| Foundation pit support is an indispensable part of foundation pit engineering,which is closely related to the interaction of foundation pit stratum information,depth,and surrounding environment.With the advancement of urbanization,the factors affecting foundation pit engineering are more and more complex,but the existing supporting design methods are lack of changes that are suitable for the actual situation.In view of the complicated factors of safety,the key to the foundation pit supporting measures is to analyze the potential failure mechanism of foundation pit.The failure mechanism of foundation pit is simulated by finite element method,and the supporting measures of foundation pit engineering are analyzed and verified.According to the typical stratum information and foundation pit accident in Jinan,the paper reveals the failure mechanism of foundation pit in Jinan typical stratum by using the PLAXIS 3D software,clarifies the failure mode of the foundation pit engineering of the alluvial stratum of the Yellow River and the alluvial proluvial stratum in front of the mountain,establishes the sliding analysis solution of the soft interlayer at the bottom of the Yellow River alluvial stratum,and determines the influence of the weak interlayer foundation pit in the middle of the area on the supporting measures,The mechanism of shallow layer collapse in the top layer of alluvial proluvial stratum is analyzed.It is proposed to use the three-dimensional finite element numerical model to determine the optimal support selection of foundation pits.The paper has made the following progress:1.The influence of weak interlayer on slope in Xiaoqinghe area of Jinan is revealed.The circular plane sliding failure mode is defined.When there is weak interlayer at the bottom of the pit,the overall failure mode of the slope changes from circular slip mode to circular plane sliding mode.According to the circular arc plane sliding failure mode,the existing supporting measures of foundation pit are analyzed,and the optimal support scheme to effectively solve the influence of soft interlayer is proposed.According to the weak interlayer of Jinan typical stratum,the analytical solution of circular arc plane sliding failure mode is established.The answer to the solution is the same as the actual situation.The safety factor of foundation pit is solved by using the analytic solution.2.The influence of soft interlayer in the middle of foundation pit on the failure mode of foundation pit is analyzed.The soft interlayer becomes the most unfavorable sliding zone.The influence of the depth and thickness of soft interlayer on the displacement of foundation pit is studied,and the design suggestions for supporting of this kind of stratum are put forward.3.The mechanical analysis of shallow collapse is carried out,the collapse failure mechanism at the top of foundation pit is determined,the combined failure mode of tension crack and sliding failure is put forward,the influence of support measures on slope stability is analyzed and the design suggestions of support are put forward.According to the combined failure mode,an analytical solution of safety factor is established for engineering use,The relationship between safety factor and slope rate is analyzed. |
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