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工程科学与技术:2021,53(6):132-141
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考虑颗粒破碎的钙质砂双屈服面模型
(1.江苏科技大学 土木工程与建筑学院,江苏 镇江 212100;2.江苏省地质环境灾害防治及修复工程研究中心,江苏 镇江 212100;3.南京水利科学研究院 岩土工程研究所,江苏 南京 210024;4.苏州科技大学,江苏 苏州 215009)
Double Yield Surface Model of Calcareous Sand Considering Particle Breakage
(1.College of Civil Eng. and Architecture, Jiangsu Univ. of Sci. and Technol., Zhenjiang 212100, China;2.Jiangsu Province Eng. Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang 212100, China;3.Geotechnical Eng. Dept., Nanjing Hydraulic Research Inst., Nanjing 210024, China;4.Suzhou Univ. of Sci. and Technol., Suzhou 215009, China)
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投稿时间:2020-12-29    修订日期:2021-08-06
中文摘要: 珊瑚岛礁主要由颗粒形状不规则、多孔隙、高压缩性、易破碎的钙质砂组成。在进行珊瑚岛礁生态开发建设时,由于其地基土钙质砂具有特殊性,有必要针对颗粒易破碎的钙质砂进行本构模型研究,为设计施工提供参考。本文通过开展不同围压下的钙质砂三轴试验并筛分颗粒,得到应力–应变关系曲线及级配变化曲线,结果表明:对于同一级配、同一密实度的钙质砂,在不同围压下存在不同程度的应变软化和剪胀性,尤其在较低围压下更为明显;存在应变软化和剪胀性的围压范围内,随着围压的增大,其偏应力峰值点和临胀点所对应的轴向应变越大;不同围压下钙质砂颗粒均出现了不同程度的颗粒破碎,且围压越大其颗粒破碎程度越大,细粒含量相对越多。同时,为准确描述考虑颗粒破碎的钙质砂应力–应变关系,基于分形理论和莫尔–库仑理论建立颗粒破碎指标对峰值内摩擦角进行修正,并结合试验数据对“南水”模型中的切线变形模量和切线体积比进行修正,明确了各材料常数的意义,建立了考虑颗粒破碎的钙质砂本构模型。采用Fortran语言将修正的本构模型汇编程序进行模拟,并与试验结果进行对比,两者较为吻合。此外,引用文献中相关试验数据对所建立的考虑颗粒破碎的钙质砂本构模型进行推广验证,表明该模型依然能较为准确地反映钙质砂在不同围压下存在的应变软化和剪胀性。
Abstract:Coral islands is mainly composed of calcareous sand with characteristics of irregular shape, multi porosity, high compressibility and friability. During the ecological development and construction of coral island, due to the particularity of calcareous sand, it is necessary to study the constitutive model of calcareous sand considering the particle breakage, to provide references for the design and construction of coral island engineering. To obtain the stress-strain and grading curves of calcareous sand, the triaxial tests with different confining pressures were carried out and the particles were screened. The test results showed that the calcareous sand with the same gradation and density had different degrees of strain softening and dilatancy under different confining pressures, especially under the lower confining pressures. In the range of confining pressure with strain softening and dilatancy, with the increase of confining pressure, the axial strain corresponding to the peak point of deviatoric stress and the critical expansion point increases. Calcareous sand had different degrees of particle breakage under different confining pressures. The higher confining pressure is, the higher degree of particle breakage is, and the more content of fine particles is. At the same time, to accurately describe the stress-strain relationship of calcareous sand, the tangent deformation modulus and tangent volume ratio of Nanjing Hydraulic Research Institute (NHRI) double yield surface model were modified. Based on the fractal theory and Mohr–Coulomb theory, the index considering particle breakage was established to modify the internal friction angle. Finally, the constitutive model of calcareous sand considering particle breakage was established, and the significance of each material constant was clarified. Fortran language was used to simulate the modified constitutive model, and the results were compared with the experimental results, which were in good agreement. Combined with the relevant experimental data in the references, the established constitutive model of calcareous sand considering particle breakage was extended and verified. The results showed that the model could accurately reflect the strain softening and dilatancy of calcareous sand under different confining pressures.
文章编号:202001131     中图分类号:TU452    文献标志码:
基金项目:国家自然科学基金项目(51979128)
作者简介:第一作者:侯贺营(1988-),男,讲师,博士.研究方向:海洋土的基本性质及土工数值分析等.E-mail:just_hyhou@163.com;通信作者:潘卓杰,E-mail:ytgcpzj@163.com
引用文本:
侯贺营,潘卓杰,姜朋明.考虑颗粒破碎的钙质砂双屈服面模型[J].工程科学与技术,2021,53(6):132-141.
HOU Heying,PAN Zhuojie,JIANG Pengming.Double Yield Surface Model of Calcareous Sand Considering Particle Breakage[J].Advanced Engineering Sciences,2021,53(6):132-141.