I. An overview1) Geotechnical FeaturesProblematical => Need to go through the soil

How doing it ?

I. An overview1) Geotechnical FeaturesProblematical => Need to go through the soil

How doing it ?

What it depends of? The nature of the soil :- hard ground- soft ground

The size of the hole we need

I. An overview1) Geotechnical Features

a) Drilling precautions

Drilling consists of breaking the cohesion of soil particlesThese particles could create several problems -> How to avoid it?

• Evacuation of the destructed materials• Cooling of the drilling head

• Walls:- to avoid rock crumbling- with bentonite or casing

I. An overview1) Geotechnical Features

a) Drilling precautions

I. An overview1) Geotechnical Features

a) Drilling precautionsb) Hard ground drilling devices

The trepan:

Oldest technique

Create a shock in rock with the blade

Evacuation with water

Heavy blade

I. An overview1) Geotechnical Features

a) Drilling precautionsb) Hard ground drilling devices

The pneumatic hammer:

Most used technique

Create a rotation to get a better drilling

Metal mass moved by a flux of air in body

Could be handled or mounted in a frame

I. An overview1) Geotechnical Features

a) Drilling precautionsb) Hard ground drilling devices

The tricone:

Fastest technique (15 m per day)

Tooth made of heavy metal

Rotation process

Injection of mud and water & cooling

I. An overview1) Geotechnical Features

a) Drilling precautionsb) Hard ground drilling devices

c) Drilling a soft ground

The auger:

Most used technique

Could drill big diameters

Rapid

Also Shovels, deflection, high pressured water…

II. Precise drilling Application

1) Project Presentation

What? 300 meters long directional drilling under a river and a train way

For? A pipeline

Why? Protection of environmentGlobal costs reducedNo loose for agriculture

Need of a geotechnical survey

II. Precise drilling Application

1) Project Presentation

2) Geotechnical survey

Rapid look of the zone:- geologic map- aerial photography

Precise tests:- 3 core drillings- Radiography of the zone

Look at the results

II. Precise drilling Application

1) Project Presentation

2) Geotechnical survey3 different areas:- alluvium (sand & pebbles)-- limestone

Try to avoid alluvium=> Deepest path drilling

Need of a resistive drill to go through the limestone

How to manage the drill

II. Precise drilling Application

1) Project Presentation2) Geotechnical survey

3) Material solutions

Look at the results