Back to TOC

Trenchless Technology & Subsurface Construction

 

Chapter 2

Survey & Site Investigation

 

Overview

 

Thorough surveys and site investigations are essential to all civil engineering projects, and especially to below-ground activities where the risk of encountering something unforeseen is at its highest. The various techniques now available should greatly reduce the chances of encountering major surprises in the course of trenchless installation, renewal or repair.

 

All trenchless systems are designed to cope with a specific range of conditions, and none is universally suitable. Knowledge of what exists below ground therefore influences not only the cost of the project, but also the choice of system to be used. The investigations required clearly vary from project to project, but three main groupings can be identified. For repair and renovation the main need is for accurate information about the size, shape, route and condition of the existing main or service, including data on any fittings or chambers. For new installations the principal requirement is for data on soil and groundwater conditions, and the location of existing mains, services and other obstructions. On-line replacement demands information on the material and dimensions of the line to be replaced, the nature of the pipe surround and the position of the line relative to adjacent pipes and cables.....................for more details