Mountain Bias Of The Shallow Arch Tunnel Bolting And Shotcrete Shoring Optimization

The double-arch tunnel is a new large span tunnel is presented with the rapid development of high way constructing in our country. However, because of its own characteristics, such as shallow depth of burial, unsymmetrical pressure, small height-to-span ratio, complex geological conditions and structural stress, the application and study of double-arch tunnel under unsymmetrical pressure is still at a preliminarily stage, and this is especially true for the systematic study on the structural design and the mechanism of the mechanical response during construction.Based on the Jiepaiao double-arch tunnel engineering of the Huaixin(Huaihua—Xinhuang) highway, the thesis primarily studies the mechanics problem of the excavating and supporting during the double-arch tunnel construction and the structure optimization by the finite element method(FEM) calculation. The present research reviewed the double-arch tunnel, structural optimization of tunnel and mechanics analysis approach at home and abroad. Basing on the actual condition and considering the special geological conditions of jiepaiao double-arch tunnel, the rule of pression and distortion of the double-arch tunnel under unsymmetrical pressure is geted by contrasting study of symmetrical and unsymmetrical pressure FEM calculation result. The advice of changing the length and angle of the anchor-hold and the thickness of the shotcrete lining on the design optimization is presented. The optimization project are discussed, and the feasibility argumentation of the optimization project is processed,in which the optimization is the sum of the anchor axial force. Then, the ADPL optimization program is written,in which the length and angle of the anchor-hold and the thickness of the shotcrete lining are automatic changed, and the bolting and shotcrete lining which can resist the unsymmetrical pressure better is geted.Finally, the present study summarizes the optimization projects of double-arch tunnel under unsymmetrical pressure and its meaning. Combining the results of FEM analysis of the tunnel, some problems and suggestions are discussed.The research is about how to improve the double-arch tunnel construction under unsymmetrical pressure such as Jiepaiao and its resisting unsymmetrical pressure better. It has the guiding significance to reduce the engineering accident because of the unsuitable design, the economizing of the construction material, and the design and construction of the similar tunnel engineering.