Settlement monitoring is essential for assessing possible problems and for managing risks associated with ground displacement on surface or underground constructions.
Settlement gauges are designed to be installed under foundations, on buildings or inside embankments or dams. Sisgeo provides some accessories for topographic monitoring related to settlement measurements, such as targets or mini-prisms.
For settlement monitoring, horizontal inclinometers are also often used: refer to the product section on horizontal inclinometers for these solutions.
The most common applications for settlement gauges are tunnels, dams, embankments, deep excavations, foundations, retaining walls, buildings affected by possible differential settlements, and Structural Health Monitoring (SHM).
H-Level is an automatic system for monitoring differential settlements in buildings, tunnels and other civil structures. The system consists of a series of H-Level gauges hydraulically connected to a reference tank located in a stable position. Each H-level gauge includes a high-resolution pressure sensor that monitors the liquid head resulting from the difference in height between the gauge and the reference tank.
The multi-point settlement system is a hydraulic system that can be used to monitor vertical displacements under embankments or earth fill dams. The system consists of a series of vibrating wire or piezoresistive pressure transducers hydraulically connected to an external reference tank. These pressure transducers, equipped with a base plate, are installed inside the embankment.
The BRS magnet extensometer is a column consisting in a guide tube, an anti-friction corrugated sheath and a number of magnetic reference rings fixed on the sheath. The column is lowered into a borehole and grouted to the surrounding soil. Any settlement or heave occurring in the ground will be transferred to the magnetic rings. A simple magnetic probe attached to a graduated flat cable inserted into the guide tube, is able to detect the position of the magnetic rings and thus the vertical movement in the ground. The BRS extensometer being not a very accurate settlement gauge, but is inexpensive and allows measurement of many reference settlement points within one column.
Fixed extensometers are basically columns used to monitor the settlement between two points. The lower point is a platform installed within an embankment or an anchor installed in a borehole. At the top head usually settlement is measured by topographic surveying. Measurements can also be taken automatic and remote by using special displacement transducers.