冻融循环作用下砾石土心墙土料的力学特性  

Mechanical properties of core-wall soil materials containing gravels subjected to freezing-thawing cycles

作　　者：商可 刘恩龙[2,3] 黄记 张贵科 俞祁浩 SHANG Ke;LIU Enlong;HUANG Ji;ZHANG Guike;YU Qihao(Qinghai Communications Technical College,Xining 810003,China;College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Yalong River Hydropower Development Company,Ltd,Chengdu 610065,China)

机构地区：[1]青海交通职业技术学院,青海西宁810003 [2]四川大学水利水电学院,四川成都610065 [3]中国科学院西北生态资源环境研究院,甘肃兰州730000 [4]雅砻江流域水电开发有限公司,四川成都610065

出　　处：《西安理工大学学报》2022年第1期112-120,共9页Journal of Xi'an University of Technology

基　　金：国家自然科学基金资助项目(41771066);雅砻江流域水电开发有限公司科学技术资助项目(LHKA-G2019006)。

摘　　要：在高海拔寒冷地区,冬季施工时气温变化导致的冻融循环会引起大坝砾石土心墙料的力学特性变化。本文以高海拔地区砾石土心墙料为研究对象,研究了冻融循环作用下三轴固结不排水时砾石心墙土料的力学特性。冻融循环的设定冻结温度为-15℃,融化温度为20℃,冻融过程中无水补给,冻结过程和融化过程各为12 h,设置了0、1、5、10、20共五组冻融循环次数,围压分别为50 kPa、100 kPa、200 kPa、400 kPa。试验结果表明试样均表现为应变硬化和体缩特性,且冻融循环作用使得砾石土的抗剪强度不断增强,且1次冻融循环后增加,10次冻融循环后趋于稳定。最后,把冻融循环对砾石土力学特性的影响考虑到双硬化本构模型的参数中,验证结果表明不同冻融次数下偏差应力和孔压的计算值与试验值均吻合较好。In cold regions at a high altitude, freezing-thawing cycles due to temperature change in the construction process in winter leads to varying mechanical properties of core-wall soil materials of dam. In the paper taking the core-wall dam materials in cold zones with high elevation as a research objective, we study the mechanical features of the gravely soil materials under consolidation drained conditions subjected to freezing-thawing cycles. The temperature is set ranging from-15 ℃ to 20 ℃, the freezing and thawing durations are both 12 h during which no water is supplied, and the freezing-thawing cycles are set to be 0, 1, 5, 10 and 20 with confining pressures of 50 kPa, 100 kPa, 200 kPa and 400 kPa respectively. Test results demonstrates that all the samples behave strain hardening and volumetric compression, and that the freezing-thawing cycles can increase the strength of the gravely soil materials gradually, which are enhanced in experiencing 1 cycle of freezing-thawing and be stable after 10 cycles of freezing-thawing. Finally, the double hardening constitutive model is employed to model the test results by revising the parameters due to the influence of freezing-thawing cycles, with the comparisons between test and computed results showing that the deviatoric stress and pore pressure agree with each other relatively well.

关 键 词：冻融循环 心墙土料 力学特性 双硬化本构模型 

分 类 号：TU43[建筑科学—岩土工程]