Jonathan Knoyle reports on a tricky rubble-strewn HDD installation under a canal in Ottawa

摘要

Cobbles and boulders are a major challenge for HDD installations and in some cases they make the technology non-viable. A thorough, well thought-out geotechnical study is vital in order to define the ground conditions so that a suitable trenchless solution can be established, a fair and practical contract prepared, and the right equipment chosen to overcome any difficult conditions.