黏土水泥浆水化固结微观特征研究

Microscopic characteristics of hydration and consolidation of clay cement slurry

通过注浆堵水方式来治理陕北地区露天煤矿水害问题,以提高注浆堵水效果,对黏土水泥浆固结体的水化过程和固结机理进行研究。采用X射线衍射试验和扫描电镜试验相结合的方法,探究不同浆液配比与不同养护龄期的水化产物含量和固结体的微观形貌特征。结果表明:浆液的水化产物主要有水化硅酸钙(C-S-H)、钙矾石以及还没完全水化的石英SiO 2,随着水化反应的进行,C-S-H和钙矾石等凝胶物质含量逐渐增加,固结体强度增强;黏土多有利于固结体生成更多的凝胶团,加强结构的抗渗性;水泥加量过少,生成的硅酸钙等胶体微粒不足,大量黏土颗粒不能有效生成凝胶物质参与固化反应,导致固结体强度不足;随着水固比的增加,固结体的孔隙也相应变少变小;在黏土水泥浆水化期间生成了大量黏土-水泥球凝胶团以及C-S-H凝胶,黏土-水泥球凝胶团之间相互吸附、连接成片,同时C-S-H对裂隙进行填充并连接成网。黏土水泥浆液水固比1.5∶1,水泥加量为20%~40%时,浆液固结体的阻水效果优异,可为工程实践提供参考。

In order to improve the effectiveness of grouting and water blocking,the method of grouting and water blocking is used to address the water damage problem in open-pit coal mines in the northern Shaanxi region.a combination of X-ray diffraction(XRD)and scanning electron microscopy(SEM)tests was used to explore the hydration product content and microscopic morphology characteristics of the consolidation body at different slurry ratios and curing ages.The results show that the hydration products of the slurry mainly include hydrated calcium silicate(C-S-H),Ettringite and quartz SiO 2 that have not been fully hydrated.With the hydration reaction,the content of gel materials such as C-S-H and Ettringite increases gradually,and the strength of the consolidated body increases.More clay is conducive to the formation of more gel clusters in the consolidation body,strengthening the impermeability of the structure.The cement dosage is too little,the generated colloidal particles such as calcium silicate are insufficient,and a large number of clay particles cannot effectively generate gel materials to participate in the curing reaction,resulting in insufficient strength of the consolidated body.As the water solid ratio increases,the pores of the consolidated body also decrease accordingly.During the hydration of clay cement slurry,a large number of clay cement ball gel clusters and C-S-H gel are generated.The clay cement ball gel clusters absorb each other and connect into pieces.C-S-H fills the cracks and connects them into a network to achieve the effect of impermeability and water plugging.When the water solid ratio of clay cement slurry is 1.5∶1 and the cement dosage is 20%~40%,the water blocking effect of the slurry consolidation body is excellent.This ratio can provide reference value for engineering practice.