秦淮东河隧洞施工过程数值模拟分析

为保证秦淮东河工程西村隧洞的顺利实施,采用有限单元法对工程区的天然应力场进行数值模拟分析,建立三洞并线计算模型,分别从新挖河道、新建隧洞及上部覆土回填三个过程进行应力应变分析。提出分层开挖及回填的单层深度取值,监测分层开挖及回填时隧洞顶部位移及应力过程变化值。研究发现,隧洞进口处上部覆土约开挖四分之一深度时,存在边坡稳定隐患。覆土回填过程中,隧洞底部因竖向应力较大,而出现向上微拱变形。研究成果可直接应用于引水隧洞工程的设计计算和施工质量控制,可在类似工程中加以推广应用。

Numerical Simulation and Analysis of Construction Process of Qinghuai East River Tunnel

In order to ensure the smooth implementation of the Xicun Tunnel in Qinghuai East River Project,the finite element method is used to carry out the numerical simulation and analysis on the natural stress field of the project area.A three-tunnel parallel calculation model is established.The stress and strain analysis is carried out in three processes of newly excavating river,newly building tunnel and upper covering backfilling.The value of single layer depth of layered excavation and backfilling is proposed to monitor the change of the displacement and stress on the top of tunnel during layered excavation and backfilling.The study shows that there is a hidden danger of slope stability when the upper covering at the entrance of tunnel is excavated to a depth of about a quarter.In the process of covering backfilling,the bottom of the tunnel presents the upward slightly arch deformation because of greater vertical stress.The study result can be directly applied to the design calculation and construction quality control of the diversion tunnel project,and can be popularized and applied in the similar projects.