厦门花岗岩残积土物理力学指标关联性定量表征初探

厦门地区花岗岩残积土的颗分试验表明其粒度呈“两头多，中间少”的特征，级配较独特。孔隙比等物性指标与压缩模量等设计中常用指标定量关联性不强，离散性大且没有明显规律。结合厦门地铁工程地质勘察资料，通过粒间状态参量、级配控制模式确定所研究土体的关键物理状态参量，分析该参量与岩土工程设计中常用指标之间的相关关系。结果表明，引入Thevanayagam提出的粒间孔隙比作为参变量，压缩模量随粒间孔隙比的增大而减小，建立了估计残积砾质黏性土、残积砂质黏性土压缩模量的经验公式。级配控制模式下的特征粒径比可以作为估计花岗岩残积土抗剪强度指标的关键参变量，黏聚力随特征粒径比的增大而增大，内摩擦角随特征粒径比的增大而减小，且线性相关性较好。文中建立的预测花岗岩残积土压缩模量、抗剪强度指标经验公式，可供厦门地区工程设计时参考。

Preliminary study of quantitative relationships between physical and mechanical indices of granite residual soil in Xiamen

The particle size distribution curves show that, there are few fine sands and silts in the investigated granite residual soils. And the unique grain size gradation of the granite residual soil results in large discreteness of the parameters commonly used in design with physical parameters. Based on engineering geology investigation reports of metro engineering in Xiamen, correlation analysis are carried out between physical state parameters such as the interfine void ratio, the granular composition and the strength parameters. Results show that, correlative equations, of residual gravel cohesive soil and residual sandy cohesive soil, can be established between intergranular state parameters, proposed by Thevanayagam, and modulus of compressibility, in which, the modulus of compressibility decreases with increasing of the interfine void ratio. And, as for estimating shear strength indices, the characteristic diameter ratio can be taken as a parametric variable. With increasing of the characteristic diameter ratio, the cohesive force increases, and the internal friction is just the opposite. The established empirical formulas of modulus of compressibility, and shear strength indices for granite residual soil in this paper, can be provided as a reference for engineering design in Xiamen.