Dredging & removal of rock strata at Inner & Outer Harbor turning Circle and LPG jetty at Visakhapatnam Port.

Need

Dredging of soft soil consisting of gravel and pebbles over laying hard strata and hard rock at Visakhapatnam Port.

Challenge

Dredging of soft soil consisting of gravel and pebbles over laying hard strata and hard rock at Visakhapatnam Port.

Solution

DDIL deploys TSHD “Vlaandraan-XX” Grab Dredger “Ketam” Backhoe Dredgers “Ave Caesar” & Dharti XIV for 3,06,000M3 of soft soil removal and 42,000M3 of hard rock removal after pre treatment by drilling and blasting method.

Work Involves

•Soft soil (overburden) removal executed with one TSHD and two Grab Dredgers of 3.0M3 Grab capacity and one split hopper barge of 1000M3 capacity.

•Dredged material loaded to barge and dumped offshore at designated location identified by the Port.

•Jet probing carried out at 3m X 3m grid to identify the rock levels in the dredging area. Jet probing carried out with a jet pipe fitted with nozzle as per specifications and connected to the pump maintaining water pumping pressure of 7.5kg/cm2. Rock levels noted by gradations pipe.

•Simultaneous drilling by two drill barges at 2m X 2m grid pattern drilling 16 holes in one position.

•Rock blasting using explosives (super gel packets) in polyethylene covers. Mille second detonators used to reduce the intensity of vibrations and impact on the existing harbor structures. Blasting impact measured in Peak Particle Velocity (PPV) and maintained as per the specifications.

•Controlled under water drilling and blasting techniques carried out under the supervision of Indian School of Mining, Dhanbad.

•Fragmented rock removed by Backhoe dredger with bucket capacity of 4M3 and loaded in to split barge of 1000M3 hopper capacity for offshore disposal at location identified by the Port.

•Onboard real time dredge monitoring and data acquisition system on backhoe dredger with dynamic positions of bucket for efficient dredging.

Result

DDIL completes project in compliance with HSE standards.