基于GHS模型和瞬态渗流-固结完全耦合的基坑开挖分析

Analysis of Foundation Pit Excavation Based on GHS Model and Complete Coupling of Transient Seepage and Consolidation

以福建省厦门市滨海东大道改造工程交叉上跨厦门地铁3号线区间隧道段基坑项目为例,采用Plaxis软件建立了基坑有限元模型并确定了土体参数,对比分析了瞬态渗流-固结完全耦合与稳态渗流-固结半耦合分析方法计算得到的基坑降水和沉降差异,以及HSS模型和稳态渗流-固结半耦合与GHS模型和瞬态渗流-固结完全耦合分析方法计算得到的基坑坑底竖向位移差异。分析结果表明:采用瞬态渗流-固结完全耦合分析方法计算得到的基坑水位变化值更接近实测值;采用GHS模型和瞬态渗流-固结完全耦合分析方法计算得到的基坑坑底竖向变形和下卧地铁隧道右线管片结构竖向位移更接近实测值;因此基于GHS模型和瞬态渗流-固结完全耦合的基坑开挖分析方法计算精度更高。

Taking the foundation pit of Binhai East Avenue Reconstruction Project in Xiamen City,Fujian Province,as an example,the finite element model of the foundation pit was established by Plaxis software and the soil parameters were determined.The foundation pit dewatering and settlement difference were compared and analyzed by transient seepage-consolidation complete coupled analysis method and steady seepage-consolidation semi coupled analysis method,and the vertical displacement difference at the bottom of the foundation pit calculated by the HSS model and steady seepage-consolidation semi coupled analysis method,GHS model and transient seepageconsolidation complete coupled analysis method.The analysis results indicate that the water level changing value of foundation pit by the transient seepage-consolidation complete coupled analysis method are more closer to the measured values;The vertical deformation of the foundation pit bottom and the vertical displacement of the right line segment structure of the underground subway tunnel calculated by the GHS model and transient seepage-consolidation complete coupled analysis method are more closer to the measured values;Therefore,the foundation pits excavation analysis of the GHS model and transient seepage-consolidation complete coupled analysis method is more accurate.