COUPLED GEOTECHNICAL-HYDROLOGICAL DESIGN OF SHALLOW FOUNDATION CONSIDERING SITE SPECIFIC DATA - THEORETICAL FRAMEWORK AND APPLICATION

Vahidreza Mahmoudabadi ； Nadarajah Ravichandran

《Journal of GeoEngineering》 13卷3期 (2018/09) Pp. 93-103

https://doi.org/10.6310/jog.201809_13(3).1

摘要

Occurrence of extreme hydrological events is frequent in recent years. These events impact the performance of many structures specially the foundations which transfer superstructure load to the ground. The shear strength and settlement of soils and foundations are influenced by the degree of saturation of the soil which varies with hydrological parameters such as rainfall, flood, and evapotranspiration. Therefore, the hydrological parameters must be incorporated in the design to obtain the optimum design for a particular location with specific geotechnical parameters. In this paper, a novel procedure, which considers the site specific hydrological parameters into the shallow foundation design, is presented with sample applications in the United States. The degree of saturation of the partially saturated soil within the influence zone of the foundation was modeled using the one-dimensional Richards' equation considering infiltration rate and water table location as the top and bottom boundary conditions, respectively. The historical rainfall data and water table locations for two study areas in Victorville, California and Levelland, Texas were obtained from the U.S. Geological Survey and National Climatic Data Center data repositories. The results from the Victorville site indicated a near 230% increase in the ultimate bearing capacity and a corresponding 80% decrease in the elastic settlement from those calculated assuming the fully saturated condition. On the other hand, there was only a small increase in bearing capacity at the Levelland site with a corresponding decrease in settlement of 40%. These significant differences in results are because of the inherent variation of the soil properties and hydrological parameters for both site locations. The results clearly indicate that shallow foundation design can be improved if the hydrological parameters are incorporated in the design procedure.

關鍵字

Shallow foundation ； hydrological parameters ； infiltration ； Richards' equation ； partially saturated soil