Analysis Of Axial Compressive Behavior Of Joint In Assembled Steel Plate-concrete Composite Silo Wall Of Underground Silo

Food is related to the national economy and people’s livelihood,and food security is an important foundation for national security.The underground silo has become an important granary type for the construction of green ecological grain storage system in China because of its significant advantages such as low-temperature grain storage,lower grain loss,environmental protection,land conservation and energy conservation.However,the underground silo is faced with the problems of waterproofing,cost and construction period.So the research group proposed the assembled steel plate-concrete composite underground silo.The wall of this new type of silo is assembled by steel plate and concrete combined precast blocks.The inner steel plate is not only a structural layer,but also waterproof layer.The prefabricated blocks of the silo wall are connected by joints to form a whole.The joint is the key component of the prefabricated structure,and the mechanical performance of the joint on the wall of the prefabricated underground silo is an important issue for this new type of underground silo.In this paper,experimental research,numerical simulation and theoretical analysis are used to study the axial compressive behavior of the silo wall joint.The main contents are as follows:(1)According to the actual working conditions,three joint forms of steel plate-concrete composite wall of prefabricated underground silo are proposed.Full-scale tests were carried out on the silo wall specimens with different joint forms,and the whole process of force,deformation,yield,failure and failure modes under axial compression were studied.Compared with the steel cavity joint specimens,the specimen filled with concrete in the joint cavity has better initial stiffness and peak load,and the peak load increase of the specimen filled with concrete in the joint cavity is more than 28% compared with two steel cavity joint specimens.(2)Finite element analysis was carried out on the silo wall specimens,and the relative difference between the peak loads of the three specimens obtained by simulation and those measured by experiment was less than 4%,which verified the correctness of the established finite element model.The mechanical properties and working mechanism of the silo wall specimens and their components during the loading process were further analyzed,and the influence rules of different joint parameters was analyzed.For the specimens filled with concrete in the joint cavity,the concrete in the joint bears about 75% of the load in the elastic stage,which effectively improves the compressive strength of the joint.For the steel cavity joint specimens,increasing the thickness of waterproof steel plate,decreasing the connection length of waterproof steel plate and increasing the stiffening rib can improve the peak load and plastic development of the joint.(3)On the basis of experiment and numerical simulation,the simplified assumptions are put forward for the silo wall joints,and the compression calculation models of different joint forms of silo wall are obtained through theoretical analysis.Furthermore,simplified calculation formulas for the elastic compressive stiffness and peak load of the corresponding joints are proposed.Through the comparative analysis of theoretical calculation value and experimental value,it is proved that the simplified calculation formulas proposed have high accuracy.