Study On The Equilibrium Law Of Embankment Humidity For The Reconstruction And Expansion Project Of Baipan Secondary Highway

Due to the long-term effects of the climatic environment and groundwater,the water content during the operation of the roadbed is often higher than the construction period.An increase in the moisture content of the subgrade will result in a decrease in the strength of the subgrade soil,a decrease in the bearing capacity,and may even cause damage to the pavement structure.Therefore,it is of great significance for the design and construction of the subgrade to correctly grasp the law of the humidity balance of the subgrade under the long-term action of the atmosphere and to understand the humidity state of the subgrade.This paper adopts literature research,field investigation,laboratory test,numerical simulation and other technical means to discuss in detail the balance law of subgrade humidity under climatic environment and groundwater conditions,and analyzes the slope rate,different subgrade height and different groundwater level.The impact on the law of the humidity balance of the roadbed,The main research contents and conclusions are as follows:1.Through the literature research on the moisture content of the roadbed and the field investigation data,it is proved that it is feasible to use VADOSE/W numerical simulation to analyze the equilibrium humidity of the unsaturated viscous subgrade soil.2.The soil water characteristic curve and the permeability curve of unsaturated clay(Baipan Road)were obtained by pressure plate test and double loop penetration test,and the saturated volumetric moisture content(38.2%)and saturated permeability coefficient(1.15E-08m/s))of unsaturated clay soil were obtained.3.VADOSE/W was used to simulate the variation of general roadbed humidity under different groundwater level,slope and height conditions of Bailu Road.The results show:1)The groundwater level is different,the time required for the soil inside the subgrade to reach the equilibrium state of the humidity is different,and the equilibrium humidity at each point inside the subgrade is also different.2)The subgrade slope is different,and the time required for the soil inside the subgrade to reach the equilibrium state of the humidity is different,but the slope has little effect on the equilibrium humidity of the soil inside the subgrade.3)The height of the subgrade is different,and the time required for the soil inside the subgrade to reach a humidity balance state is different,but the equilibrium humidity at the center of the subgrade is the same.4.The VADOSE/W was used to simulate the humidity change of the low embankment on the Bailu Road,and the influence of the groundwater level on the humidity of the low embankment was analyzed in detail.The results show:l)On the central axis of the low embankment,the volumetric water content of the subgrade soil gradually increases with time,and the volumetric water content of the lower soil increases rapidly in the subgrade operation 0-2a,and the volumetric water content in the middle and upper soil is 0-2.7a.It grows faster and then stabilizes until the interior of the subgrade reaches a state of humidity equilibrium.2)The influence of groundwater on the equilibrium humidity of the roadbed is more significant.The higher the groundwater level,the shorter the time required for the dwarf embankment to reach the equilibrium state of humidity,and the equilibrium water content of the central point of the low embankment is also different.