CPD Specifier May 2015 issue January 2014

Structural Repair --- Project Case Story --- Oxford Hydrotechnics Canal Chamber Grouting Date Completed - 09/01/14 Duration - 4 days Project Value - £16,000 (within budget) THE PROBLEM Oxford Hydrotechnics were approached to solve a problem of closing off 4 redundant abstraction chambers at the side of a canal. The chambers presented a number of issues that hindered typical chamber closure solutions including: being fully submerged in canal water and each chamber having its own, differing set of dimensions. The chambers were open on the canal side with various weirs and gratings and had varying levels of obstruction, with silt and debris present. The chambers needed to be plugged without affecting the canal or nearby factory and were also required to be water tight, a specification that presented a high level of difficulty when factoring in the open sides to the chamber. THE SOLUTION The chambers were blown using a compressed air lance to move the silt and organic debris back into the canal. Oxford Hydrotechnics engineers devised a solution of making and installing oversized geo-textile grout bags into the chambers. The bags were then inflated using Natcem AC (a natural Cement product). As the bags were inflated, they took up the internal dimensions of each chamber, acting as flexible shutters. THE RESULTS After a day of initial setting up and silt cleaning, the four chambers were successfully grouted. The use of Natural Cement meant that the solution was harmless to the environment and was self-levelling. The use of porous Terram geotextile during the fabrication of the bags prevented them from collapsing under water pressure when in situ and meant that the canal water could be displaced as the bags were filled with cement. The installed grout bags formed permanent water tight seals, satisfying the requirement of both the client and the Canal and River Trust. www.h2ox.net 01869 346001 Reader Enquiry: 44 Leak Sealing - Ground Stabilisation - Void Filling - Structural Repairs - Concrete Repairs - Cement Grouting Reader Enquiry: 45 28

CPD Specifier May 2015 issue January 2014 | Page 28