Application Of Underground Diaphragm Wall In The Foundation Pit Engineering Of Circular Underground Warehouse

China,as a major grain producing country, how to guarantee the grain safety in is a very important problem. The granary construction is safeguard food safety is important, underground silos with green energy saving and environmental protection and other features, so it has good prospects for development.This topic comes from the food service project of Ministry of science and technology of ecological storage and technical system of new type warehouse development "(201413007).The main research is the application of underground diaphragm wall supporting in the foundation pit engineering of underground barn.It takes an underground warehouse construction project as an example, according to the relevant norms, using application of means of theory analysis, mechanical calculation and numerical simulation analysis of underground diaphragm wall supporting in deep circular excavation were studied.The main research contents and conclusions of this paper are as follows:(1)Based on the specification, based on the comparative study of various supporting methods, the design scheme of the project is determined: underground diaphragm wall supporting and lining wall.(2)By considering the arching effect of plane elastic foundation beam method, Lizheng software for computing platform, the design scheme of calculated, that underground diaphragm wall structure calculation result is: maximum displacement in the middle of underground diaphragm wall, the value of 4.7 mm; the maximum shear force in continuous middle wall, the value for the 129.36kN; bending moment of maximum-279.25kN*m, maximum is also in the middle of underground diaphragm wall.(3)Using ABAQUS software and on the whole the foundation pit engineering numerical simulation calculation, it is concluded that the calculation result is: foundation pit at the bottom of the maximum vertical displacement 23.4mm and minimum vertical displacement 7.1mm; surface subsidence the maximum value for 11.34 mm in distance foundation pit edge 5m surface, as far away from the direction of the foundation pit is gradually reduced, until tends to zero so far. After the excavation of soil stress due to self gravity to generate the maximum stress for 280.13 MPa and soil surface stress is the minimum. The underground diaphragm wall stress distribution is at the toe of the wall stress maximum stress value for 838.72MPa; underground diaphragm wall lateral displacement maximum 6.23 mm and top lateral displacement is small, 2.27 mm and lateral displacement as a whole is combined parabola type.(4)By comparison with 2D considering arch effect of plane elastic foundation beam method to get the results and using three dimensional numerical simulation of the gap between the results of the analysis within the scope allowed by the engineering, and graphic method to calculate the cost is low, so in the engineering practice by considering the arching effect of plane elastic foundation beam method can meet the requirements.(5)Due to the practical engineering of a large number of circular underground diaphragm wall supporting is not absolute round, often close to the round of the regular polygon, the consideration of the arch effect of plane elastic foundation beam method in the application of the need for a correction, based on the relevant laws of the study found that regular polygon underground diaphragm wall supporting structure, the pit deformation is smaller than the circular underground diaphragm wall supporting structure, while the middle deformation is larger than that of the circular underground diaphragm wall supporting structure, when the edge for a long time can be regarded as the circular pit does not need to modify, and the number of edges is less is not the method.(6)The underground diaphragm wall supporting "two wall one" engineering technology has a good economy and security in the circular foundation pit, it is worthy of popularization and application.