Optimize Selection Of Retaining And Protecting Projects And Analysis Of Excavation Stability For Large Deep Foundation Pit Along The River

Today,China's economic situation is excellent,the degree of social development is also steadily improving,but with the face,is the urban construction land is also declining,making us more to the height of the search for space.The higher the height of the building,the depth of the pit is also deeper and deeper,deep foundation pit engineering is becoming more and more important,and its complexity is more significant than before.Along the river city benefited from the advantages of its geographical location,the development of more rapid,accompanied by a large number of projects along the Yangtze River area construction,Riverside large deep foundation pit more and more,the scale is gradually increased.Such excavation works compared to the previous urban foundation pit project to be more complex and varied,the excavation depth,excavation area,compact,surrounded by building and underground pipelines and other facilities intensive,the surrounding environment sensitive and complex,The surrounding environmental protection requirements are higher,the environmental risk of the foundation pit project increases.At the same time,due to being located on both sides of the river,the river has become an adequate supply of water,and for such large-scale deep foundation pit works.Support construction period will be longer.Do not avoid the river flood season.On the scene of the water retaining structure is a huge test,and flood season will also threaten the safety of the foundation pit project,which is also large and deep foundation pit engineering safety along the river made a more stringent requirements.At the same time,we note that at present China's Riverside large deep foundation pit project is not a lot.The relevant design theory has yet to be further studied.The design of the dependence on the experience is relatively high.Based on the case-based reasoning theory,this paper summarizes the success stories of the large-scale deep foundation pit support project in recent years,and establishes the optimal model of the deep foundation pit support scheme of Riverside,and applies this model to a base The results show that the model is effective and feasible.The stability of the excavation system is analyzed by numerical simulation software.The main work and research results are as follows:(1)summarizes several commonly used composite support systems at present,analyzes their advantages and disadvantages and the scope of application,and summarizes the problems and shortcomings in the support design at the present stage.(2)system introduced the case-based reasoning theory,its basic principles and work processes to make a detailed description.This paper introduces the basic knowledge of rough set theory,introduces the concept of information entropy,and uses rough set theory to solve the importance of index.Based on the knowledge of information entropy,the weight value of the required index can be determined objectively.(3)The success stories of Riverside deep foundation pit support in recent years were collected and discussed.The influencing factors of the optimization of the foundation pit support scheme along the river were analyzed and discussed,and six main influencing indexes were established.Case Representation Method and Case Base of Large Deep Foundation Pit Support.(4)Based on the weight formula of information entropy,the weight of each major influence index is determined from the foundation part and the supporting structure of Riverside deep foundation pit.The nearest neighbor method is used to establish the deep foundation pit(Including the structure of the envelope and the part of the supporting structure)of the Riverside large foundation pit support system.(5)By calculating the weight of the influencing factors,the most important factor influencing the selection of the support scheme of the deep foundation pit along the river is the distance of the Riverside,which also reflects the largest engineering of the foundation pit Difficulty: near the river.River water will serve as the groundwater supply water source,so that the groundwater content increased,but also on the side wall of the pit to produce an additional side of the pressure,which makes the Riverside foundation pit support requirements than other types of deep foundation pit requirements higher,Indicating that the weight calculated by this method is in line with engineering practice.(6)Taking the example of a Riverside foundation pit project as an example,the system of the foundation pit along the river support scheme is used to optimize the support project.Then,the recommended foundation pit support scheme is opened with GEO5 software.The stability and reliability of the proposed scheme are verified,which proves that the optimal model of this scheme is feasible and effective in practical application.