广州市南沙区软土物理力学指标统计分析

根据广州市南沙区实际工程中收集到的共计299组软土试验成果,针对软土不同含水率区间,对南沙区软土基本物理力学指标进行了分区统计和分析,给出了软土强度指标、变形指标与含水率的关系,并与珠海横琴新区软土的相关力学特性进行了对比分析。结果表明:在相同含水率情况下,横琴新区软土压缩模量、直接快剪黏聚力、直接快剪内摩擦角等指标均低于南沙区软土指标,横琴新区软土指标相对更差;随含水率的增加,南沙区与横琴新区软土的压缩模量、直接快剪黏聚力呈较一致的递减趋势;直接快剪内摩擦角呈不同的变化趋势,南沙区软土直接快剪内摩擦角呈上下波动的趋势,无明显增减规律,横琴新区软土直接快剪内摩擦角指标呈递减趋势。研究结果给出了不同含水率区间软土指标的统计范围,可供南沙区及横琴新区的软土工程设计与施工参考或借鉴。

Statistic Analysis of Physical and Mechanical Indexes of Soft Soil in Nansha of Guangzhou City

According to a total of 299 sets of soft soil test results collected from actual projects in Nansha District of Guangzhou, the basic physical and mechanical indexes of soft soil in Nansha are analyzed and classified corresponding to different moisture content intervals of soft soil. The relationships of strength index and deformation index against moisture content of soft soil are given and the results are compared with those of soft soil in Hengqin area, Zhuhai City. Results reveal that at given moisture content, the compressive modulus, direct shear cohesion and direct shear internal friction angle of soft soil from Hengqin are lower than those from Nansha, indicating that the indexes of soft soil in Nansha are superior. With the increase of moisture content, the compressive modulus and direct shear cohesion of soft soils both from Nansha and Hengqin display a consistent decreasing trend; however, direct shear internal friction angle exhibits different trends — direct shear internal friction angle of soft soil from Nansha fluctuates with no obvious reduction, while that from Hengqin declines evidently. In addition, the statistical ranges of soft soil indexes in different moisture content intervals are also given for reference for soft soil engineering design in Nansha and Hengqin.