Certificate of occupational health and safety management system

What is the treatment principle of sunken ship salvage underwater engineering? The basic principle of underwater engineering is chemical grouting. Chemical grouting is to inject the pressure polymer m

1. Underwater search: two search team members in each group enter the water in the order planned in advance. The team member who arrives at the bottom table first must wait until another team member a

Dredging is an underwater earthwork excavation project that uses manpower or machinery to dredge, expand or excavate deep rivers, lakes and other waters. For a long time, channel dredging has been an