摘要
钙质砂颗粒具有多孔、形状不规则、易破碎等特性,对其工程性质有很大的影响。为探讨钙质砂粒径、形状对其压缩性的影响,本文对取自南海某岛屿的钙质砂颗粒依据其粒径与形状进行分组,进而对不同组分的钙质砂颗粒进行矿物成分分析、形状参数统计,并进行侧限压缩试验。统计分析表明:钙质砂按照颗粒形状可分为块状、枝状与生物碎屑状;矿物成分均为以文石为主的碳酸钙矿物,且不同粒径、形状的钙质砂矿物成分组成相似。侧限压缩试验结果显示:钙质砂的压缩变形以不可恢复的塑性变形为主,试样压缩可分为初始压密阶段和颗粒破碎阶段,在初始压密阶段(竖向压力p=0~100 kPa),试样压缩变形主要依赖颗粒间的运动与重新排列,小粒径试样压缩量较大;在颗粒破碎阶段(p>200 kPa),颗粒破碎控制试样压缩变形,颗粒越大越容易发生颗粒破碎,使得大粒径试样压缩量较大;枝状颗粒的压缩性远大于块状颗粒和生物碎屑状颗粒。
Particles of calcareous sand,labeled as porous,irregular shaped,easily crushable,etc.,have great influence on its engineering properties.To investigate the effect of particle size and shape on its compressibility,we group the samples from an island in the South China Sea into different particle sizes and shapes,and conduct mineral composition analysis and statistical analysis of the particle shapes,and oedometer tests.Statistical analysis shows that the sand particles can be classified into massive granules,arborescent granules,and bioclastic granules in terms of particle shape.The mineral composition is mainly aragonite-based calcium carbonate,and similar mineral composition is also found in calcareous sand with different particle sizes and shapes.The oedometer tests illustrate compressive deformation of the sand is mainly an irreversible plastic deformation that occurs through two stages-initial compaction and particle crushing.In initial compaction(vertical pressure p=0-100 kPa),the deformation of the sample mainly depends on movement and rearrangement of particles,as a consequence,a sample with small particle size has larger compression in this stage;As p increases further,particles begin to crush(p>200 kPa in this stage)and the deformation is controlled by particle crushing.Larger particles are broken more easily,and thus more compressive deformation occurs to a sample of larger particle size.In addition,compressibility of arborescent granules is also much greater than that of massive and bioclastic granules.
作者
袁泉
李文龙
高燕
张洪宇
武志毅
YUAN Quan;LI Wenlong;GAO Yan;ZHANG Hongyu;WU Zhiyi(Guangzhou Metro Design and Research Institute CO.,LTD.,Guangzhou 510010;School of Earth Sciences and Engineering,Sun Yat-sen University,Guangzhou 510275;Guangdong Province Key Lab of Geodynamics and Geohazards,Guangzhou 510275)
出处
《水力发电学报》
EI
CSCD
北大核心
2020年第2期32-43,共12页
Journal of Hydroelectric Engineering
基金
国家自然科学基金(41807244)
广州市自然科学基金(201904010415).
关键词
土力学
钙质砂
颗粒形状
压缩特征
颗粒破碎
soil mechanics
calcareous sand
particle shape
compression characteristics
particle crushing
作者简介
袁泉(1984—),男,博士.E-mail:yuanquan@dtsjy.com;李文龙(1996—),男,硕士生.Email:liwl26@mail2.sysu.edu.cn;通信作者:高燕(1984—),女,副教授.E-mail:gaoyan25@mail.sysu.edu.cn
