There are clear benefits to having utilities buried underground. For a start, an underground utilities service lasts far longer than its above-ground equivalent. However, there are also significant challenges as well.
The underground utility space is increasingly overcrowded. The kinds of vital services all jostling for space underground include electrical, storm sewer, sanitary sewer, and water mains. Adding, extending, maintaining and managing the millions of kilometers of pipes and cables is becoming more and more of an issue.
When constructing underground utility services, there are a variety of methods which can be used. The most common are trenching and horizontal directional drilling. Finding the best and most sustainable solution going forward involves careful assessment of the best methods of installing each particular underground utilities service.
Trenching is the traditional method for putting utilities underground. It makes sense, and in many respects is technologically the least complicated method.
Trenching involves excavating a hole – since this is generally following a continuous linear path, it is a trench – into which the utilities are placed. Everything is then backfilled with earth once the lines or pipes are laid in place.
The technique is simple, but it still requires careful planning and issues such as the soil conditions, ground and surface water, and surface load all need to be considered when a utility trench is planned and executed.
Generally, the only way to access and repair utilities laid in trenches is to re-excavate.
Horizontal Directional Drilling
This is a method which is trenchless and therefore is favored for its reduced environmental impact. It involves drilling a vertical pilot bore hole along the path of the planned utility.
Currently, this method is used in places where traditional trenching is not possible: under roads, under rivers or existing built structures. It gets the utility services from one point to another largely without disturbing the surface.
It is more costly than trenching, but there are obvious advantages, and at times it is the only option.
There are a few other trenchless techniques that are also available. Pipe ramming, moling, and microtunneling can all be used.
Utilitors, or utility tunnels
There is increasing interest in utility tunnels. These are larger mixed-use corridors underground, which are able to hold a variety of services together. There are definite advantages to this, as it manages the underground congestion and also often allows better and less destructive access options for maintenance and additions to the network.
The expense is the major barrier which limits the extent this method is used for utility services. There are also some compatibility and liability issues which you must negotiate to make the system work.
The best method for placing utility service lines underground depends largely on the specific service and the circumstances. Construction of an underground utilities service in Michigan can involve a variety of the above methods.