Even Arch Tunnel Of Mechanical Property Analysis And Design And Construction Optimized

Based on 1~# and 3~# double-arch tunnels of Yao-shui-xia in the Huangyuan— Daotanghe first class highway Qinghai Province, by field measurements, the paper analyses the variable characters of compressive stress in the first lining ,and the contact stress between first and second lining, and concrete strain and stress in the second lining. Applying the finite element program 2D — a ,different construction methods which had been used in 1~# and 3~# tunnels were made a simulative analysis.The results of FEA was compared with that of field survey, some beneficial conclusion were educed.On the basis of field observation and FEA, the paper puts forward "steps and headings method" in the III class surrounding rock .Through FEA, this method was put into construction and favorable effects were obtained. Aimed to the double-arch tunnel, unsymmetrical design of the structure of the first lining was putted forward and analyzed .The feasibility was proved by theory, which established a foundation for the actual use.