Tectonic shear zones in the London Clay Formation
In: Geotechnique: the international journal of soil mechanics. Institution of Civil Engineers: London. ISSN 0016-8505; e-ISSN 1751-7656, more
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| Keyword |
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| Author keywords |
clays; fabric=structure of soils; labora- tory tests; shear strength |
| Authors | | Top |
- Chandler, R.J.
- Willis, M.R.
- Hamilton, P.S.
- Andreou, I.
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| Abstract |
Subhorizontal shear zones observed in the London Clay Formation are described. The physical properties of the shear zones are examined, and it is demonstrated both that they are of tectonic origin, the result of bedding plane slip during minor folding, and that they were probably formed before there had been any significant erosion of the London Clay or later overlying formations. The occurrence of the shear zones is reviewed, and it is shown that similar features have been recorded in other areas to the west of London, and it seems likely that they will be encountered elsewhere in the London basin, wherever minor folding occurs. The shape of the London Clay Formation—Reading Formation interface appears to give an indication of the degree of folding, and hence of the possible occurrence of shear zones. The displacements of the shear zones examined are believed to be small, perhaps only a few centimetres, and consequently the strength along the shear zones is probably slightly above the true large-displacement residual, although it is suggested that the drained strength of the shear zone should be assumed to be close to the field residual strength. |
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