酸性循环侵蚀下灰岩-土体渗透特性研究
Effect of acid cyclic corrosion on permeability characteristics of limestone-soil composite
李杰 1程龙飞 1孙大典 1任怡桦 1李雙衡1
作者信息
- 1. 重庆三峡学院 土木工程学院,重庆 404100
- 折叠
摘要
为研究酸性循环侵蚀程度对灰岩-土体渗透特性的影响,将酸性循环腐蚀后的灰岩试样与黏性红土制成岩-土组合体,在试验设置的4～14 水力梯度范围内开展变水头试验,并引入有效腐蚀深度建立了界面渗透系数分析计算模型.结果表明:灰岩-土组合体渗透曲线呈短暂下降—相对稳定—逐渐上升 3 个阶段变化,拟合渗流速度与水力梯度具有良好线性关系,符合达西定律;灰岩-土组合体渗透系数随灰岩腐蚀程度增加而增大,增幅先减小后增加;灰岩界面渗透系数随腐蚀程度增大而减小,减幅急剧降低,推断是孔隙曲折度变化对界面渗透性造成的影响;对比灰岩-土组合体理论渗水量与实际渗水量可知,模型在短暂下降-相对稳定渗透阶段误差较小,模型适用性较好;结合灰岩试样腐蚀后SEM图像、灰岩-土组合体与纯土渗透曲线对比及渗透作用下灰岩质量损失可知,岩体结构的存在与岩样微观结构的改变,会导致灰岩-土体渗透性增强和抗水力侵蚀能力降低.
Abstract
In order to investigate the influence of acid cyclic erosion degree on the permeability characteristics of limestone-soil composite,the limestone samples after acid cyclic corrosion and cohesive laterite were used to make a limestone-soil com-posite.A variable water head test was carried out with the hydraulic gradient of 4 to 14,and the effective corrosion depth was in-troduced to propose an analysis and calculation model of interface permeability coefficient.The results showed that the permeabili-ty curve of limestone-soil composite showed a three stages change of transient decline,relative stability and gradual rise.The fit-ting seepage velocity had a good linear relationship with the hydraulic gradient,which conforms to Darcy law.The permeability co-efficient of limestone-soil composite increased with the increasing of limestone corrosion degree,and the increase rate decreased first and then increased.The permeability coefficient of limestone interface decreased with the increasing of corrosion degree,and the decrease rate decreased sharply,inferring that the change of pore tortuosity affects the interface permeability.Comparing the theoretical seepage volume with the actual seepage volume,it can be seen that the error between them was small in the transient decline and relative stability seepage stages,proving the applicability of the model.Combined with the SEM images of limestone samples after corrosion,the comparison on permeability curves between limestone-soil composite and pure soil,and the mass loss of limestone under seepage,we concluded that the existence of rock mass structure and the change of rock microstructure will lead to the permeability enhancement of limestone-soil composite and the deterioration of water erosion resistance.
关键词
水力侵蚀/酸性循环侵蚀/灰岩-土组合体/灰岩界面/渗透特性Key words
water erosion/acid cycle corrosion/limestone-soil composite/limestone interface/permeability characteristic引用本文复制引用
基金项目
在渝高校与中科院所属院所合作项目(HZ2021012)
出版年
2024
国家科技期刊平台
NSTL
万方数据