糯扎渡水电站心墙料现场碾压试验及掺砾工艺研究

Study on field compaction test for core wall material and gravel mixing technology at Nuozhadu Hydropower Station

糯扎渡水电站心墙堆石坝坝高261．5m，同等坝型高度全国第一，世界第四。采用风化料掺硬岩（角砾岩或花岗岩）碎石料作心墙防渗料，国内尚属首次，国际上也不多见。在可行性研究及招标设计阶段，为论证风化混合料掺35％硬岩料（以下简称掺砾料）作为心墙防渗料的可行性、可靠性，进行了Ⅰ、Ⅱ期现场碾压试验及掺砾工艺试验研究，得出混合料天然含水率在14．5～23％范围的混合料掺入55％的角砾岩碎石料具有可掺性及可碾性，掺砾后心墙料压实性得到明显改善，通过混掺工艺试验确定掺砾料土石厚度比为0．5：1．05，不仅简化了施工工艺，而且心墙料的压实性、渗透性及强度可满足高心墙堆石坝的设计要求。

Nuozhadu Hydropower Station is 261.5m high, and is ranked the first place in China and the fourth place in the world among the equivalent dam types. The weathered rock mixed with hard rock （rubblerock or granite） gravel is used as anti-seepage material of core wall, which is reportedly the first application in China and is also seldom seen in the world. At the feasibility study and bid invitation design stage, in order to demonstrate the feasibility and reliability that the weathered mixture mixed with 35% hard rock （gravel mixture） is used as anti-seepage material of core wall, the study on phase I and II field compaction test and gravel mixing technology is made, so that the mixture whose natural moisture content is within the scope of 14.5~23% is mixed with 35% rubblerock gravel has mixing and compaction performance and the compactibility of core wall material mixed with gravel is obviously improved. The test for mixing technology can be applied to determine the thickness ratio of earth-rock of the material mixed with gravel being 0.5： 1.03, thereby not only simplifying the construction technology and enabling the compaction, permeability and strength of the core wall material to meet the design requirements of the core wall rockfill dam.