大朝山水电站上、下游土石围堰和高压喷射灌浆防渗墙设计

Design of Upstream/Downstream Earth Rockfill Cofferdams and Highpressure Gunite Impervious Wall for The Dachaoshan Hydropower Project

大朝山水电站上游临时土石围堰和下游土石过水围堰基础覆盖层厚、透水性强，具有深水填筑，要求闭气时间短等特点。在设计中，通过堰型选择，采用堰体粘土心墙、覆盖层高压喷射灌浆板墙防渗型式。下游土石过水围堰采用混凝土楔型体结合钢筋笼块石护面等新技术，解决了土石围堰防渗和渡汛保护问题。

The upstream temporary earth and rockfill cofferdam and the downstream earth and rockfill over-topping cofferdam are characterized by their foundations having thick overburden and high permeability as well as under _ water placement and short closing time for the construction of the Dachaoshan Hydropower Project. A clay core earth and rockfill cofferdam with a high pressure gunite impervious wall in the overburden has been built through comparison between different types of cofferdams in the desigm , and the new technique has been employed for the downstream earth and roxkfill overtopping cofferdam, which is composed of a concrete wedge _ shaped body in combination with reinforcing _caged block stones to solve impermeability and protection problem during flood seasons.