Figure 1:
Significance of stress history of soil for key geotechnical parameters.
Figure 2:
Common approach to determine preconsolidation stress of soil on the basis of oedometer test.
Figure 3:
Casagrande's procedure (1936) for determination of preconsolidation stress in soils.
Table 1:
Examples of methods for determination of preconsolidation stress.
| METHOD | PROCEDURE | HORIZONTAL AXIS | VERTICAL AXIS |
|---|---|---|---|
| Casagrande (1936) | Graphical | log s’ | e |
| Van Zelst (1948) | Graphical | log s’ | e |
| Burmister (1951) | Graphical | log s’ | e |
| Schmertmann (1955) | Graphical | log s’ | e |
| Pacheco Silva (1970) | Graphical | log s’ | e |
| Sällfors (1975) | Graphical | logs’ | e |
| Becker et al. (1987) | Graphical | s’ | W-Energy Work |
| Jose et al. (1989) | Graphical | log s’ | loge |
| Şenol, Seglamer (2000) | Graphical | log s’ | s’e |
| Janbu (1969) | Direct | s’ | e,M |
| Janbu, Senneset (1979) | Direct | s’ | e, M,Cv |
| Tavenas et al. (1979) | Direct | s’ | s’∙e |
| Butterfield (1979) | Direct | log p’ | lnV = [ln(1+e)] |
Figure 4:
Examples of methods for determination of preconsolidation stress: a) Sällfors (1975), b) Tavenas (1979), and c) Janbu (1969).
Table 2:
Characterization of mechanisms contributing to distribution of yield stress in a soil profile (on the basis on Jamiolkowski et al. (1985)).
| Category | Description | Stress History Profile |
|---|---|---|
| A) Mechanical One-Dimensional | 1) Changes in total vertical stress (overburden, glaciers, etc.) 2) Changes in pore pressure (water table, seepage conditions, etc.) | Uniform with constant s’p-s’v0 (except with seepage) |
| B) Desiccation | 1) Drying due to evaporation vegetation, etc. 2) Drying due to freezing | Often highly erratic |
| C) Drained Creep (Aging) | 1) Long-term secondary compression | Uniform with constant s’p/s’v0 |
| D) Physicochemical | 1) Natural cementation due to carbonates, silica, etc. 2) Other causes of bonding due to ion exchange, thixotropy, “weathering,” etc. | Not uniform |
Figure 5.
Influence of a test procedure on determination of value of preconsolidation stress (a-Das, 1983, b-Crawford, 1964).
Figure 6:
Influence of sample disturbance on shape of compressibility curves of soil (on the basis of Ladd (1977)).
Figure 7:
Comparison of yield stress determined by various methods (Wdowska, 2010).
Figure 8:
Schematic diagrams of compressibility curves in linear and logarithmic scale of vertical stress.
Figure 9:
Compressibility curves for reconstituted samples: a) low-plasticity clay, b) high-plasticity clay.
Figure 10:
Compressibility curves for undisturbed samples: a) low-plasticity clay, b) high-plasticity clay.
Figure 11:
Examples of determination of preconsolidation stress on reconstituted material of low (a) and high (b) plasticity clays (Wdowska, 2010).
Figure 12:
Comparison of compressibility curves of reconstituted and undisturbed material (Ip = 26.2%).
Figure 13:
Comparison of determined preconsolidation (yield) stress with various methods.