Study On The Failure Pattern Of Loess Cave Dwelling Under The Effect Of Irrigation

Loess cave dwellings,the products bred by the Chinese ancestors,wisdom and the loess environment,are the unique landscape in loess areas.The fai.lure of loess cave dwellings does not only threaten people's properties and lives,but also restricts the efficient exploitation of land resources in.loess cave dwelling regions.However,the investigation on mechanism of stability and failure of loess cave dwellings is still insufficient currently.Here,the loess cave dwellings in a farming irrigation region were selected as study objects.Through information collection,investigation,the UAV aerial survey,sampling and experiments,physical model simulation and so on,the comprehensive deformation and failure response characteristics and failure patterns of loess cave dwellings under irrigation were revealed.The main conclusions of this study are as follows:(1)The classification scheme of failure of loess cave dwellings including three categories with eight types was proposed.Concretely,the classification scheme comprises kiln face failure(scouring type,spalling type and collapse type),kiln wall failure(shrinkage-crack type and spalling type)and kiln structure failure(local roof-fall type,seepage type and overlying soil collapse type).(2)The simulating experiment of a loess cave dwelling with irrigation was carried out,and the kiln roof pressure,kiln wall pressure,kiln roof settlement and displacement vector field on kiln face were monitored.The results showed that kiln wall pressure and displacement vector field on kiln face didn't have significant changes under irrigation.During the process of irrigation,the quasi-periodical varying regulation of kiln roof pressure can be concluded as fluctuantly increasing-stablely fluctuating-suddenly decreasing-fluctuantly increasing-stablely fluctuating".For the kiln roof settlement,its varying process can be divided into three stages:"increasing with discontinuous creep-increasing with continuous creep-increasing suddenly".(3)The correlation between overlying land types and failure of loess cave dwellings was discussed,and three failure patterns were presented,including "the failure pattern of seepage with cracks extending","the failure pattern of cracking with water-wind erosion" and "the failure pattern of collapse with structural planes softening".Meanwhile,the failure process of seepage and collapse of loess cave dwellings under irrigation can be concluded as "kiln loess softening and deforming-local seepage-seepage zones extending-local water inflow-outlets of water inflow increasing-kiln wall and roof spalling-water inrush-kiln collapse".