Spectral element formulation for rock-socketed mono-pile under horizontal dynamic loads. Issue 169 (June 2023)

• Record Type: Journal Article
• Authors: Das, Rishab; Manna, Bappaditya; Banerjee, Arnab
• Is Part Of: Soil dynamics and earthquake engineering. Issue 169(2023)
• Publication Date: 2023-06
• Subjects: Dynamics -- Mono-pile -- Visco-elastic -- Rock-socketed; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2023.107863
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: The current study entails a thorough investigation of the dynamic response of a mono-pile foundation in homogeneous soil and varied layered soil–rock conditions under horizontal dynamic loads. A sequence of visco-elastic springs linked along its length represents the mono-pile immersed in elastic half space. The frequency dependent stiffness and damping of a mono-pile foundation embedded in layered elastic half space are developed using spectral element formulation. The variations in stiffness and damping with frequency for various soil–rock systems are demonstrated. The dynamic response characteristics of the pile were found to be influenced by the depth of the rock-socketed pile. The presence of the underlying layer of stiffer layer of rock enhances the overall stiffness of the system. The frequency versus amplitude responses of a mono-pile supported heavy mass block for both horizontal translation and rocking motion are calculated using the stiffness and damping of the mono-pile under various soil rock conditions. The horizontal amplitude of the pile decreases with increasing pile rock socketing depth. The resonant amplitudes for rocking motion increases as the pile's rock socketing depth increases. Finally, the changes in natural frequency and peak amplitudes with varied pile slenderness ratios are investigated for diverse pile–soil–rock conditions. Highlights: A thorough investigation is made into the dynamic response properties of a mono-pile foundation embedded in five different types of rocks overlain by soil for coupled motions of horizontal translation and pile tip rotation. A novel approach using the Spectral element formulation (SEM) and Static condensation methods (SCM) is implemented to obtain the dynamic stiffness and damping functions of the rock-socketed pile. The impact of the varying rock-socketing depths and soil-rock combinations on the natural frequency and modal amplitudes of the pile-supported block foundation is thoroughly investigated. This study examines the effect of the pile's slenderness ratio on the natural frequency and resonant amplitudes.