摘要
珊瑚砂颗粒形状不规则且易破碎,其抗剪强度曲线呈现明显的非线性特征,显著增加珊瑚砂岛礁工程设计与计算的复杂性。以中国南海珊瑚砂为研究对象,开展不同级配珊瑚砂的大型直剪试验研究,探索颗粒咬合、翻滚及破碎等作用对珊瑚砂抗剪强度的影响规律。结果表明:在低法向应力作用下(σ≤100 kPa),颗粒咬合和翻滚等作用导致珊瑚砂的抗剪强度曲线急剧上升;随着法向应力的增大,颗粒破碎作用使珊瑚砂的抗剪强度曲线变得平缓;颗粒越粗、法向应力越大,珊瑚砂颗粒破碎越明显,对珊瑚砂抗剪强度的影响越显著;采用经典的摩尔-库伦强度准则进行线性拟合得到180~360 kPa畸高的表观黏聚力,与珊瑚砂无黏性土的基本特性不符,亟待建立珊瑚砂非线性强度准则及计算公式。
The irregular shape and fragility of coral sand particles result in a distinct nonlinear pattern in their shear strength curves,posing significant challenges for the design and calculation of coral sand-based island and reef engineering projects.This study focuses on coral sand from the South China Sea,conducting large-scale direct shear tests on coral sand samples with different gradations to investigate how factors such as particle interlocking,rolling,and crushing affect shear strength.The results show that under low normal stress(σ≤100 kPa),particle interlocking and rolling cause a rapid increase in shear strength;as the normal stress increases,particle crushing makes the shear strength curve flatter.The coarser the particles and the greater the normal stress,the more pronounced the crushing of coral sand particles becomes,and the more significant its impact on the shear strength of coral sand.The classic linear fitting of the Mohr-Coulomb strength criterion tends to yield abnormally high apparent cohesion values of 180 to 360 kPa,which contradicts the fundamental characteristic of coral sand as a cohesionless soil.Therefore,it is urgent to establish a nonlinear strength criterion and corresponding calculation formulas specifically for coral sand.
作者
邱匡东
史元祺
曹振中
骆湘龙
钟永斌
QIU Kuang-dong;SHI Yuan-qi;CAO Zhen-zhong;LUO Xiang-long;ZHONG Yong-bin(Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China;Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)
出处
《河南城建学院学报》
2025年第4期6-12,共7页
Journal of Henan University of Urban Construction
基金
国家自然科学基金项目(51968015)。
关键词
珊瑚砂
非线性强度特征
大型直剪
抗剪强度
coral sand
nonlinear strength characteristics
large-scale direct shear
shear strength
