Research On Model Test And Damage Identification Of Uneven Settlement Foundation Spherical Tank

Large group of liquefied petroleum gas spherical tanks built on soft soil foundation will experience varying degrees of settlement under the gravity of the spherical tanks themselves and the liquid medium.The uneven settlement of the foundation will have a significant impact on the structural performance of spherical tanks,posing a serious threat to their gas storage safety.Therefore,this paper combines spherical tank model experiments to develop static and dynamic testing techniques for spherical tanks,and studies the static/dynamic changes of spherical tanks under uneven settlement;Based on finite element model correction technology,a damage identification method for spherical tank structures under non-uniform settlement is studied.The specific content is as follows:Based on the structural characteristics of large liquefied petroleum balloon tanks in service,a 1.5m~3spherical tank model is designed and constructed according to the similarity theory.A hydraulic simulation test system for uneven settlement of the spherical tank model foundation is developed,and a static and dynamic comprehensive test device for the spherical tank model under uneven settlement is developed.To lay the foundation for the development of static and dynamic testing technology for large spherical tanks under uneven settlement and the research of structural damage identification methods.Conduct modal tests and stress testing research on spherical tank models under uniform and uneven settlement of the foundation.In response to the large and complex structure of in-service spherical tanks,sensor optimization is used to determine the location and quantity of modal and stress testing sensors,and establish a spherical tank testing model.Based on the modal test and stress test results of the spherical tank model,analyze the static and dynamic performance changes of the spherical tank structure under uneven settlement of the foundation.Conduct numerical modal analysis and stress analysis research on spherical tank models under uniform and non-uniform settlement of the foundation.Establish a multi-scale numerical model for in-service spherical tanks based on their structural characteristics.Based on numerical models of spherical tanks at different scales,this study investigates the changes in liquid level height and equivalent stress of pillars under uneven settlement of the foundation,as well as the changes in modal parameters when different numbers of pillars are fixed and weakened at the bottom under local settlement of the foundation.Conduct theoretical research on the degree of freedom matching of spherical tank models.A sensitivity analysis based Bayesian finite element model correction method for spherical tanks is proposed by matching the static and dynamic test data of the spherical tank model with the multi-scale numerical model of the spherical tank,including the measurement points and nodes,testing degrees of freedom and calculated degrees of freedom,and testing vibration modes and calculated vibration modes.By modifying the dual finite element model of modal parameters and strain parameters,identification and correlation analysis of the modal parameters of the spherical tank structure under six conditions of local settlement of the foundation were carried out.By modifying the parameter change rate and trajectory,the location of damage to the pillars of the spherical tank model under local settlement of the foundation was analyzed and identified.On the basis of the modified spherical tank damage model,crack propagation analysis was conducted at the damage location to verify the reliability of the damage identification method for the spherical tank model.Through this paper’s research,a static and dynamic comprehensive testing system for spherical tank models under non-uniform foundation settlement has been developed.A finite element model correction method for spherical tanks that combines testing and analysis has been proposed,and a damage identification technology for spherical tank structures based on the model correction method has been developed.This research achievement provides an effective method and means for the safety analysis and evaluation of spherical tanks under current foundation settlement.