Technical note: The beneficial role of a natural permeable layer in slope stabilization by drainage trenches

• Main Authors: G. Urciuoli, L. Comegna, M. Pirone, L. Picarelli
• Format: Article
• Language: English
• Published: Copernicus Publications 2020-04-01
• Series: Hydrology and Earth System Sciences
• Online Access: https://www.hydrol-earth-syst-sci.net/24/1669/2020/hess-24-1669-2020.pdf

<p>Slope stabilization through drainage trenches is a classic approach in geotechnical engineering. Considering the low hydraulic conductivity of the soils in which this measure is usually adopted, a major constraint to the use of trenches is the time required to obtain a significant pore pressure decrease, here called <q>time lag</q>. In fact, especially when the slope safety factor is small, the use of drainage trenches may be a risky approach due to the probability that slope deformations will damage the system well before it will become fully operative.</p><p>However, this paper shows that the presence of persistent permeable natural soil layers can provide a significant benefit by increasing drainage efficiency and reducing time lag. As a matter of fact, any permeable layer that is intercepted by trenches may operate as part of the global hydraulic system, reducing the drainage paths.</p><p>A simplified approach to designing a drainage system that accounts for the presence of a persistent permeable layer is proposed. This approach, which can exploit solutions available in the literature for parallel drainage trenches, has been validated by numerical analyses.</p>