Soft Foundation Deformation Field Monitoring And Numerical Analysis Of Highway In Cold Region

The mainly facing geological issue is soft foundation subsidence deformation when Highway constructed on soft foundation. With the construction of national arterial highway, local highway network will be upgraded and improved soon. The number of constructing highway on the soft foundation in cold regions is growing. In order to know well the deformation characteristics and laws of soft foundation in each time period, soft foundation characteristics have been studied. Based on the existing soil ground deformation theory, considering the special Northeast geological and environment climate, Qiqihar-Fuyu soft foundation section of national highway 111 has been chosen as test section. The soft foundation deformation on the test section have been monitored and analyzed,the treatment effect of plastic drainage plate and sand wick based on measured data have been compared and evaluated. According to finite element model of elastic-plastic theory, ABAQUS finite element software have been used for numerical calculation of soft foundation deformation on the test section,The result have been compared with the measured data and the result was analyzed.The results show that:soft soil engineering properties show soft plastic state in cold region, and it is high-pressure plastic soil, but the soft foundation characteristics are better than the soft soil in coastal areas. The analysis of site monitoring data shows that the increasing of shoulder soil pressure are caused by the formation of frozen shall, and lead to comparatively large vertical deformation of the shoulder. In the early frozen stage and the site of shallow freezing depth, soft foundation shows inverse displacement.During the embankment fill process, the vertical and horizontal displacement of soft foundation increased significantly. The maximum lateral displacement occurs in the subsurface depth of 0.25 to 0.45 times of the soft soil. With the dissipation of pore water pressure, the effective stress increases and the soil strength increased, the level of horizontal displacement changed a little, which shows the trend of lateral contraction. The range of increasing pore water value pressure of plastic drainage plate is higher than Sand Wick, whose pore water pressure dissipation faster, so it's more conducive to the consolidation and drainage of soft soil. The numerical model results are consistent with the measured data. The parameterμ,k and M are more sensitivity to the model,so they should be sampled in the field and valued by data provided from the field test or laboratory test. The research results could provide theoretical basis for soft foundation highway design and construction quality control in cold region.