广吸力范围内国道G310路基黄土水力力学特性试验研究*

为探讨广吸力范围内国道G310路基黄土水力力学特性，采用WP4C仪、压力板法、滤纸法和蒸汽平衡法对其开展持水特性试验，用全自动直剪仪对具有不同初始干密度和不同吸力的试样进行强度特性试验，并结合压汞试验进行微观分析。根据上述试验数据提出快速预测抗剪强度公式。试验结果表明:随着初始干密度的增加，积聚体间孔隙体积发生收缩，积聚体内孔隙占主要作用。广吸力范围内试样的土水特征曲线随着初始干密度增大而向右上方偏移，而孔隙比随吸力的增加基本不变。抗剪强度随着初始干密度增大而增大，且随着吸力增加而增加。应力-应变曲线低吸力范围呈应变硬化现象，高吸力范围呈应变软化现象。利用Khalili & Khabbaz模型预测的抗剪强度值与实测值非常接近，因此该模型可用于预测广吸力范围内非饱和黄土的抗剪强度。

Experimental study on hydraulic characteristics of loess in subgrade of National Highway G310 in wide suction range

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.