风积沙路基土土-水特征曲线温度效应研究

风积沙非饱和土是沙漠地区公路路基主要填筑材料，其力学性能受赋存气候环境温度影响显著。为研究温度变化对风积沙路基土土-水特性影响规律，在考虑温度对非饱和土表面张力和润湿系数综合影响的基础上，推导建立能够反映温度变化效应的土-水特征曲线模型方程，并基于ASTM D5298滤纸法测试不同干密度风积沙路基土土样在20℃、40℃和60℃条件下达到平衡时的土-水特征曲线，验证建立模型的合理性。结果表明：风积沙土-水特征理论模型曲线与实测值吻合良好，相关系数均在0.93以上，模型合理有效；在高温或低吸力区，温度对风积沙土-水特性影响显著，随着温度升高，土-水特征曲线整体向右下方偏移；在含水率较低的高吸力区，风积沙基质吸力对干密度变化更加敏感，干密度越大，基质吸力越大。所得结论为利用非饱和土理论研究风积沙路基土力学性能奠定了理论基础。

Temperature Effect of Soil-water on Characteristic Curve of Aeolian Sand Subgrade Soil

Unsaturated aeolian sand is the main highway subgrade filling material in desert areas, and its mechanical properties are significantly affected by ambient temperature. To study the influence of temperature changes on the soil-water characteristics of aeolian sand subgrade soil, the broad influence of temperature on the surface tension and wetting coefficient of unsaturated soil was considered. Furthermore, the soil-water characteristic curve model equation, which can reflect the effect of temperature changes, was derived. Based on the ASTM D5298 filter paper method, the variations in the soil-water characteristic curves for different dry densities were measured when the aeolian sand subgrade soil samples reached equilibrium at 20℃, 40℃, and 60℃ to verify the rationality of the established model. The theoretical model curves of the aeolian sand soil-water characteristics agree well with the measured values. Additionally, the correlation coefficients all exceed 0.93, indicating that the model is reasonable and effective. In the high-temperature or low-suction zone, the temperature has a significant influence on the aeolian sand soil-water characteristics. As the temperature increases, the soil-water characteristic curve shifts to the lower right. In the high-suction zone with low water content, the aeolian sand matrix suction is more sensitive to dry density changes. The greater is the dry density, the greater is the matrix suction. This research can lay a theoretical foundation for studying the mechanical properties of aeolian sand subgrade soil by using the unsaturated soil theory.