张炳晖,刘帅宇,谢艳华,汤斌,韩伟超

• 1:桂林理工大学土木工程学院
• 2:桂林航天工业学院能源与建筑环境学院

摘要(Abstract)：

【目的】为研究振动扰动作用下湛江组结构性黏土的力学特性和微观结构的演变机制，【方法】利用电动调频振动台对原状土施加不同的振动频率、振动时间，制备出扰动度不同的黏土试样，对试样开展无侧限抗压强度试验和扫描电镜(SEM)试验，获取土体的力学特征和微观损伤规律。【结果】结果显示：振动扰动后，土体无侧限抗压强度下降显著，试样的应力-应变曲线为应变软化型；扰动土的破坏应变随振动时间和振动频率的增加而降低，且都大于原状土的破坏应变；振动频率一定时，扰动度整体随着振动时间的延长而增大，且振动前期扰动度增速较快，振动后期扰动度增速渐趋缓慢；当振动频率为20 Hz时，振动60 min后，延长振动时间，试样无侧限抗压强度无显著变化，振动频率为35 Hz和50 Hz的试样并未出现类似结果；对于不同振动频率的曲线，随着振动频率的增加，曲线整体发生上移；微观参数分形维数和孔隙概率熵与扰动度的关系为正相关，面积概率分布指数与扰动度的关系为负相关，扰动后孔隙表面形态更复杂，扭曲程度更高，大面积孔隙增多，孔隙定向排列更加趋于无序。【结论】结果表明：湛江组结构性黏土在经历振动扰动作用后，土体强度会显著降低。通过扫描电镜试验可发现强度下降的本质是土样微观结构的改变，振动扰动作用使得黏土微观结构从蜂窝—紧密絮凝组合结构变成松散的絮凝结构，黏土颗粒单元体之间的接触方式、排列规则均发生改变，土体强度折损的主要因素是黏土颗粒之间胶质联结键的断裂。研究成果能为解释土体扰动损伤过程中所产生的宏观现象提供理论依据。

关键词(KeyWords)： 湛江组结构性黏土;振动扰动;应力-应变曲线;扰动度;微观机理;力学性能;模型试验

Abstract:

Keywords:

基金项目(Foundation): 广西自然科学基金项目(2024GXNSFAA010450);; 广西高校中青年教师科研基础能力提升项目(2022KY0786);; 国家自然科学基金项目(11962004)

作者(Author): 张炳晖,刘帅宇,谢艳华,汤斌,韩伟超

DOI: 10.13928/j.cnki.wrahe.2024.10.014

参考文献(References)：

• [1] 姚珩珩，夏远野，刘胜娥.海口地区第四系湛江组灰色黏土的工程地质特性[J].港工技术，2001,1(2):54-55.YAO Hengheng,XIA Yuanye,LIU Sheng′e.Engineering geological characteristics of gray clay of the Quaternary Zhanjiang Formation in Haikou area [J].Port Engineering Technology,2001,1(2):54-55.
• [2] 吴卫华.关于湛江灰色黏土的几个岩土工程问题[J].城市勘测，2002(4):43-44.WU Weihua.Several geotechnical engineering issues on Zhanjiang gray clay [J].Urban Survey,2002(4):43-44.
• [3] 单子宁.湛江组结构性黏土的强度特性试验研究[D].武汉：武汉科技大学，2014.SHAN Zining.Experimental study on strength characteristics of Zhanjiang Formation structural clay[D].Wuhan:Wuhan University of Science and Technology,2014.
• [4] 孔令伟，臧濛，郭爱国，等.湛江强结构性黏土强度特性的应力路径效应[J].岩土力学，2015,36(S1):19-24.KONG Lingwei,ZANG Meng,GUO Aiguo,et al.Stress path effect on the strength properties of Zhanjiang strongly structural clay [J].Rock and Soil Mechanics,2015,36(S1):19-24.
• [5] 刘炳恒，孔令伟，舒荣军，等.湛江结构性黏土在三维应力下的力学特性与强度准则[J].岩土力学，2021,42(11):3090-3100.LIU Bingheng,KONG Lingwei,SHU Rongjun,et al.Mechanical properties and strength criteria of Zhanjiang structural clay under three-dimensional stress [J].Rock and Soil Mechanics,2021,42(11):3090-3100.
• [6] 赵盛男，霍玉龙，汤斌.湛江组结构性黏土触变性正交试验及其触变强度预测模型[J].岩土力学，2023,44(S1):1-9.ZHAO Shengnan,HUO Yulong,TANG Bin.Orthogonal test of thixotropy of structural clay in Zhanjiang Formation and its thixotropic strength prediction model [J].Rock and Soil Mechanics,2023,44(S1):1-9.
• [7] 汤斌，张一鸣，王婷，等.湛江组结构性黏土变形特性试验研究[J].科学技术与工程，2016,16(9):247-252.TANG Bin,ZHANG Yiming,WANG Ting,et al.Experimental study on deformation characteristics of structural clay in Zhanjiang Formation [J].Science,Technology and Engineering,2016,16(9):247-252.
• [8] 李志鹏.降雨条件下湛江组结构性黏土结构及渗流特性研究[D].武汉：武汉科技大学，2022.LI Zhipeng.Research on the structure and seepage characteristics of structural clay in the Zhanjiang Formation under rainfall conditions[D].Wuhan:Wuhan University of Science and Technology,2022.
• [9] 王玲玲，冯治国.湛江组结构性黏土渗透系数特性的研究[J].土工基础，2020,34(6):736-739.WANG Lingling,FENG Zhiguo.Research on the permeability coefficient characteristics of structural clay in the Zhanjiang Formation [J].Geotechnical Foundation,2020,34(6):736-739.
• [10] 张目极，殷建风，王巍，等.湛江组结构性黏土物理力学特性对其触变性的影响[J].工程地质学报，2021,29(4):1240-1246.ZHANG Muji,YIN Jianfeng,WANG Wei,et al.Effects of physical and mechanical properties of structural clay in the Zhanjiang Formation on its thixotropy [J].Journal of Engineering Geology,2021,29(4):1240-1246.
• [11] 舒荣军，孔令伟，师文卓，等.湛江结构性黏土自钻旁压试验的加载速率效应[J].岩土力学，2021,42(6):1557-1567.SHU Rongjun,KONG Lingwei,SHI Wenzhuo,et al.Loading rate effect in self-drilling side pressure test of Zhanjiang structural clay [J].Rock and Soil Mechanics,2021,42(6):1557-1567.
• [12] 陈东升，周标和，吴春燕，等.沉桩方式及桩型对湛江组结构性黏土中单桩承载力时效性的影响[J].科学技术与工程，2020,20(29):12071-12077.CHEN Dongsheng,ZHOU Biaohe,WU Chunyan,et al.Effects of pile sinking methods and pile types on the timeliness of single pile bearing capacity in structural clay of the Zhanjiang Formation [J].Science,Technology and Engineering,2020,20(29):12071-12077.
• [13] 沈建华，汪稔，朱长歧.湛江组灰色黏土空间展布规律研究[J].岩土力学，2013,34(S1):331-336.SHEN Jianhua,WANG Nen,ZHU Changqi.Study on the spatial distribution rules of gray clay in the Zhanjiang Formation [J].Rock and Soil Mechanics,2013,34(S1):331-336.
• [14] ZHOU B,TANG B,KANG J.A Constitutive Model of Clay Considering Structural Failure[J].Frontiers in Materials,2021,8:697181.
• [15] 刘文静.振动扰动含细粒土砂强度特性试验研究[D].北京：中国科学院大学，2015.LIU Wenjing.Experimental study on the strength characteristics of fine-grained soil and sand disturbed by vibration[D].Beijing:University of Chinese Academy of Sciences,2015.
• [16] 邓永锋，刘松玉.扰动对软土强度影响规律研究[J].岩石力学与工程学报，2007,26(9):1940-1944.DENG Yongfeng,LIU Songyu.Research on the influence of disturbance on the strength of soft soil [J].Transactions of Rock Mechanics and Engineering,2007,26(9):1940-1944.
• [17] 姚正.扰动程度对湛江组结构性黏土触变性影响的试验研究[D].桂林：桂林理工大学，2022.YAO Zheng.Experimental study on the effect of disturbance degree on thixotropy of structural clay in Zhanjiang Formation [D].Guilin :Guilin University of Technology,2022.
• [18] 谭罗荣.黏性土微观结构定向性的X射线衍射研究[J].科学通报，1981,26(4):236-239.TAN Luorong.X-ray diffraction study on the microstructure orientation of cohesive soil [J].Science Bulletin,1981,26(4):236-239.
• [19] 沈建华，汪稔，郑郧，等.湛江组结构性黏土区域微观结构特性研究[J].岩土力学，2013,34(7):1931-1936.SHEN Jianhua,WANG Min,ZHENG Yun,et al.Research on regional microstructure characteristics of structural clay in Zhanjiang Formation [J].Rock and Soil Mechanics,2013,34(7):1931-1936.
• [20] 王传杰，汤斌.上覆压力对湛江组结构性黏土触变性的影响机制[J].科学技术与工程，2023,23(4):1650-1657.WANG Chuanjie,TANG Bin.Influence mechanism of overburden pressure on thixotropy of structural clay in Zhanjiang Formation [J].Science,Technology and Engineering,2023,23(4):1650-1657.
• [21] 中华人民共和国住房和城乡建设部.土工试验方法标准：GB/T 50123—2019[S].北京：中国计划出版社.Ministry of Housing and Urban-Rural Development of the People′s Republic of China.Geotechnical Test Method Standard:GB/T 50123—2019 [S].Beijing:China Planning Press.
• [22] 李涛，钱寿易.土样扰动影响的评价及其先期固结压力的确定[J].岩土工程学报，1987(5):21-30.LI Tao,QIAN Shouyi.Evaluation of the influence of soil sample disturbance and determination of early consolidation pressure [J].Chinese Journal of Geotechnical Engineering,1987(5):21-30.
• [23] 汤强，刘春，顾颖凡，等.土体SEM图像微观结构的识别和统计方法[J].桂林理工大学学报，2017,37(3):547-552.TANG Qiang,LIU Chun,GU Yingfan,et al.Identification and statistical methods of microstructure of soil SEM images [J].Journal of Guilin University of Technology,2017,37(3):547-552.
• [24] 李佳明，唐世斌，毕鹏雁，等.土体微观结构定量分析方法探讨[J].实验室研究与探索，2022,41(3):34-41.LI Jiaming,TANG Shibin,BI Pengyan,et al.Discussion on quantitative analysis methods of soil microstructure [J].Laboratory Research and Exploration,2022,41(3):34-41.
• [25] LIU C,TANG C S,SHI B,et al.Automatic quantification of crack patterns by image processing[J].Computers and Geosciences,2013,57:77-80.
• [26] LIU C,SHI B,ZHOU J,et al.Quantification and characterization of microporosity by image processing,geometric measurement and statistical methods:Application on SEM images of clay materials[J].Applied Clay Science,2011,54(1):97-106.
• [27] 张先伟，孔令伟，王静.针对黏性土胶质联结特征的SEM-EDS试验研究[J].岩土力学，2013,34(S2):195-203.ZHANG Xianwei,KONG Lingwei,WANG Jing.SEM-EDS experimental study on colloid bonding characteristics of cohesive soil [J].Rock and Soil Mechanics,2013,34(S2):195-203.