聚–消能复合垫层保护下的水平建基面开挖方法研究

Horizontal foundation surface excavation method under the protection of energy shaped and dissipation composite cushion

为实现水工建筑物水平建基面的快速开挖,提出用于竖直炮孔的聚–消能复合垫层结构,并通过混凝土配合比试验研制出了制作聚–消能结构的高波阻抗混凝土材料。利用基于LS-DYNA二次开发的爆破损伤数值仿真技术分析了该复合垫层对炮孔底部损伤特性的影响,论证其用于水平建基面开挖的可行性;并结合在白鹤滩水电站的爆破试验,测试爆后控制基面的超欠挖和爆破损伤深度,验证该复合垫层爆破方法的使用效果。结果表明,聚–消能复合垫层保护下的水平建基面开挖方法能有效控制水平建基面开挖的超欠挖和爆破损伤深度,获得良好的建基面效果,同时,该方法能够充分利用开挖工作面,可实现水平建基面的快速大规模开挖,提高生产效率。

In order to improve the excavation efficiency of hydraulic structures＇ horizontal rock foundation,an energy shaped and dissipation composite cushion is presented,and developed iron sand concrete with high wave impedance used as energy shaped structure construction material. It analyzed the composite cushion＇s impact on damage properties at the bottom of blasting holes,and proved its feasibility to be used for foundation surface excavation by using blasting damage numerical simulation technology based on LS-DYNA secondary development. Furthermore,it verified the composite cushion＇s actual effect by carrying out blasting field experiments in Baihetan hydropower station,where controlled surface over excavation and under excavation amount,and explosion damage depth were measured. The results showed that the composite structure enhanced rock fracture degree in horizontal direction and reduced the vertical damage depth at the bottom of blasting holes. Thus it effectively reduced the over and under excavation amount and controlled foundation surface fluctuation,helping to achieve a good rock foundation. Also,it could make full use of the excavation work face and achieve one-time forming of vertical blasting holes, which could realize rock foundation rapid excavation on a large scale.