土工基础

›› 2017, Vol. 31 ›› Issue (2): 226-230.

• 工程实录 • 上一篇    下一篇

珊瑚碎屑钙质砂的抗剪特性

李金戈1，况 辉2   

  1. （1.桂林理工大学 广西岩土力学与工程重点实验室，广西桂林 541004；
    2.中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室，武汉 430071）
  • 收稿日期:2016-03-25 修回日期:2016-04-05 出版日期:2017-04-20 发布日期:2017-05-04
  • 作者简介:李金戈（1991-），男，硕士研究生，研究方向为钙质砂力学特性。

Direct Shear Mechanical Characteristics of the Calcareous Coral Sand

LI Jinge1, KUANG Hui2   

  1. (1.Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering, Guilin University of Technology, Guilin 541004;
    2.State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071)
  • Received:2016-03-25 Revised:2016-04-05 Online:2017-04-20 Published:2017-05-04

摘要： 珊瑚碎屑钙质砂是海洋沉积物中的一种，其强度低、形状不规则、内孔隙多和易破碎等性质和普通石英砂有很大差异。通过对取自南沙群岛永暑礁附近海域的钙质砂进行大型剪切试验，分析得到轴压、剪切速率和级配对钙质砂力学特性的影响。试验结果表明，钙质砂的抗剪强度在达到峰值之后都会出现应变软化现象，随后略微增长并且达到稳定。随着剪切速率的降低和轴压增大，试验土体的抗剪强度持续增加，出现的颗粒破碎增多，土体的剪胀量减小；随着级配粗颗粒的增加，土体的最大抗剪强度和颗粒破碎持续增加，并且在P5=65.14%情况下达到峰值，之后随着粗颗粒含量的增多而降低。

关键词: 钙质砂, 颗粒破碎, 抗剪强度, 剪切速率, P5

Abstract: The coral clastic calcareous sand generally consists of the remains of marine organism, which is different from the common quartz sand. It has the characteristics of low strength, irregular shape, internal porosity and easy fragmentation. The axial stress, shearing rate and the sample grain size distribution on the mechanical properties of the calcareous sand were investigated on the coral sand samples from Yongshu Reef, South China Sea. The results indicate that, the calcareous sand has the shear softening property, that is, the strain softening is observed after the stress pasts its peak values. This softening reaches stable after a large strain. With the reduction of the shearing rate and the increase of the axial stress, the sample shear strength will increase and the more particle breakage and the less dilatancy of the sample are observed. With the increase of coarse grains in the sample, the shear strength and the particle breakage increase and reach the peak values at the percentage of particles weight greater than 5 mm of 65.14%.

Key words: Calcareous Sand, Particle Breakage, Shear Strength, Shear Rate, Percentage of Particles Weight Greater Than 5 mm