An Elastic Visco-Plastic Model for Soft Soil with Reference to Radial Consolidation
The time-dependent stress–strain behaviour of soft soil due to its viscous nature affects its long-term settlement and pore water dissipation. A novel mathematical model developed using the Peaceman–Rachford ADI scheme (P–R FD Scheme) can describe the visco-plastic behaviour of soft clay with a non-Darcian flow function; this model is a combination of the basic radial consolidation equation developed by Barron and Bjerrum’s time-equivalent (Bjerrum in Geotechnique 17:81–118, 1967) concept that incorporates Yin and Graham’s (Can Geotech J 26:199–209, 1989b) visco-plastic parameters. The settlement and excess pore water pressure obtained from this model are then compared with preexisting models such as a Class C prediction for the Ballina trial embankment at National Field Testing Facility (NFTF). This elastic visco-plastic model provides better results in terms of settlement and pore water pressure with the field data, although the excess pore water pressure that did not dissipate after one year is mainly due to the piezometers becoming biologically and chemically clogged in terrain with acid sulphate soil (ASS).
KeywordsVisco-plastic Soft soil Peaceman–Rachford ADI Class C prediction
The authors would like to thank the Centre of Geo-mechanics and Railway Engineering (CGRE), University of Wollongong, for providing a scholarship for the first authors’ Ph.D. study. The efforts of university technicians (Cameron Neilson, Ritchie Mclean, and Alan Grant) during fieldwork and laboratory setup are gratefully acknowledged, as is the dedication provided by Dr. Richard Kelly and Prof. Scott Sloan as they managed the Ballina trial embankment project.
- Bergado D, Anderson L, Miura N, Balasubramaniam A (1996) Soft ground improvement in lowland and other environments. ASCEGoogle Scholar
- Bjerrum L (1967) Engineering geology of Norwegian normally-consolidated marine clays as related to settlement of buildings. Geotechnique 17:81–118Google Scholar
- Hansbo S (1960) Consolidation of clay, with special reference to influence of vertical sand drains.Proc Swed Geotech Inst 18:160Google Scholar
- Indraratna B, Baral P, Ameratung J, Kendaragama B (2017) Potential biological and chemical clogging of piezometer filters in acid sulphate soil. Aust Geomech J 52(2):79–85Google Scholar
- Yin JH, Graham J (1989a) General elastovisco plastic constitutive relationship for 1-d straining in clays. In: 3rd international symposium on numerical models in geomechanics, Niagara FallsGoogle Scholar