Field compaction tests on rockfill dams based on surface settlement method

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.