The model EHOS-35 hydraulic overflow settlement system is suitable for measurement of settlement or heave in an embankment of a dam or infills where the settlement cell (sensor) and terminal structure or observation room can be nearly at the same elevation.
The hydraulic overflow settlement gage works on the ‘U’ tube principle. It consists of a graduated standpipe and a sealed settlement cell with three accesses - first for an overflow pipe which is connected by a nylon tubing to the standpipe, second allows the drainage of excess water from the cell and the third access allows atmospheric pressure to be maintained inside the cell. The cell is installed in soil fill and the standpipe on the firm ground outside the structure. De-aired water is filled in the standpipe and tubing connecting it to the cell. Comparing the water level in the standpipe with earlier readings taken gives the settlement/ heave to which the cell is subjected.