Application Research Of Double-row Pile Supporting Structure In Foundation Pit Engineering

With the rapid development of China’s economy,in architectural terms,both the high-rise buildings and the utilization for the underground space have been rapidly improved.At the same time,the scale of deep foundation excavation has gradually increased,thus,many problems about the design of deep foundation pit supporting structure have also emerged one after another.In most cases,the double row pile support structure belongs to a new kind of supporting forms.Generally speaking,it has the relatively large lateral stiffness.Therefore,it can restrict the deformation of the supporting structure to a great extent.In addition,compared with other enclosure structures,its enclosure depth is also deep relatively.The construction period can be shortened to a large extent.Up to now,the double-row pile supporting structure has become one of the first choices among the schemes of the deep foundation pit supporting structure.However,talking of the aspect of its calculation method,it is not mature enough.As far as the present situation is concerned,the existing calculation models can’t reflect the actual stress of structure basically.Therefore,it is very significant to carry out research in this field.In the research process of this paper,firstly,the research present situation of deep foundation pit and the characteristics of common supporting structures will be briefly analyzed.Based on the existing research results at present,the calculation model of the typical double-row pile supporting structure will be discussed,and the advantages and disadvantages of each model will be given the corresponding elaborations in the paper.Secondly,the portal double-row piles and the soil volume scaling coefficient method will be mainly adopted in the paper.What’ more,based on the elastic resistance method and the limit equilibrium theory,the formulas for calculating the internal force deformation of the double-row pile supporting structure will be given in this paper.The corresponding MATLAB calculation programs will be compiled for the calculation,and the row spacing,front and rear pile stiffness and other influencing rules will be obtained in the end.Finally,the foundation pit engineering of some construction will be taken as the main case study object in this paper.Aiming at the influencing rule of different excavation depth on the bending moment and displacement of double-row pile supporting structure,the limit equilibrium method,the elastic resistance method and the finite element method(MIDAS GTS)will be adopted to make a detailed calculation and analysis.What’s more,the final calculation results and the actual measurement results have been compared together,thus the rationality and validity of these kinds of methods will be verified.