【摘要】 使用回转钻探取芯工艺的地质勘探中,在遇到全风化花岗岩地层时,易产生塌孔埋钻事故,导致取芯失败。本文对孔壁被水浸泡和未被浸泡两种状态进行了受力分析,探讨了影响孔壁稳定性的一些因素。然后从钻井液、钻具及施工操作三方面提出了使全风化花岗岩孔壁稳定性的措施。通过上述分析,对全风化岩层这些特殊类岩土的钻探工作提供了参考,有利于取芯钻进的顺利进行。更多还原

【Abstract】 When the rotary drilling technique is used in the geological exploration for the completely decomposed granite formation,it is easy to lead the accidents with the wall collapse and burying the drilling tools,which result in the failure of core drilling.The stress analysis under the two states where the borehole wall is immersed in water or not immersed in water is carried out,and some factors to affect the stability of the borehole wall are discussed.Some measures in the aspects of the drilling fluid,the drilling tools and the constriction operation are proposed to improve the stability of the borehole wall in completely decomposed granite formation.The above analysis provides some references for the drilling work in special strata such as the completely decomposed granite formation,which is helpful to the core drilling.更多还原