南阳膨胀土非饱和剪切特性试验研究

选取河南南阳膨胀土采用非饱和直剪仪进行控制吸力条件下的直剪试验。试验结果表明,在不同的基质吸力和竖向荷载下,重塑膨胀土试样由于结构性遭到彻底的破坏,应力应变关系表现为应变硬化特性。在400kPa吸力范围内,非饱和强度与吸力基本呈线性增长关系,南阳膨胀土的非饱和抗剪强度参数约b为16.4°,验证了非饱和土的双变量强度公式的适用性。

Study on Shear Strength Characteristics of Expansive Soil of Nanyang City

The shear strength characteristics of a typical expansive soil from Nanyang City were studied by performing suction controlled direct shear tests. The test results shows that the stress-strain curves of the remoulded expansive soil samples were stress-hardening owing to competely damage of the soil construction under different matric suctions and vertical stresses. The effect of matric suction on the frictional resistance increases with an increase of the net normal stresses during the matric suction range from 50 to 400 kPa. The friction angle with respect to changes in matric suction = 16.4°, which proved the applicability of the double stress variables strength equation.