ABSTRACT
This chapter describes the state-of-the-art horizontal and directional drilling techniques adopted for laying of water and sewer pipelines, telephone cables, gas pipelines under highways, railtracks, canals and built-up areas without disturbing normal life. Steering devices, such as steerable cutting heads, have been built and successfully used to mechanically adjust the direction of auger-bored road crossings and therefore the line and grade. Water is introduced into the front casing pipe behind the cutting head by means of a pumping system. As in horizontal auger boring, when groundwater is known or anticipated a dewatering system of sufficient capacity to handle the flow should be maintained at the site until its operation can be safely halted. Machines of various capacities for installing pipe from 100 mm diameter to 800 mm diameter with casing up to 120 m in different kinds of soils are available.
