Study On The Engineering Characteristics Of Embankment On Slope Soft-Soil Foundation

Slope soft-soil foundation means the soil foundation whose surface or bottom presents slope and soft. The stability and deformation of establishing embankment upon such foundation are much concerned by engineers and technicians. Generally, such slope soft-soil foundation often needs to be reinforced due to its poor stability under the load of embankment. And studying the engineering characteristics of slope soft-soil foundation will provide useful reference and guidance for such as engineering reconnaissance, design, construction and others. Therefore, the following work is carried out on lab geotechnical centrifuge model and stability analysis.(1) The soil whose physic-mechanics parameters are similar to that of a typical slope soft-soil foundation is selected and four groups of centrifuge model tests are carried out. The tests include: level soft foundation embankment, slope soft-soil foundation (1:10), slope soft-soil foundation (1:10) with the reinforcement of driven piles and stabilizing piles. According to the test results, the deformation characteristics of level soft-soil foundation and slope soft-soil foundation under the load of embankment are analyzed. The effects of driven piles and stabilizing piles reinforcements are compared. The respective influence of the two reinforcement means upon foundation deformation is discussed and useful suggestions on how to use the two means are finally put forward.(2) By using the professional geotechnical software "GEO-SLOPE", the foundation stability under different circumstances is analyzed. The intensity parameters of soft-soil foundation obtained from centrifuge model tests of slope soft foundation and lab geotechnical tests are reasoned out. How the change of C, φ values of soft-soil will influence the foundation stability is analyzed. How the change of space between driven piles and stabilizing piles and how the change of exertion coefficient of the between-pile soil intensity parameters will influence the foundation stability are analyzed. The safe space between piles of different reinforcement schemes is initially confirmed.The test results and stability analysis indicates that: It is safer to construct embankment upon level soft-soil foundation than slope soft-soil foundation (1:10). The deformation of level foundation is generally symmetric of road central line and the deformation of slope foundation is mainly concentrated on the border side of the declivity. Both driven piles and stabilizing piles can maintain the foundation stability and the former means works better than the later. Stabilizing piles are better used with other reinforcement means if the project is strict with foundation subside. The foundation stability builds up by the increase of C values of soft soil. When using both driven piles and stabilizing piles to reinforce soft foundation, as the space between piles grows, the intensity exertion coefficient parameters of between-pile soil then reduces and the foundation stability becomes worse. In this thesis, the safe space between driven piles is 2 meters and stabilizing piles 6 meters.