SEVERAL PROBLEMS ON DEMOLISHING THIRD PHASE RCC COFFERDAM OF THREE GORGES DAM PROJECTS BY BLASTING

摘要

Third phase cofferdam of Three Gorges Dam Projects is made of roll compact concrete (RCC). It is one of the longest cofferdams to be demolished in the world. And there is no example on demolishing it to use for reference. In this paper, a series of experimental results are presented. They include 1:36 model experiment with uniformity concrete, 1:15, 1:20 model experiment with layer concrete, 1:5 in situ experiments and an engineering test with RCC for blasting demolition. It is shown that the cofferdam overturn schedule is feasible. But if the charge position is not reasonable or designed by experience of rock blasting only, overturn schedule will be not realization. Some results are recorded by pictures and recording pictures. By analysis these results, it is given that there may be a time scale that plays an important role in blasting damaging structure and that both layer characteristic of RCC and deep water are important factor to blasting effective.