A mathematical model for sub-soil stress estimation using smooth steel roller for landmine neutralization

Mechanical devices have been used to transfer force from ground surface to subsurface for the purpose of landmine neutralization. However, the data of this force transfer are not currently available. In this study, force transfer or pressure propagation in soil was theoretically analyzed using pressure bulbs. A model of sub-soil stress under the action of a steel roller was developed based on Boussinesq's equation. A smooth steel roller was tested in an indoor soil bin that is capable of testing prototype mechanical demining devices. Sub-soil forces were measured using load cells at four different depths (50, 100, 150, 200 mm). Experimental variables were roller travel speeds (1, 3, 5 km/h) and the vertical loads (20, 40, 60 kN) applied to the roller. Sub-soil forces significantly increased with increasing vertical load. For vertical loads of 40 and 60 kN, increasing travel speed reduced sub-soil forces at all four depths measured. At vertical load of 20 kN, higher travel speeds did not cause significant changes in sub-soil forces. Based on these results, methods of operating this roller to achieve a certain levels of sub-soil forces for neutralizing landmines were recommended. Experimental results were used to evaluate the model developed for subsurface soil stress distribution. The average relative error of the model was 21.8% over the test results.