Evaluation And Simulation Of Deep Foundation Pit Support Scheme In Soft Soil

With the rapid development of China's economy,the development and utilization of underground space is further.The technical challenges and risks of excavation and support of soft soil deep foundation pit in the circumlittoral developed zone are also increasing.The excavation and support of deep excavation in soft soil are characterized by soil slippage,instable foundation pit,pile displacement,pit bottom uplift and water leakage of retaining structure,also threaten buildings and underground pipelines Therefore,the preference and successful implement of the deep foundation pit support scheme of urban soft soils play a significant role in the whole foundation pit project,which has great influences on the four great goals of the project as well as the protection of the surrounding environment.This requires the project manager not only to select the economic and reasonable deep excavation support program,but also to take appropriate methods to help its implementation.Based on the analysis of the factors affecting the support of deep foundation pit in soft soil,this paper establishes a comprehensive evaluation index system based on the transformation project of Qingdao Beer City,and analyzes the synthetic weight by means of game aggregation theory.Soft soil deep foundation pit support scheme is optimized,and the selected scheme is simulated and implemented.The main research contents including:(1)This paper combines the research actuality of the foundation pit support scheme at first,and expounds the characteristics of the deep foundation pit and the technical requirements of the support,the form of support and its appropriate conditions and scope,the evaluation principle of the support scheme and so on.Then,it summarizes the problems which should be focused in the construction of deep foundation pit of soft soil,finally introduces the application of BIM technology in the implementation of engineering project.(2)To determine the evaluation index system.Based on the combination of expert investigation and field investigation,the influencing factors of deep foundation pit support scheme are collected and analyzed.By this,principal component analysis is used to optimize the existing factors,reducing the adverse impact from factor correlation and overlap for decision-making,and the index system could reduce the dimension and simplify.At last,the total cost of the foundation pit engineering,the total construction period,and the stability of the supporting structure as well as the effectiveness of the soft soil treatment technology areselected from the 15 indexes such as the original construction cost,the feasibility of the construction technology and the difficulty of the construction,the effectiveness of the precipitation program and the impact of the project on these environment 6 indicators.(3)To determine the indicator weight.Based on the OWA operator and the information entropy,the subjective and objective weights are aggregated to obtain the comprehensive weight.The combined weights of the six indicators were 0.227,0.28,0.202,0.126,0.120 and0.104.(4)To select the optimized project.This paper uses the Regid theory as the guiding ideology to establish the optimal decision model of the Lattie order to optimize the support scheme of the deep foundation pit of Qingdao Beer City.It is the combination support form of "Bored Pile + High Pressure Jet Grouting Pile + Bolt Stretch" in Qingdao Beer City Reconstruction Project.The form of support will be better with the foundation pit of the water,water work,and this combination of support form is more economical and easier to operate and play a significant role.(5)To simulate the optimization program.Doing the implementation of three-dimensional model of deep foundation pit of Qingdao Beer City renovation project,the progress of articulation,collision inspection and other simulation implementation by BIM technology,we can find out the lack of design drawings,and have real-time control to help managers to take better control of costs and duration,in order to improve management efficiency.In this paper,through the analysis of the above content,we achieve a good effect for the construction enterprises in the soft foundation of deep excavation works in the process of better alternative decision-making options.At the same time,combined with building information model(BIM)technology for auxiliary construction,in order to improve their management efficiency and overall management level provides a theoretical basis and model support.