临水偏压高架承台深基坑支护变形影响分析

Analysis of Deformation Influence of Deep Foundation Pit Support for By-Water & Bias-Pressure Viaduct Platform

城市高架建设中,受道路红线、河道蓝线等限制,高架局部沿河道布设。高架承台位于河岸岸坡时,由于河岸边坡以及陆域施工荷载引起偏压影响,造成承台基坑处于偏压受力工况,给设计和施工带来较大难题。通过研究偏压深基坑受力状态及其特点,采用反压填土,使得深基坑开挖过程中偏压状态合理、可控。嘉闵高架承台深基坑试验段的监测成果表明,基坑钢板桩施工对桥梁桩基变位影响在可控范围内,但实测桩基变形值约为允许值的77.3%,仍需引起足够重视。

Expanding of the urban road construction,limited to road red line and river blue line,the elevated highway will be layout along the river.The Elevated foundation will be located at the river bank.Owing to the imbalance load in this condition,it brings great difficulty to design and construction.In the excavation of the biaspressure deep foundation,the deformation stability of surrounding environment should be controlled,while the bridge piles deformation should be given attention too.Through the analysis of stress condition of the bias-pressure deep foundation,the back pressure fill method is used to make the excavation of deep foundation reasonable and controllable.In the test section of Jiamin viaduct deep foundation,the deformation of the bridge pile measured during the foundation support construction is acceptable,but the value can reach77.3%of the permitted value,this deformation should be taken seriously.