Experience in tunnel burial with suction dredge

Conclusions.

• 1. The method described here for later burial (after laying) of tunnels with suction dredges has proved to be quite effective. Despite the wide diversity of conditions affecting burial technology for underwater pipelines (resting on the bottom of waterways or inadequately buried), the technology in question can serve as the basis for pipeline burial with suction dredges under conditions different from those described here.

• 2. Burial of tunnels that are first laid on the bottom of waterways (before trenching) or that have been inadequately buried is particularly expedient in rivers with unstable channels (e.g., the Amudar'ya and others), where a great deal of time elapses between digging of the trench and lowering the underwater pipeline into it, since the excavation process is strongly dependent on conditions.

• 3. When a tunnel is buried in the bottom of a waterway by the technology under consideration, the trench volume excavated and hence the amount of material moved is less by a factor of several tens (about 40, judging from foreign experience) than that for a trench dug before the pipeline is laid. This is the main reason why working with suction dredges is comparatively inexpensive.