Food is a matter of national transport and people’s livelihood,and ensuring food security is an eternal issue.The Ministry of Housing and Urban-Rural Development issued the "Thirteenth Five-Year Plan" for the development and utilization of urban underground space,pointing out that "adhere to the policy of combining peacetime and wartime,and coordinating underground and above ground,and encourage the development of vertical layered threedimensional sum and horizontal related space connectivity".Semi-underground double-storey squat silos respond to the relevant policies,can improve land efficiency,reduce tons of grain occupancy index,with shallow round storage grain volume,high degree of mechanization and underground storage using shallow ground energy,to ensure the quality of grain storage double advantage,to meet the basic requirements of the current high standard green grain warehouse construction,can promote the sustainable development of the grain storage industry.Based on the key R&D and promotion special project of Henan Province(No.212102110191),analyze the mechanical properties of semi-underground double-storey squat silo for static grain storage,and obtain the force change law of the silo body at different stages,different working conditions and different grain storage heights by the theoretical analysis,the experimental research and the numerical simulation in this paper.The main research works are as follows:(1)Based on the classical mechanics theory and plate and shell theory,the study of the force mechanism of the semi-underground double-storey squat silo is carried out.The structural loads(constant load and live load)received by the semi-subterranean double-layered shallow circular silo are analyzed according to the actual hydrogeological conditions of the proposed site,and the thin-walled cylindrical silo wall,circular thin plate middle layer and inverted conical silo bottom of the semi-underground double-storey squat silos are theoretically studied respectively.(2)The numerical analysis model of the semi-subterranean double-layered shallow circular silo was constructed and experimentally verified.The numerical simulation of the semi-underground double-storey squat silo was carried out by the finite element software,and the finite element model was established by using solid cells,and the boundary conditions were set according to the site geological conditions and the actual state,and the numerical analysis model of the semi-underground double-storey squat silo was constructed and experimentally verified.(3)The numerical simulation was used to study the mechanical properties of the semiunderground double-storey squat silo during the construction stage.Two specific stages before and after the backfilling of the underground soil layer in the construction process are studied,and the peak stress of the bottom of the bin before backfilling and the peak stress of the wall after backfilling are obtained by simulation;the maximum stress and displacement deformation of the bin are obtained by comparative analysis before and after backfilling,which can provide theoretical guidance for the engineering design and safe construction of the semi-underground double-storey squat silo.(4)The numerical simulations were used to study the mechanical properties of the semiunderground double-storey squat silo under normal use phase of static grain storage.The stresses and displacements under this condition were obtained by simulating different working conditions,and the most unfavorable working conditions were analyzed,and the displacements under the most unfavorable working conditions were analyzed accordingly;the mechanical properties of the semi-underground double-storey squat silos were studied under different loading heights,and the stresses of the upper and lower two layers of the silo walls,the middle layer and the bottom of the silo were analyzed respectively,and the stress law of the semi-underground double-storey squat silo under static grain storage conditions was obtained.This study is of great significance to the sustainable and high-quality development of the grain storage industry,and helps to save energy,land and losses.The research can provide theoretical support and technical reference for the engineering design and safe grain storage of semi-underground double-storey squat silo,lay the foundation for the promotion and application of new silo types,and have important economic,social and environmental significance for promoting the development of new grain storage silo structures and green and safe grain storage. |