Under The Seasonal Thawing Environment The Subsidence Analysis To The Soft Subsoil

With the development of fundamental construction in Northeast area more high-level roads are constructed on the groundwork of soft soil. Sedimentation of soft soil groundwork in this area has the features of bigger transformation, serious uneven sedimentation and longer stable sedimentary period, and also more influences from geology and climate. These features seriously affect the long stability of the roads and its safe use, and make it more difficult for the construction in Northeast area. Therefore, the research on the sedimentation of soft soil during the period of seasonal freeze thawing is very important for the construction of roads in this area. The thesis first analyzes the characteristics of the soft soil and its sedimentary groundwork, concerning the special environment of geology and climate in this area introduces some theories connected with the research, and makes deep analysis aiming at sedimentary mechanism, stress strain and influential factors; Second, the thesis studies some of calculating theories and methods of soft soil groundwork and the ways to deal with, has a comparable analysis on the feasibility and necessity of the application of plastic drain bars in the cold area, based at the practical data finds out the three ways of calculation which are useful to ascertain the final amount of sedimentation and its rules; finally, combining with the research of application of the method of drainage with drain bars dealing with the soft soil groundwork in the high-level roads in Northeast cold area, based on the observatory sedimentary materials of soft soil groundwork in the ring highway of Harbin, the thesis analyzes the main reasons affecting sedimentation, calculates the sedimentation of soft soil groundwork with the three ways and makes discussions and analysis, and gets results which accord with the actual projects. Concerning with the selection of the ways of calculation the thesis indicates all of them including layerwise summation method, double curve method and logarithm curve method can meet the demands of the projects. The thesis indicates a very bright future for the application of the way of drainage with drain bars in Northeast cold area.