非饱和泥质粉砂岩蠕变特性及其模型

Compressive Creep Property and Model for Unsaturated Argillaceous Siltstone

摘要:

以南宁第三系泥质粉砂软岩为研究对象，开展非饱和三轴压缩蠕变试验，分析含水率对岩石蠕变特性的影响；再在既有五元件蠕变模型中，引入非线性黏塑性元件，构建泥质粉砂岩的七元件非饱和压缩蠕变模型，分析相关蠕变参数的变化规律。结果表明，随着含水率增加，泥质粉砂岩的蠕变变形和蠕变速率显著增加，且蠕变长期强度明显降低，表明水对泥质粉砂岩蠕变变形影响显著；新建七元件模型较好地拟合了非饱和泥质粉砂岩全过程蠕变曲线。

Abstract:

In this paper， the tertiary argillaceous siltaceous soft rock was extracted from a subway station construction site in Nanning， China. Triaxial compression creep tests were conducted and influences of water content on creep properties of the unsaturated argillaceous siltstone were analyzed. Meanwhile， a nonlinear viscoplastic component was embedded into a five-component viscoelastic model and a seven-component unsaturated compression creep model for the argillaceous siltstone was built. Using this model， the variations of the creep parameters were analyzed. The results show that as water content increases， the creep deformation and creep rate of the argillaceous siltstone significantly increase， while the long-term creep strength obviously decreases， indicating that water has an important impact on the creep deformation of the argillaceous siltstone. The newly built seven-component nonlinear viscoelastoplastic model well simulates the whole creep process curves.