Mechanical and microstructural degradation of pile-surrounding mudstone induced by dynamic pile driving: A multi-scale experimental study

IF 4.6 2区工程技术 Q1 ENGINEERING, GEOLOGICAL

Soil Dynamics and Earthquake Engineering Pub Date : 2025-09-18 DOI:10.1016/j.soildyn.2025.109810

Jichao Yin , Xiaoyu Bai , Nan Yan , Yamei Zhang , Lin Cui , Yu Cong , Mingyi Zhang

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引用次数: 0

Abstract

Mudstone's mechanical properties are extremely susceptible to engineering disturbances, and studying the effects of dynamic pile driving (DPD) is crucial for geotechnical stability and pile foundation design. This study conducts a multi-scale experimental investigation, including uniaxial and triaxial tests, and scanning electron microscope (SEM) analyses, to examine the mechanical and structural degradation of pile-surrounding mudstone induced by DPD using an 8.3 t hammer at 1 Hz. Results show that uniaxial compressive strength (UCS), elasticity modulus (E), internal cohesion (c), and internal friction angle (φ) decreased by an average of 28.66 %, 41.24 %, 13.12 %, and 56.18 %, respectively. The disturbed mudstone exhibited significant plastic characteristics, with both strain hardening and softening. Multi-scale analyses reveal that cracks and pores increased markedly in number and connectivity, evolving from scattered distributions to dense networks, which closely correlate with the observed mechanical deterioration. Strength reduction varied around the pile, with the least strength loss occurring in the compaction zone below the pile end due to densification from pile penetration. These findings are supported by standard penetration test (SPT) results before and after pile driving, indicating that pre-driving geological surveys overestimate mudstone strength and may pose potential engineering risks.

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动力打桩引起的桩周泥岩力学与微观结构退化：多尺度试验研究

泥岩的力学特性极易受到工程扰动的影响，研究动力打桩对泥岩岩土稳定性和桩基设计的影响至关重要。本研究采用单轴、三轴、扫描电镜（SEM）等多尺度试验研究，采用8.3 t、1hz的锤击，研究DPD对桩周泥岩力学和结构的破坏作用。结果表明：单轴抗压强度（UCS）、弹性模量(E)、内黏聚力(c)和内摩擦角（φ）分别平均降低28.66%、41.24%、13.12%和56.18%；扰动泥岩表现出明显的塑性特征，既有应变硬化，也有应变软化。多尺度分析表明，裂缝和孔隙的数量和连通性显著增加，从分散分布到密集网络，这与观察到的力学劣化密切相关。强度损失在桩周有所不同，桩端以下的密实区由于桩入致密实造成的强度损失最小。这些发现得到了打桩前后标准贯入试验（SPT）结果的支持，表明打桩前地质调查高估了泥岩强度，可能带来潜在的工程风险。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Soil Dynamics and Earthquake Engineering 工程技术-地球科学综合

CiteScore

7.50

自引率

15.00%

发文量

446

审稿时长

8 months

期刊介绍： The journal aims to encourage and enhance the role of mechanics and other disciplines as they relate to earthquake engineering by providing opportunities for the publication of the work of applied mathematicians, engineers and other applied scientists involved in solving problems closely related to the field of earthquake engineering and geotechnical earthquake engineering. Emphasis is placed on new concepts and techniques, but case histories will also be published if they enhance the presentation and understanding of new technical concepts.