Study on influence range of excavation of foundation pit with asymmetric envelope structure and its influence on existing narrow-long foundation pit
In order to study the influence range and depth of the excavation process on the surrounding soil and envelope structure,and the range and specific degree of the superimposed influence of different excavation stages on the adjacent nar-row-long foundation pit during the construction of foundation pit with asymmetric envelope structure,taking a transportation hub foundation pit project in Shanghai as a case,the monitoring data of the foundation pit excavation process were analyzed,and the construction process of new foundation pit and its influence on the existing narrow-long foundation pit were simulated by the finite element method. The results show that the main influence range of foundation pit excavation on surrounding soil is about 2.2 times the depth of foundation pit excavation. The deep horizontal displacement of the envelope structure presents a "spoon" shape,which is large in the upper and middle part and small in the lower part. The influence depth of foundation pit excavation on the envelope structure is 1.6 times the excavation depth. The excavation of the new foundation pit has a su-perimposed effect on the deformation of the existing foundation pit,and the greatest influence appear at the junction of the two pits,which makes the deformation there expand to 3.9 times of the original value. The influence range of soil excavation in the first layer is 100％ of the excavation area of the existing foundation pit,while the influence range of soil excavation in the sec-ond to fifth layers is only 23.4％ of the excavation area of the existing foundation pit. The research results can provide refer-ence for the excavation influence range of asymmetric envelope structure foundation pit engineering and similar envelope structure design schemes.
foundation pit monitoringasymmetric envelope structureinfluence rangenumerical simulationnarrow-long foundation pit
万方数据
维普
