一、掘凿工程重力堰堤的基础,必须建筑作坚固致密的岩盘上,所以岩盘表面的砂土及可能遭受风化的部分,必须全部剥除。至少应剥除到2～3m的程度。岩盘经掘凿之后,应尽量将其表面凿成凹凸状态,藉以防止堤體滑动,并提高其安定度。此外尚须在上流面下底设置较深的止水沟,防止由底部岩盘发生漏水现象,并降低其 1. Excavation Engineering The foundation of the gravity weir must be constructed as a strong compact disk so that the surface of the disk must be completely stripped of the sand and the parts that may be subject to weathering. At least should be stripped to the extent of 2 ~ 3m. After excavation and excavation of the rock disk, the surface of the rock disk should be chiseled into a concave-convex state so as to prevent the bank from sliding and improve its stability. In addition, it is still necessary to provide a deeper gutter at the bottom of the upper surface to prevent water leakage from the bottom plate and reduce its