Comparison of the Cyclic Liquefaction Susceptibility of Calcareous and Siliceous Sand: An Energy-Based Perspective

Abstract

Calcareous sands, which are prevalent in low latitude coastal regions, are commonly used as filling or foundation materials in onshore and offshore engineering projects. These sands possess unique geological and geotechnical characteristics, resulting in distinct seismic liquefaction behaviors compared with siliceous sands. Few studies have been reported on the energy-based liquefaction assessment of calcareous sands and its relation to conventional stress-based analysis results. This study conducted undrained cyclic triaxial tests on calcareous sand from the South China Sea under various levels of static shear stress and compared the results with those of siliceous Toyoura sand, which has a similar grading curve. Among the three identified failure mechanisms in calcareous sand, the occurrence of flow liquefaction in loose samples subjected to extensional static stress is particularly significant but has previously received limited attention. Interestingly, compared to Toyoura sand, calcareous sand generally has a more stable interlocking fabric that resists cyclic failure but exhibits relatively lower resistance under large static shear conditions. This study also demonstrates that static shear substantially affects energy evolution and pore pressure generation in soils. A unified relationship is established by relating the normalized pore pressure build-up to energy across all tested conditions. Furthermore, an energy-based interpretation is developed to uniquely correlate the energy capacity with the cyclic resistance and stiffness of both calcareous and siliceous sands. This correlation provides valuable guidance for the development of a unified energy-based evaluation of liquefaction susceptibility using strength or stiffness data from the conventional stress-based method.

Topics & Concepts