The Stability Of Deep Foundation Pit Adjacent To Highway

Hefei is at the peck of its economic development.With the development of the NO.1 subway and NO.2 subway, all kinds of deep foundation pits appear. In this paper, we take the NO.6 shaft deep foundation pit as an example. Combining the numerical simulation and the monitoring data, we have an analysis on the stability of NO.6 shaft deep foundation pit under the bias load.The NO.6 shaft deep foundation pit is in adjacent to the 312 state road(He Ning high-speed section) and under the bias load, the effect of subgrade bias function on the stability of the foundation pit can not be ignored. Now,the norm have no specific provisions for the foundation pit’s design and construction under the bias load, so developing the research on the stability and the deformation of the bias load under the subgrade has an important significance. In this paper,we combine the theoretical analysis, numerical simulation and the monitoring data of the foundation pit and have a research on the stability of the retaining structure and finally identified the following main research contents:(1) Based on reading lots of documents, we summarize the current research on the stability theory of deep foundation pit and its calculation method at home and abroad;(2) By using the MIDAS GTS-NX finite element analysis software, we have a two-dimensional numerical simulation on the excavation for the NO.6 deep foundation pit in accordance with the practical excavation. We analysis the deformation law of supporting structure and the surface subsidence law of NO.6 shaft deep foundation pit under the 312 National Highway extremely bias load, and we compared it with the monitoring data;(3) The influence factors of deep foundation pit under the bias load such as the embedded depth of the retaining pile, the influence of the roadbed distance and other factors were studied, and optimization the design of the structure. At last, we give a few comments and suggestions for the design of the foundation pit;(4) According to the actual engineering situation, we establish a 3D numerical model of NO.6 shaft deep foundation pit. The 3D numerical model can reflect the actual situation in the project more. Finally, we have an research on the deformation of surface subsidence, retaining structure and soil heave according to the results of 3D numerical simulation.(5) By means of monitoring method,we have an detail analysis of the NO.6 shaft deep foundation under the bias load and sum up the law on the deformation of the pile body(horizontal displacement, vertical displacement), the settlement law, the change of axial force and the 312 National Highway Subgrade variation(settlement of subgrade, subgrade’s horizontal displacement) etc;...