增湿条件下兰州Q_3原状黄土的强度特性

The strength characteristics of undisturbed Loess under humidified condition

采用总应力法,讨论了增湿条件下兰州地区Q3原状黄土应力-应变曲线特征,分析了增湿过程中含水量及围压对极限强度、抗剪强度参数的影响。结果表明:兰州地区Q3原状黄土的强度受含水量变化的影响较大,在低围压时含水量对黄土强度的影响更显著。随着含水量的增大,粘聚力、内摩擦角逐渐减小;粘聚力与含水量之间呈二次多项式关系,内摩擦角与含水量之间呈线性关系。利用摩尔库伦破坏准则得出兰州地区Q3原状黄土增湿条件下极限强度与含水量、围压的计算公式。

Using the total stress method, we discussed the stress - strain curve characteristics and the water content, analyzed the effects of pressure in the process of humidifying on the ultimate strength and shear strength parameters of the undisturbed loess （ Q3 ） in Lanzhou. The results show that the strength of the undisturbed loess （ Q3 ） in Lanzhou is strongly influenced by water content changes, and under the low confining pressure the influ- ence of water content on loess strength is more significant. As the water content increases, cohesion and internal friction angle decrease. There is a quadratic polynomial form between cohesion and water content, a linear rela- tionship between the angle of internal friction and moisture. Molar - Coulomb criterion was applied to develop the formula of ultimate strength and water content and confining pressure under humidified conditions undisturbed loess （ Q3 ） in Lanzhou.