Reinforced Earth Retaining Soil-structure Dynamic Characteristics

The technology of modern reinforced earth is a new earthen technology that it has been developing since 1 960s. Reinforce earth retaining wall is one of the main types which has been applied extensively at home and abroad. Up to now, however, more attention has been paid to build and perfect rules and standards of the design in application and research. The theoretical analysis is only thought of statics. Research of the dynamic characteristics of reinforced earth structure has become a resistless important task when the express highway and express railway are built and the reinforced earth retaining walls are widely applied. This paper is to solve such problems by analysis application and research state of geosynthetics. As a whole, the research work of this dissertation can be summarized follows:1.In accordance with my design patent, namely, reinforced earth retaining wall of R C net, and based on the analysis of the work mechanism, failure pattern, bearing capacity and stability of the reinforced earth, a new concept is expounded, namely, the reinforced earth wall which is thought of as a compound structure increase not only C but also ~ in comparison with non-reinforced earth. Some bearing capacity formula are first introduced under the circumstances that the reinforced earth wall fails because of the breakage of material or inadequate cohesion between reinforcements and soil.2.By analyzing and comparing the soil抯 stress-strain relation of the non-linear-elasticity and elastoplasticity, An elastoplastic constitutive model of reinforced earth is created for numerical calculating, and the dynamic stress-strain relations is derived.3.According to the theoretical analysis and the experimental study on the engineering characteristics of some kinds of typical materials, some achievements have been made as follows:Deformed functions of the reinforced earth materials are established by the tests of loaded-unloaded stress-strain relations.IvI4{~i~Primary influence factors have been found out about frictional characteristics. The friction coefficient, critical vertical loads and critical frictional resistance strength have been worked out by means of the pullout tests under the different vertical loads, analysis of frictional characteristics between soil and material and analysis of the different work mechanism between direct shear test and pullout tests.The creep characteristic parameters of some typical reinforcement materials have been obtained by the creep tests under the loads for a long time and the rheological analysis.4.Concerning the problem arising in the implementation of Code of the Measurement of Geosynthetics Materials, some methods are probed of the statistical analysis and processing of the experimental datum, and some proposals are put forward for further revision of the codes.5.Some important dynamic responsive parameters are worked out about the reinforced earth structure under the impelling loads of train by model tests and analysis of dynamic characteristics.6.According to Palmgren-Miner抯 theories of fatigue damage accumulation and the analysis of the dynamic strength and dynamic deformation of reinforced earth retaining wall, the fatigue damage of the reinforced earth retaining wall has been analyzed and its measurement standard has been concluded for the first time.7.By comparing numerical analysis methods, a common analytical programme has been worked out with elastic-plastic model and finite elements method to analyzing reinforced earth retaining structure under the dynamic loads of train. The programme can solve two-dimensional stresses, strains and axial symmetry problems with different yield criteria. A satisfying solution has been put forward to the contact boundary between reinforcements and soil. The special problem of two contact plane elements at the joint between plate and strip has been solved.