膨胀土的强度与力学特性

通过三轴试验与侧限压缩试验, 研究了膨胀土的强度、超固结性和压缩指标; 建立了胀缩指标与抗剪强度的关系, 分析了膨胀土的结构特征、矿物成分及外界条件等因素对其变形和强度的影响。研究结果表明: 膨胀土具有超固结性, 且超固结性越明显, 从峰值强度达到稳定强度状态时所需的变形越大, 抗剪强度也越大; 裂隙越发育, 其压缩性越高, 超固结性越弱, 抗剪强度指标越小。给出了膨胀土抗剪强度指标的变化范围: 固结排水条件下的粘聚力变化范围为19.8~25.5 kPa, 内摩擦角变化范围为10°~19°; 固结不排水条件下的粘聚力变化范围为23.0~35.3 kPa, 内摩擦角变化范围为3°~14°; 不固结不排水条件下的粘聚力变化范围为37.0~55.0 kPa, 内摩擦角为0°。

Strength and mechanic property of expansive soil

Strength, over consolidation and compression index of expansive soil were studied by triaxial test and confined compression test, the relationship between swell-shrinking index and shear strength was set up, the influences of structural feature, mineral composition and outside factors on deformation and strength property were analyzed.Study result shows that expansive soil has the property of over consolidation, shear strength increases with the over consolidation, the better the fissures develop, the higher the compressibility is, the weaker the over consolidation is, and the smaller the shear strength index is.The variation extents of shear strength index are put forward, cohesion changes from 19.8 kPa to 25.5 kPa, and internal friction angle changes from 10° to 19° under consolidated-drained compression test; cohesion changes from 23.0 kPa to 35.3 kPa, and internal friction angle changes from 3° to 14° under consolidated-undrained compression test; cohesion changes from 37.0 kPa to 55.0 kPa, and internal friction angle is 0° under unconsolidated-undrained compression test.