Seite - 683 - in Book of Full Papers - Symposium Hydro Engineering

operation, the trench is back-filled and compacted. An example of calculated deformation on the sensor placed on the top of the wall section I presented in Fig. 9. Deformation is plotted as a function of position along the wall and as a function of time. Fig. 9 Recorded deformations on a levee wall as a function of position and time In the plot it is possible to observe the daily expansion-contraction cycles of the wall due to temperature fluctuations. It is also possible to localize the expansion joints along the levee wall that shows a different behavior. In case of an event along the levee section, a localized deformation peak will appear in the visualization software and would automatically trip an alarm. 4.2. APPLICATION: PENSTOCK MOVEMENT MONITORING PROJECT – NENDAZ (CH) The penstock of an important mountain dam in the Swiss Alps, is subject to rock mass movements that can influence its mechanical performance (Jordan Papilloud 2015). In order to provide a safe installation, the penstock is made of several pipe sections welded together in order to form a more flexible pipe, thus allowing a higher degree of movement. Nevertheless a deformation monitoring system is necessary to detect any abnormal penstock deformation and penstock curvature. In addition to this, the penstock access tunnel is also affected by concrete cracking due to the water pore pressure and rock movements. A distributed strain monitoring system was selected because of its capability to 683