万安溪面板堆石坝石料的调查与应用

Investigation on Rock Material for Wan'anxi Concrete Face Rock-fill Dam and Its Application

万安溪坝址附近为巨斑粗粒似斑状花岗岩，风化覆盖层深厚，难以找到覆盖层薄、储量大的好料场。经不断勘察摸索，发现只有在大岩体的边缘相或顶部边缘相有细粒花岗岩存在，并在其保护下才有风化覆盖层薄的粗、细粒结构并存的花岗岩体存在。花岗岩石质坚硬，抗水性强，其矿物成分中，钾、斜长石占２／３以上，长石矿物有两组中等解理，解理面间的连结力小于晶粒间的连结力，有利于冲击旋转钻造孔，使钻头的消耗不致于过大。节理裂隙发育的花岗岩，可一次性微差爆破，开采出所需级配的堆石料和过渡料。

Rocks nearby Wan'anxi damsite are almost sranite-porphyry. It is difficult to find out a rich quarry with thin covering layer there. Throush continuous investisation, it is discovered that there exists finegrained granite only in the side or the top marginal petrographic factes of a large volume of rock,and that there also ealsts coarse and fine grain mixed sranite only under its protection. The granite is hard and strong water-proof. Among its mineral ingredients,potassium and plagioclase account for two thirds or more. There are two sets of medium cleavages in plagioclase. The link force between the cleavages is smaller than that between its grains. This is beneficial to drill holes with a rotary-percussion drill so that the drill head would not be consumed too quickly. Rock-fill material and transition material can be obtained by millisecond blasting of the granite that is created in joint crack.