Study On Deformation And Ultimate Load Of Unbonded Pre-stressed Reinforced Earth Retaining Wall

The unbonded prestressing reinforced earth retaining wall is composed of wall panels,side pressure plates,prestressing tendons and fillers.By stretching prestressing tendons,side pressure plates and wall panels connected with tendons are driven,so that fillers in reinforced area are in an active restraint state,thereby improving mechanical properties of reinforced soil.In this paper,finite element method is used to analyze deformation and ultimate load of the wall on rigid foundation.Ultimate load acting on top of non-reinforced wall is studied by arc-length loading method.Lateral displacement of wall panel,settlement of top of wall,earth pressure on back of wall panel,internal force of prestressing tendon,ultimate load on top of wall,distribution of plastic strain zone and principal stress in filler under prestressing force of prestressing tendon are discussed.Parametric analysis is carried out,and effects of prestressing force position of prestressing tendon,length of prestressing tendon,area of side pressure plate,friction coefficient between filler and foundation on deformation of wall and ultimate load on top of wall are discussed.Following research results are obtained:(1)When pre-tension force is applied,settlement of top of wall decreases with increase of distance from wall panel to position between wall panel and side-pressing plate,while settlement of top of wall increases first and then decreases until it becomes stable behind side-pressing plate.Pre-tension force can reduce increment of lateral displacement and settlement of wall panel caused by load on top of wall.When sinusoidal wave is input in direction of horizontal displacement of foundation,pretension force can significantly reduce lateral displacement of wall panel and settlement of top of wall.Along direction of wall height,lateral displacement of wall panel decreases more and more.(2)When pre-tension force is applied,lateral displacement of panels decreases with increase of length of prestressing tendons,area of side pressure plate and friction coefficient between filler and foundation.(3)When pre-tension force is applied,with increase of pre-tension value and area of side pressure plate,position of pre-tension force moves up,and settlement of wall top between wall panel and side pressure plate decreases gradually,while settlement of wall top after side pressure plate increases gradually.(4)When pre-tension force is applied,horizontal earth pressure on back of panel increases first and then decreases along wall height.When prestressing force is applied to one layer of prestressing tendons,internal force of other layers of prestressing tendons will be reduced.(5)With change of friction coefficient between filler and foundation,failure modes of wall can be divided into two types: first type of failure mode,sliding surface will pass through reinforced body,and pre-tension will cause sliding surface to move down,angle between sliding surface and horizontal line to decrease,and stability coefficient of filler to increase,and pre-tension will increase ultimate load of top of wall;second type of failure mode,sliding surface through bottom of reinforced body,pre-tension force will cause decline of ultimate load on top of wall.(6)Under first failure mode,ultimate load on top of wall increases with increase of prestressing force,length of prestressing tendons,area of side pressure plate,friction coefficient between filler and foundation,and decrease of position of prestressing force.