Analysis Of Water Holding Characteristics And Slope Stability Of Nanyang Expansive Soil

Expansive soil is swelling,fissure and over-consolidated in the expansion.Undisturbed expansive soil and reshape the expansion of the expansive soil performance difference is remarkable.Research that excavation process of expansive soil is unloading disturbance induced a promoting factor of expansive soil slope engineering disasters.The expansive soil of different unloading disturbance state characteristics for optimization of expansive soil slope engineering construction and design is of great significance."Anhydrous landslide",holding water characteristics of swelling has an important influence on mechanical properties of expansive soil.Now the research is mainly focused on the dry-wet circulation and initial moisture content on the influence of the expansive soil swelling and strength parameters,the research of this important variables for the hydration time less.Water absorption expansion of expansive soil and water loss contraction process corresponding to soil water characteristic curve of moisture absorption and dehumidifying process,due to the characteristics of expansion and contraction.Therefore,it is different from general clay soil-water features.So the development state of different disturbance and the hydration time of expansive soil's expansibility and expansion of hygroscopicity and moisture of soil suction process are researched,which may deepen the expansive soil expansion characteristics and moisture characteristics,slope engineering design to provide the reference for the expansive soil area.Based on the background of instability and failure of expansive soil slope excavation,I use Nan Yang expansive soil as the research object,using the indoor experiment,theoretical analysis and numerical calculation,the method of combination of unsaturated soil mechanics,structure of expansive soil,I mainly studied the influence of soil water characteristic curve and different disturbance state and the hydration time evolvement of expansive soil swelling;Finally,through the finite element software ANSYS,to the expansion of the expansive soil under different hydration time characteristics on the influence law of slope stability analysis and discussion,provide theoretical basis for expansive soil area disaster prevention and control of slope.In this paper,the research content and research results are as follows:(1)Considering hygroscopicity-dehumidifying of the expansive soil moisture suction process characteristics in the studySelection of undisturbed expansive soil samples with the same dry density reshape the expansive soil samples,the pressure plate apparatus of soil sample is wet-hygroscopic and through study the whole process of soil water characteristic curve and different matrix suction soils of mesoscopic analysis(mercury injection test),I found that the pore structure and pore distribution are the main cause of affecting soil water characteristic curve;The solution method of Nan Yang expansive soil samples was studied by means of soil water characteristic curve,compared with method of income curve of pressure plate.By Van Genuchten model,Fredlund xing3 parameter model,Fredlund xing4 parameter model and Gardner model of undisturbed expansive soil with the same dry density reshape the expansive soil soil water characteristic curve fitting,found four model fitting effect is good.Compare the small suction range(less than 1200 k Pa)(suction)and the suction range(less than 286 MPa)(suction)model fitting parameters,I found its fitting parameters are different.(2)The deformation characteristics of expansive soil under different hydration time testSimulation of slope excavation,in the different unloading range(80 k Pa proposed k Pa,40,160 k Pa,240 k Pa)after the hydration time of different consolidation process,and then carry out different hydration time(to 0 d,1 d,10 d,60 d and 90 d)characteristics of deformation of expansive soil under test,found that the greater the unloading disturbance amplitude,the higher the rate of the expansion of the expansive soil.The expansion of the expansive soil rate increased slightly with the increase of hydration time,generally completely stable at around 10 d,24 h inflation rate is greater than the specification requirements.Based on the lattice expansion theory explains.(3)The expansive soil slope stability studyThrough ANSYS software on the hydration time and different unloading amplitude of expansive soil slope stability analysis,I found that the hydration time and unloading rate has certain influence on the stability of expansive soil.