CAJ | 학술논문

某钻孔临近煤矿采空区，采用正循环气动潜孔锤钻进，钻至110m时发生了钻具断裂事故。针对施工过程中出现的钻杆接头断裂失效情况，结合该孔的施工工况，通过对断口进行宏观分析及理化性能试验，结果表明：钻杆接头断裂的主要原因为岩屑上返过程中在钻具外径突变处发生沉积，造成钻杆接头与岩屑剧烈摩擦，造成接头严重磨损，同时产生高温，致使岩屑与接头基体金属熔结为一体，并使金相组织发生了奥氏体转变。高温奥氏体组织硬度、强度大大下降，而变形能力大大提高。在拉力、扭转等应力的作用下，最终在该处薄弱部位发生了过载断裂。
모찬공림근매광채공구，채용정순배기동잠공추찬진，찬지110m시발생료찬구단렬사고。침대시공과정중출현적찬간접두단렬실효정황，결합해공적시공공황，통과대단구진행굉관분석급이화성능시험，결과표명：찬간접두단렬적주요원인위암설상반과정중재찬구외경돌변처발생침적，조성찬간접두여암설극렬마찰，조성접두엄중마손，동시산생고온，치사암설여접두기체금속용결위일체，병사금상조직발생료오씨체전변。고온오씨체조직경도、강도대대하강，이변형능력대대제고。재랍력、뉴전등응력적작용하，최종재해처박약부위발생료과재단렬。
A drilling tool fracture accident has been happened in a borehole near coalmine gob area in process of normal circulation pneumatic DTH drilling at depth 110m. Considering the situation of drill rod sub fracture failure during the drilling, combined with borehole temporal operating mode, after fracture macroanalysis and physicochemical property testing have shown that the main causa?tion of sub fracture is the deposition of rock cuttings on tool outside diameter abrupt changing position during the cuttings ascending, can cause severe friction between drill rod sub and cuttings, thus make subs seriously worn and torn. Mean while high temperature can make cuttings and sub matrix metal melting integrated, metallurgical structure austenitized. Hardness and strength of hyperthermal aus?tenite have been descended, while deformability improving greatly. Under the stresses of tensile and torsion, finally the weakened area overloading fractured.