Modeling of Deformations of Fine Clayey Soils Stabilized Using Sugar Cane Molasses: Extension of the Ferber Model

Abstract

This work presents a theoretical study based on the instability of fine soils stabilized with sugar cane molasses. Indeed, this stabilization is only effective during the dry season in the town of Nkayi due to the scarcity or non-existence of rainfall. This being the case, let us suppose that humidification influences the intrinsic parameters of the earth materials (suction, porosity) and even the stabilization capacity of the molasses, we can try to understand the instability phenomenon that occurs within the structural matrix of the material when it is solicited during periods of heavy rainfall. The current models which study the deformation of the proposed fine soils, relate the inter-aggregate voids, the intra-aggregate voids, the stability index, the suction of the soil material and the relative humidity of the environment. Also, the theoretical study of these models shows that the inter-aggregate voids increase with relative humidity, the intra-aggregate voids decrease with increasing relative humidity and the stability index decreases with increasing relative humidity.Similarly, inter-aggregate voids decrease with increasing suction, intra-aggregate voids increase with suction and the stability index increases with suction.However, with the extension of Ferber's model, the breaking point of the earth material is obtained using these same models, i.e. this minimum point beyond which the adhesion forces in the aggregate and between the aggregates become low to ensure cohesion between the aggregates in the material for a long time. All in all, this point is significant for Pr (=35.768%, =0.5262, =0.078, = 0.0005 262), and S=146 MPa (suction value) and is defined as the breaking point below which the cohesion of the aggregates is not evident. This proposed model mathematically translates both the effects of relative humidity and suction on voids in earth materials. It also explains the deformations that take place in earth materials at the microstructure level (intra-aggregate voids and inter-aggregate voids) under the effect of moisture or suction.