松散坝基灌浆加固的封孔浆体性能研究  

Research on Slurry-Sealing Property for Borehole Blocking Materials Applied in Discrete Dam Foundation Pressure Grouting

作　　者：葛建 梁经纬[3] 付强 汤金华[2] GE Jian;LIANG Jingwei;FU Qiang;TANG Jinhua(Civil and Transportation Engineering College,Hohai University,Nanjing 210098,China;School of Civil Engineering,Nantong Vocational University,Nantong 226001,China;Hunan Water Resources and Hydropower Research Institute,Changsha 410007,China)

机构地区：[1]河海大学土木与交通学院,江苏南京210098 [2]南通职业大学建工学院,江苏南通226001 [3]湖南省水利水电科学研究院,湖南长沙410007

出　　处：《人民黄河》2020年第3期133-135,139,共4页Yellow River

基　　金：江苏省教育厅优秀中青年教师境外研修项目(2016)

摘　　要：压力灌浆是对松散坝基进行防渗加固的有效手段,但在松散土石混合体压力灌浆防渗施工中存在难封孔、低压重复劈裂、难以起压等问题。从封孔浆体劈裂破坏模型、封孔浆体止浆机制及浆液性能对封孔止浆效果的影响等方面对封孔浆体止浆性能进行了研究。结果表明:影响封孔浆体劈裂压力及保压时间的因素主要有浆料强度、裂隙开度、浆液流变性及浆体高度;封孔浆体的劈裂压力与注浆料的流变性相关,随封孔浆料强度的增大而相应变大;封孔浆体劈裂压力随裂隙开度的增大而降低,裂隙开度对劈裂压力的影响随封孔浆体高度的增加明显增大;适当提高封孔浆体强度可以有效减小裂隙开度,提高封孔浆液浓度也有利于获得较大的塑性黏度和屈服应力,确保浆体封孔效果。Rock grouting has been extensively adopted to be a suitable method applied to seepage prevention and consolidation in discrete dam foundations.However,when constructed in fissured formations comprising unconsolidated earth and rock masses,practical problems,for ex⁃ample leakage in borehole sealing,borehole splitting repeatedly at low pressure,and unstable grouting pressure have often been raised and hindered future application of this technique.This study intended to explain the features of grout mixes in borehole blocking,on the bases of fracturing failure model of borehole sealant,mechanism of grouting slurry blocking,and the relationships between grouting mixes and bore⁃hole sealing effect.It is suggested that yielding strengths of grouting mixes,widths of fissures,rheological properties and depths of sealant mi⁃xes dominate multitudes and lasting time of splitting pressure.In the meantime,our study also proposed that the splitting pressure of borehole sealant has a close relationship with the cohesion of the mix and develops with yielding strength increment of grouting mix.The splitting pres⁃sure of a mix tends to decrease with the increase of fissure width.The tendency aggravates with the depth increase of borehole sealant.Impro⁃ving sealant yielding strength obtains appropriate effect of fissure width reduction.Furthermore,increasing concentration of grouting mixes generates larger viscosity and yielding strength,which is effective in assuring the action of borehole blocking.

关 键 词：坝基 防渗加固 压力灌浆 封孔止浆 宾汉姆流体模型 浆体劈裂压力 

分 类 号：TV41[水利工程—水工结构工程]