石泉大坝坝顶倒垂孔施工技术探讨

Discussions on the construction technology of reversed pendent hole in dam crest of Shiquan Dam

倒垂线是大坝位移监测的主要设施之一,常与引张线和正垂装置配合使用,具有较高的监测精度。石泉水电站于1998年开始实施大坝监测系统自动化改造工程。大坝规划设置5条坝顶倒垂线。倒垂孔施工过程中,对钻孔及纠偏,孔斜检测,保护管安装及埋设,锚块、垂线安装及埋设,浮体组安装等,均采取了严格的技术措施;对坝左倒垂孔孔斜偏差超标提出了有效的解决办法,实施效果良好,保证了倒垂孔的安装精度。

The reversed pendent hole is one of primary methods in dam displacement monitoring by means of cooperating with tensional line and the perpendicular device. The automation rehabilitation project of Shiquan dam monitoring system was put into practice in 1998. Five reversed pendent holes were arranged in Shiquan dam. In the course of constructing reversed pendent hole, the strict measures were used in boring hole, surveying degree of inclined line, correcting its error, and installing protective steel tube, anchor, the line of perpendicular, and buoy. The effective method of correcting lean super-scale in left reversed pendent hole was brought forward. The results were satisfactory, and the installing precision of reversed pendent hole was ensured.