一、软土的工程特性淤泥、淤泥质土及天然强度低、压缩性高、透水性小的一般黏性土称为软土。大部分软土的天然含水量30%～70%,孔隙比1.0～1.9,渗透系数为10-8～10-9cm/s,压缩性系数为0.005～0.02,抗剪强度低(快剪粘聚力在10Mpa左右,快剪内摩擦角0～5°),具有触变性,流变性显著.对于高速公路,标准贯击次数小于4,无侧限抗压强度小于50Kpa, First, the engineering characteristics of soft soil Silt, muddy soil and natural low strength, high compressibility, water permeability of the general clay called soft soil. Most of the soft soil has a natural water content of 30% -70%, a porosity of 1.0-1.9, a permeability coefficient of 10-8-10-9 cm / s, a compressibility coefficient of 0.005-0.02, and a low shear strength Force is about 10Mpa, fast shear internal friction angle 0 ~ 5 °), with thixotropy, rheological significantly.For the expressway, the standard number of penetrations less than 4, the unconfined compressive strength of less than 50Kpa,