摘要
盐渍土、冻土作为特殊土一直是岩土工程领域研究的热点,但盐渍化冻土与结构之间的相互作用却鲜有报道。为研究山东季冻区、盐碱地渠系工程破坏问题,开展了氯盐、硫酸盐渍土在不同含盐量、不同法向应力条件下与混凝土衬砌冻结接触面的直剪试验研究。结果表明:冻结接触面剪切破坏的性状与含盐类型和含盐量均有关,随氯化钠含量的增加,破坏性状由脆性破坏转为塑性破坏,且氯化钠含量约为2%时是破坏性状的转折点,硫酸钠含量的增加,不会改变接触面的脆性破坏性状;初始冻结强度来源于接触面上冰晶的胶结作用,随含盐量的增大,冻结强度降低,且含盐类型对冻结强度影响不同,氯化钠比硫酸钠对初始冻结强度降低作用更显著,当氯化钠含量接近2%、硫酸钠含量超过4%时,接触面完全丧失初始冻结强度;随着含盐量的增大,内摩擦角由不变到开始减小,黏聚力由开始降低到趋于稳定。
Saline soil and frozen soil have been considered as special soils and have been widely studied in geotechnical engineering. However,few studies have been done on the interface between frozen saline soil and concrete lining. In order to study the frozen damage of an irrigation canal system in Shandong Province,a series of direct shear tests on interface between frozen saline soil and concrete lining,with different salt types,different salt contents and different normal stresses,were performed to study the mechanical properties of the frozen interface. The test results show that the failure model of the frozen interface relies on the salt type and salt content. When the salt content is less than 2%,the direct shear strength of the interface decreases rapidly after the peak value. However,when the salt content is larger than 2%,the failure model is different from that with small salt content. It changes from brittle failure to plastic failure with the increase of salt content. When the content of NaCl is more than2%,the frozen strength of the interface is completely lost. While for Na2SO4,when its content is more than 4%,the initial frozen strength approaches to zero. The effect of salt content on the shear strength of the interface is as follows:as salt content increases,the internal friction angle decreases with the increase of salt content;The cohesion decreases from its initial value to a constant with the increase of salt content.
作者
孙兆辉
卞汉兵
鹿翔宇
章赛泽
邱秀梅
SUN Zhaohui;BIAN Hanbing;LU Xiangyu;ZHANG Saize;QIU Xiumei(College of Water Conservancy and Civil Engineering,Shandong Agricultural University,Taian 271018,China;LEM3 CNRS 7239,Universite de Lorraine,Metz 57045,France)
出处
《防灾减灾工程学报》
CSCD
北大核心
2020年第2期236-242,共7页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家十二五科技支撑计划(2015BAB07B05)
山东省重点研发计划(2017GSF16104)资助。
关键词
盐渍土
接触面
冻结强度
直剪试验
saline soil
interface
frozen strength
direct shear test
