Study and application of control indices for filling quality of high concrete face rockfill dams

Based on the filling gradation of rockfill of Aertashi high concrete face dam under construction, field large-scale relative density tests are carried out. The three-factor map is used to study the design method of the double-control filling standards of porosity and relative density of the rockfill. Based on the pit detection data of the rockfill, the corresponding on-site filling quality control process is explained. The results show that: (1) The filling gradation of the rockfill of Aertashi concrete face dam is basically in accordance with the fractal distribution, the fractal dimension of particle size is between 2.516 and 2.633, and the compaction performance is superior. (2) From the different scales of the similar method, the relative density test results of the rockfill can be obtained. The scale effect of dry density of the rockfill is already small when the maximum particle diameter reaches 400 mm. The three-factor map can be directly produced by using the relative density test results of the maximum control particle diameter equal to gradation of 400 mm as the basis for evaluating the compaction quality of the rockfill on site. (3) For the rockfill satisfying the design porosity of not more than 19%, the relative density must not be less than 0.76 if the relative density is required to be compacted. There are still 15% of the test pits that do not meet the compaction requirements of the double-control filling standards. The porosity of the rockfill is greatly affected by the gradation. The rockfill that meets the porosity requirements cannot guarantee sufficient compaction. It is theoretically not suitable as the compaction standards for the rockfill. (4) The double-controlled filling standards of porosity and relative density provide a theoretical basis for the design of well-graded and fully compacted rockfill. They can better meet the deformation control requirements of high rockfill dams and are the foundation for ensuring the safety of theirconstruction and operation. © 2020, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.