Influence of Some Factors on the Stability of Soft Soil Subgrade

The effects of some factors on the soft soil subgrade stability are simulated and analyzed by Bishop's method.The factors include the intensity parameters,the cohesion and the friction angle of the filled soil layer and natural soft soil layer,the unit weight of filled soil layer,the thickness of underground soft soil layer.The influence mechanism is simulated in three cases: simple subgrade with one side vacant,higher water lever subgrade with one side vacant,higher embankment subgrade with one side vacant.The result indicates that: 1.the stability of the soft soil subgrade is enhanced as the cohesion and friction angle increases,but drops along with the increase of unit weight of the filled soil;2.in some range of the thickness of the underground soft soil,the stability of the soft soil subgrade decreases as the thickness of the underground soft soil increases;3.high water level and high embankment reduces the stability of the soft soil subgrade to a certain extent;4.in the same soil layer,the comparative influence of the cohesion and the friction angle depends on the thickness proportion of this layer in the whole stability influential soil,as well as the is influence for different soil layers.