Numerical Simulation of Cutting Tests on Layered Sand and Clay
Type:
Presented during:
WODCON XXII - Enhance the Harmony between Dredging and Ecology
Authors:
A.M. Talmon, M. Martinelli and H.J. Luger
Abstract
"Offshore cable and pipe laying activities are intensifying worldwide. In the area of interest encountered soil can be strong and frequently consist of lamina of sand and clay. When soil strengths are beyond what can be excavated by jetting one has to turn to mechanical excavation tools. The development of such a cutting tool is the primary reason for the research reported here. Important to the cutter design is the prediction of cutting forces. There are few models on the cutting of homogeneous sand and homogeneous clay, either empirical or numerical. In many practice situation, especially in river delta areas and continental seas, cutting has to be performed in sand/clay layered soil. The influence of both cutting processes on each other in case of multiple soil transitions in such intensive layered pockets is not well investigated as yet. In this paper physical tests and numerical simulations of cutting layered sand and clay are presented. Two-dimensional numerical simulations are conducted by the Material Point Method (MPM) and results are compared with two-dimensional cutting force measurements in the centre of the blade. The calculated sand cutting force corresponds well with the measurement. For layered sand and clay, similar trends are revealed in laboratory measurements and numerical calculations. Employing MPM broadens the scope of possibilities in cutting force calculation by enabling analysis of layered soils and revealing interactions between the adjacent layers, but also 3-dimensional cutting processes calculations are within reach."
Keywords: subsea trenching, laboratory measurements, cutting, MPM