复杂地质条件下定向连续取芯钻探难点及对策

广州市轨道交通7号线二期工程在大沙东站—姬堂站区间过广九铁路段、加庄站—科丰路站区间过广深高速段成功应用了定向连续取芯钻探勘察。过广九铁路段完成连续取芯696.42 m,过广深高速段完成连续取芯399.98 m。钻探范围地层较为复杂,钻探过程中出现了严重的地面冒浆、孔内漏浆、塌孔、钻探遇阻等技术难点。针对钻探难点,采用优化泥浆配置、水泥固井、优化钻进压力、双层管跟管钻进、护壁泥浆配合注、压水泥浆固井、冲击钻进等措施。积累了针对定向连续取芯钻探遇浅部软弱地层、断裂和孤石的钻探技术及泥浆配比经验。

Drilling Difficulties in Directional Continuous Coring under Complex Geological Conditions and the Countermeasures

In the second phase engineering of Guangzhou Rail Transit Line 7, where the interval between Dasha East Station—Jitang Station passing through Guangzhou—Kowloon Railway section, and the interval between Jiazhuang Station—Kefeng Road Station passing through Guangzhou—Shenzhen Highway section, directional continuous core drilling prospecting was applied successfully. There completed 696.42 m continuous coring in the interval passing through Guangzhou—Kowloon Railway section, and 399.98 m coring in the interval passing through Guangzhou—Shenzhen Highway section. Within the scope of drilling, complex strata led to the technical difficulties, such as serious slurry emitting on the ground, slurry leaking in the hole, hole collapse, drilling resistance and so on. Against these difficulties, the measures including slurry proportioning optimization, well cementing, drilling pressure optimization, double-layer pipe following drilling, slurry supporting, well cementing by pressing slurry, impact drilling, were used. Thus the experiences of directional continuous coring and slurry proportioning in shallow weak strata, fractures and lonestones, were accumulated.