Quality Control Aspects for Casing Material and Coarse Filter for Earth Core Rockfill Dam

Abstract

Blasted prototype rockfill material from a multipurpose irrigation project which is under construction in India is considered for its quality control / assurance for this paper. The maximum particle size (dmax) of blasted rockfill material used in construction of the above project is 600 mm, and the maximum particle size of inclined and horizontal coarse filters is 20 mm and 80 mm, respectively. Following tests were conducted at site to check the quality and determine the field density, moisture content, grain size distribution and permeability as per relevant standards and field experiences: (i)In-situ (Field) Density [1, 2](ii)Moisture Content [3](iii)Prototype Grain Size Distribution for Casing and Filter Materials [4](iv)Permeability [5] All the above-mentioned tests were conducted at different stages/frequency of construction and determined material parameters. The results are presented, and necessary preventive action was also highlighted. From the testing, the test results were collected, i.e., field density, moisture content, field permeability, gradation, coefficient of uniformity (Cu), coefficient of curvature (Cc), finer percentage (>75 µ) and compared with design values. From the comparison, it is observed that the parameters determined from field tests almost match with design values. Highlighted all the observed deviations and provided the corrective measures based on the field conditions. Therefore, the quality control measures are very much essential to ensure the safety of the structure.