宁南地区红黏土的强度特性研究

Strength property of red clay in southern region of Ningxia

文章通过试验研究了宁南地区红黏土物理力学性质及胀缩性,结果表明,该红黏土的液、塑限较低,具有一定的胀缩性;分析了含水率w与黏聚力c、内摩擦角φ、基质吸力S、膨胀力P的关系,发现S、P与w之间呈良好的指数函数关系,c与w呈幂函数关系,φ与w呈线性关系;通过拟合得到适用于宁南地区红黏土的非饱和强度公式,该公式通过膨胀力来表示由吸力引起的强度部分,避开了量测基质吸力的麻烦,以一种相对简单有效的方式来确定非饱和红黏土的抗剪强度。

Based on a series of laboratory experiment, this paper presents the physical property and shrink-swell property of the red clay in southern region of Ningxia. The result shows that it has low liquid and plastic limits and certain shrink-swell ability. The interrelation between water content w and cohesion c, angle of internal friction φ, matric suction S, expansion-pressure P is analyzed. Good index functions between S, P and w, a power function between c and w, a linear relation between φ and w are found. And the strength formula which is appropriate for the unsaturated red clay in southern region of Ningxia is obtained. This formula avoids the problem of measuring the matric suction and computes the shear strength of unsaturated red clay in a simple and efficient way.