinct element method
