冻结作用下土石坝护坡土石混合体水分迁移试验研究  

Experimental study on water transfer of soil-rock mixtures under freezing action

作　　者：李卓[1,2] 姜鑫 张继勋[3] 赵昱 王虞清 鲁洋[3] LI Zhuo;JIANG Xin;ZHANG Jixun;ZHAO Yu;WANG Yuqing;LU Yang(Dam Safety Management Department,Nanjing Hydraulic Research Institute,Nanjing 210029,China;Dam Safety Management Center of the Ministry of Water Resources,Nanjing 210029,China;College of Water Conservancy and Hydropower,Hohai University,Nanjing 210024,China)

机构地区：[1]南京水利科学研究院大坝安全与管理研究所,江苏南京210029 [2]水利部大坝安全管理中心,江苏南京210029 [3]河海大学水利水电学院,江苏南京210024

出　　处：《岩土工程学报》2024年第5期959-967,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51979173,52109123)。

摘　　要：土石坝护坡冻胀破坏主要由护坡砂砾料垫层、坝体填土自身冻胀和水分迁移共同作用引起。针对寒区土石坝护坡普遍存在的隆起、错位、坍塌等冻胀破坏问题,以寒区某土石坝护坡工程砂砾料垫层、坝体填土为研究对象,采用自研的土石混合体水分迁移冻结模型试验装置系统,开展了补水条件下单向冻结模型试验研究,研究了温度、含石量、水分迁移对土石坝护坡土石混合体冻胀特性的影响。研究结果表明:温度、含石量对土石混合体的冻胀特性影响显著;水分迁移受土石含量、温度和含水率影响,护坡砂砾料垫层和坝体填土含水率越大,冻结过程中水分迁移量越大,水分相变成冰的条件越充分;土、石分层对黏土温度变化影响较大,黏土和砾石分层可有效减小水分迁移量和冻胀量,对土石坝护坡防冻胀是有利的;土石混合体内部孔隙水相变成冰并在试样内部形成分凝冰是冻胀量增加的主要原因,土石混合体原位冻胀以及冻结过程中分凝冰的生长使冻胀量不断增加,且补水量越大,试样冻胀量就越大;不同温度、含石量下试样的冻胀量均随补水量的增加而基本呈线性增大,且含石量对冻胀量增加速率影响较小,温度对冻胀量增加速率影响较显著。研究成果可为寒区土石坝护坡设计和运行管理提供科学依据和技术支撑,补充了碾压式土石坝设计规范中的护坡设计。The frost-heaving failure of earth-rock dam slopes is mainly caused by the combined action of sand and gravel cushion,frost heaving of dam fills and water migration.Aiming at the common frost-heaving damage problems such as uplift,dislocation and collapse of earth-rock dam slopes in cold areas,taking the sand and gravel cushion and dam fills as the research object,a self-developed water-transfer freezing test system for the earth-rock mixtures is used to carry out a one-way freezing model test study under water refill conditions.The effects of temperature,rock content and water migration on the frost-heaving characteristics of the soil-rock mixtures for slope protection of earth-rock dams are studied.The results show that the temperature and stone content have significant effects on the frost-heaving characteristics of the soil-rock mixtures.The water migration is affected by the soil and rock content,temperature and water content.The larger the water content of slope protection sand and gravel and dam fills,the greater the water migration during freezing,and the more sufficient the conditions for water phase to become ice.The stratification of soil and rock has a great influence on the soil temperature.The stratification of soil and gravel can effectively reduce the water migration and frost heaving,which is beneficial for the slope protection and frost-heaving prevention of the earth-rock dams.The main reason for the increase of the frost heaving is that the pore water phase in the soil-rock mixtures becomes ice and forms segregated ice in the samples.The in-situ frost heaving of the soil-rock mixtures and the growth of the segregated ice during the freezing process make the frost-heaving amount increase continuously.The freeze-heaving quantity of the samples under different temperatures and rock contents basically increases linearly with the increase of the water recharge,and the different rock contents have small effects on the rate of the freeze-heaving increase,while the different temperatures have a signif

关 键 词：土石坝 土石混合体 水分迁移 冻胀破坏 冻结作用 

分 类 号：TU433[建筑科学—岩土工程]