含双承压水地层中地连墙槽壁稳定性有限元分析

Finite Element Analysis of Trench Stability of Diaphragm Wall in the Formation with Double Confined Water

为进行渗流作用下双承压含水层地连墙槽壁破坏模式分析,采用有限元ABAQUS结合强度折减法对苏州春申湖路快速化改造工程湖区地下连续墙进行数值分析,确定了槽壁滑裂面位置和滑动体形状,得到槽壁整体稳定性安全系数。结果表明:渗透系数大的粉砂层有效渗透速度较大,且有效渗透速度随着土体强度折减次数的增加呈现线性增加趋势;结合强度折减法确定了渗流作用下双承压含水层在成槽开挖中的破坏模式,含承压水的双粉砂层底端最先出现塑性区,随后塑性区由双粉砂层向中间扩展,滑裂面形状最终呈现弓字状;双粉砂层成槽开挖之间存在相互耦合影响。结合实测结果进行对比分析,数值计算结果和声波实测较为吻合,从而验证了数值分析的准确性。

In order to analyze the failure mode of the diaphragm wall of double confined aquifer under the action of seepage,the finite element ABAQUS combined with strength reduction method is adopted to numerically analyze the underground diaphragm wall of Suzhou Chunshenhu Road Rapid Transformation Project,determine the position of the slip surface and the shape of the sliding body,and obtain the safety factor of the overall stability of the trench wall.The results show that,the silty sand layer with large permeability coefficient has larger effective seepage velocity,and the effective penetration rate is increased with the increase of soil strength degradation times by a linear increasing trend;by using the strength reduction method,the failure mode of double confined aquifers under the action of seepage in trench excavation is determined,that is,the double silty sand layers with confined water first appear plastic zone in the lower end,then the plastic zone expands from the double silty sand layers to the middle area,and finally a bow-type slip surface is formed;and there is a mutual coupling effect between the double silty sand layers during trench excavation.Comparing with the measured results,the numerical calculation results are in good agreement with the acoustic measured results,which verifies the accuracy of numerical analysis.