The Choice Of Shallow Submersion And Unsymmetrical Loaded Double-arch Tunnel's Plan Of Construction And Structure Optimization

Along with our country's highway rapid development, double-arch tunnel which take one kind of special tunnel style more and more widely to use, by the terrain and the route selection influence, double-arch tunnel mostly have the shallow submersion and unsymmetrical loaded problem, in addition to the double-arch tunnel's structure to be complex, the structure stressful condition constructs the working procedure influence to be big, therefore, it has the necessity to the shallow submersion and unsymmetrical loaded double-arch tunnel's different construction process to carry on the numerical analysis, in order to determines the reasonable job practice and the structural style.This article used the numerical simulation method analysis 5 kind of different ground inclination angles and 4 kind of different burying depth situation double-arch tunnel's initial period supports, the center pillar and second lining's finally and biggest big and small principal stress and the displacement has conducted the detailed research. Through the numerical simulation result contrastive analysis, we can see: ground inclination angle's influence to the double-arch tunnel's structure stress and stablity is bigger than the influence of depth; When the ground inclination angle is smaller than 25°, the construction working procedure of excavate deeply side first to be more reasonable; When the ground inclination angle is bigger than 25°, in the construction, if we can guarantee the center pillar's stability through methods of center pillar backfill and monitoring measure, the construction working procedure of excavates the deeply side first to be more reasonable, if we cannot guarantee, the construction working procedure of excavate shallow side first to be more reasonable.According to numerical simulation's result of the shallow submersion and unsymmetrical loaded double-arch tunnel, the article optimize and analysis the center pillar and second lining of double-arch tunnel. The findings indicated:"the board and pillar integrated"center pillar has effect on reduces the center pillar's low board stress concentration, reduces big and small principal stress of the center pillar and reduces second lining's big principal stress; Uses the asymmetrical second lining structure is completely feasible, the thickness of latter excavated hole's second lining can be reduced 25% to 35%.