Dr. Nadarajah Ravichandran (Associate Professor of Civil Engineering) and Vahidreza Mahmoudabadi received the GeoEngineering (JOG) Best Paper Award of 2018. The Editorial Board of GeoEngineering presents this award annually and is the most prestigious annual award provided by JOG. Only a single award is given among all JOG papers published in 2018. Ravichandran and Mahmoudabadi co-authored the paper and accepted the award on March 9th at the annual GeoEngineering conference in Taipei, Taiwan.
The paper “Coupled Geotechnical-Hydrological Design of Shallow Foundation Considering Site Specific Data – Theoretical Framework and Application” focuses on extreme hyrdological events.
According to the National Climatic Data Center (NCDC), nearly 30 percent of the contiguous U.S. experienced moderate to extreme hydrological events such as heavy rainfall, flood, and drought which ultimately influence the spatial and temporal variation of degree of saturation of the subsurface soil. The effect of degree of saturation of the soil on its mechanical and flow behaviors is well documented in recent years. These two observations clearly show that design of any geotechnical systems must be performed considering the hydrological parameters to accurately quantify their performance.
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.