水位升降过程中细粒流失促进堆石料湿化变形的试验研究  

Experimental study on the effect of fine particle loss promoting the wetting deformation of rockfills

作　　者：王刚[1,2] 任恒萱[1,2] 金伟 乐建华 黄辉 WANG Gang;REN Hengxuan;JIN Wei;LE Jianhua;HUANG Hui(Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing 400045,China;School of Civil Engineering,Chongqing University,Chongqing 400044,China;Chengdu Engineering Corporation Limited,Power China,Chengdu 610072,China;Sichuan Company of China Huadian Corporation Ltd.,Chengdu 610095,China;China Huadian Corporation Ltd.,Beijing 100031,China)

机构地区：[1]山地城镇建设与新技术教育部重点实验室,重庆400045 [2]重庆大学土木工程学院,重庆400044 [3]中国电建集团成都勘测设计院有限公司,四川成都610072 [4]中国华电集团有限公司四川分公司,四川成都610095 [5]中国华电集团有限公司,北京100031

出　　处：《水利学报》2024年第4期428-436,共9页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(52079012);中国电建重点科技项目(KJ-2023-169)。

摘　　要：堆石料在周期性水位循环升降作用下会产生细粒流失现象,从而加剧堆石料的湿化变形。以某发生显著后期变形的心墙堆石坝的上游堆石料为研究对象,采用侧限压缩潜蚀试验装置,针对连续和间断两种颗粒级配的试样,对比开展了恒定水位和升降水位条件下的单轴固结湿化变形试验,得到了轴向应变和细粒流失量的发展过程。试验结果证实,周期性水位升降引起的细粒流失会促进湿化变形的发展,其影响程度与颗粒级配、竖向压力、水位升降速率及初始含水率有关。连续级配试样的内部稳定性优于间断级配试样,细粒流失量更少,因此提高堆石料级配的连续性会降低细粒流失对湿化变形的促进作用。增大竖向压力会提高堆石料内部颗粒间约束力,降低细粒流失量,从而降低细粒流失对湿化变形的促进作用。水位升降速率的提高会增大水对颗粒的渗透力,从而增大细粒流失量,加大湿化变形。增大初始含水率会提高堆石料的压实性,颗粒排列更紧密,细粒流失困难,降低了细粒流失对湿化变形的促进作用。Under situations of the periodical water level fluctuations,the fine particles in rockfills might be washed out,thereby promoting the wetting-induced long-term deformation of rockfills.To reveal the mechanism of the large long-term deformation of a rock-fill dam,a series of comparative oedometer erosion tests were conducted on the samples with both continuous and discontinuous particle gradations of the dam’s upstream rockfill under constant and fluctuating water level conditions respectively.The histories of the axial strain and fine particle loss were recorded under different conditions.The comparative test results confirmed that the water level fluctuation can lead to considerable amount of particle loss and thus aggravate the wetting deformation,and the influencing extent depends on the particle gradation,surcharge pressure,the falling speed of water level and initial water content.The specimens of a continuous gradation are internally stable and exhibit smaller amount of fine particle loss than the specimens of a gap gradation,and consequently,fine particle loss has less significant effect on the wetting deformation.Higher surcharge pressure can reduce the promotion effect of fine particle loss on wetting deformation because of the less particle loss under the higher particle interaction forces.The fine particle loss increases with the increasing falling speed of water level,and therefore,larger wetting deformation was observed under the tests of higher water discharge rate.Increasing the initial water content will improve the compactness of the rockfill material,resulting in a tighter particle arrangement and difficulty in fine particle loss,thereby fine particle loss has less significant effect on the wetting deformation.

关 键 词：岩土力学 堆石料 湿化变形 细粒流失 周期性水位升降 

分 类 号：TU411[建筑科学—岩土工程]