Page - 892 - in Book of Full Papers - Symposium Hydro Engineering

[2] Examine the gate control system of the dam and appurtenant structures . [3] Check the conditions of dam foundation, the seepage of the dam and the possibility of landslides in the reservoir area . [4] Monitor and examine the abnormality of the dam and appurtenant structures. [5] In case that the water level in the reservoir cannot be controlled, resulting in rapid overflow over the dam crest and the dam is likely to break down, evacuation of people from the project area should be implemented immediately as well as the notification of related agencies located at the downstream. 2] Earthquakes may impact dams and can cause unusual conditions to the dams. In case of earthquakes, the inspection of the dams and appurtenant structure conditions after the earthquakes is recommended. Dam conditions and seismic response will be measured by using the dam instruments, such as Survey Monument, Piezometer and Accelerograph, which are already installed. Normal Level: An earthquake takes place more than 200 km away from the dam and does not certainly cause any effects to the stability of the dam. Alert Level: An earthquake of magnitude and distance according to ICOLD (1988), or an earthquake which causes ground acceleration at the foundation and is severe enough to cause a few impacts to the dam, occurs ) for example, the accelerograph responds the seismic waves of > 0.02g to <0.2g, which does not cause damage to the dam.( Alarm Level: The earthquake generates ground acceleration of >0.2g at the dam foundation or the magnitude and the distance of the earthquake from the dam according to Sadigh )1997(’s energy attenuation model causes the ground acceleration of 0.2g at the dam foundation, which is serious enough to cause damage to the dam. 3] In case of landslides in a reservoir, the inspection and the evaluation of landslide locations and sizes is recommended, including the massive waves that may cause overflow to the dam crest .Scrap, rock and soil mass which block the water flow should be moved out .It is recommended to inform the dam safety section to evaluate the damage of the dam and appurtenant structures. 5. DAM REHABILITATION Moreover, Royal irrigation department decided to rehabilitate Mae Suai dam. Repair works shall be able to solve the leakage problem and make the dam to perform well with the future earthquake. The dam rehabilitation will be done in two parts. First, the RCC blocks on the earth dam crest will be removed and replaced by the flexible and vibration resistance structure. The GRS wall with the cutoff sheet pile will be used as shown in Figure 10. GRS wall consists of reinforce gabion. The gabion wall is anchored to the gabion in the opposite side in order to provide additional confining pressure near the slope face and hence 892