卵石地层桩基施工中可捞石钻具的研制及应用

On the Development and Application of the Stone-Fishing Drilling Machine and Tools for and to the Construction of Pile Foundation in the Pebble Stratum

在含有较大卵石的地层中施工桩基时,采用常规方式钻进,效率低、易塌孔超挖。针对卵石地层,尤其是含有较大漂石的卵石地层桩基施工难题,研制了一种具有捞石功能的钻具,配合回转反循环钻机使用。该钻具兼具反循环和捞石两种排渣系统,较大卵石通过捞石系统排出,其余钻渣通过泥浆反循环排出,为钻孔桩施工提供了一种新的思路。介绍了可捞石钻具的结构、制作及应用技术。实践表明,该钻具节约了钻孔过程中破碎较大卵石的时间,提高了钻进效率;同时回转反循环施工对孔壁扰动小,减少了坍孔超挖,取得了较好的综合效果。

When construction is performed in a stratum of relatively big pebbles,if the common drilling method were used to bore holes,the efficiency would be rather low,with the collapse of the hole liable to happening frequently,as a result of which over-digging is unavoidable.Aiming at solving the difficult problem of performing the construction of the pile foundation in a stratum of relatively big pebbles,a new type of stone-fishing drilling machine and tools is developed,which may be used in combination with the reverse circulation drill.This type of drilling machine and tools has two different discharging systems with the functions of both the reverse circulation and fishing stones.The big pebbles can be fished with the stone-fishing system while other slags can be discharged with the slurry-reverse-circulation system.The development of this type of drilling machine and tools provides a new thinking way for the construction of bored holes.The structural composition,making and application techniques of the stone-fishing drilling machine and tools are introduced in detail in the paper.Construction practice shows that the stone-fishing drilling machine and tools help save the time of breaking big pebbles,and much improve the drilling efficiency.Meanwhile,owing to the fact that the reverse circulation construction with this type of drilling machine and tools helps reduce the disturbance to the hole wall,both the collapse of the bored holes and over-digging are reduced,with comparatively better comprehensive benefit achieved.