岩溶地区桥梁基桩施工技术

Construction Techniques for Foundation Piles of a Bridge in Karst Region

鼎湖特大桥位于岩溶发育区,裂隙发育,溶沟、溶槽、溶洞众多。前期施工时,根据79号墩试验桩及65号墩基桩成孔工艺试验成果,斜岩面钻孔施工时采取回填片石及混凝土的处理措施;溶洞地质钻孔施工时根据岩溶具体情况可采取预注浆、挤石造壁、跟进钢护筒的处理措施。针对施工中常出现的桩孔漏浆、偏孔、塌孔、扩径及卡钻问题,采取有效的预防处理措施保证了施工安全及基桩质量。经检验,该桥基桩合格率为100%。

The Dinghu Lake Bridge is located in the developed karst region where the karst gaps are developed and the karst gullies, troughs and cavities can be found here and there. At the early stage of construction, when the boring of the foundation piles was carried out in the inclined rock surfaces, the surfaces were handled by backfilling pebbles and casting concrete in accordance with the testing results of the trial piles for Pier No. 79 and the bored hole construction technology for Pier No. 65 and before the boring was carried out in cavity ground, the measures of grouting the ground in advance and squeezing the rock underground to form walls, followed by the utilization of sleel casings, were taken according to the specific conditions of the karst. In the light of the common problems like the slurry leakage in the bored holes, offsetting and collapse of the holes, expanding of the holes and clamping of boring bits, the effective precaution measures were taken and the construction safety and quality of the piles were thus ensured. The inspection of the piles of the bridge proved that the qualified rate of the piles was 100 %.