Research On Deep Foundation Ditch Of Qunguang Mainland Square Building In Chengdu

The foundation ditch of QunGuang mainland square building is 23. 8m deep and is located in east side of ChunXi road which is in the business core zone of ChengDu. Important city roads and high-rise buildings are around the foundation ditch which is the deepest and its environmental safety is the most important in ChengDu even in the southwest area. This text research on the earth pressure,bracing scheme and the parameter of the bracing structure relying on this deep foundation ditch engineering. The main results gained can be summed up as follows:(1) Carrying through theory analyse according to the intensity and distorting of the lower mudstone on the base of referring to the traditional earth pressure calculation theory, extract calculation principle and method about the earth pressure of the deep foundation ditch composing of unconsolidated covering layer and rock mass.(2)Analyse the existed shortage of the thickness weighted simplified method about the physical mechanical parameter of the soil horizons first and then starting from the angle of equivalent internal force of the bracing structure, extract the simplified calculation principle and method which is corresponding to the physical mechanical parameter of the soil horizons and equivalent internal force of the bracing structure. Comparing with the results which are calculated according to the traditional earth pressure calculation method, it indicate that the simplified method extracted in this text is more appropriate.(3)Aim at the difficulty of looking for inflection point when using equivalent beam method to analyse the pile anchor structure in soil horizons with high cohesive strength, extract mapping method and equivalent bending moment method to ensure the location and value of the bracing. The effect is verified preferably in this foundation ditch engineering.(4) Arguing on the bracing scheme according to the previous methods and the secure requirement of this foundation ditch, it educe that adopt pile anchor bracing scheme is safe credible economical and appropriate. It can offer gist for engineering design.(5)Check the reliability and rationality of previous methods by using plane finite element numerical simulation calculation.(6)Comparing the numerical analysis result with the actual monitoring result, it indicate that the actual displacement of the top location of the pile is smaller than calculated value because of not considering the three-dimensional effect in numerical calculation model,but their variable trend is consistent.