Force-time behaviour of tine implements | |
| Author | Rajaram, Govindarajan |
| Call Number | AIT Thesis no.AE-87-14 |
| Subject(s) | Tillage Soil moisture |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The soil failure and the corresponding force-time behaviour for flat rigid tines in clay soil were studied under quasi-static condition. The nature of the failure as the tine advances in the soil was found to depend on the soil moisture level. Four distinct failure patterns were identified at four of the observed moisture levels, namely 5 .2%, 18.3%, 28.6% and 42% dry basis (db). In dry soils with moisture levels below the plastic limit the failures are periodic and the corresponding force-time curves are cyclic with distinct peak and trough values. At 5.2% db moisture level each failure means compression and isolation of specific volumes of soil in front of the tine from the rest of the soil mass. The soil resistance reaches peak values just before each failure occurs and falls back rapidly to trough values immediately after each of the failures. At 18 . 3% db moisture level each failure means the fracturing of specific volumes of soil in front of the tine. The soil resistance reaches peak values whenever the soil fractures and, falls back gradually to trough values whenever the frac- ~ured soil mass collapses. In wet soils with moisture levels above the plastic limit the failure is steady-state and the corresponding force-time curves initially increase and reach a maximum stabilizing value. At 28.6% db moisture level the failure means the flow of soil deforming along the tine-soil interface. The mechanism of this failure is analogous to chip formation in metal cutting. At 42.0% db moisture level the failure means the ready flow of soil up and around the tine. A comparison of the observed failure patterns and the recorded force-time behaviour with the predicted values using the passive earth pressure theory indicates that the theory can neither explain the soil failure patterns nor predict the soil resistance at all moisture levels of the experimental soil. |
| Year | 1987 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Gee-Clough, D. |
| Examination Committee(s) | Gupta, Chandra P. ;Balasubramaniam, A.S. |
| Scholarship Donor(s) | The Government of Japan |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1987 |