Mechanism Research Of Geogrid-reinforced Retaining Wallsubjected To Load From Strip Foundation At The Top Surface Of Wall

In recent years, geosynthetics have been increasingly applied in various geotechnicalengineering through the advantages of high strength, corrosion resistance and flexibility. Amongthe geosynthetics, geogrids characterized by high tensile strength and low elongation, wereextensively used in a variety of retaining walls, slopes, embankments, dams and design of bridgeabutments. At present, the geogrid reinforced retaining wall, due to cost saving, stability andsimple and fast construction techniques, has been widely used in geotechnical projects. Currently,a brandly-new application of geogrid-reinforced soil(GRS) wall built as foundation is to supportthe footings of the brigde abutment, which has the potential of eliminating the use of traditionaldeep dountations. By the method of controlling the same soil types and relative density of soilsfor GRS wall and reinforced embankment of approaching road, the differential settlementbetween the bridge abutment and approaching roadway at the two ends of bridge can be adjustedthe same step and the phenomena of bump at the bridge would be definitely alleviated. However,compared with traditional GRS retaining wall structure, there are some remarkable differences inthe GRS bridge abutment system. The GRS wall, which supports the bridge structures andembankment behind the abutment wall, is presented different performances, such as vertical andhorizontal displacement of the wall, settlement of the bridge footing, distributions of the earthpressure and strains and stresses of reinforcement. Therefore, the performance of GRS wallssubjected to load from footing at the top surface of walls, including ultimate bearing capacity ofbridge footings, deformation characteristics, stresses in reinforcements and failure mode of walls,was investigated by combination of a series of experimental tests and numerical analysis. Themain contents include:(1) On the basis of the superior engineering properties and structure characteristics ofgeogrids reinforced structure and then state-of-the-arts of GRS retaining wall are presented indetail as well.(2) Based on the structural characteristics of GRS retaining wall subjected to load from stripfooting at the top surface of wall, a series of experimental tests have been carried out to figureout the mechanism of GRS retaing walls through varying the distance between foundation andpanel, the width of foundation, the length of reinforcement and the connection modes betweenpanel and reinforcement. (3) Based on numerical analysis software Flac3.0and model test results, the measured andcalculated values for stresses and deformation are compared, and then the performance of GRSretaining wall subjected to static loads has been further analyzed, especially for the deformationof front wall, stresses of reinforcements and the failure mode of the retaining wall.(4) Based on the results of test and numerical analysis results, the key factors of design forGRS wall subjected to load from strip foundation at the top of walls are given by the followingparameters, such as determination of the best distance between bridge foundation and panel ofwall, the length, the tensile strength and layer spacing of reinforcement, the width of foundationand so on.