环端面不平整条件下衬砌管片抗剪承载特性研究OA北大核心CSTPCDEI

The unevenness of ring faces(or the local gaps due to gaskets)is inevitable during the assembling of lining segments,which could cause the cracking or damage of segments and might endanger the safety of lining structure in severe cases.Based on the shear resistance prototype test of lining segment,the refined numerical simulation for the P2-typed standard segment was established upon the ABAQUS numerical platform.The jacking plates were placed on the top of segment,the gaskets are placed at the bottom of segment,and the right gasket was left empty to form a local gap.The uniform load was gradually applied upon the top of segment through jacking plates.The mechanical responses of the segment with local void condition were analyzed under the gradual action of jacking force.The cracking process and the shearing capacity of segment with uneven ring face condition were well focused on.The simulation results show that the 1st crack appears on the upper part of segment inner surface with 2 mm under the jacking force of 850 kN.When the jacking force increases to 1 120 kN,the vertical displacement of the segment bottom reaches 6 mm.Another two new cracks appear on the segment inner surface,and the 1st crack further expands to the outer surface and develops into the penetrating cracks.The cracking process of the segment is described sequentially as inner surface → upper ring surface → outer surface.Considering the potential risk of leakage of water caused by penetrating cracks,the shear capacity(yield load)of P2-typed standard segment was determined to be approximately 1 120 kN.Comparing the numerical simulation results with the prototype test,the cracking expansion,the distribution pattern and the shearing capacity obtained from both two means were almost consistent,which implies the reliability of numerical simulation.These results can provide reference for the design and construction of shield tunnel.