膨胀土用作路基填料的工程特性及改良方案研究OA

To improve expansive soil for use in subgrade embankment,a study on its expansion characteristics and improvement measures was conducted based on laboratory tests.The results show that the soil in the test area is characterized by high liquid limit and high plasticity index,and is classified as moderately expansive soil when used as subgrade fill material.The permeability coefficient exhibits a three-stage variation with increasing numbers of tests,which is the main factor influencing the expansion ratio of soil samples at different locations.The swelling pressure shows a positive correlation with time and eventually tends to stabilize;the expansion ratio is negatively correlated with applied load,gradually approaching zero.When the applied load exceeds the stabilized swelling pressure,the soil enters a collapsible state.The test curves of expansion characteristics are fitted to exponential function equations with a consistent structure,allowing the allowable swelling pressure to be determined based on the allowable deformation value of the soil.After comparing four improved utilization schemes,the optimal solution was found to be the addition of 3%cement with a compaction degree of 94%.