摘要
为研究环向施工接缝中温度对膨润土膨胀性能及其微观结构演化的影响,在不同温度条件下对环向施工接缝中压实膨润土开展膨胀力试验,并在接缝封闭后进行含水率、干密度和孔隙结构测试,分析膨胀性能与微观结构演化的联系。结果表明:膨胀力时程曲线呈现单峰型,先增至峰值后下降并最终趋于稳定。膨润土膨胀过程动力学平衡由结合水膜增厚、层叠体裂解、孔隙坍塌和扩散双层增厚所形成的“楔”力主导,导致膨润土从竖向侧限到恒体积的受力状态演化。在高温条件下,试样内部含水率梯度增大、干密度梯度减小的趋势更加明显。随着温度升高,蒙脱石膨胀系数和水分子扩散系数增加,加速了蒙脱石水化膨胀,更多孔隙被膨胀后的蒙脱石占据。较高温度下,水分子进入蒙脱石层间,促进了水化反应、层叠体裂解和孔隙坍塌,进而降低了总孔隙比并增强了膨润土膨胀性能。
To investigate the swelling properties and microstructure evolution of compacted bentonite in an annular technological void under different temperatures,swelling pressure tests are conducted on compacted bentonite in an annular technological void.After technological void is closed,water content,dry density and microstructures is determined,respectively.Results show that the swelling pressure time-history curve shows a single-peak pattern,initially rising to the peak before falling and stabilizing.The dynamic equilibrium of the“wedge”force,formed by the thickening of bound water film,laminar cleavage,pore collapse and thickening of diffusion double layers,dominates the force states from the vertical lateral limit to the constant volume.Higher temperatures intensify the increase water content and decrease dry density from the interior to the exterior.The swelling behavior is enhanced by the increase in montmorillonite expansive coefficient and water molecule diffusive coefficient with temperature,leading to more inter-assemblage pores being occupied by the swollen matrix.At higher temperatures,more water molecules entered the interlayers,causing higher hydration reactions,lamellar cleavage,and pore collapse,which reduced the total void ratio and enhanced the swelling properties.
作者
闫旭升
王琼
苏薇
叶为民
张丰收
刘宜春
YAN Xusheng;WANG Qiong;SU Wei;YE Weimin;ZHANG Fengshou;LIU Yichun(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical&Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)
出处
《岩土工程学报》
北大核心
2026年第1期177-186,共10页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(42172298,42002289)
国家重点研发计划项目课题(2019YFC1509900)
中央高校基本科研业务费项目(22120230229)
中国博士后科学基金面上项目(2022M722428)。
关键词
压实膨润土
温度
施工接缝
膨胀力
孔隙结构
水化膨胀
compacted bentonite
temperature
technological void
swelling pressure
pore structure
hydration expansion
