material point method for geotechnical problems involving large deformation
TRANSCRIPT
Material Point Method for Geotechnical Problems Involving Large Deformation
Lorenzo R. †, Cunha R. P. * and Cordão Neto M.P.* * Professor at Geotechnical Pos-Graduation Program
University of Brasilia Campus Darcy Ribeiro, SG12 Brasilia, Brasil
e-mail: [email protected], web page: www.geotecnia.unb.br
† PhD. student. Geotechnical Pos-Graduation Program University of Brasilia
Email: [email protected]
ABSTRACT
In geotechnical engineering and foundations there are problems that involve large deformations, contact between bodies and penetration. In this case, Material Point Method (MPM) can be an alternative to Finite Element Method (FEM) which can improve the quality of analisys. The MPM models the soil as a group of Lagrangean particles that are moved over a fix Eulerian mesh. This way, the problems of distortion that arise in large deformation problems are solved [1]. The contact algorithm used in the MPM is described by [2] and forbids inter-penetration but allows sliding with friction, separation and rolling. Generalized Interpolation Material Point Method (GIMP) was introduce by [3] aiming to avoid numerical problems and computational instability.
There are several codes of GIMP. In this paper a code developed by [4] called NairnMPM is used. This code allows doing 2D and 3D dynamic analysis and can handle any defined material type. A very well-known geotechnical model (Modified Cam Clay) was implemented in NairnMPM. The simulation of oedometric and triaxial tests are presented and discussed.
Also, a plain strain simulation of a driving sheet pile wall of the HDR-4 subway project in Chicago was done [5]. The results of ground movement were compared with the field measurements reported by [5] and with the calculations presented in [6].
REFERENCES
[1] S. G. Bardenhagen, J. U. Brackbill, and D. Sulsky, “The material-point method for granular materials,” Computer Methods in Applied Mechanics and Engineering, vol. 187, no. 3–4, pp. 529–541, Jul. 2000.
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[3] S. G. Bardenhagen and E. M. Kober, “The Generalized Interpolation Material Point Method,” Tech Science Press, vol. 5, no. 6, pp. 477–495, 2004.
[4] J. Nairn, “Source code and documentation for NairnMPM Code for Material Point Calculations. http://oregonstate. edu/∼nairnj/.” 2011.
[5] R. J. Finno, D. K. Atmatzidis, and S. M. Nerby, “Dround response to sheet pile installation in clay,” in Proceedings of 2dn Int. Conf. on Case Histories in Geotech. Engrg., 1988, pp. 1297–1301.
[6] C. Sagaseta and A. J. Whittle, “Prediction of Ground Movements due to Pile Driving in Clay,” Journal of Geotechnical and Geoenvironmental Engineering, vol. 127, no. 1, pp. 55–66, 2001.