Analysis of Stress Characteristics of Lining Structures in Super-Large-Span Tunnel
To study the stress characteristics of the lining structure of a super-large-span tunnel,a three-dimensional numerical analysis model was established based on a double hole eight lane tunnel in Xiamen.Combined with on-site measurements,the stress characteristics on the lining structure and the load sharing ratio of the secondary lining were studied.The study shows that:(1)the stress exerted by the surrounding rock pressure on the initial support is smaller than the initial geostress of the surrounding rock,and the self stability ability of the surrounding rock is able to bear part of the surrounding rock load;under the action of dismantling the temporary partition wall and the weight of the secondary lining,the internal force of the initial support is redistributed.(2)The initial support shares about 90%of the surrounding rock load,and the sharing ratio at the foot of the arch is between 85.7%and 94%.(3)For strata with good geological conditions,the support strength of the secondary lining can be optimized and designed to save engineering costs.
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