Studies On The One-Dimensional Nonlinear Large Strain Consolidation Theory Of Structured Soil Induced By The Drop Of Groundwater Level

Land subsidence is a serious environmental geological disaster with long duration,wide range of influence and irreversible process.There are many reasons for land subsidence,and over-exploitation of groundwater is one of the main causes of land subsidence.At present,many scholars at home and abroad have conducted in-depth research on the one-dimensional consolidation of soft soil caused by precipitation,but most theoretical studies are still limited to one-dimensional consolidation of single-layer foundations,and the geometric nonlinear changes in the consolidation process,nonlinear changes in compression seepage,and structural characteristics cannot be considered.Therefore,it is of great theoretical and practical significance to study the one-dimensional nonlinear large strain consolidation theory of structural soil induced by precipitation.In this paper,a series of studies on the large strain consolidation of structurally weak aquifers induced by precipitation are carried out by semi-analytical methods,and the effects of consolidation properties and parameters are analyzed and discussed.Main tasks as follows:(1)The large strain consolidation caused by groundwater drawdown was analyzed using semi-analytical method,and the self-weight of the soil,the nonlinear variations of compressibility and permeability,as well as changes in thickness during consolidation were considered.Then the calculation results are compiled into a calculation program,and the consolidation traits under different conditions are compared and analyzed.(2)The nonlinear large strain consolidation model of structured soils was established considering the nonlinear variations of the compressibility and permeability,the nonlinear variations of the yield stress and the change of the thickness of the soil.The problem was solved by semi-analytical method,and the effects of structure,precipitation rate and precipitation height on the consolidation behavior were analyzed.(3)The consolidation model of a single-layer structural aquifer is extended to a layer-consolidation problem.The one-dimensional large strain consolidation of the layered structural aquifer caused by groundwater drawdown is analyzed,and the nonlinearity of the self-weight,compressibility and permeability,the variation of the structural yield stress with the change of self-weight,and the stratification of different soil properties are considered.The problem was solved by semi-analytical method,and the consolidation behaviors of layered structural soils as well as the influences of soil properties on consolidation were analyzed.