Project Name:
Tideway Eastern Section – Chambers Wharf (CHAWF)

Main Contractor/Client:
Joint venture of Costain Ltd., Vinci Construction Grands Projects and Bachy Soletanche

21st to 23rd April 2021

Issue, Problem, Task Description

As a result of historic settlement of the Cofferdam infill material a void had been created between the underside of the external gantry crane pile capes and the fill material. In order for the Gantry Crane to work at its full capacity there was a requirement to fill the void space with a suitable product.

The pile caps are 1000mm deep and the average depth of void was determined to be 30mm over an area of approximately 107 m2.

Method, Equipment, Materials

26 x 50mm diameter core holes were placed through the pile caps to the underside. CK-Tech Ltd used 50mm x 500mm mechanical packers secured in each of the cored holes. A Desoi L36-2C Pneumatic reciprocating pump with extended delivery lines was used to inject a 2 component Urea Silicate MasterRoc MP 368, commonly used to stick rock strata together, into each packer. Volumes at each packer varied between 30 and 50 litres and the maximum pressure required to inject the product was 5 bar. In all cases, with the exception of two packers, an endoscope was used to confirm that product was witnessed in each core hole after injection. The two exceptions were filled with product injected through adjacent packers.

Summary of Resources

The works were completed in 3 days by a two-man team from CK-Tech Ltd using:

  • 1050 litres of MasterRoc MP368
  • 26 x Desoi 50mm x 500mm Mechanical Injection Packers
  • Desoi L36-2C Pneumatic Reciprocating Injection Pump