Experimental Study On Double Reinforced Retaining Wall And Its Numerical Simulated Analysis

As a new retaining engineering structure, double reinforced retaining wall is built by filling earth between two concrete slabs, which are equal in height and connected by one/more pulling ropes. This structure is superior in low-costing, material-saving, less field-occupancy and lighter structure. Once slabs being installed, the filling and pressing of earth can be done by machine, which enlarges the wall's application in sites where man-soil-filling is futile effort for their unfavorable location, such as suburban district railway, high-grade highways and city road. This dissertation is a further study of "New Structuring Theory of Double Vertical Co-arching Highway Embankment and Its Emulating Study " (a scientific project sponsored by Traffic Department of Hubei Province, ratification number [2003]570)Analyzing model experiment, it is obtained that the distributive laws of earth pressure on wall's back and the pulling strain in mutually pulled reinforcement, the needed parameter of the design and the calculation concerned, it is found out that the distributive laws is different from the Rankin and Coulomb earth pressure laws. On the basis of model experiment, a segment of double reinforced earth retaining wall, with 9.6 meters in height and 80 meters in length, is built in the reconstruction engineering of Yuanan --Dangyang national defense highway. In order to research the deformation and stress of this structure, a testing study is made on full-scale, the testing contents mainly include tensile force of the reinforcements, lateral earth pressures on the facing, vertical earth pressures at the base and horizontal displacements of the facing. It's disclosed that the lateral earth pressure is in non-linear distribution and changes with the thickness of earth filling, the deformation of such flexible double earth reinforced retaining wall is restrained by reinforcement. With the increasing of filling earth height, a dynamic equilibrium is formed between earth pressure causing wall's deformation and pull-out frictionalforce of reinforcement. The earth pressure conversed by the tensile force of reinforcement has the identical change trend as that of earth pressure measured by earth pressure sensors. The majority of tested earth pressure is within the boundary of steady earth pressure and active one. The tensile force of each layer's reinforcement increases continuously with the filling height and the distribution of reinforcement tensile force varies with its height. The researching result shows the wall's strain endurance and deformation can fulfill the requirement of to be endurable, steady and safe.On the other hand, since mutual anchor reinforcement is used in complicated environment of earth-rock mixture and water, how to deal successfully with its anticorrosion becomes a key step to widen reinforcement's application. By carrying out contrastive testing and consulting relative materials, it is offered that a new type of anticorrosion coating for reinforcement (which is mainly formed from epoxy resin) and the optimal proportion of anticorrosion coating. Moreover the acid resistance, alkali resistance and salt tolerance of different proportion coating are discussed. With the help of MTS-810 fatigue tester, it is measured that the jacking strength of different proportion coating reinforcements which are corroded rapidly. Taking the anticorrosion coating's economical virtue, satisfactory bonding strength, flexibility, anticorrosion, application ability and mechanical properties into consideration, the author offers a better mix of the coaling which can be applied to mutual anchor reinforcement, then the technological process of coating reinforcements' anticorrosion and mentions the matters needing attention are set forth.Adopting the general-purpose finite analysis program ANSYS, it was carried out that both two-dimension and three-dimension finite element analysis of double reinforced earth retaining wall built on soft soil, DP model is chosen to simulate the non-linearity of soil, the distribution law of the lateral earth pressures on the facing, the vertical stresses on the base, the displacements of the wall's facing and theembankment settlements are analyzed and studied. The results of the finite element method (FEM) are in accordance with the in-site measurement, the results manifest the FEM is reasonable for analyzing the double reinforced earth retaining wall. It also shows that mutual anchor reinforcement can restrain embankment's lateral deformation and foundation upheaval plays important role in reducing uneven settlement and raising the embankment integral stabilization. Due to mutual anchor reinforcement, each segment's responding stress and displacement of double reinforced earth retaining wall can be obtained by FEM analysis. By optimization analysis of the parameter concerned, the analysis examines that the effect of changing foundation-soil character is more remarkable than that of changing filling soil character to the stress and deformation of earth retaining wall. The FEM analysis results can be applied to practical engineering as a reference for controlling strength and displacement.