砾石土粗粒含量对高土石坝蓄水期渗流的影响  

Influence of coarse-grained content in gravelly soil on seepage of high earth-rock dam during impoundment

作　　者：常利营 叶发明 陈群[3] CHANG Liying;YE Faming;CHEN Qun(College of Safety Engineering,Henan University of Engineering,Zhengzhou451191,China;Power China Chengdu Engineering Corporation Limited,Chengdu 610072,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu610065,China)

机构地区：[1]河南工程学院安全工程学院,河南郑州451191 [2]中国电建集团成都勘测设计研究院有限公司,四川成都610072 [3]四川大学水力学与山区河流保护国家重点试验室,四川成都610065

出　　处：《人民长江》2021年第6期141-147,共7页Yangtze River

基　　金：国家自然科学基金项目(41977239)。

摘　　要：针对心墙砾石土可能出现粗粒含量不满足规范要求的问题,为了研究砾石土粗粒含量对坝体渗流安全的影响,以两河口心墙堆石坝为典型案例,建立坝体典型横剖面有限元模型。通过对心墙单元随机抽样并赋值较大渗透系数的方法模拟心墙内局部砾石土含量超标的情况,采用非饱和渗流理论对高土石坝蓄水期渗流进行数值模拟。结果表明:匀速蓄水工况下,无论砾石土粗粒含量是否超标,蓄水过程中心墙内最大渗透坡降都随蓄水速度的增加显著增大,对心墙渗透稳定不利;匀速蓄水过程中,砾石土粗粒含量超标时心墙内最大渗透坡降都比不超标时大,最大增幅约50%,但增大幅度与超标率和蓄水速度相关性不明显;采用合适的分期蓄水方案,即使心墙存在粗粒含量超标的情况,蓄水过程中心墙内坡降值都会明显降低,基本能够满足较短时间内完成水库蓄水并保证大坝渗流安全的工程需要,因此在实际工程设计中应合理设计蓄水方案。The coarse-grained content in core wall gravelly soil may be larger than 50%and this does not meet the standard requirement,which may have a great influence on seepage safety of high earth-rock dam.A finite element model was established based on the typical dam section of the Lianghekou core wall rockfill dam.Through random sampling,the elements in the corewallwere assigned with high permeability coefficient to simulate the case of local coarse-grained content exceeding 50%.The influence of coarse-grained content in the gravelly soil was studied according to the unsaturated seepage theory.The results show that the maximum seepage gradient in the corewall increases greatly with the impounding speed under even impounding,no matter the coarse-grained content exceeds 50%or not,which is adverse for seepage stability of core wall.For the case that the coarse-grained content is larger than 50%,the maximum seepage gradient during impoundment is greater than that of case that the coarse-grained content is not larger than 50%,and the growth rate is up to 50%,however the growth of maximum seepage gradient has a weak relationship with the un-attainment rate and the impoundment speed.By adopting a suitable staging impoundment scheme,the maximum seepage gradient has an obvious decrease even if the coarse-grained content is larger than 50%,which can meet the demand of safe impoundment within a short time,so the impoundment scheme should be designed appropriately in engineering practice.

关 键 词：砾石土 粗粒含量 渗流安全 蓄水速度 分期蓄水 

分 类 号：TU641.1[建筑科学—建筑技术科学]