Highway Arch Tunnel Structure Optimization Study

Along with the wide application of double-arc tunnel in our country, double-arc tunnel has exposed more and more problem. For example, its perturbation more to rock and middle-wall's stability is difficult to guarantee during the construction process; after building up, the concrete of middle-wall and the second shell emergence fracture and the leakage on the top of middle-wall, etc. At this current situation, this paper proceeded numerical simulation study to double-arc tunnel construction process, Then regarded the result as a basement and took a series of optimization measures to double-arc tunnel in succession.In this paper, combining with ANSYS we expound the numerical analysis methods & ways to simulation of tunnel construction. Taking the construction method named "three headings method" as an example, a 2D numerical simulation was carried on by elasto-plastic FEM with ANSYS 6.1. From the result, we got the displacement trends of middle-wall in the course of constructing, gave improve suggestion to the establishment of "heading hole" & the middle-wall's refilling method and brought up the view that the double-arc tunnel should be studied and designed by an enormous section of equivalent". The next, in order to deal the leakage on the top of middle-wall, introduced steel construction trially into tunnel and gave a new section form(the double-arc tunnel of middle-wall made of steel); then, aim at the double-arc tunnel of middle-wall made of steel, we gave a new construct way called "expand excavating method with middle leading hole". At last, in order to verifying its feasibility, aid by ANSYS, we gone on dynamic numerical simulation analysis to the new section form double-arc tunnel adopted expand excavating method with middle leading hole, and the result of calculation with new section form tunnel compared with the data of present double-arc tunnel, proved the validity optimized.This paper analysis the reason that double-arc runners problem produced during the course of constructing and serving at present, Having carried on the helpful try in the double-arc tunnel's optimization, the conclusion will has certain directive significance to double-arc tunnel's researching and building in the future...