Study on control effect of pile load in shield tunnel on tunnel floating caused by foundation pit excavation
The excavation of foundation pit will cause the floating of the underlying shield tunnel,and the loading in the tunnel can effectively control the floating.Using the two-stage method,the formula for calculating the floating of shield tunnel caused by the excavation of foundation pit with the stacking measures in tunnel was derived in this paper.Firstly,the image source method was used to calculate the tunnel additional stress caused by the bottom uplift of foundation pit excavation.The method that can consider the soil condition was used to calculate the tunnel additional stress caused by the load in the tunnel,and the total additional stress was superimposed.Secondly,the force and deformation of the tunnel were calculated by using the cooperative model of rotation and staggered platform.Midas finite element software was used to model the specific working conditions,and the numerical simulation results of tunnel longitudinal bulge were compared with the formula calculation results.The results show that the calculated results of the proposed method are in good agreement with the finite element simulation results,which verifies the rationality of the proposed method.It is assumed that the excavation length of the foundation pit is L,and the optimal load range is within±L/3 from the load center.The control effect is weakened when the optimal load range is exceeded.The soil internal friction angle has great influence on tunnel deformation.The smaller the soil internal friction angle,the better the control effect of pile load on tunnel deformation.
foundation pit engineeringshield tunnelstacking in tunnelimage source methodadditional stress
魏纲、周烨波、王哲、翁家华
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浙大城市学院浙江省城市盾构隧道安全建造与智能养护重点实验室,浙江杭州,310015
浙大城市学院城市基础设施智能化浙江省工程研究中心,浙江杭州,310015
浙江工业大学岩土工程研究所,浙江杭州,310014
基坑工程 盾构隧道 隧道内堆载 影像源法 附加应力
浙江省基础公益研究计划项目Basic Public Welfare Research Program of Zhejiang Province
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