往返渗流与干湿循环诱发土壤结构损伤的协同效应分析  

Analysis on soil structural damage induced by synergistic effects of upward-downward seepage and drying-wetting cycle

作　　者：陈勇[1,2] 夏雨 闵泽鑫 夏振尧[1,2] 王世梅[1,2] CHEN Yong;XIA Yu;MIN Zexin;XIA Zhenyao;WANG Shimei(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area of Ministry of Education,China Three Gorges University,Yichang 443002,China;College of Civil Engineering and Architecture,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,宜昌443002 [2]三峡大学土木与建筑学院,宜昌443002

出　　处：《农业工程学报》2025年第5期57-67,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金面上项目(42272317);国家自然科学基金区域发展联合基金重点项目(U21A2031)。

摘　　要：库水位周期涨落会促使消落带土壤经历往返渗流和干湿循环作用,潜蚀和干裂诱发的土壤结构损伤是三峡库区水土流失的关键诱因。为探究潜蚀和干裂的演化进程和协同效应,采用自主研制的模拟试验系统,针对不良级配土壤,分别完成多周期的往返渗流与干湿循环的单独作用及二者交替联合作用,监测土壤内细颗粒流失规律和表层裂隙发育进程。结果表明:往返渗流单独作用下壤中潜蚀通道发展呈现随机性和持续性,干湿循环单独作用下壤表裂隙发育具有记忆性和缓增性,壤中细颗粒流失率和壤表裂隙率均表现为随周期次数而增多并逐渐趋稳;二者交替联合作用下,壤中潜蚀会形成渗流孔洞,并破坏土壤连续性,同时增加表层细粒含量,进而导致裂隙发育加剧;壤表开裂也会加速细颗粒从土中剥离,并增大优势通道的扩展,从而提高随后试验周期的颗粒流失率;经历5个周期联合作用下的颗粒累积流失率比往返渗流单独作用高116.67%、壤表裂隙率比干湿循环单独作用高73.33%,对土壤结构损伤具有显著的协同加剧效应。研究成果对加深消落带土壤结构损伤机制的认知、揭示水土流失和岸线后退演化规律具有重要的参考价值。The periodic fluctuations of reservoir water level can often cause the soil in the hydro-fluctuation belt to the upwarddownward seepage and dry-wet cycles.The soil structure damage can also be induced by erosion and dry cracking.This study aims to investigate the evolution and synergistic effect of suffusion and dry cracking during soil erosion in the reservoir area.A simulation experimental system was self-developed to separately perform the multiple cycles of upward-downward seepage and dry wet cycles.Their alternating combined effects were also utilized to obtain the poorly graded soils.A systematic investigation was carried out to monitor the fine particle loss in the soil and the development of surface cracks during simulation.An analysis was also made to explore the influence of surface dry cracking on the suffusion and the influence of suffusion during dry shrinkage cracking.A summary was finally given on the synergistic effect of suffusion and dry cracking on soil structure damage.The results showed that there was the random and persistent development of suffusion channels in soil under the individual action of upward-downward seepage.Multiple periodic upward-downward seepage was used to wash away the originally blocked or deposited fine particles,indicating the"repeated washing"behavior.A stronger degree of particle loss was also found than that in the persistence of one-way seepage.The suffusion damage was attributed to the overall pore structure of the soil.The development of soil surface cracks shared the memory and gradual increase under the single action of dry-wet cycles.Once new cracks occurred at the old cracks,there was a slow increase in the width and gradual blunting of openings.There was an increase in the loss ratio of fine particles in the soil and the ratio of soil surface cracks,as the number of cycles gradually stabilized.The cracking damage was characterized by the destruction of soil integrity.The suffusion in soil was induced to form the seepage holes,and then disrupt the soil continu

关 键 词：水土流失 往返渗流 干湿循环 颗粒流失率 裂隙率 结构损伤 

分 类 号：TU443[建筑科学—岩土工程]