To identify the required parameters of grouting operations in scrutinising the design and execution of seal curtain of the Balvabin dam site, the test grouting operations were conducted in a part of the seal curtain zone located in the riverbed. The test grouting was carried out in the vertical and angled rows according to the properties of discontinuities in the dam foundation zone to intersect the maximum discontinuities. Afterwards, the obtained results were analysed and finally due to the not groutable of the rock mass at the depths of more than 10 metres and according to the presence of peripheral gallery in the foundation, the execution of seal grouting operations was postponed until next dewatering. The measurements after the dewatering of the dam indicate whether grouting is required or it can be eliminated. With the grouting gallery being available, the grouting can be carried out at any other time.
