Moisture And Heat Transfer Characteristics And Numerical Simulation Analysis Of Red Clay Slope Under Climate Effect

Red clay is a kind of regional special soil,Its special secondary pore structure and mineral composition make the engineering properties of red clay more complicated than other types of soil.Red clay is widely distributed in southern of China,especially in Guangxi.The red clay slopes in this area are usually unsaturated under typical climatic conditions,and the soil strength and overall stability are largely affected by water and energy exchange between atmosphere and soil.Therefore,it is of great significance to study the wet and hot properties of red clay slope under the action of climate.Taking the red clay slope of Guilin as the research object,a series of studies have been carried out around the core problem of moisture and heat transfer of the slope,mainly including the following aspects:1.The hydraulic characteristics of red clay slope soil were studied systematically.The saturated permeability coefficient of red clay was obtained by permeability test.The Water-holding Properties of red clay with different dry densities were studied by pressure membrane apparatus.The results showed that the higher the dry density of red clay,the more compact the soil,the higher the air intake value,and the better the water-holding capacity.The permeability curve function of unsaturated red clay is obtained by fitting the soil-water characteristic curve and saturated permeability coefficient with VG model,which provides data support for later numerical simulation.2.The variation of thermal conductivity of red clay with matrix suction was studied,and the effect of the dynamic change of solid,liquid and gas phases on the thermal conductivity of red clay was revealed.The experimental results show that the heat transfer between soils is mainly through the particle-water-particle path before the air intake value.The thermal conductivity of soils increases slightly with the increase of suction and reaches the maximum at the air intake value.The thermal conductivity of soil gradually decreases.3.Based on the in-situ monitoring of the slope,the real-time monitoring of the meteorological data,soil temperature and moisture content is realized.The monitoring results show that the humidity and heat characteristics of the red clay slope are significantly affected by the atmospheric effect,and the soil moisture content and temperature fluctuate with the season.Soil moisture is mainly affected by rainfall and evaporation,and soil temperature is mainly affected by atmospheric temperature and solar radiation.The change of temperature shows obvious hysteresis with the increase of depth.The change of temperature can indirectly reflect the migration characteristics of soil moisture.The coupling effect of the two factors promotes the migration of soil moisture and heat.4.Based on Darcy's law of unsaturated soil water flow and heat transfer control equation of porous media,coupled numerical simulation of seepage field and temperature field of slope is carried out based on the finite element numerical model of slope.The results of Coupled Simulation of seepage field and temperature field,the law of interaction between two fields and the mechanism of mutual influence are analyzed,and the red clay is revealed.The coupled mechanism of moisture and heat transfer in soil slopes.5.Based on GeoStudio finite element numerical simulation software,the finite element numerical model of slope is established.The monitoring meteorological data are brought into the software to simulate the influence of climate on the humidity and heat characteristics of slope...