Analysis Of Interaction Of Modular Building In Substation And Foundation And Isolation Technology In High-Intensity Areas

Modular buildings are a new type of green building with a high construction speed,high industrialization ratio,and excellent quality.The development of modular buildings is beneficial for promoting the transformation and upgrading of the construction industry towards industrialization,digitization,and greenery.Modular buildings of indoor substations are a new type of building system for new infrastructures of smart grids,which has advantages such as green,low-carbon,small footprint,and stable and reliable equipment performance.When constructing modular buildings for substations in high-intensity areas,using isolation technology can effectively reduce the impact of horizontal seismic effects,If the combined action of the upper structure and foundation is considered,the project cost can be effectively reduced.However,there is a lack of extensive research on the interaction between modular buildings and foundations and on seismic isolation techniques for indoor substations in high-intensity areas.This article is based on outdoor vertical static-load tests of a rigid pile composite foundation of a modular building.The theoretical calculation method of the interaction was analyzed in detail,and analytical solution calculation formula of the pile-soil load-sharing ratio and composite modulus were obtained.The effects of different parameters on the upper structure and various load-bearing bodies of the foundation were analyzed.The isolation performance of modular buildings in substations in high-intensity areas was analyzed based on a composite foundation shaking-table model test and an integrated isolation design.The main research findings are as follows.1.The theoretical calculation method for the interaction between modular buildings and foundation was analyzed,and the finite element method and substructure method were used to solve the interaction between modular buildings in substations and foundation.2.Based on the theory of the shear displacement method,an analytical solution for the load-sharing ratio and composite modulus of the pile-soil in modular building with a rigid pile composite foundation was derived.The calculation formula for the analytical solution reflects parameters,such as the thickness and modulus of the cushion layer,the length,diameter,replacement rate of the rigid pile,and soil characteristics.The experimental data and numerical calculation results were compared and analyzed.3.A vertical static-load scale model test was conducted to simulate the outdoor construction process of a rigid pile composite foundation for modular building.A finite element calculation model was established to analyze the effects of changes in parameters such as upper module floor,rigid pile length,diameter,replacement rate,cushion layer modulus,raft stiffness,etc.on the stress bodies of upper module components,raft foundation,and rigid pile composite foundation.Through experiments and numerical analysis,it was found that an increase in the stiffness of the upper module decreases the axial force per unit floor area of the central column,but increases the axial force per unit floor area of the side and corner columns.An increase in the length of the rigid pile can decrease the settlement of the raft foundation.Increasing the diameter of rigid piles decreases foundation settlement and pile top stress.An increase in the replacement rate of rigid piles decreases the settlement of the raft foundation,increases the load borne by the rigid piles,and decreases the stress at the pile top.In addition,an increase in the modulus of the cushion layer decreases the settlement of the raft foundation and increases the load resisted by the rigid pile.An increase in raft stiffness decreases the axial force of the corner column,increases the axial force of the edge and center columns,increases the axial force of the corner pile,decreases the axial force of the edge and center piles,and decreases the differential settlement of the raft.4.A composite foundation vibration table simulation test was conducted,and three different seismic waves were applied to the model.The composite foundation vibration table earthquake simulation test was completed under different acceleration amplitudes.The variations in acceleration at different regions under seismic excitation were obtained,and the seismic isolation performance of the cushion layer in the composite foundation was analyzed.Experimental analysis found that the cushion layer in the composite foundation has a significant seismic isolation effect.When a horizontal earthquake occurs,the cushion layer plays a role in energy dissipation,which can reduce the seismic effect on the buildings above the cushion layer.5.Basic isolation technology was adopted for modular buildings in all the indoor substations in high-intensity areas,and an integrated isolation design and analysis were performed.The effectiveness of the isolation design was verified,and the seismic response of modular buildings in substations after adopting basic isolation and non-isolation structures was analyzed.The calculation analysis shows that in different vibration modes,the period and damping ratio of the isolation structure increase,and the period is significantly extended,which can effectively reduce the horizontal seismic effect.