The paper presents a new prefabricated bio-engineering structure for the support of unstable soil.This prefabricated structure is made of a steel frame which is completely filled with soil and a face made of tree trun...The paper presents a new prefabricated bio-engineering structure for the support of unstable soil.This prefabricated structure is made of a steel frame which is completely filled with soil and a face made of tree trunks among which scions or autochthonous bushes are planted.Due to the difficulties in interpreting the complex interaction between soil and structure during the installation and lifetime,an in situ test was carried out in order to evaluate the state of stress in the steel frame and to understand the global behavior of the structure under service loads.On the basis of the obtained results,a procedure for checking the structure safety was proposed and discussed.An easy design method was developed during the research.Moreover,the use of this type of prefabricated structure shows several advantages,such as good performances in terms of stabilizing effects,and easy assembly and transport.展开更多
In unstable soils, a special erosion process termed suffusion can occur under the effect of relatively low hydraulic gradient. The critical hydraulic gradient of an unstable soil is smaller than in stable soils, which...In unstable soils, a special erosion process termed suffusion can occur under the effect of relatively low hydraulic gradient. The critical hydraulic gradient of an unstable soil is smaller than in stable soils, which is described by a reduction factor α. According to a theory of Skempton and Brogan (1994) [1], this reduction factor is related to the stress conditions in the soil. In an unstable soil, the average stresses acting in the fine portion are believed to be smaller than the average stresses in the coarse portion. It is assumed that the stress ratio and the reduction factor for the hydraulic gradient are almost equal. In order to prove this theory, laboratory tests and discrete element modelings are carried out. Models of stable and unstable soils are established, and the stresses inside the sample are analysed. It is found that indeed in unstable soils the coarse grains are subject to larger stresses. The stress ratios in stable soils are almost unity, whereas in unstable soils smaller stress ratios, which are dependent on the soil composition and on the relative density of the soil, are obtained. A comparison between the results of erosion tests and numerical modeling shows that the stress ratios and the reduction factors are strongly related, as assumed by Skempton and Brogan (1994) [1].展开更多
文摘The paper presents a new prefabricated bio-engineering structure for the support of unstable soil.This prefabricated structure is made of a steel frame which is completely filled with soil and a face made of tree trunks among which scions or autochthonous bushes are planted.Due to the difficulties in interpreting the complex interaction between soil and structure during the installation and lifetime,an in situ test was carried out in order to evaluate the state of stress in the steel frame and to understand the global behavior of the structure under service loads.On the basis of the obtained results,a procedure for checking the structure safety was proposed and discussed.An easy design method was developed during the research.Moreover,the use of this type of prefabricated structure shows several advantages,such as good performances in terms of stabilizing effects,and easy assembly and transport.
文摘In unstable soils, a special erosion process termed suffusion can occur under the effect of relatively low hydraulic gradient. The critical hydraulic gradient of an unstable soil is smaller than in stable soils, which is described by a reduction factor α. According to a theory of Skempton and Brogan (1994) [1], this reduction factor is related to the stress conditions in the soil. In an unstable soil, the average stresses acting in the fine portion are believed to be smaller than the average stresses in the coarse portion. It is assumed that the stress ratio and the reduction factor for the hydraulic gradient are almost equal. In order to prove this theory, laboratory tests and discrete element modelings are carried out. Models of stable and unstable soils are established, and the stresses inside the sample are analysed. It is found that indeed in unstable soils the coarse grains are subject to larger stresses. The stress ratios in stable soils are almost unity, whereas in unstable soils smaller stress ratios, which are dependent on the soil composition and on the relative density of the soil, are obtained. A comparison between the results of erosion tests and numerical modeling shows that the stress ratios and the reduction factors are strongly related, as assumed by Skempton and Brogan (1994) [1].
