天然沉积中间土的力学特性研究

长江口北岸天然沉积土主要由粉粒和细砂粒组成，其渗透系数介于10^-7-10^-3cm/s之间，既不属于完全排水的砂性土，也不属于完全不排水的粘性土，针对这样的天然沉积中间土的我国研究并不多见。通过大量的物理力学试验，探讨了天然沉积中间土的物理力学性状，结果表明天然沉积中间土具有类似于软粘土的物理性质，但原位静力触探试验显示其天然沉积中间土的原位强度却与天然含水量分布在塑限附近的硬粘土差不多。研究结果亦表明颗粒分布对天然沉积中间土的原位强度有较大的影响。同时采用灰理论中的关联度分析，对这类中间土物理状态指标与力学特征指标间相关性进行了分析，认为孔隙比用于亚砂土稠度划分，含水比用于亚粘土、粘土稠度划分更加合理。

Mechanical properties of natural sedimentary intermediate soils

Natural sedimentary ground deposited in the north shore of the Yangtze River delta mainly consists of silty and fine sandy soils. The permeability varies within 10^-7-10^-3 cm/s, less than the order of 10^-3cm/s responsible for completely drained condition but larger than the order of 10^7cm/s responsible for completely undrained condition. Little study has been carried out on such natural intermediate soils in China. In this study, a series of physical and mechanical tests were performed on both the undisturbed and the remolded samples obtained from three sites in the north shore of the Yangtze River delta along Tongqi highway. The results indicate that the physical properties are similar to natural clayey soils with moderate sensitivity, but the tip resistance obtained by the in-situ cone penetration tests is almost the same as that of stiff clayey soils with liquidity index almost equal to zero. This study also illustrates that the grain size distributions of natural sedimentary intermediate soils have a significant effect on tip resistance. The grey correlation analysis utilized to analyses correlation between physical state index and mechanical character index for this clayey intermediate soils. It is clearly discovered that the void ratio utilized for sandy loam consistency partition and water content ratio for the silty clay and the clay consistency division are much more rational.