Study On Seismic Response Of The Traditional Earth-sheltered Cave Dwelling

Traditional cave dwelling is one of the modern residential houses form which evolved from the ancient cave.It created by working people of during one thousand years of life practice in China.Traditional cave dwelling has a rich history in humanistic value.The cave in occurrence in raw soil has its unique ecological advantages,thermal insulation,warm in winter and cool in summer,little consumption in the process of construction and use of traditional energy sources.It is also a real zero residential energy consumption,energy from maintaining residential.In addition to its unique ecological advantages,the traditional cave dwelling has a stable structure,safe and durable,even if traditional cave dwelling is in such an earthquake-prone area,it standing there are one hundred examples of success.However,construction of the traditional cave dwelling did not consider the effect of seismic action in the long-term practice.Research shows that the traditional cave dwelling will be in serious damage under the action of earthquake.The existing traditional cave dwelling are being used.Once the earthquake disaster occurred,It will happen serious damage,directly affect the people's life and property safety,and cause immeasurable loss.At present,The research is still relatively scarce in traditional cave dwelling's seismic response,and little research in the influence of factors on the seismic response involves structure size.Aiming at the shortcomings of the existing research,we Need carry out the research work of cave dwelling's dynamic response under the earthquake,and dissect the influence of size factors.In conclusion,this paper based on the “ Twelve-Five-Year ” national science and technology support projects subject(project number: 2014BAL06B03)carried out following works:(1)Through on-the-spot investigation,we obtain the data of traditional cave dwelling's structure size.Based on dates,Statistical analysis the scope of the overlying soil thickness,span of kiln,and leg width.The size data of cave dwelling in western region of Henan is concentrated,and dates discrete degree is small.(2)Do undisturbed loess mechanics performance test.Soil sample is from tradition kiln in the area of traditional cave dwelling.Obtain undisturbed loess basic indicators such as density,elastic modulus,Angle of internal friction and cohesion.The experimental results showed that: in depth of cave dwelling,The soil consist of loess powder soil and a small number of loess powder clay.The soil has relatively homogeneous and a good performance.(3)Established the dynamic analysis model of traditional cave dwelling,and explore the establishment of the model of artificial boundary.Derived calculation formula of the earthquake equivalent nodal force,and realize applying the viscoelastic artificial boundary under seismic load.Put the classic problem of lamb and exogenous wave input problem as examples for calculation.Experience tends that the built model and seismic load applied method are reasonable and effective.(4)Use metod for Modal analysis of traditional cave dwelling,Get natural frequency and modal characteristics of the cave dwelling's model.Model's basic natural vibration period is 0.6243 s.And low order modes are whole vibration,and high order modes are local vibration of back covering soil.transverse vibration has a greatest effect to cave dwelling's structure,back and leg of cave dwelling are the most violent vibration in the process.(5)Input Horizontal seismic for dynamic time history analysis.Analysis cave dwelling's structure dynamic response regularity under frequent earthquake and Severe earthquake action.Traditional cave dwelling is safe under frequent earthquake,but Severe earthquake action leads to damage.Cave dwelling's structure deformation of each part are relatively consistent,but in a complex stress state.Seismic response along the depth direction has amplification effect from inner to outer.The largest dynamic response is at cliff face of center hole.The arch feet,and leg of cave dwelling is the most weakest positions of cave dwelling under earthquake action.(6)Make thickness of covering soil;the span length of cave;cave spacing as variables.Analysis the size impact factors on the seismic response.Analysis shows that: under the action of earthquake,the increase of Covering soil thickness is beneficial to improve the stress state of the soil arch,But too large thickness of the overlying soil will possible make the soil damage.Smaller kiln span can keep soilarch in pressure state,so as to effectively improve soil arch stress condition.With the increase of leg width kiln.cave dwelling's dynamic response is reduced.Large leg width can promote more seismic performance for traditional cave dwelling.