Study On The Modeling Tests Of Double-Arch Highway Tunnel

When constructing senior highways in China, the project of double-arch tunnel is often adopted in special geologic and limited topography districts in order to meet the need of road type and outspreading road, to get better technological and economical purpose. At present considerable amount twin-bore tunnels have been constructed in our country. But there are many problems in the construction and mobilization of the double-arch tunnels such as construction method is single, construction mechanics not defmitude and the theory of design and construction that we can make for reference is scarce.Based on the Xiaojinkou double-arch tunnel engineering of the Guanghui highway, taking geometric similarity ratio Cl=25 and bulk density similarity ratio Cγ=1 as basic similarity ratio and grouping according to class of surrounding rock, so as to achieve complete similarity of various controlled physical and mechanical parameters in the elastic range and strictly simulate the characteristic of surrounding rock, physical property, original earth stress field, stiffness of support structures and support time, excavation process . 18 groups of similar modeling tests of whole construction process are completed for class II and III surrounding rock with such four construction methods as middle-pilot-and -lateral-pilots, double-section-and-lateral-pilots, middle-pilot-and-half-section and middle-pilot-and-full-section. To study the results of every boring method, the results of the tunnel convergence, the inner force of anchor pipe, the stress between the surrounding rock and support and inner force of liner are gained in the difference construction method in class II and III surrounding rock. And adopting FEM to carry out 2D numerical simulation analysis on whole construction of Xiaojinkou double-arch tunnel body section, completing 5 groups of elastic-plastic numerical simulation analysis on whole construction process in class II and III surrounding rock with the four construction methods mentioned above. At last, the thesis draw the conclusion of reasonable construction technology of Xiaojinkou double-arch tunnel in class II and III surrounding rock and the mechanic property of the support.