A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 2005

A Distinct Element Methods (DEM) simulation model of soil deformation by tine in a soil bin system was developed. To test of the feasibility of this technique, a series of DEM simulations were conducted using several thousand particles within soil bin boundaries. Soil particles are represented as circular bodies with tine as moving wall. Simulated model of DEM for soil-tine interaction using VB 6.0 and SQL server technology provided good user interface and functionality. Program generated pictures of each step, which were easy to validate The simulation was done by taking the sandy soil with the average size (D50) of 0.37 mm with uniformity co-efficient (D60/D10) of 2.34. This simulation qualitatively and quantitatively reproduced the force distance behaviour and soil failure pattern. These were validated with the actual results and also the distinct formation of soil wedge. The soil failure for all the simulation was by progressive shear. The shear surface emerged from tool tip horizontally and after a distance of about 5 to 10 cm it progressed towards the soil surface. During simulation it was observed that soil below the tool tip remained undisturbed in all experiments, which was also observed by Pathak (1991). Average shear angle was 27±20 for all the tools studied which was very close to theoretical angle (TT/4 - O/2) of 26.50 for sand. Due to development of additional shear line, a wedge like soil block was formed adjacent to the tool face, which moved upward very slowly. The surcharge height increased exponentially with tool displacement at decreasing rate and became constant after a distance of about 40 to 50 cm, which represented the stage of dynamic stability. Simulated failure area was statistically close to experimental failure area.