Foundation Monitoring and Analysis in Interval Wenti Road to Wuli River in Shenyang Subway Line 2
|Keywords||subway deep foundation monitoring numerical simulation analysis of deformation warning|
With the development of China’s economic, the ground transportation is becoming increasingly difficult to meet the demand of the Urban’s transport development. More and more cities begin to develop the underground transport, which promots the development of the Mass Transit Railway Technology. Deepening excavation method is widely used as an effective way in the construction of subway station. The construction theory about the excavation and support method is one of the most important problems in the subway area. The deformation in the foundation excavation process will not only affect the safety of subway construction and progress, but also cause dangerous to the adjacent buildings, the underground pipe network and other municipal facilities.Whether we can predict and control the deformation of the surrounding soil is often the key to the success of deep foundation construction. This paper is based on the monitoring project of the excavation foundation between Wenti Road Station to Wulihe Station in the second line of the Shenyang sub way. We used the numerical simulation method to forecast the deformation and force which may occur in the envelope structure. At the same time, we monitored the deformation and force during the process of the foundation works.Then the monitoring results and analyzed results were compared and verified the reliability of prediction. The main research works in this article were as follows:Firstly, used the Midas/GTS software which is commonly used in geotechnical engineering to setup the model to analysis the deformation and force of the envelop structure during every construction stage.Secondly, discussed the monitoring of deep foundation system and working principle, studied the basis for monitoring, content and results. And than came to the conclusion that, the piles deformation was smaller during the initial excavation, gradually increased with the deepening of the excavation, and no longer growth after the excavation was completed. Deformation of single pile was in accordance with the laws of that from the lower part to the upper part, the defomation was gradually increased.With the pit deepened, the steel supporting’s axial force were gradually increased and duced a little after the next steel supporting was set up, but soon increased again and became stable after the foundation excavation was in the end. With the deepening of the excavation, the overall trend of the steel bar axial force showed a gradual increase at first, has a slight reduction after the steel supporting was set up, but increased again as the excavation deepened.Thirdly, Analysis the numerical simulation results and the actual monitoring results, Finally come to the conclusion:the envelope structure deformation analysised by the MIDAS /GTS software has the same law with the deformation from the actual mointering, so the sofrware can be used to find a dangerous parts of the foundation to make the reinforcement as soon as possible to prevent accidents. However, during the process of modeling, simulation load can not be fully consistent with the actual situation. And during the actual construction process, the weather conditions change will have a big impact on the deformation of the foundation, but the analysis can’t simulated those sudden changes,so the actual monitering is still very useful.