Critical Buckling Strain And Strain Analysis Under Settlement Of The Gas Pipeline In Utility Tunnel

The critical buckling strain and the strain under differential settlement of the gas pipeline in the utility tunnel have been analyzed to provide theoretical basis for safety.The buckling deformation of gas pipeline under the combined action of internal pressure,axial force and bending moment is simulated by numerical analysis.The critical buckling strain of gas pipeline is determined by using the curve characteristics of global curvature and local curvature graph.And the critical buckling strain prediction formula suitable for gas pipeline in utility tunnel with little radius-thickness ratio has been fitted.The yield strength and yield ratio of engineering steel have been obtained through the material performance test to predict and calculate the minimum critical buckling strain of the three specifications of gas pipelines.Thus,timely monitoring and management of gas pipeline strain can be used to avoid the occurrence of gas pipeline buckling accident in the utility tunnel.Due to the influence of leakage,surrounding load changes,earthquake and the other factors,the differential settlement of the utility tunnel will occur,which will lead to the displacement changes of the pipeline support structures.The strain distribution of gas pipeline under the differential settlement has been simulated by this characteristic.When the local settlement occurs in the utility tunnel,affecting only a single pipeline support structure,the settlement reaches the monitoring limit of 50 mm.In addition,when the utility tunnel generates a large range of differential settlement and the maximum settlement difference of adjacent supporting structures reaches 70 mm,the gas pipeline strain in the utility tunnel is all within the elastic range without buckling deformation.Gas pipeline accesses utility tunnel is safely under specified requirements and monitoring.