Research Of New Technique In Circular Up-to-Down Excavation

Up-to-Down construction technology,combined with main structure and remaining structure,is the best selection for constructing basements or some other underground structures.New problems and new styles appear with the developing of constructing technology.Following are the main subjects to discuss,based on the research work of up-to-down technology of circular deep pit engineering.Expound the history and current situation of up-to-down construction technology.Indicated that futher progress of up-to-down technology should be made by the upgrading of construction.Analyzed the difficulties of'digging-milling method'on constructing diaphragm concrete wall,offered suggestions and plans,analyzed the results.Analyzed the principles and control methods of slip casting around pile,proved the feasibility of slip casting method by comparison of end production. Analyzed the difficulties of extreme long bored piles,raised some plans based on the former tests.Proposed different tests for extreme long high-pressure stirring pile,took another test based on the results of former tests,summarized measures of anti-pipe-laying.Analyzed the traits of concrete pouring underwater,raised the plans for pouring high class concrete and displaceing of different concrete.Part-by-part lifting methods and verticality control measures taken to meet the demand of long steel tube lifting and vertical deflection.