合肥粉质黏土 HSS 模型参数的试验研究

小应变硬化(hardening soil-small, HSS)模型是基于硬化土(hardening soil, HS)模型并考虑土体的小应变特性而提出的。基坑开挖过程中对于土体主要是卸荷作用, 且大部分区域土体均处于小应变状态, 因此, HSS模型对于基坑开挖过程的数值分析有较好的适用性。由于 HSS模型参数较多, 在实际工程应用中更多的是经验取值, 且目前有关合肥地区硬塑性粉质黏土的 HSS模型参数的研究比较缺乏。文章针对合肥典型硬塑性粉质黏土层开展 HSS模型参数的试验研究, 利用固结仪、GDS饱和土动三轴仪和弯曲元波速测试系统, 获得粉质黏土层 HSS模型的主要参数, 建立部分参数间的比例关系, 并与已有文献的相关试验结果进行比较分析, 总结不同地区粉质黏土层部分参数之间的比例关系, 为实际工程应用提供参考。通过采用 HSS模型和摩尔-库伦(Mohr-Coulomb, M-C)模型对合肥地区某基坑实例进行分析, 并将模型计算结果与实测结果进行对比, 验证了 HSS模型用于分析基坑工程数值模拟的适用性及试验获得 HSS模型参数的准确性。

The hardening soil-small(HSS) model was proposed based on the hardening soil(HS) model considering the small strain characteristics of the soil. The soil is primarily subjected to unloading during the excavation process of the foundation pit, and most areas of the soil are in a small strain state. Therefore, the HSS model has good applicability for numerical analysis of the excavation process of the foundation pit. Due to the large number of parameters in the HSS model, empirical values are more commonly used in practical engineering applications, and there is currently a lack of research on the parameters of the HSS model for hard plastic silty clay in the Hefei area. This paper conducted experimental research on the parameters of the HSS model for typical hard plastic silty clay layers in Hefei. The main parameters of the HSS model for silty clay layers were obtained using consolidation apparatus, GDS saturated soil dynamic triaxial apparatus, and bender element wave velocity testing system. The proportional relationship between some parameters was established, and compared with relevant experimental results in existing literature. The proportional relationship between some parameters of silty clay layers in different regions was summarized, providing reference for practical engineering applications. By using the HSS model and the Mohr-Coulomb(M-C) model to analyze a certain foundation pit example in Hefei area, and comparing the analysis results with the measured results, the applicability of the HSS model for analyzing the numerical simulation of foundation pit engineering and the accuracy of the HSS model parameters obtained through experiments were verified.