Dynamic characteristics of marine soft clay under variable phase difference and initial static shear stress

• Published in: Marine georesources & geotechnology Vol. 38; no. 7; pp. 770 - 785
• Main Authors: Dong, Wenqian, Hu, Xiuqing, Zhang, Yan, Fu, Hongtao
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 08.08.2020; Taylor & Francis Ltd
• Subjects: Clay; Cyclic loading; Cyclic loads; cyclic strength; Dynamic characteristics; Earthquake loads; Fatigue strength; Initial shear stress; Laboratory tests; marine soft clay; phase difference; Phase shift; Retaining walls; S waves; Shear modulus; Shear strain; Shear stress; Soft clay; Soil; Soil layers; Soils; Stress propagation
• ISSN: 1064-119X; 1521-0618
• DOI: 10.1080/1064119X.2019.1622159

Under seismic loading, the soil layer is subjected to multidirectional cyclic shear stress with different amplitudes and frequencies because of the coupling of multiple shear waves and the soil element within a slope or behind a retaining wall is subjected to initial static shear stress before subjected to cyclic loading. Due to the complexity of seismic loading propagation, a phase difference exists between the initial static shear stress and cyclic shear stress. To investigate the influence of the phase difference and initial static shear stress on cyclic shear strain, cyclic modulus, and cyclic strength, a series of laboratory tests are performed on Wenzhou marine soft clay by multi-directional simple shear system, which can simulate the actual state better by controlling the horizontal cyclic stress in the x and y directions simultaneously. As the phase difference varies from 0° to 90°, the dynamic shear modulus increases and cyclic strain accumulation decreases with an increasing number of cycles. The shear strain increases with the initial shear stress.