Application And Study On The Support Of Deep Foundation Pit Of Hospital No.1 Jilin University

With the development of our our country national economy, on one hand, people develop and make use of underground space continuously, and the deep foundation pit engineering becomes more and more, so as deep to the foundation pit depth scoop out. on the other hand, for the sake of satisfy development underground space of demand, our county had substantially developed in the deep foundation pit engineering theories, design calculation method, construction techniques, monitor means and so on, also appeared some new support methods and techniques. The support of deep foundation pit engineering often adopt theories calculation combine together with region experience of half experience with half theories of the method to carry on design currently, in a certain mean, successful engineering experiences usually more important.The support of deep foundation pit technique has already obtain a lot of successful experience in different regions and different kinds of geology condition, some fields have even obtained international level, but in order to fit the demand of modernization economy construction, further research and improvement is still needed.There are some problems that usually exist in the construction process of the support of deep foundation pit engineering, such as, unqualified in digging with soil layer and side ascent supporting, great differences between construction process and design, design job unfit actual circumstance ,overlooking of construction monitor and etc.Aiming at the application of the deep foundation pit protect engineering ,the research stresses emphasis on the depth of foundation pit, soil quality circumstance, periphery environment…etc. The mail contents of the work and results are as follows:1. The text research the general situation of the field area and the geology condition of the engineering.The distance of the foundation pit from the south to the north is 164.8m, and the east to the west is 206.5m. The grade difference of the south and the north is 7.57m.According to the request of the design, the underground engineering should excavate a foundation pit with the depth of 12.0m~19.8m, which is the deepest foundation pit in changchun.The surrounding environment of the foundation pit is complicated, with many buildings and pipelines underground close to it.The foundation pit digs deeply, and it's surrounding place is in great demand.The layer of the underground soil in this area can be divided into 8F, miscellaneous fill soil, powder quality to glue soil, glue soil, mire rock and so on.2. According to the analysis of various impart factor of this engineering combined with the actual circumstance of the engineering, then the choice and analysis for the support of Foundation Pit Project is carried out.The Support of Foundation Pit includes a lot of methods, which support method to adopt is needing a assurance research at the earliest stage in the concretion engineering, the choice of Foundation Pit of Support main depends on the comprehensive concatenation and analysis scoop out depth, rock-soil of property, environment circumstance of foundation pit surrounding and condition of construction etc. factor.When choosing project for support of Deep Foundation Pit of Hospital NO.1 Jlin University, first research the technique of request of the method of support of the foundation pit; and then research and study various Support structure of characteristic with apply scope, and analysis various influence factor of this Foundation pit engineering creation of influence at last, synthesize an analysis choice and assurance foundation pit of support a project.Because the area of foundation pit is too big and the shape of the foundation pit is an anomaly, and the impact factor of Foundation pit surroundings is more complicated.Therefore, we dissimilate demarcate foundation pit of side ascent according to impact factor.Then assure each area rightness foundation pit support structure depend on the analysis of various impact factor.Then discuss and adjust the primary election project, at last assure each area's type of Support structure.Mainly chose to use tow kinds of Support structure are stake anchor (priestesses anchor pole + the stake of black soil) structure and compound the soil nail wall (priestesses anchor pole +soil nail ) structure.3.Design the calculation for the selection of foundation pit support structure which has been made, provide correspond of parameter for the support of foundation. Invest date according to actual circumstance and geology of analysis of the engineering. Because the foundation pit will be a bit deep. To satisfied the strength and the stability for the foundation pit, stake anchor adopted many fulcrum of support structure.So the design of the support adopted the equal beam method in many fulcrum wall calculation and design theory to calculate the internal force and design is based on the reinforced concrete circular piece of a curved design structure. And then calculate the internal force of the single pile by the equal rigidity method. Finally, assurance the diameter of the pile and calculate the bar of the pile. Au point of the anti-dint which is come form the equal beam method is the minimum anti-pull force which is undertake by the anchor.After multiply safety coefficient 1.3, the solid length Le according to the anchor pole extreme limit anti-each anchor pole of valid the anchor, the non-anchor solid length Lo to define the distance of building and stability geologic strata of actual distance assume empress mutually add to get an anchor pole length with the anchor solid length.The soil nail to support of the design calculation according to《foundation pit and soil nail technique regulations》CECS96: 97, after the calculation and design above, according to the result, define each support structure of construction parameter.4.The management of the foundation pit support construction. Do the preparation work well before the process of the construction. After a great deal of investigation of the geology, combining the theories calculation of the support structure design drawn up a construction plan. Summary some management and control measure under construction. Analyses the part landslide accident which appears in support structure 7th areas.The corpus engineering was completed in 2007. Only the part of 7th area occurred trouble for the unknown water. Because of information-based in time feed back, there was not dead and injured trouble severely. Others which choose the deep foundation pit protect engineering complete the protect of mission.Original building and underground facilities and pipeline, especially original cultural building were not subjected to bad influence.Form the economy performance and society comprehensive perforce, this engineering of the deep foundation pit protect obtained very nice effect. It is able to provide solid and beneficial certificated data in similar and related engineering.