Modeling of Semi-mechanistic approach for Geo-synthetic Reinforced Flexible Pavement Design

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4. Modeling of Semi-mechanistic approach for Geo-synthetic Reinforced Flexible Pavement Design

Reinforced flexible pavement is being constructed to increase pavement service life and make optimal use of geosynthetics. Appropriate selection of geogrids stiffness within the asphalt concrete layer and proper choice of subgrade materials may lead to the workable solution. Rut depth estimation under the various contact pressure with the varying subgrade modulus is the best approach to identifying the suitable geogrids range. A 2D axis-symmetrical numerical model is developed to simulate the typical pavement response under heavy traffic loading. Elasto-plastic behavior of soil material was considered for base and subgrade layer. Initially, the developed numerical model was validated with the published experimental simulations and the obtained numerical results are in good agreement with experimental results. Further, rut depth for the various subgrade modulus, cyclic wheel loading and geogrid stiffnesses were estimated form the numerical simulations. The results show the beneficial effect of the appropriate range of geogrid stiffness in the asphalt concrete layer. Therefore, a series of parametric analysis was done to optimize the design requirements for the use of geogrid material for pavements, which includes, (1) Evaluation of vertical surface deformation for cyclic wheel loading of 700 kPa, (2) Effect of subgrade modulus on the rut depth for wheel loading varying from of 200 to 1000 kPa. The results indicated a maximum change in the rut depth for the lower subgrade modulus. This behaviour implies a significant dependency of rut depth on subgrade modulus which is important aspect for the soil selection based on CBR values, and (3) Maximum reduction in the rut depth is achieved for the subgrade modulus of 20 MPa for the geogrid stiffness varying from 100 kN/m to 400 kN/m. Thus, the selection of geogrid with stiffness greater than 400 kN/m is advisable for the better long-term performance of the pavement.

9th International Congress on Environmental Geotechnics (ICEG2023)

Advances in Numerical Modeling