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倒垂孔是钻探工程中的高难度钻孔，用于水电站重要建筑物的水平位移观测。钻孔孔斜率应在０．５‰以内，钻孔终孔有效孔径不小于Φ１４６ｍｍ。西北院勘测总队１９９２年８月，承担了青铜峡水电站大坝倒垂孔钻探施工，该电站坝址区为奥陶系灰岩、页台、砂岩互层，岩层倾角６８°，灰台内有溶洞存在，地质构造复杂，倒垂孔钻探施工十分困难。经过反复探索，尤其对钻孔孔斜问题进行分折，总结教训，提出了相应处理措施，克服了地质条件的影响因素，成功的总结出一套在陡倾角地层中钻深倒垂孔的施工技术。
Inverted hole is a drilled hole in the drilling project, which is used for horizontal displacement observation of important buildings in hydropower station. Bored hole slope should be within 0.5 ‰, the effective diameter of the hole drilling hole is not less than Φ146mm. In August 1992, Northwest Academy Survey Corps undertook the construction of inverted-vertical-hole drilling of Qingtongxia Hydropower Station. The dam site of the power station is an inter-layer of limestone, page block and sandstone with an inclination of 68 °. There are The existence of karst cave, complex geological structure, inverted hole drilling construction is very difficult. After repeated exploration, especially on the drilling hole slope problem is divided, lessons learned, put forward the corresponding treatment measures to overcome the geological conditions of the influencing factors, the successful conclusion of a set of steep dip formations in the drilling down the inverted hole construction technology.