Shaking Table Test And Numerical Simulation Analysis On The Strengthening Performance Of Free-standing Brick Cave Dwelling

Cave dwellings are typical traditional dwellings in the Loess Plateau region of China,and also an important historical and cultural heritage in China.They have the ecological advantages of warmer winter and cooler summer,thermal insulation,sound insulation and fire protection,and environmental protection.In recent years,tens of thousands of cave dwellings have collapsed due to frequent earthquakes and other natural disasters,which seriously threatened the lives and property safety of residents.Therefore,it is urgent to carry out seismic reinforcement studies on the cave dwellings.At present,the research on cave dwellings mainly focuses on the disease and mechanical properties of loess cave dwellings,but there is very little research on the seismic strengthening of the cave dwellings,especially the research on the seismic strengthening of the free-standing brick cave dwellings is basically at a blank stage.Based on the major strategies of“precision poverty alleviation” and “seismic reconstruction of rural houses in highintensity areas” implemented by the state.Through the analysis and research on the seismic damage characteristics and seismic performance of the independent brick hoop cave dwellings in the northwest region,combined with the local economic level,the research group proposed a method for strengthening the free-standing brick hoop cave dwelling with polypropylene packing belt net cement mortar.Through the shaking table test,the effectiveness and feasibility of this reinforcement method were verified.The research results can provide a theoretical basis for the repair and reinforcement of freestanding brick cave dwelling.The main work of this article is as follows:(1)The free-standing brick cave dwelling in Gulou South Street,Linfen City,Shanxi Province was selected as a prototype,and an underweight model was made.After the shaking table test was performed,the damage was analyzed.By comparing the safety and economics of the reinforcement scheme,polypropylene was selected for packaging.The reinforcement method with mortar surface layer reinforced the seismic damage model of the brick cave dwelling shaking table test conducted by the research team in the early stage,and carried out detailed research on its material properties and reinforcement construction technology.(2)Through the shaking table test of the reinforced model structure,the dynamic characteristics and dynamic response law of the reinforced model structure were studied.The torsional effect and energy dissipation capacity of the reinforced model structure are analyzed.The analysis results show that as the input acceleration peak increases,the natural frequency and stiffness of the model structure decrease,and the damping ratio increases;the acceleration response along the vertical height direction increases,the acceleration response of the side hole acceleration is greater than the middle cave,and the acceleration response of the arch and arch footing increases from the inside to the outside in the depth direction,the maximum interlayer displacement angle at the arch foot is 1/29,The maximum value of the torsion angle is 0.0027 rad.;when loaded to 1.0g,the model has not collapsed,which shows that the reinforcement method of the polypropylene bale belt net cement mortar surface layer has a significant effect on the seismic damage model,and it shows that its method can improve the seismic performance of seismic damage model.(3)Combined with the experimental phenomena and experimental analysis results,the seismic performance of the reinforced independent brick hoop kiln was analyzed.The analysis results show that: the arch foot is at a variable cross-section,which is prone to stress concentration,resulting in the largest damage at the arch foot;the side kiln leg size It is much larger than the middle cave leg,which leads to a large difference in the lateral stiffness.The crack in the middle arch foot appears before the side arch foot.(4)The finite element analysis software ABAQUS is used to establish a calculation model for the analysis of the reinforced free-standing brick cave dwelling in the polypropylene packing belt mortar surface.The calculation results are in good agreement with the test results.Analyze the whole process of model dynamic damage under the action of Seismic.In this paper,the time series and spatial distribution characteristics of the plastic zone of the structure are studied,and the dynamic response of the model structure under earthquake is analyzed.