Study On Geogrid-Reinforced-Earth Characterisic Test And Aseismic Technique

The reinforced earth technique has been used for many years. As the advancement of reinforcement materials, the geogrid is used widely in preventing and treating problems of subgrade strengthening and soft-soil foundation treatment in the highway,railway etc. fields, thanks to its most highlighted reinforcement effect. In the high earthquake intensity area, however, the research about geogrid's interaction mechanism,reinforcement effect etc. is scarce. This paper found that geogrid equals to earthquake isolation and reduction through earthquake damages survey of reinforced earth embankment , and direct shear test,drawing test,vibration table test and therefore it is a good seismic strengthening method in embankment engineering.Basic work of this paper is earthquake damages survey of typical embankment working points which added up to 10 after Great Sichuan Earthquake on DuWen road where reinforced earth embankment working points are 8, others are unreinforced. This survey revealed: the performance of reinforced earth embankment is much better than unreinforced. After that, 14 groups direct shear tests were carried out in the conditions of different compactness to compare reinforced and unreinforced, and different shear angle in the reinforced condition, and 4 groups drawing test in the circumstances of varied compactness, to research on the properties of reinforced earth. The main conclusions are: 1) the equivalent cohesion and comprehensive internal friction angel improved after reinforced with geogrid, proved it can improve stability and integrity effectively, and has good aseismic performance in the aseismic point; 2) in the direct shear test of different angel, the reinforcement effect is bad when the angle of shear plane is 45°.If geogrid is placed vertically, the construction is inconvenient. Obviously level reinforcement can not only ensure reinforcement effect but also favor construction in site. In fundmental theory aspect, 2 groups model test were did on vibration table to compare layered soil and reinforced layered soil, and discovered that seismic amplifying effects reduced evidently through reinforcement.Aseismic technique will be promoted greatly by Weichuan Great Earthquake. Finally, conventional aseismic codes in different countries such as Japan,US,EU,New Zealande,China etc. are compared and contrasted, and summarized trends in domestic and abroad aseismic field, then pointed out differences and discussed some revised contents of existing Aseismic Design Code of Highway Engineerings in our country.