强震作用下跨断层管道柔性接口抗震加固研究

Seismic rehabilitation of push-on joints for pipelines across faults under high-severity earthquakes

强烈地震引起的地面永久性大变形是导致埋地供水管线损坏的主要威胁之一。该研究借鉴链式结构的设计思想,基于传统承插式管道接口形式,研发了一种新型管道抗震接口,其可支持一定的轴向伸缩自由变形。当接口变形量达至极限状态时,接口发生自锁现象并能提供较高的抗拉承载力,进而带动相邻管道滑移,以抵消断层错动引起的变形量。针对新型抗震接口开展了轴向力学性能试验,并建立了跨断层下的管线数值模型;同时,数值结果与相关全尺寸试验进行对比验证。该研究以土体压实条件和断层穿越管道位置作为关键变量,研究了加固前后断层错动下承插式管道的力学响应。研究结果表明:提出的抗震接口能够有效地提高管道抵抗地面大变形能力,并且提高接口的轴向抗拉拔能力是提升管道抗断层错动能力的关键;对于松砂土跨断层下的承插式管道接口震损较为严重;断层穿越管道不同的位置会造成不同的接口变形规律;国内规范中管道接口的转角限值过于保守,不利于对跨断层承插式管道安全性能进行合理验算。

The permanent large ground deformation caused by strong earthquake is one of the main threats leading to the damage of buried water supply pipeline.Based on the idea of chain pipe structure,this study proposes a new type of seismic joint on the traditional socketed joint,which allows a certain deformation of the joint in the axial direction,and when the deformation of the joint reaches the limit state,the joint occurs self-locking phenomenon and can provide a certain axial load-bearing capacity,so that it can drive the adjacent pip movement to offset the deformation caused by fault movement.In order to study the strain capacity of the new seismic joint when subjected to large ground deformation,this study conducted relevant tests and established a two-dimensional finite element model,while the numerical results were compared with relevant full-scale tests for verification.In this study,the mechanical response of the socketed pipe under fault movement before and after reinforcement was investigated,using soil compaction conditions and fault crossing pipe location as key variables.The results show that:the proposed seismic joint can effectively improve the resistance of the pipe to large ground deformation,and improving the axial pullout resistance of the joint is the key to improve the resistance of the pipe to fault movement;the loose sandy soil stratum is not conducive to ensuring the confinement of the cross-fault socketed pipe;different locations of the fault crossing the pipeline will cause different joint deformation patterns;the corner limits of the pipe joint in the domestic code are too conservative,which is not conducive to the strengthening of the cross-fault socketed pipe.It is not conducive to the reasonable judgment of the safety performance of cross-fault socketed pipe.