基于表面沉降法的堆石坝现场碾压试验分析
Field compaction tests on rockfill dams based on surface settlement method
-
摘要: 长河坝是目前国内已建成的高度第二、填筑总量第一的世界级高堆石坝,主体部分是以当地石料填筑的坝壳体,其碾压密实质量直接影响坝体施工及运营期的变形稳定。长期以来,堆石体的压实质量主要依靠挖坑测试法通过干密度指标来评估,不仅费时费力,且误差较大。依托长河坝水电站坝体堆石料的现场碾压试验,采用表面沉降法对压实质量进行评估,并与现场挖坑灌水法实测得到的密度进行对比。结果表明:采用表面沉降法计算的密度与挖坑灌水法实测密度基本吻合,现场压实质量可以通过沉降量或沉降率来控制;表面沉降法操作简单,可有效保证填筑质量,加快施工进度,为堆石体碾压特性研究提供了新的途径,具有较好的实用价值。Abstract: Changheba Dam has been a world-class high rockfill dam in China with the second highest height and the first largest filling volume in the world. The dam body is the dam shell filled by the local rock, and its compaction quality directly affects the dam construction and the deformation and stability during operation. For a long time, the pit excavation test method is mainly employed to evaluate the compaction quality of the rockfill through the dry density index, which takes time and labor with large errors. Based on the field compaction tests on dam rockfill of Changheba Hydropower Station, the compaction quality is evaluated by the surface settlement method to compare with the density measured by the pit excavation and irrigation method on site. The results show that the density calculated by the surface settlement method is basally consistent with that measured by the pit excavation and irrigation method, the field compaction quality can be controlled by the settlement or the settlement rate, and the surface settlement method is easily operated, which can effectively guarantee the filling quality and accelerate the construction progress, thus providing a new way for studying the compaction characteristics of the rockfill with better practical value.