The materials studied were lateritic soils from Souza-Mbanga-Cameroon, with a view to their better use in road geotechnics. In order to achieve the set objective, the work was carried out in two phases, firstly in the...The materials studied were lateritic soils from Souza-Mbanga-Cameroon, with a view to their better use in road geotechnics. In order to achieve the set objective, the work was carried out in two phases, firstly in the field, to provide a morpho-structural description of the soil profiles, followed by a laboratory phase to analyse the samples collected in the field. The results of the physical characterisation of the soil samples show that, for average values, the water content is 9.87%, the percentage of fines 48%, the plasticity index 21.6%, the liquidity limit 50.91%, and the consistency index 1.97. These soils are classified as silty sands in the LCPC classification and as fine soils in the GTR classification. The average value of the maximum dry density is 1.81 g/cm<sup>3</sup> and that of the water content at the modified Proctor optimum is 16.24%. The CBR index is between 1.8% and 17.8%, showing that these soils belong to classes S1, S2, S3, S4 and S5. Souza-Mbanga lateritic soils can be used in their natural state as subgrades.展开更多
The present study is inscribed within the framework of the amelioration of the soils of the Santchou plain for employment as pavement subgrade. The bearing capacity proposed by these soils at their respective optimum ...The present study is inscribed within the framework of the amelioration of the soils of the Santchou plain for employment as pavement subgrade. The bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental California Bearing Ratio (CBR) values of the studied soils are more important than the ones prescribed by the American Association of State Highway and Transportation Officials Classification system (AASHTO) for A5, A6, and A7 types. The stabilization of this soils with lime has been chosen to improve the bearing capacity and by association, their resilient modulus. The results of this study show that the increase of lime content is not proportional with the increase of the expected mechanical performances. In fact, the literature explains that when the lime content arrives at an optimum, the mechanical parameters no longer increase, but decrease significantly. After this optimum, the soil stabilization no longer shows advantages in the increase of geo-mechanical properties of soils.展开更多
The present study is inscribed within the framework of the geotechnical characterization of the soils of the Santchou plain, their classification for employment as pavement subgrade, various identification tests were ...The present study is inscribed within the framework of the geotechnical characterization of the soils of the Santchou plain, their classification for employment as pavement subgrade, various identification tests were carried out on the samples. The results obtained showed that with a wide range of different grain sizes, the studied soils showed low content in clay grains and dominance of either sand grains or silt grains, this can be explaining how most of these soil are poorly graded. According to the USDA textural classification, the grain size distribution of these soils makes them to be classified as Silty Loam types to Sandy Loam types. Despite of their organic matter content which is less than 10%, according to their respective methylene blue values, the soils studied along the section should be mainly loamy soil of medium plasticity to clayed soil, therefore showing a sensibility of its behavior to variation of water content. That last one is confirmed by the consistency parameters of these soils which show intermediate plasticity to highly plastic. Also, the bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental CBR values of the studied soils are more important than the ones prescribed by the AASHTO Classification system for A5, A6, and A7 types, and the French Highway Earthworks Manual Classifications system (GTR) for the corresponding A2 and A3 types.展开更多
文摘The materials studied were lateritic soils from Souza-Mbanga-Cameroon, with a view to their better use in road geotechnics. In order to achieve the set objective, the work was carried out in two phases, firstly in the field, to provide a morpho-structural description of the soil profiles, followed by a laboratory phase to analyse the samples collected in the field. The results of the physical characterisation of the soil samples show that, for average values, the water content is 9.87%, the percentage of fines 48%, the plasticity index 21.6%, the liquidity limit 50.91%, and the consistency index 1.97. These soils are classified as silty sands in the LCPC classification and as fine soils in the GTR classification. The average value of the maximum dry density is 1.81 g/cm<sup>3</sup> and that of the water content at the modified Proctor optimum is 16.24%. The CBR index is between 1.8% and 17.8%, showing that these soils belong to classes S1, S2, S3, S4 and S5. Souza-Mbanga lateritic soils can be used in their natural state as subgrades.
文摘The present study is inscribed within the framework of the amelioration of the soils of the Santchou plain for employment as pavement subgrade. The bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental California Bearing Ratio (CBR) values of the studied soils are more important than the ones prescribed by the American Association of State Highway and Transportation Officials Classification system (AASHTO) for A5, A6, and A7 types. The stabilization of this soils with lime has been chosen to improve the bearing capacity and by association, their resilient modulus. The results of this study show that the increase of lime content is not proportional with the increase of the expected mechanical performances. In fact, the literature explains that when the lime content arrives at an optimum, the mechanical parameters no longer increase, but decrease significantly. After this optimum, the soil stabilization no longer shows advantages in the increase of geo-mechanical properties of soils.
文摘The present study is inscribed within the framework of the geotechnical characterization of the soils of the Santchou plain, their classification for employment as pavement subgrade, various identification tests were carried out on the samples. The results obtained showed that with a wide range of different grain sizes, the studied soils showed low content in clay grains and dominance of either sand grains or silt grains, this can be explaining how most of these soil are poorly graded. According to the USDA textural classification, the grain size distribution of these soils makes them to be classified as Silty Loam types to Sandy Loam types. Despite of their organic matter content which is less than 10%, according to their respective methylene blue values, the soils studied along the section should be mainly loamy soil of medium plasticity to clayed soil, therefore showing a sensibility of its behavior to variation of water content. That last one is confirmed by the consistency parameters of these soils which show intermediate plasticity to highly plastic. Also, the bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental CBR values of the studied soils are more important than the ones prescribed by the AASHTO Classification system for A5, A6, and A7 types, and the French Highway Earthworks Manual Classifications system (GTR) for the corresponding A2 and A3 types.
