旋挖钻机在岩溶地区干作业成孔方法与质量控制

Dry rotary borehole drilling and quality control in the karst area

摘要:

在沪昆铁路盘州站桩基施工中，采用旋挖钻机干作业成孔，成孔过程中近1/3的桩基遇到了溶洞。通过分析不同病害情况，针对在岩溶地层施工中遇到的无充填和半充填溶洞地质条件，分别采取了土石回填筑壁、反转复压，素混凝土挤扩成孔、分段成型，钢护筒护壁、挡截桩混凝土，斜岩找平、重新钻进，定位回填、水泥固化等技术措施，完成了桩基的施工任务。

Abstract:

In the construction of pile foundation at the Panzhou Station of the Shanghai-Kunming Railway, the rotary drill rig was used to dry-drill the holes, and dissolved caves were encountered in drilling of nearly 1/3 the foundation piles. Based on the analysis of different adverse situations, and according to the geological conditions of unfilled and semi-filled karst caves encountered, specific technical measures were adopted, including wall construction by backfilling soil and stone and compaction by reverse rotation, sinking boreholes section by section by squeezing plain concrete, protection of borehole walls and retaining of pile concrete with casing, leveling of uneven rock surface and re-drilling, point-backfilling and cementation; as a result, the pile foundation was successfully completed.