Abstract:In order to investigate the hydraulic characteristics of loess in the subgrade of National Highway G310 in a wide suction range,the water retention characteristic experiments of loess were carried out by using the WP4C instrument,pressure plate method,filter paper method and vapor equilibrium method.The automatic direct shear instrument was used to test the strength characteristics of specimens with different initial dry densities and different suctions,and the microanalysis was carried out by the mercury intrusion test.The formula for fast predicting the shear strength was put forward based on the above test data.The results showed that the volume of inter-aggregate pore contracted with the increasing initial dry density,and the inter-aggregate pore played a major role.The soil-water characteristic curve of specimens shifted to the upper right with the increasing initial dry density in the wide suction range,while the void ratio of specimens was basically unchanged with the increasing suction.The shear strength increased with the increasing initial dry density,as well as suction.The stress-strain curve presented the strain hardening at low suction and strain softening at high suction.The shear strength prediction by the Khalili & Khabbaz model was very close to the measured value,so the model can be used to predict the shear strength of unsaturated loess in a wide suction range.
