Numerical Study on Enhancing the Bearing Capacity of Shallow Foundation Using Geosynthetics

Abstract

Geosynthetic materials such as geogrid or geotextile are often used to compose a reinforced earth to improve the engineering properties of weak soils. These materials provide extra tensile resistance by interaction with surrounding soils. The geosynthetic materials have long been used to reinforce earth slopes, but relatively little study have been performed on their usage for the reinforcement of shallow foundation. In order to provide practice engineers with parameters to optimize their design, the effectiveness of reinforced shallow foundation was studied numerically by using a commercial finite difference program -Fast Lagrangian Analysis of Continua (FLAC). The bearing capacity of an unreinforced strip foundation was simulated and compared with Terzaghi's theoretical solution to verify the correctness of the numerical model. The effects of various parameters, such as the burial depth, length of the reinforcement material, number of reinforcement layers, arrangement of reinforcement layers, and the strength of soil on the bearing capacity were then studied. Results of this study verify that the reinforced shallow foundation can provide higher bearing capacity, especially for weak soils. It was found that a buried depth of 0.4 times the width of foundation yields the optimum bearing capacity increase. The most economical reinforcement length is about 2 to 3 times the width of the foundation. Adding an additional layer of reinforcement was found to further increase the bearing capacity. 64Innovative and Sustainable Use of Geomaterials and Geosystems GSP 245

Laboratory Testing of Enhancing the Bearing Capacity of Strip Footing with Woven Geotextiles

“…Therefore, the optimum burial depth is about 0.4 times footing width. This value is similar to previous numerical simulation performed by the authors (Lai et. al., 2014).…”

“…In order to obtain a base line for the effectiveness of reinforcement and to verify the validity of the test results, two duplicate tests were performed on unreinforced dry sand prepared using the procedures stated in the previous section. Results of these tests were compared with numerical simulation performed previously (Lai et. al., 2014), and the ultimate bearing capacity, q u , was also compared with value calculated using Terzaghi's Equation:…”

“…In order to provide the practice engineers with parameters that can optimize their design of reinforced shallow foundations, the effects of reinforcement length, burial depth, number of layers and distance between layers on the bearing capacity of a strip footing were studied numerically in the previous paper by the authors (Lai et. al., 2014).…”