Study On The Impact Of Villages And Towns’ Raw Soil Structure On Seismic Vulnerability

Earthquakes are common natural disasters.The occurrence of earthquakes can damage building structures and even threaten people’s lives and property.At present,performance-based seismic design and seismic risk assessment have received the attention of scholars all over the world,but most of the research on seismic vulnerability is concentrated on steel structure buildings,concrete buildings and masonry structures.Earthquake-resistant designs and risk assessments for rural and township raw-soil structures are rare.Villages and towns’ raw-soil structures are often severely damaged when subjected to an earthquake,which brings serious hidden dangers to the property safety of the vast rural people.For this reason,it is necessary to study the seismic fortification standards suitable for the raw soil structures in villages and towns,and study the seismic structural measures suitable for the raw soil structures in villages and towns in light of actual conditions.At present,the research on the seismic performance of raw soil structures is mostly the pseudo-static test of a single component or the shaking table test and numerical simulation analysis that only considers a single earthquake action.There are few studies considering the vulnerability of the raw soil structure under earthquake action.In summary,considering the effects of earthquakes to analyze the seismic vulnerability of the raw soil structures in villages and towns is of great significance for the evaluation of earthquake disaster losses and structural improvements.This paper takes the typical single-layer raw soil structure in Chinese villages and towns as the research object.Based on the dynamic time history analysis and probabilistic seismic demand analysis methods,the seismic vulnerability of the raw soil structure is analyzed,and then the earthquake action on the raw soil structure is studied.The impact of vulnerability.The main contents are as follows:(1)Using ABAQUS finite element analysis software,a finite element model of a roofless raw soil structure house and a raw soil structure house attached with a colored steel roof were established.In order to study the impact of earthquake action on the seismic vulnerability of the raw soil structure,first of all The two structures are determined by static analysis to determine the characteristics of their displacement under only their own weight and roof load.Modal analysis of the two structures shows that the setting of the color steel roof enhances the structural rigidity and shortens the natural vibration period of the structure.(2)Select 80 real ground motions,based on the nonlinear dynamic time history analysis method,extract the top displacement and interstory displacement angles of the structure in each nonlinear time history analysis,and analyze the raw soil structure under earthquake action.Seismic response characteristics,the effect of the attachment of the color steel roof on the seismic response of the raw soil structure is studied.By controlling the size of the PGA,the earthquake level,and the epicenter distance of the analysis,the results show that as the magnitude increases,the PGA increases and the earthquake distance decreases,the maximum displacement of the top layer,the inter-story displacement and the inter-story displacement angle show a significant expansion trend.And the PGA size is one of the main factors affecting the displacement of the top floor of the raw soil structure building.The attachment of the color steel roof obviously affects the overall seismic performance of the structure,and the seismic performance is weakened under the same conditions.(3)Using the theoretical calculation vulnerability analysis method based on numerical simulation,based on the probabilistic seismic demand model,using the vulnerability function,the seismic vulnerability analysis of the raw soil structure is carried out.The seismic vulnerability curve of the raw soil structure under the action of the earthquake is obtained based on the maximum inter-story displacement angle.By comparing the vulnerability results,the color steel roof setting,the difference in earthquake type,and the difference in the ultimate failure state are analyzed and studied quantitatively from the perspective of probability.The impact of the vulnerability of the raw soil structure.The results show that the setting of color steel roof has little effect on the vulnerability of the raw soil structure to the limit state of minor damage,but with the gradual deepening of the limit state,the effect of color steel roof on increasing the vulnerability of the structure becomes more and more obvious.Increase the probability of serious damage or collapse of the structure.With the increase of PGA,the probability of exceeding the limit state and the increasing rate of the probability of exceeding the structure gradually decrease.The impact of ground motion on the vulnerability of the structure is minimal when the structure is slightly damaged.The impact of ground motion on the vulnerability of the structure is greater in the state of severe damage and collapsed damage.As the limit state deepens,the impact of ground motion becomes more obvious.The type of earthquake has a strong influence on the vulnerability of the structure.Under the same PGA condition,as the magnitude of the earthquake decreases and the epicenter distance increases,the vulnerability of the raw soil structure increases.