Seite - 1332 - in Book of Full Papers - Symposium Hydro Engineering

Figure 5 shows displacement of x & y directions. As a result, there was little difference between before and after earthquake, but figure 6 shows that displacement of z direction before earthquake was different from after that. This could mean that all points had a change and small displacement occurred on a dam. It was difficult to estimate exactly how much settlement occurred or whether settlement occurred really or not because survey system also had a possibility to be affected by earthquake Due to a change of only vertical displacements, it was analyzed additionally how much vertical displacement for all points changed. Figure 7 shows vertical displacement of all points. Lines with rectangular shape are average measured data before earthquake. Period of data is 2 years ago from occurring gyeongju earthquake. Lines with circle shape are average measured data after earthquake. Period of data is 1 month from occurring gyeongju earthquake. As a result, middle section of dam structure changed larger than other sections. Maximum displacement was about 8.5mm on the middle of dam crest. Figure 7. Status of vertical displacement before & after gyeongju earthquake 2.2. LEAKAGE MEASURING Dam structure is always storing amount of water, but perfect blocking of infiltration water is difficult. If infiltration water is increased, dam operators or engineers can think that an Interlocking of rock fill zone or a joint between faced concrete have a problem. Therefore, in order to properly operate and maintain structures for rock fill dam type, it is very important to check leakage measuring. The number of leakage measuring points in subject dam is one and this is located at the tip of downstream slope. Currently, quantity of leakage and water quality is measured automatically every hour. 1332