Abstract:

In pebble bed and transitional bed between weathered granite and pebble bed, caisson often meets boulders, which may hold the cutting edge. The problems of difficult sinking and inclination of caisson are presented. By underwater blasting technology for lossening rocks and divers’ treatments, the boulders at the cutting edge are cleared (the biggest boulder has the diameter of 1.4m), which ensures the sinking of the caisson to the desinged elevation with the required accuracy.