Drilling and sounding for ground investigation

Among geological and geotechnical reconnaissance methods, drilling and boreholes play an important role because of the information they can provide on their own, or through the addition of complementary information systems.

The main areas of drilling activity can be grouped under the following headings:

• finding and exploiting useful materials :

  • ores,

  • charcoal,

  • water,

  • oil,

  • quarry materials ;

• soil reconnaissance for geological, geotechnical, hydrogeological and pedological studies;

• soil preparation for civil engineering works:

  • bored piles,

  • injections.

This article focuses on the last four headings, including quarry reconnaissance, which is linked to them through the supply of materials for construction and paving.

Although drilling is a very old technique, it has developed considerably with mining and oil exploration, and has benefited from a number of decisive technical innovations, such as :

• the use of very hard materials and special steels;

• compressed air ;

• hydraulic transmission.

The civil engineering survey uses equipment that is, in a way, a scale model of oilfield machinery.

There is a wide range of equipment on the market, with machines and tools of varying degrees of specialization, to meet the needs of different types of problem.

We will review the various drilling and probing methods and the main types of equipment in relation to the problems they are called upon to address.

We'll also take a look at some of the equipment and techniques designed to enhance the value of operations that are always costly in terms of investment and running costs.