刻槽纠斜钻具在湖南怀化火车西站非开挖水平孔中的应用

Application of drilling tools of deviation correction for trenchless horizontal boreholes in the western railway station in Huaihua City,Hunan

在非开挖水平孔的施工中,当钻具由松散地层进入完整硬岩地层时,如果遇层角小,钻孔很容易沿接触面滑行而发生钻孔上漂。因为松散地层对钻具的约束力太小,这类钻孔的纠斜没有很好的解决办法。文章介绍了刻槽纠斜钻具及纠斜方法,在怀化火车西站非开挖水平孔的施工中发挥了很好的作用。钻具主要由岩芯管、加重块和大出刃平底刀片组成,加重块在重力作用下迫使钻具下沉起到部分纠斜作用;大出刃刀片在回转力和加重块重力的作用下在钻孔下邦的岩石上刻槽使钻具下沉,进一步增大纠斜量,二者配合产生很好的纠斜效果。通过多次刻槽使钻孔逐步下移,达到纠斜的目的。

When the drilling tool pass through loosen formation to the hard-rock stratum, if the dip angle becomes smaller, the trenchless horizontal borehole is easily deviated along the stratum boundary. Considering that the loose formation has little binding force on the drilling tool, there is no proper solution to deviation correction. This paper will introduce the authors innovation of the drilling tool and method of notch groove for deviation correction, which have played an effective role in trenehless horizontal borehole in West- ern Railway Station of Huaihua City, Hunan Province. The drilling tool is mainly composed of the core barrel, the weighting block and the full exposure fiat-bottom blade. Firstly, with gravity, the weighting block forces the drilling tool to sink down words, which partially leads to deviation correction.Secondly, with gyroscopic force and gravity, the full exposure fiat-bottom blade notches groove at underly- ing hard-rockalso forces the drilling tool to sink down, which will increase the deviation correction. Therefore, the combination of using the above two solutions could make much better effect on correcting the deviation. It has been concluded that repeating the notch grooves could cause the drilling holes move downward gradually to correct the deviation.