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钻探施工中，为了将岩粉排出孔外，冲洗液通过钻杆送入孔内，自钻头端部连续喷出，如图1所示。一旦钻遇裂隙层时，冲洗液漏入裂隙内，岩粉急剧下降并沉积在环状间隙最下端的岩心管接头的肩部，提升钻杆时使岩心管提不上来。如果使用空气洗井，钻至上述裂隙层时，携带岩粉的空气流速下降，上返中的岩粉下沉，孔壁被高速回转的钻杆磕打，结果如图2所示，孔壁上结成岩粉硬块。因此，提升岩心管时会造成卡钻。
In the drilling construction, in order to discharge the rock powder out of the hole, the rinse liquid is sent into the hole through the drill pipe, and continuously discharged from the end of the drill bit, as shown in FIG. 1. Once the fracture layer is drilled, the flushing fluid leaks into the fracture and the rock powder rapidly descends and deposits on the shoulder of the core pipe joint at the lowermost end of the annular gap, raising the drill pipe so that the core pipe can not be raised. If air flushing is used, the flow rate of air carrying rock dust decreases when the rock is drilled to the above-mentioned fractured layer, and the rock powder on the returning rock sinks and the wall of the rock is knocked by a drill pipe rotating at a high speed. As a result, as shown in FIG. 2, On the formation of hard rock powder. Therefore, lifting the core tube can cause sticking.