Sánchez, M.; Gens, A.; Victoria, M.; Olivella, S. International journal of geomechanics Vol. 16, num. 6, p. D4016015-1-D4016015-17 DOI: 10.1061/(ASCE)GM.1943-5622.0000728 Data de publicació: 2016-12 Article en revista
This work presents a fully coupled formulation developed to handle engineering problems in unsaturated (and saturated) soils that present two dominant void levels. The proposed framework assumes the presence of two porous media linked through a mass-transfer term between them. In its more general form, the proposed approach allows the consideration of nonisothermal multiphase flow coupled with the mechanical problem. The double-porosity formulation was implemented in a finite-element code and has been used to analyze a variety of engineering problems. The approach is especially suitable for cases in which the material exhibits a strong coupling between the mechanical and the hydraulic problems in both media, such as with swelling clays. For those types of problems, the proposed formulation is used in conjunction with the mechanical double-structure model already proposed by the authors. This paper presents the coupled formulation and the application of the proposed approach to problems involving expansive unsaturated clays. Very satisfactory results were obtained in these analyses. -
Damians, I.P.; Bathurst, R.J.; Lloret, A.; Josa, A. International journal of geomechanics Vol. 16, num. 4, p. 04015103-1-04015103-14 DOI: 10.1061/(ASCE)GM.1943-5622.0000632 Data de publicació: 2016-08 Article en revista
This paper reports the results of a numerical parametric study focused on the prediction of vertical load distribution and vertical gap compression between precast concrete facing panel units in steel-reinforced soil walls ranging in height from 6 to 24 m. The vertical compression was accommodated by polymeric bearing pads placed at the horizontal joints between panels during construction. This paper demonstrates how gap compression and magnitude of vertical load transmitted between horizontal joints are influenced by joint location along the height of the wall, joint compressibility, and backfill and foundation soil stiffness. The summary plots in this study can be used to estimate the number and type (stiffness) of the bearing pads to ensure a target minimum gap thickness at the end of construction, to demonstrate the relative influence of wall height and different material component properties on vertical load levels and gap compression, or as a benchmark to test numerical models used for project-specific design. The paper also demonstrates that although the load factor (ratio of vertical load at a horizontal joint to weight of panels above the joint) and joint compression are relatively insensitive to foundation stiffness, the total settlement at the top of the wall facing is very sensitive to foundation stiffness. This paper examines the quantitative consequences of using a simple linear compressive stress–strain model for the bearing pads versus amultilinear model that is better able to capture the response of bearing pads taken to greater compression. The study demonstrates that qualitative trends in vertical load factor are preserved when a more advanced stress-dependent stiffness soil hardening model is used for the backfill soil as compared with the simpler linear elastic Mohr–Coulomb model. Although there were differences in vertical loads and gap compressionwith the use of both soilmodels for the backfill, the differenceswere small and not of practical concern.
Damians, I.P.; Bathurst, R.J.; Josa, A.; Lloret, A. International journal of geomechanics Vol. 15, num. 1, p. 04014037-1-04014037-15 DOI: 10.1061/(ASCE)GM.1943-5622.0000394 Data de publicació: 2015-02-01 Article en revista
The paper describes the results and lessons learned using aFEMmodel to simulate quantitative performance features of the Minnow Creek steel- strip reinforced soil wall structure located in the United States. The Minnow Creek Wall structure was constructed and instrumented in 1999. It is a unique case study because of the comprehensive measurements that were taken to record a wide range of wall performance features. Two different constitutive models for the soil were used (a linear- elastic Mohr- Coulomb model and hardening soil model with a Mohr- Coulomb failure criterion), and numerical outcomes were compared with physical measurements. The numerical results were shown to be sensitive to boundary conditions assumed at the toe of the wall. The generally encouraging agreement between physical and numerically predicted results gives confidence that commercial FEMsoftware packages can be useful for the analysis and design of these types of structures, provided that care is taken in the selection of input parameters. (C) 2014 American Society of Civil Engineers.
The paper describes the results and lessons learned using a PLAXIS finite element method (FEM) model to simulate quantitative performance features of the Minnow Creek steel strip reinforced soil wall structure located in the USA. The Minnow Creek Wall structure was constructed and instrumented in 1999. It is a unique case study because of the comprehensive measurements that were taken to record a wide range of wall performance features. Two different constitutive models for the soil were used (linear-elastic Mohr-Coulomb and Hardening Soil model with Mohr-Coulomb failure criterion) and numerical outcomes compared with physical measurements. The numerical results were shown to be sensitive to boundary conditions assumed at the toe of the wall. The generally encouraging agreement between physical and numerically predicted results gives confidence that commercial FEM software packages can be useful for the analysis and design of these types of structures provided that care is taken in the selection of input parameters.
Larese, A.; Rossi, R.; Oñate, E.; Toledo, M. A.; Morán, R.; Campos, H. International journal of geomechanics p. 04014060-1-04014060-23 DOI: 10.1061/(ASCE)GM.1943-5622.0000345 Data de publicació: 2013-08 Article en revista
This paper aims to present and validate a numerical technique for the simulation of the overtopping and onset of failure in rockfill dams due to mass sliding. This goal is achieved by coupling a fluid dynamic model for the simulation of the free surface and through-flow problems, with a numerical technique for the calculation of the rockfill response and deformation. Both the flow within the dam body and in its surroundings are taken into account. An extensive validation of the resulting computational method is performed by solving several failure problems on physical models of rockfill dams for which experimental results have been obtained by the authors.