tailieunhanh - Dam Safety and Low Cost Spillway Designs

Tăng đập an toàn bằng cách tham gia vào tài khoản quan trọng hơn lũ lụt đi qua đập tràn, là một mối quan tâm lớn trên toàn thế giới. Tuy nhiên, các chi phí tương ứng có thể trở thành rất cao và đôi khi không thể chịu đựng nổi đối với các nước developping: Có thể tìm thấy các giải pháp an toàn và kinh tế thích nghi với các tình huống hiện tại địa phương? Điều này cần xem xét lại của lũ lụt thông thường và tiêu chuẩn thiết kế | Dam Safety and Low Cost Spillway Designs By F. Lempérière . Vigny Hydrocoop France 5 th International Conference on Dam Engineering Lisbon - 14-16 February 2007 THE CHALLENGE Increasing dams safety by taking into account more important floods passing through spillways is a major concern all around the world. But corresponding costs may become very high and sometimes unbearable for developping countries Is it possible to find safe and economical solutions well adapted to the existing local situations This needs a review of the usual floods and design criteria. FLOODS AND DESIGN CRITERIA The criteria for spillway design are based upon two floods the traditional Design Flood chosen most often with a yearly probability between 1 100 and 1 1 000 and the Check Flood . The true safety of dams refer to the Check Flood sometimes chosen as the Probable Maximum Flood to which the dam must resist without failure and not to the Design Flood during which the dam must be normally operated without damages and the water level of the reservoir is kept well under the dam crest freeboard . The . discharge may be 3 or 4 times the discharge of the flood of probability 1 100. It may be in the range of 500 m3 s for 10 km2 catchment area 10 000 m3 s for 1 000 km2 The challenge remains to withstand such high floods at low cost. Accepting a reservoir level close to embankments crest no freeboard and possibly over concrete dams crest and some damages such as loss of fuse devices during very exceptional floods allows for optimizing various economical solutions as described here after. COSTS ANALYSIS If - q1 is the discharge of the design flood - q2 is the gap between q1 and the discharge of the check flood the discharge of the check flood is q1 q2 and should be as high as possible for best safety. If - cl is the cost per m3 s for discharge of q1 - c2 is the cost per m3 s for discharge of q2 the total cost for the check flood is c1q1 c2q2 and should be as low as possible for cost .