Stabilization of clayey soil using fibre reinforcement

The paper presents experimental and numerical investigations on crack evolution during desiccation, on unsaturated, compacted and reinforced clay using natural Alfa fibres. The effect of fibre content is investigated and a comparison between experimental and numerical simulations is made. A modified model for tensile strength is updated in the finite element program CODE_BRIGHT and used to predict tensile cracks induced by desiccation on reinforced soil. The results show that the soil desiccation cracking behaviour is significantly influenced by fibre inclusion and that experimental and numerical results are in good agreement.Postprint (published version

Tensile strength during drying of remoulded and compacted clay: the role of fabric and water retention

The paper presents an experimental investigation on the tensile strength of an unsaturated clay, both in remoulded and compacted states. To complete the experimental study, a new apparatus was designed with the purpose of determining direct tensile stress under controlled-displacement or controlled-force. The design exploits a direct shear test box, which was adapted to the scope of this investigation. Three different hydro-mechanical paths were followed before the tensile strength was determined: a) drying paths on remoulded samples; b) drying paths after compaction at different initial water contents; and c) dynamic compaction at different water contents, hence at different suctions and degrees of saturation. A microstructural investigation was also performed to better understand the experimental results and obtain the most relevant physical parameters. The preparation methods induced different initial fabrics, which dominated the water retention properties, as well as the tensile strength behaviour. A recent model for water retention, including the effects of multimodal fabric, was calibrated on available data and used to predict the suction of the samples along the drying paths, where direct information was not available. A simple model for tensile strength was proposed for its evolution, which included the role of multimodal fabric and their different water storage capabilities, the evolution of dry density and the initial water content (at the beginning of the tensile test path). For the compacted sample, typically showing a multimodal pore size distribution, the tensile strength was found to be a function of the state variables describing the macropore network. Dry density increases on drying appeared in all the cases to dominate the tensile response, Water exchange and suction increase were well correlated to the tensile response evolution.Peer ReviewedPostprint (author's final draft

Numerical simulation of rainfall tests on small-scale slope model

Rainfall-induced landslides are becoming ever more frequent in many regions in the world. In general, the slope failures occur during or immediately after the rainfall. In Tunisia, several regions are concerned by deep or shallow landslides induced by rainwater infiltration, particular in Beja (Tibar). However, due to the high cost of field tests, the quantification of rainwater effects still not adequately clarified. Different small scale slope models were used to study landslide as a result of change in saturation degree. In this paper, we present numerical simulation of rainfall tests on small scale model used clayey soil from a landslide site in Beja, Tibar. The aim of this paper is to study landslide in small scale clayey slope used the same characteristics and conditions of the experimental model realised by Rolando et al. (2004). For this simulation, we will use the numerical approach used to simulate rainfall tests already developed by Rolando et al. (2004). Numerical simulation is conducted using CODE-BRIGHT software

Numerical simulation of rainfall tests on small-scale slope model

Rainfall-induced landslides are becoming ever more frequent in many regions in the world. In general, the slope failures occur during or immediately after the rainfall. In Tunisia, several regions are concerned by deep or shallow landslides induced by rainwater infiltration, particular in Beja (Tibar). However, due to the high cost of field tests, the quantification of rainwater effects still not adequately clarified. Different small scale slope models were used to study landslide as a result of change in saturation degree. In this paper, we present numerical simulation of rainfall tests on small scale model used clayey soil from a landslide site in Beja, Tibar. The aim of this paper is to study landslide in small scale clayey slope used the same characteristics and conditions of the experimental model realised by Rolando et al. (2004). For this simulation, we will use the numerical approach used to simulate rainfall tests already developed by Rolando et al. (2004). Numerical simulation is conducted using CODE-BRIGHT software

Tensile strength during drying of remoulded and compacted clay: the role of fabric and water retention

The paper presents an experimental investigation on the tensile strength of an unsaturated clay, both in remoulded and compacted states. To complete the experimental study, a new apparatus was designed with the purpose of determining direct tensile stress under controlled-displacement or controlled-force. The design exploits a direct shear test box, which was adapted to the scope of this investigation. Three different hydro-mechanical paths were followed before the tensile strength was determined: a) drying paths on remoulded samples; b) drying paths after compaction at different initial water contents; and c) dynamic compaction at different water contents, hence at different suctions and degrees of saturation. A microstructural investigation was also performed to better understand the experimental results and obtain the most relevant physical parameters. The preparation methods induced different initial fabrics, which dominated the water retention properties, as well as the tensile strength behaviour. A recent model for water retention, including the effects of multimodal fabric, was calibrated on available data and used to predict the suction of the samples along the drying paths, where direct information was not available. A simple model for tensile strength was proposed for its evolution, which included the role of multimodal fabric and their different water storage capabilities, the evolution of dry density and the initial water content (at the beginning of the tensile test path). For the compacted sample, typically showing a multimodal pore size distribution, the tensile strength was found to be a function of the state variables describing the macropore network. Dry density increases on drying appeared in all the cases to dominate the tensile response, Water exchange and suction increase were well correlated to the tensile response evolution.Peer Reviewe

Stabilization of clayey soil using fibre reinforcement

The paper presents experimental and numerical investigations on crack evolution during desiccation, on unsaturated, compacted and reinforced clay using natural Alfa fibres. The effect of fibre content is investigated and a comparison between experimental and numerical simulations is made. A modified model for tensile strength is updated in the finite element program CODE_BRIGHT and used to predict tensile cracks induced by desiccation on reinforced soil. The results show that the soil desiccation cracking behaviour is significantly influenced by fibre inclusion and that experimental and numerical results are in good agreement

Stabilization of clayey soil using fibre reinforcement

The paper presents experimental and numerical investigations on crack evolution during desiccation, on unsaturated, compacted and reinforced clay using natural Alfa fibres. The effect of fibre content is investigated and a comparison between experimental and numerical simulations is made. A modified model for tensile strength is updated in the finite element program CODE_BRIGHT and used to predict tensile cracks induced by desiccation on reinforced soil. The results show that the soil desiccation cracking behaviour is significantly influenced by fibre inclusion and that experimental and numerical results are in good agreement