一种用于非饱和黄土钻探的双管螺旋钻

A Dual Tube Auger for Unsaturated Loess Drilling

为了满足非饱和黄土连续原状取芯的要求,参考美国已成熟的螺旋空心钻技术,设计了一种双管螺旋钻具。该钻具结合双管单动岩芯钻和螺旋钻的双重功能,通过螺旋叶片旋进土中,外围土体顺叶片上涌,贴在叶片间的外壁上;里面的空心部分则可以套取土样,使其免受扰动。钻具提出后,清除掉外壁上的土体,卸下钻头,取出里面的土样,不仅可用于土的鉴定,也可用于室内试验。试验表明其钻探取样效果良好,但对钻机动力和工艺要求较高。该钻探技术主要用于黄土滑坡钻探,通过连续取得原状土芯,从中识别和鉴定滑动带。

Referring the conventional used hollow stem auger in America, the authors designed a kind of dual tube auger which combines the functions of both the conventional dual tube rock auger and the continuous flight soil auger. With rotation of the drilling rod, the cutter head would cut down the outer ring part of the soil and keep the inner rounded part without disturbing. Meanwhile, the cuttings of the soil outside would go along the flight auger and the soil core inside goes into the inner wall up. The soil cohered on the flight of the outer tube is taken off while the soil core in the inner wall is taken out. The soil core keeps dry and intact. The samples could be used to not only identify the slip zone, but to do the laboratory tests for physical and mechanical properties. In situ drilling tests suggest that the quality of the loess core taken by this auger is much better but it exhausts more power and need more complicated skills than that by conventional methods applied at present in China.