Modern tunnels are often constructed in environments where there is an immense weight of rock and soil above them (e.g. through mountains) or at significant depths (e.g. to carry road or rail traffic under a river, part of an ocean, or other large body of water), and many of them extend for substantial distances.

These tunnels are subject to many stresses, which can increase the deeper and longer they go. Movement of rock, soil and other geological features, seismic activity, and a host of other factors can add to the stress that a tunnel must withstand and threaten their integrity and stability.

Aside from the already substantial stresses that new tunnels must withstand, some metropolitan and other areas contain tunnels that were constructed long ago (in a few cases, these tunnels may be as much as a hundred years old and still in use). Due to their age, these tunnels must also be carefully monitored.

As tunnels are built at greater depths, extend longer, and age, monitoring their status becomes ever more important. However, the longer, deeper and older tunnels get, the harder it becomes to monitor them, especially by traditional, manual means.

Fortunately, up-to-date technologies make it possible to perform wireless tunnel monitoring. Typically, a wireless tunnel monitoring system would consist of an array of extensometers connected to a central monitoring system.

The SMART MPBX (multi-point borehole extensometer) is small, versatile, durable, and easy to install.

The Loadsensing LS-G6 System is a versatile, easy-to-install, low-maintenance, long-range wireless data acquisition system that is ideal for monitoring an array of SMART MPBXs used as the information-gathering component of a wireless tunnel monitoring system.