Simulación numérica de una estructura de pavimento flexible reforzada con geo celdas, apoyada sobre subrasantes continuas y discontinuas

Abstract

“Sabana de Bogotá” region in central Colombia, is a region with lacustrine clays forming the subsoil for engineering projects. In the recent past, these clays have exhibited desiccation problems because of the deepening of the free water level, implying the development of semi-vertical desiccation cracks, compromising the concept of “continuity” classically defined in soil mechanics. Based on the above, the critical role of discontinuity to determine the performance of flexible pavement structures for roads and their reinforcement including geocells is a primarily goal for sustainable development in this region. The geocells inclusion within the pavement structure as the subgrade improvement has had a boom during the last years in the country, this has generated designs where it is despised the real impact of this over the time in the structure. The complexity of this problems has become necessary the search of numeric tools that allow to simulate and to considerate, at least globally, all the uncertainties in the geotechnical problem’s analysis. Accordingly, Dynamic Finite Element Analysis (FEM), were used in this work to explore the influence of discontinuities in the performance of a reinforced pavement structure in the sector Siberia-Tenjo, incorporing the results of previous works. Four constitutive models were made with the study area features, considering two alternatives for the pavement structure: improvement of the subgrade with big stones locally known as “rajon” and improvement of the subgrade with geocells. For both alternatives, the dynamic behavior was established using PLAXIS3D on a continuous and discontinuous subgrade (that presents cracking), to this latter, it was assumed: cracks with a width of 3 m and 20m and a depth of 2m. Once the dynamic study was completed, it was evidenced that for the continuous and discontinuous subgrade of the geocells implementation as the subgrade improvement, it presents a decrease in the vertical and horizontals movements from 4% to 16% range. Regard to the displacements obtained between the discontinuous subgrade and the continuous subgrade, it is possible to identify as the buffer of the dynamic loads in the first instant of time, for the continuous subgrade, it is around 7 m, while for the discontinuous subgrade it is around 13 m, this shows an increase by almost twice as much. In the same way, it is observed as the loads move over the discontinuous subgrade, the displacements increase.