At 09:15 a.m. on September 8, 2009, the cofferdams of No. 1 and No. 2 docks (400,000-ton and 300,000-ton capacity) at Jiangnanshan Shipbuilding and Repair Base of Zhongji Shipbuilding Co., Ltd. were successfully demolished by blasting. The total length of the cofferdams was approximately 230 m. The composite cofferdams consisted of 155 bored piles, high-pressure jet grouting piles, bedrock, concrete retaining walls, masonry blocks, and backfill materials.

The blasting was carried out using high-precision non-electric millisecond delay hole-by-hole blasting technology. The entire blasting process lasted 2.6 seconds, and hazardous effects including flyrock, vibration, and water shock waves were all controlled within the designed limits. This project represented another successful blasting demolition of a composite cofferdam completed by our company.