Liquefaction resistance of saturated and partly saturated clean sand under scenario earthquakes: numerical investigations

Chavan, D and Sitharam, TG and Anbazhagan, P (2023) Liquefaction resistance of saturated and partly saturated clean sand under scenario earthquakes: numerical investigations. In: Sadhana - Academy Proceedings in Engineering Sciences, 48 (3).

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Abstract

Over last few years, induced desaturation is being considered as a new cost effective and environment friendly liquefaction mitigation technique. The present study investigates the effect of partial saturation on the liquefaction resistance of the soil domain. Three degrees of saturation were considered: 99%, 89.5% and 81.4%. Different thickness and position of the partly saturated zone were considered. A two-dimensional finite element model of soil ground of thickness of 30 m was subjected to four earthquake records from India. For fully saturated condition, increase in the permeability: (a) reduced magnitude of excess pore pressure, (b) increased rate of pore pressure dissipation and (c) increased acceleration at the ground surface. Investigation revealed that thickness of the partly saturated zone, with the degree of saturation of 81.4%, can be kept between 5 m to 15 m to prevent liquefaction under strong to very strong earthquakes having peak acceleration between 0.10 g to 0.36 g. Amplification factor at the ground surface for the degree of saturation of 81.4% was found to be in the range of 0.32 to 1.76. This implies that desaturation of clean sand up to the degree of saturation of 80% is enough to achieve the two-fold goal: (1) to prevent liquefaction and (2) to keep the acceleration amplification low. Residual lateral displacement was found to be a function of the degree of saturation, thickness and position of the partly saturated zone and input motion. Further reduction in the degree of saturation may amplify motion significantly owing to the presence of high matric suction, though this issue needs further investigation.

Item Type:	Journal Article
Publication:	Sadhana - Academy Proceedings in Engineering Sciences
Publisher:	Springer
Additional Information:	The copyright for this article belongs to the Springer.
Keywords:	Amplification; Degree of saturation; Finite element; Liquefaction; Pore pressure ratio
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	14 Jul 2023 06:16
Last Modified:	14 Jul 2023 06:16
URI:	https://eprints.iisc.ac.in/id/eprint/82382

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