壁画地仗中盐分的毛细输送机制研究

发布时间：2018-06-26 06:53

本文选题：壁画地仗 + 盐害　；参考：《岩土力学》2016年01期

【摘要】：设计了专门的毛细水输盐模拟试验装置,在精确控制温度、湿度和供水水头的情况下,监测不同孔隙溶液在含盐及脱盐澄板土地仗中的毛细迁移特征。水盐迁移前后,测定模拟地仗的导热系数、孔隙半径变化,从微观角度判断外来盐分及地仗内存在的盐分对地仗盐害的贡献。试验结果表明,溶液毛细迁移速率由大到小排列为KCl与Na_2SO_4混合溶液KCl溶液Na_2SO_4溶液H_2O。毛细上升速度随着试样高度的增加逐渐减慢,而且脱盐澄板土中的毛细上升速率大于天然澄板土中的速率。孔隙溶液电导率随试样高度增加呈递增趋势,且天然澄板土试样的电导率普遍高于脱盐澄板土。试样的导热系数随高度的增加出现先减小后增加的总体趋势。脱盐澄板土与天然澄板土相比,孔径分布密度偏向小孔径方向;当迁移溶液为混合盐时,孔径分布较单一盐溶液时集中。模拟试验结果发现,毛细输送的外来盐分(特别是硫酸盐和氯化物复合盐)造成的土体盐胀破坏比土中既有盐分更加显著,说明控制降水入渗引起的化学淋滤作用对预防顶层洞窟壁画盐害具有重要意义。
[Abstract]:A special capillary water salt transport simulation test device was designed to monitor the capillary migration characteristics of different pore solutions in salt-bearing and desalted Chengban land under the condition of accurately controlling temperature humidity and water supply head. Before and after water and salt migration, the thermal conductivity and pore radius of simulated ground poles were measured, and the contribution of external salts and salt existing in the field to salt damage was judged from the microscopic point of view. The results show that the capillary migration rate of the solution is arranged from large to small as KCl and Na2SO4 mixed solution KCl solution Na2SO4 solution H _ 2O _ 4 solution. The increase rate of capillary is slower with the increase of sample height, and the increase rate of capillary in desalted cinnamon soil is higher than that in natural cinnamon soil. The conductivity of pore solution is increasing with the increase of sample height, and the conductivity of natural charred soil is generally higher than that of desalted cinnamon soil. The thermal conductivity of the sample decreases first and then increases with the increase of height. The density of pore size distribution of desalted soil is smaller than that of natural soil, and when the migration solution is mixed, the pore size distribution is more concentrated than that of single salt solution. The simulation results show that the salt dilatation of soil caused by capillary transport salt (especially sulfate and chloride compound salt) is more significant than that of existing salt in soil. It shows that controlling the chemical leaching caused by precipitation infiltration is of great significance to prevent the salt damage of the top cave murals.
【作者单位】：兰州大学土木工程与力学学院西部灾害与环境力学教育部重点实验室;江苏省地质矿产局第三地质大队;兰州大学西部环境教育部重点实验室;
【基金】：甘肃省科技重大专项计划项目:多场耦合下敦煌石窟围岩风化与壁画盐害机制试验装置研发(No.1102FKDF014)~~
【分类号】：TU43

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