Experimental Study On Capillary Action Of Compacted Loess

Loess is widely distributed in China,accounting for more than 6% of the land area.More and more water pipelines are built in the loess area,which provides more water channels for the Loess and greatly increases the probability of loess collapsing.Therefore,it is of great significance to study the rise of loess capillary for engineering practice and disaster prevention in loess area.However,the current prediction equation is quite different from the actual situation,which is one of the problems to be solved urgently.Based on the capillary test results,this paper analyzes and verifies the traditional calculation formula of capillary rising height,carries out semipermeable-membrane method and soil sample charge test on the compacted loess,improves the formula to make it conform to the Loess capillary rising situation,and then simulates the capillary rising process of the compacted loess column,improves the radius value method,obtains relevant data,and calculates its capillary The following achievements have been made in water rising height:(1)The wet state of capillary wall has a great influence on the rise of capillary.The rising height of capillary in the fully wet state is the highest and the fastest;the rising height of capillary in the incomplete dry state is higher than that in the dry state when the inner diameter of capillary is larger than the critical aperture,and lower than that in the dry state when the inner diameter is smaller than the critical aperture.(2)In the condition of incomplete drying,the smaller the pore size is,the higher the capillary rises.The relationship between the pore size and the capillary rise height is asymmetric parabola.(3)A method for calculating the viscosity resistance based on the capillary pressure curve is proposed.The viscosity resistance is related to the pore radius and the rising height of capillary.(4)A calculation method is put forward.When calculating the rising height of capillary,the factors such as capillary density and soluble salt change are taken into account.Comparing the calculation results after considering relevant factors with the relevant measured results,it is found that the formula has high accuracy.(5)The simulation results show that the calculation method proposed in this paper has good adaptability.