珊瑚砂中桩贯入过程的声发射特征  

ACOUSTIC EMISSION CHARACTERISTICS DURING PILE PENETRATION PROCESS IN CORAL SAND

作　　者：毛无卫 陈洁朋 潘龙 MAO Wuwei;CHEN Jiepeng;PAN Long(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院地下建筑与工程系,上海200092

出　　处：《工程地质学报》2024年第5期1872-1879,共8页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:42472342)。

摘　　要：珊瑚砂地基中桩基础的力学特性是近年来岛礁工程中关注的热点问题之一。鉴于珊瑚砂颗粒易于破碎、颗粒表面粗糙等特点,在受力状态下易产生声发射信号,以往的研究在单元尺度进行了较多的成功应用。本文通过一组模型桩加载试验,研究珊瑚砂中桩贯入过程的声发射参数特征及演化规律。试验结果表明:声发射参数与模型桩荷载之间存在高度关联性,两者随贯入深度的变化规律相似并存在明显的三阶段演化特征;密实度对声发射的影响机制较为复杂,更密实的珊瑚砂地基对应的声发射信号不一定更强,当累计贯入深度达到40 mm时,两种密实度地基的声发射参数值总体差别不大;往复加载时,当荷载较小时(初始加载阶段),声发射事件不活跃,表现出Kaiser效应。总体上看,除声发射事件的平均幅值在初始加载阶段的变化特征区别较大外,其他声发射参数(声发射事件计数、振铃计数、能量)的变化规律较为相似。The mechanical properties of pile foundations in coral sand ground have emerged as a major focus in reef island engineering in recent years.Given the mechanical characteristics of coral sand,such as its tendency to fracture and its rough surfaces,acoustic emission signals are easily generated under stress.This study explores the characteristics and evolution of acoustic emission parameters during the pile penetration process in coral sand through a series of model pile penetration tests.The results reveal a strong correlation between acoustic emission parameters and model pile loading,with both exhibiting similar variation patterns with penetration depth and displaying distinct three-stage evolution characteristics.The effect of density on acoustic emission is more complex;a denser coral sand foundation does not necessarily produce stronger acoustic emission signals.When the cumulative penetration depth reaches 40mm,the acoustic emission parameter values for foundations with different densities are generally similar.Under cyclic loading,acoustic emission events remain inactive and exhibit a certain Kaiser effect at low loads(initial loading stage).Overall,aside from the notable differences in the average amplitude of acoustic emission events during the initial loading stage,other parameters(such as event count,ring-down count,and energy)show similar variation patterns.

关 键 词：桩基础 珊瑚砂 声发射 承载力 KAISER效应 

分 类 号：TU411[建筑科学—岩土工程]