摘要
盐渍劣化与风蚀损耗效应是干旱区土遗址底部掏蚀病害形成和发展过程中的控制性进程。盐分运移与富集的途径、土体抗风蚀能力盐渍劣化的本质是其中两个关键问题。通过集中降雨过程3处土遗址温度、含水率和介电常数的实时监测,发现地基和掏蚀区两处土体温度、含水率变化存在的较大的时间梯度差异为盐分通过毛细作用向掏蚀区发生运移和聚集提供了动力和运载媒介。以监测结果为依据,通过对完成不同期次干湿循环养护的不同含盐类型、含盐量的遗址土重塑样的颗粒分析和风洞吹蚀试验,表明干旱区年际发生的集中式降雨过程所促使的盐分富集增量和干湿次数累加所导致的土体粗粉粒化和粒度均一化是盐渍过程对掏蚀区土体抗风蚀能力产生劣化的本质原因。
The effects of saline deterioration and aeolian ullage are the important controlling process for the formation and development of undercutting disease at the bottom of earthen sites in arid regions. Among them, the traces of movement and enrichment of salts and the essence of saline deterioration for anti-erosion ability of soil are the two key issues. Through real-time monitoring of the temperature, moisture and permittivity of three typical sites during concentrated rainfall process, it is found that the larger time gradient difference exists between the changes of temperature and moisture content in soils located in foundation and undercutting areas, providing much power and being a transportation medium for salt to migrate and accumulate into undercutting areas by capillary action. Based on the above monitoring results, and by analyzing the particle sizes and conducting wind erosion experiments on remolded samples of site soils which have experienced different stages of wetting-drying cycles and been cured under different salt types and contents, it is shown that the essential reason for deterioration of soil resistance to wind erosion in undercutting areas is the salt enrichment increment caused by the annual concentrated rainfall in the arid areas and coarse-grained soils and the uniform particle sizes caused by wetting-drying cycles.
作者
崔凯
关喜鹏
谌文武
陈蒙蒙
韩文峰
CUI Kai GUAN Xi-peng CHEN Wen-wu CHEN Meng-meng HAN Wen-feng(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province, Lanzhou University of Technology, Lanzhou 730050, China Key Laboratory of Mechanics on Disaster and Environment in Western China （Lanzhou university）, Ministry of Education, Lanzhou 730000, China Western Center for Disaster Mitigation in Civil Engineering of Ministry of Education of China, Lanzhou 730050, China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2017年第10期1777-1784,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51208245
41562015)
教育部长江学者创新团队支持计划项目(2017IRT17051)
甘肃省高校基本科研业务费专项资金项目
关键词
掏蚀区
盐渍劣化
梯度差异
风蚀模数
粒度均一化
undercutting area
salinized deterioration
gradient variation
wind erosion modulus
homogenization granularity
