PEOPLE

Dr Yi-Pik (Helen) Cheng

Dr Yi-Pik (Helen) Cheng
Department: Civil, Geomatic and Environmental Engineering
Position: Permanent staff
Institution: UCL
Phone: +44 (0)20 7679 4407
Website: Website

Research Summary:

Helen's primary research topic has been the micro-mechanics of soil plasticity. She would like to experimentally observe and numerically simulate the various micro-structure of soils. Through the experimental work, granular breakage was shown to exist before a conventionally considered "yield point" of the e-log p' plot. Both granular rearrangement and breakage contributed to the linear plastic compression behaviour of a freshly deposited sand, which was also shown different from the elastic unloading. The breakage mechanism of a loose sand was seen different from a dense sand; this contributed to a difference in the soil compressibility before the normal compression line. The numerical simulations of crushable soil were performed using the software (PFC3D) of Discrete Element Method (DEM). The observed experimental work was confirmed numerically. In addition, a framework of plasticity based on particle crushing and rearrangement was proposed.
Recent EPSRC grant: "Discrete Element Modelling of Transitional Soils" Transitional soils are types of soils that are neither sands nor clays, and do not follow the conventional patterns of deformation called the Critical State framework of Soil Mechanics. This research proposed to used the computational Discrete Element Method (DEM) to understand the hidden physical factors at the level of individual particle interactions that contribute to their atypical behaviour. This research aims to start on July 2008. A post-doctoral research associate will be recruited and a few workstations will be purchased. The project will also make use of the HPCs at UCL to perform the simulation works.

Keywords:

Soil Mechanics, Discrete Elements Methods, Distinct Elements Methods