Analysis of the effects of heavy rainfall and high temperature on hydraulic behavior of aeolian sand subgrade
Aeolian sand is the main filling material for railway/highway subgrades in desert areas in Inner Mongolia.In recent years,heavy rainfall and high temperature events have occurred frequently in this region,resulting in significant changes in the hydraulic characteristics of aeolian sand,such as volume water content and pore pressure,and a decrease in shear strength,which can lead to subgrade deformation and landslides,jeopardizing subgrade stability.To investigate the impact of heavy rainfall and high temperature on the hydraulic behavior and stability of aeolian sand subgrade,the aeolian sand subgrade in desert areas in Inner Mongolia was selected and two types of drying-wetting cycle conditions were designed according to the climate characteristics of central Inner Mongolia:short-term heavy rainfall-evaporation and continuous rainfall-evaporation.The change laws of moisture content and pore pressure of aeolian sand subgrade with time and depth under different conditions were analyzed by numerical simulation method.The results show that during the initial stage of heavy rainfall,the infiltration rate is equal to the rainfall intensity.As the rainfall process continues,the infiltration capacity of the aeolian sand subgrade decreases continuously.When the water content of the surface layer of the subgrade reaches saturation,the infiltration rate becomes equal to the saturated permeability coefficient of the aeolian sand subgrade soil.Under the same rainfall precipitation,continuous rainfall leads to higher infiltration than short-term heavy rainfall,resulting in greater changes in moisture content,pore pressure,and infiltration depth in aeolian sand subgrade.Specifically,the infiltration depth under continuous and short-term heavy rainfall is 5.65 m and 3.29 m,respectively.Rainfall leads to an increase in the volumetric water content of aeolian sand roadbeds,accompanied by a decrease in pore pressure.The effect of high-temperature evaporation on the hydraulic behavior of the roadbed is opposite to that of rainfall.As the subgrade depth increases,the impact of heavy rainfall and high temperature on the water content and pore pressure of aeolian sand subgrade weakens and the lag effect becomes more significant.The research results can provide a theoretical basis for the design and maintenance of aeolian sand subgrade in desert areas.
万方数据
维普
