Study on the Influence of Freeze-thaw Deterioration of Surrounding Rock on the Stability of Tunnel in Seasonal Cold Area
The freeze-thaw damage of surrounding rock will cause the deformation pressure of lining to increase,which will adversely affect the stability of lining,which is a key problem in the research of tunnel engineering in seasonal cold area.In this paper,the stress-strain curves of sandstone under different freeze-thaw cycles and compression tests are obtained,and then the deformation parameters and strength parameters of surrounding rock are obtained from the stress-strain curves.Finally,the change rule of rock mechanics parameters is embedded into ABAQUS software to numerically analyze the long-term stability of the tunnel under freeze-thaw cycle,and the stress field and displacement field of surrounding rock and lining under 0,6,12,18 and 24 cycles of freeze-thaw cycle are obtained respectively.The results show that:① With the increase of the number of freeze-thaw cycles,the maximum and minimum principal stresses on the surrounding rock decrease linearly;② The maximum principal stress,the minimum principal stress and the displacement of the lining increase exponentially;③ Compared with the condition without freeze-thaw,the maximum and minimum principal stresses of surrounding rock after 24 freeze-thaw cycles de-creased by 43.69%and 20.66%,respectively;④ The maximum principal stress,minimum principal stress of lining and maxi-mum settlement of vault increased by 13.64%,15.75%and 49.36%respectively.In the design of tunnel support in cold area,it is necessary to consider the problem that the self-stability of surrounding rock attenuates under freezing and thawing action,which leads to the increase of the force of supporting structure.
tunnel in cold regiontunnel stabilityfreeze-thaw cyclesurrounding rockstress fielddisplacement field
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