Zuo, L;
Xu, L;
Baudet, BA;
Gao, C;
Huang, C;
(2020)
The structure degradation of a silty loess induced by long-term water seepage.
Engineering Geology
, 272
, Article 105634. 10.1016/j.enggeo.2020.105634.
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Abstract
Loess is a typical silt-sized Aeolian soil that is widely deposited and possesses a fragile soil structure susceptible to collapse upon wetting. The instability of shallow loess slopes is well documented, but deeper failures triggered by rainfall and irrigation can also occur. In the case of long-term seepage, clay particles and salts have been observed to leach out of the loess slopes. This paper presents a systematic laboratory study of the effects of water conditions on the mechanical behaviour of silty loess, with isotropic compression and bender element tests carried out on natural and reconstituted loess recovered at 10 m depth from a site in China. The results show that saturation causes reduction in both the compression yield stress and small strain stiffness of the soil, and that after being exposed to seepage, they decrease further. The possible mechanism of structure degradation is investigated by means of microscopic and chemical analyses, and it is found that seepage will cause the pore ions concentration to reduce with a loss of clay mineral bonding strength, resulting in the detachment of silt particles from aggregates. This work highlights the importance of monitoring the water outflow in the field at the loess slope edge, since it may causes large deformation in the long-term.
| Type: | Article |
|---|---|
| Title: | The structure degradation of a silty loess induced by long-term water seepage |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.enggeo.2020.105634 |
| Publisher version: | https://doi.org/10.1016/j.enggeo.2020.105634 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Loess, Laboratory tests, Seepage, Soil structure, Compression, Small strain stiffness |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10095002 |
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