Critical Height Of The Reinforced Slope And Comparison On Design Methods Of The Reinforced Retaining Wall

Since the concept of the "reinforced soil" was put forward by the France engineer Vidal H., the reinforced retaining walls and slopes were extensively used in civil engineering, railway, highway, and so on, because of the especial advantages, the design codes on the reinforced retaining walls and slopes were made out in each country. In the present codes, the maximum height of the reinforced retaining wall was limited (for example, the height of single wall was less than 10m in our railway engineering), but the limits were mostly based on the practice. So, determining the critical height of the reinforced slopes from theory was a key problem to be worth studying.The present code 《Standard for application of geosynthetics in hydraulic and hydro-power engineering》 (SL/T225-98) in our country was similar to the American code 《FHWA-NHI-00-043》 of American Federal Highway Administration on design of the reinforced retaining wall, but there were some differences between the two design codes, especially for the design of the geogrid reinforced retaining wall. So, it was necessary to compare the two design codes on the reinforced retaining wall (especially for the geogrid), which could be used as reference for modification of our country design codes.The main research work began around the two questions in the paper, as follows:1. The applications and developments of geosynthetics in our country and abroad were extensively summarized, especially for the present study on the reinforced retaining walls and slopes;2. The property and the basic principle of the reinforced soil structure was summarized;3. The computation formulations on the critical height of reinforced slope were deduced by limit analysis method based on the classical plasticity theory and the generalized plasticity theory, compared with the previous experimental values of the reinforced slopes, showing that the formulations were feasible;4. Each influence factor on the critical height of the reinforced slope was analyzed, sensibilities of influence factors on the critical height of the vertical reinforced slope were analyzed by orthogonal test;5. The China design code 《Standard for application of geosynthetics in hydraulic andhydro-power engineering )> ( SL/T225-98 ) and the American design code ((FHWA-NHI-00-043)) were compared, the differences were explicitly explained by a design example, at the same time, the influence of the design parameters was analyzed; 6. The shortcomings of the paper and the research directions were pointed out for the advanced research.