乌东德电站导流洞直柱形堵头衬砌与围岩接触研究

Study on interface characteristics of concrete lining and surrounding rock at plug section of diversion tunnel of Wudongde Hydropower Station

大型水电站导流洞封堵永久堵头一般选择在围岩条件相对较好且与大坝防渗帷幕相交的洞段,堵头型式一般采用楔形结构。为了避免二次开挖,达到简化施工、加快进度的目的,乌东德水电站导流洞永久堵头采用直柱形结构型式。这要求准确查明堵头段衬砌混凝土、喷混凝土和围岩的接触情况。为此,选取具备研究条件的5号导流洞开展研究工作,采用钻孔取芯、彩电、声波测试、平面超声横波成像检测及室内试验等手段,查明了堵头段各接触面的接触状况。以测试及试验成果为基础,类比相似工程并结合地质条件,给出了堵头段各接触面的物理力学参数建议值,为堵头设计提供依据。这一研究方法及成果可为其他类似工程提供借鉴。

The diversion tunnel permanent plugs of large hydropower stations are generally located at the tunnel section which intersects with the dam anti-seepage curtain and the surrounding rock condition is well. The edge-shaped structure is usually adopted as permanent diversion tunnel plug. In order to avoid the secondary excavation, simplify the construction and speed up the progress, straight column plug was adopted in Wudongde Hydropower Station, which requires to ascertain interface condition between rock mass and concrete lining and shotcrete. Therefore, rock core drilling sampling, colour TV display, wave testing, plane ultrasonic s-wave imaging detection and shear test were used to investigate the interfaces in the plug section. Based on the test results and by referring similar projects, the shear strength parameter of the interfaces is recommended. The result provides basis for the design of diversion tunnel plug.