Stress-strain relationships in wet clay soil and some applications | |
| Author | Wang, Jinjun |
| Call Number | AIT Diss. no.AE-91-01 |
| Subject(s) | Clay soils Strains and stresses |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AE-91-01 |
| Abstract | This study was conducted to acquire a better understanding of the mechanism of wet clay soil tool interaction. Soil specimen tests were first conducted to study the soil element behaviour. These tests include uniaxial compression test, uniaxial tension test, triaxial compression test and direct shear test. A wide tine test and a smaller soil bin test were further Conducted to investigate two dimensional soil tool interaction. In addition soil-metal failure test was also conducted. Besides measurement of force displacement relation, in all the tests the observed soil side surface was marked with a grid and the grid deformation was recorded by film or video. The deformation pattern was analysed by using a digitizer and a computer. The specimen experiments showed that the soil stress strain relation was hyperbolic; the soil failure pattern was pronounced distortion as well as shear lines; when the stress was less than 90% of its maximum value, the deformation nonuniformity in the compression and tension tests was not significant and the soil volume change was negligible. In the tine experiment, the force displacement curves were found to be hyperbolic. No Rankine zone could be seen. It was observed that the soil deformation pattern depended on the tool rake angle: 1) for small rake angles, soil deformed in a narrow zone leading up from the tool tip and there were tensile cracks near the tool tip: soil on either side was undeformed: no wedge developed. 2) in the case of bigger rake angles, soil in front of the tool failed by distortion with small shear lines and big soil-soil slip lines. 3) for rake angles equal or bigger than 90° an elliptical wedge formed in front of the tool surface. The soil deformation pattern was found to be different from the one assumed in the passive earth pressure theory. On the basis of the experimental work, the Finite Element Method was used to simulate the tine soil cutting. The hyperbolic nonlinear model determined from the compression tests was used as the constitution model. Tensile strength was the measured value from the uniaxial test. Interface parameters used were determined from the adhesion and friction test and shear box test. Predicted and experimental results were in good agreement. Calculated results also indicated limitations of the passive earth pressure theory. On the basis of above work the mechanism of wet clay soil~tool interaction, including tensile, shear, wedge, progressive failure, the relation between soil failure patterns and soil properties, etc., was discussed. |
| Year | 1991 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AE-91-01 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Gee-Clough; |
| Examination Committee(s) | Gupta, C. P.;Balasubramaniam, A. S.;Worsak Kanok-Nukulchai; |
| Scholarship Donor(s) | Australian Government; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1991 |