掺复合浆液堆石料压缩特性试验研究

针对高堆石坝坝体变形大且持续时间长的问题，提出了一种提高堆石体压缩模量、减缓流变变形的方法，即利用易流动、后期硬化的高掺粉煤灰水泥砂浆（简称复合浆液）在堆石体摊铺过程中充填堆石体孔隙，在施工碾压的基础上进一步减小堆石体孔隙率。首先，通过观测复合浆液在透明玻璃球中的流动性态，研究不同配比与掺量对复合浆液流动特性的影响；然后，通过侧限压缩和流变试验，研究掺复合浆液堆石料的压缩模量、流变变形的变化规律。试验结果表明：复合浆液在颗粒体孔隙中的流动性能与粉煤灰掺比、水胶比、砂粒最大粒径以及掺量有关；复合浆液的掺入能有效提高堆石料压缩模量，减少流变变形，且对于软岩料、级配不良料效果更为明显；复合浆液在堆石料中主要起到了充填、胶结与润滑作用。

Experimental study of compression characteristics of rockfill materials with composite grout

Due to the large deformation and its long time dependent characteristic of high rockfill dams, a method of using composite grout to increase the compression modulus and reduce creep deformation of rockfill materials is proposed for high rockfill dams. The composite grout is a mixture of fly ash and cement with the characteristics of easy flow and post hardening. The composite grout was first sprinkled on the surface of rockfills, which later infiltrated into the rockfills during the process of rolling compaction. Flow tests on glass balls were conducted to study the effects of mixture ratios and contents of composite grout on its flow characteristics. Confined compression tests and creep tests were finally carried out to investigate the compression modulus and creep deformation of rockfills with composite grout. The results show that the flow property of composite grout is related to the fly ash content, water-to-binder ratio, maximum sand size and mixed content. The filling of composite grout can effectively increase the compression modulus and decrease creep deformation of rockfills, especially for soft rock materials and poorly-graded rockfills. The composite grout mainly plays the role of filling, cementation and lubrication in rockfills.