采用组合钻具进行跟管钻进，通过随钻跟入的套管保护孔壁，解决因钻孔垮塌导致钻探效率和岩心采取率低等技术难题。

The problems of low drilling efficiency and low core recovery due to borehole collapse were solved with pulling in casing while drilling through using combined BHA with casing.

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煤矿井下可回收锚杆一般用于煤层巷道，由于锚杆钻孔的变形和塌孔等原因，用普通套筒扳手拆卸锚杆时，因不能给锚杆提供轴向拉力，很难将锚杆拆卸拔出。

It is difficult to pull out the bolt with ordinary socket wrench that can not provide axial tension because of the bolt drilling hole deformation and the collapse of holes.

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针对桩位偏移、桩孔倾斜、塌孔等旋挖钻孔混凝土灌注桩常见的质量问题，就其产生的原因进行了分析，并提出相应的预防措施和处理办法。

According to common problems on spiral excavation drilled-pouring pile, including deviation of pile, declivity of hole, slumped hole, it analyzes reasons and puts forward relative prevention measures.

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