Analysis Of Characteristics Of The Stress Of The Foundation Pit Retaining Structure With Double-row Piles Based On The Theory Of Soil Arching

Retaining structure with double-row piles in foundation pit supporting is amore recent form of support. This supporting form with the lateral stiffness ofsupport, construction convenient and safe and economic control graduall yaccepted by geotechnical engineering design personnel, and is used infoundation pit engineering with poor soil and complex surrounding environmentand the construction land red line clear constraints is put forward.Scholars at home and abroad doing a lot research on cantilever double-rowpiles supporting structure, puts forward all kinds of theoretical calculationmethods, although has been applied to engineering practice, but so far the theoryof double row piles has not formed the design and calculation theory widel yaccepted. On the basic of comparative anal ysis of various theories andcalculation methods, this paper, first of all, doing a mutual support anal ysis for avariet y of theoretical, then through monitoring data double-row piles supportingstructure that successful used in the actual project, derived the double-row pilessupporting structure mechanics anal ysis and calculation formula, and thenthrough the geotechnical engineering anal ysis software to anal ysis everyparameters that could influence the double row pile retaining performance. Thethesis mainl y includes the following sections:1. Summarize the research status and present application situation and themain calculation method about double-row piles supporting structure indomestic and overseas.Put forward the research purpose and researchinnovations of the thesis.2. Based on the theory and method of existing double-row piles supportingcalculation, this paper derived calculating method of Critical slip surface andafter piles soil pressure. And deduces the calculation method of soil betweenpiles, and establish the pile deflection differential equation of double row pile toanal ysis stress and deformation. Iterative formulas of differential equation isdeduced through boundary conditions, get a calculating method for calculatingthe stress and strain of double row pile.3. Through the project example, using the large finite element anal ysis software Midas-GTS to establish the same finite element anal ysis model as theactual support of double-row piles supporting structure, and compared the actualmonitoring data and the model calculation values, verified the accuracy of themodel. Through changing the compression modulus of soil between piles, pilereinforcement depth of soil, pile top and Contact beam connection and Pilestiffness changes analysis the horizontal displacement of retaining structurewith double-row piles and pile stiffness, and anal ysis the pile spacing influenceto the soil arching effect between piles.This paper concludes calculation formula of the active earth pressure afterpiles, soil stress between piles and pile body displacement and bendingmoment.This paper offered a new theory anal ysis method for double row pilesin foundation pit supporting, which has a great theoretical and practicalsignificance for studying on the mechanism of double-row piles supportingmechanism.