Research On Excavation Mechanical Effect And Influencing Factorson Stability Of Pile-anchor Supporting Structurein Deep Foundation Pit

With a variety of large-scale integrated transport hub construction, came into a lotof large complex deep foundation, double pile retaining structure to facilitate itsconstruction, which will help many advantages such as earth excavation pit isincreasingly used in deep supporting a large pit. Therefore, studies of deep foundationexcavation mechanical effect of double-row piles supporting structure, analyze stabilityof double piles, double pile retaining structure factors for optimizing the design andengineering applications supporting structure is of great significance. This papersummarizes the relevant research results at home and abroad on the basis of QingdaoCity, a comprehensive transportation hub, deep excavation project engineeringbackground, theoretical analysis and numerical simulation of excavation process ofspatial effects, double pile supporting structure of the force and deformationcharacteristics, different excavation widths, different pile connection, different pilecoupling beam cross-sectional dimensions and different pile arrangement deformationand stress effects on pile retaining structure were more systematic studied. The maincontents and conclusions are as follows:①Analysising the advantages and disadvantages of existing calculation methodson the structure of double piles and various calculation methods, focusing on theadvantages of numerical analysis methods.②Using numerical analysis method to establish a numerical model based on theactual support structure parameters and the surrounding geology excavation, excavationprocess simulation based on the construction program, comparative analysis of thedeformation at different locations in a large pit-row piles retaining structure and theforce given the scope of the excavation pit corner space and large pit in effect doublethe most unfavorable distribution area pile retaining structure.③Selecting the typical cross-section in the most unfavorable distribution areadouble piles structure during excavation response to double-pile retaining structuremechanics were studied, obtained during excavation double piles deformation andstress distribution of retaining structures, close to the earth excavation pit at the bottomof the pile lateral deformation of large double, double pile retaining structure in front ofthe pile load sharing is greater than the back pile.④Studing the influences of excavation width, pile top connection, even the top of the pile beam cross-sectional dimensions and pile arrangement on double pilesstructural deformation and force, the findings show that: with the width of theexcavation increases, double pile retaining structure were increased stress anddeformation; pile when connecting the front and rear double row of piles and pile thewhole effect is basically the same connection supporting structure; pile coupling beamcross-sectional dimensions of1dx0.5d (d for the front row of the pile diameter), thedouble-row piles minimum overall force structure can effectively control thedeformation; greater impact in different ways on the double pile fabric pile retainingstructure deformation and force.