Study On Pile-anchor's Co-operation And Pile Anchor Retaining Structure's Permanent

Based on the case of pile-anchor support in Jinan,with finite element software PLAXIS 3D,using soil-harden model,the research about pile-anchor collaboration effect and sheltering effect is undertaken,and in terms of pile-anchor,the permanent supporting structure of deep foundation pit support is established.The following results have been achieved:1.Pile-anchor collaboration effect(1)In pile-anchor structure,when the anchor group effect occurs,the critical horizontal space of anchor cables decrease as the increasing value of prestressing force.The critical space is confirmed under different prestressing forces in the engineering geological condition of Jinan.(2)The arrangement form of the successively large prestressing force and successively decrease longitudinal space of anchor cable from the top down is better for the displacement control of supporting structure.(3)Displacement control of support-pile should focus on control of anchor cable and be with the supplement of control of support-pile.The design process follow the principle of "strengthen anchor and weaken pile".2.Sheltering effect of support-pileSupport-pile can decrease the soil pressure of basement external-wall significantly.Through fitting some engineering simulation results,the distribution curve for basement external-wall soil pressure was derived with support-pile existing,and the reduction factor k is introduced on the basement of formula of static earth pressure.The formula for basement external-wall soil pressure weakness can provide references for other similar engineering.3.The permanent supporting structure of deep foundation pitA combination of support-piles and underground main structure as the permanent support structure is formed by setting connected devices.According to the simulation results,in permanent support structure,the soil pressure outside the pit is mainly bore by support piles and horizontal structures,and the basement external-wall only account for the pressure generated from the back-filled soil,which is far less than static soil pressure.Therefore,the basement external-wall could be designed according to structural requirements under the condition of no water.