宁波软土物理力学参数概率分布及相关性研究

Probability and correlation between physical and mechanical parameters of soft clays in Ningbo rail transit engineering

根据宁波1、2号线轨道交通工程的地质勘察资料,研究了宁波地区软土力学参数的分布规律,建立了宁波地区软土力学指标与物理指标之间的经验公式。结果表明:1)各软土层的压缩系数a、压缩模量Es、固结快剪黏聚力cc和固结快剪内摩擦角φc离散程度较小,且呈较好的正态分布规律,而各软土层的快剪黏聚力cq和快剪内摩擦角φq离散程度较大,近似呈正态分布。2)a与w、e之间呈正线性相关关系,a和ρ之间呈负线性相关关系;Es与w、e之间呈负指数关系,Es和ρ之间呈正指数关系;各软土层的cq、cc、φq和φc与e、IP之间均呈负线性相关。研究结果可为宁波地区岩土工程设计的参数取值提供依据。

According to the first-stage geological investigation reports of the line 1 and line 2 of Ningbo rail transit, the probability distribution of mechanical parameters of soft clays in Ningbo area were studied. Empirical equations between mechanical and physical indexes were established. It was found that the compression coefficient （a）, compression modulus （Es）, consolidated quick shear cohesion force （cc） and consolidated quick shear internal friction angle （φc） of each soft layer in Ningbo area had little variation and all showed good nor- mal distribution. However, the quick shear cohesion force （Cq） and quick shear internal friction angle （φq） of each soft layer had much variation and showed approximately normal distribution. Moreover, the compression coefficient presented a positive linear correlation with the physical parameters like void ratio and water content, but a negative linear correlation with the density. Furthermore, the statistical data indicated a negative exponential correlation between the compression modulus and the void ratio and water content, while a positive exponential correlation was found between the compression modulus and the density. In the end, the mechanical parameters, i. e , Cq, φq, cc and φc, were in a negative linear correlation with the physical parameters like void ratio and liquid index. Our study could provide a basis for the geotechnical investigation and design in Ningbo area.