The Engineering Geological Characteristics And Stability Of Numerical Analysis Of Soft Soil In Haipu Interchange

Most region of Guizhou is mountainous with carbonate rocks widely distributed and a high annual rainfall. Its groundwater dynamic is under a good condition and a large number of soft soil are distributed at the low-lying place with karst development. The nature of soft soil is special and complex, especially in mountainous areas where the soft soil is randomly scattered with the characteristics---having its own range of composition, thickness changing significantly and complex topography and geological conditions. To solve these problems, this thesis carried out a series of tests on the engineering geological characteristics of soft soil and made numerical simulating analysis on the stability of soft-soil roadbed based on the test results and existing diseases. Following are the findings:(1)There is a high content of clay minerals on the study area with strong hydrophilic and expansion in terms of laboratory test analysis. When the clay mineral is absorbing water, the expansion of montmorillonite in the clay mineral would push other surrounding soft soil. When subjected to weight or heavy rains, the sensitivity rheology would be increased. Iron content is high in the soil and the organic matter in soft soil region could deoxidize iron oxide and reduce its cementation. Besides, a strong hydrodynamic force makes free iron loss, soil cement weaken, void ratio increase, compression strengthen and bond between soil particles reduce. Meanwhile, the soil under load thixotropic has been enhanced.(2) The correlation among pore ratio, water content, plastic limit and sampling depth is tested through the sample linear regression analysis. It shows that pore ratio, water content and sampling depth are positive correlation; liquid limit, plastic limit and water content are also positively correlated relationship which is quiet high correlation; the coefficient of consolidation as well as modulus of compression first falls and then rises with the depth increasing; the coefficient of consolidation and water content are negative correlation and the correlation is relatively high, which means the greater water content, the longer time consolidation of soft soil required.(3) It found that embankment slope is unstable and has a larger displacement through the displacement and strain simulation study of cement mixing pile embankment slope. The embankment sliding surface are most likely to occur at the position where there is mucky soil. For shallower area of mucky soil, the most horizontal displacement all occurs at the mucky soil, while for the vertical displacement, the side with thick muddy soil sinks much larger than the other side; for deeper area of muddy soil, it is affected slightly by the sub-grade and the horizontal displacement happens on the filling and clay layers. The largest floating area is on both sides of the sub-grade that is the vertical displacement and the maximum sinking area is beneath the roadbed, which all occur in the filling and clay layers.