Special Section on Advanced Modeling and Numerical Simulations in Geomechanics

Abstract

This special section of the International Journal of Geomechanics contains selected papers that are based on the presentations at the GeoHunan International Conference: Challenges and Recent Advances in Pavement Technologies and Transportation Geotechnics, held in Changsha, Hunan, China, on August 3–6, 2009. The subject of geomechanics has come a long way in developing constitutive models for geomaterials, including nontraditional materials. Yet, there are complex geomechanics problems that do not have well-defined constitutive models and solutions. Recently, advanced modeling and numerical simulation techniques such as neural network, bound theorem, and centrifuge modeling have been employed to solve some of those geomechanics problems. Owing to the rapid expansion in the use of computer software, nonlinear numerical analysis or neural network modeling has become very popular among researchers and practicing engineers in recent years. Although theoretical models have been around for a long time, it has always been challenging to develop such models. Recently, small-scale centrifuge-based simulations have shown a promising capability of modeling prototype geostructures without a gravityinduced in situ stress field. This special section contains six full-length papers covering such advanced modeling and numerical simulations, different from traditional constitutive modeling, in geomechanics. The paper contributed by Xiang et al. discusses settlement prediction on a chimney foundation by a neural network. In their work, seven models with different input series were developed. The optimal model was determined by comparing the forecasting performance. Xiao et al. carried out numerical simulations of a single pile in expansive soil and extensively studied the load transfer mechanism and soil-pile interaction. Chen and Yu present a study on centrifuge modeling, in which staged construction on a reinforced lime-stabilized embankment was simulated by spinning the model at various g-levels. Centrifuge test results were used to verify and validate their numerical analysis. A comprehensive literature review on constitutive modeling of unsaturated soil is presented by Zhang and Li. Some limitations in the framework of the Barcelona Basic Model are discussed, and a new approach is proposed to overcome the limitations. Fu et al. investigated the compressive behavior of anchored rock masses through a series of physical model tests. The test results were compared with specimens without anchor bolts. It was concluded that the improvement attributable to vertical bolts is more effective. Zhao et al. employed an upper bound limit analysis to evaluate the ultimate pullout capacity of horizontal shallow plate anchors. Dilation and nonlinear behavior of soil was found to have profound effects on the ultimate pullout capacity.