岩溶地区上高层建筑的基础设计是建筑工程中地基处理的难点。岩溶地基存在土洞溶洞多,岩面起伏大、地下水不可预见等特点,使得岩溶地基高层建筑基础设计具有极大的挑战性。对一个卵石土岩溶地基高层建筑进行基础设计,通过现场土的载荷板试验、夯扩桩复合地基载荷试验、冲孔桩复合地基载荷试验等现场原位试验,获得了丰富可靠的资料,根据试验结果和场地覆盖层厚度、岩溶发育情况进行科学的计算分析,最后采用筏板下多桩型复合地基处理方案,该方案既能满足承载力及沉降的要求,又同时考虑了溶洞坍塌及沉降不均的风险,且更为经济。将计算沉降与实际观测结果进行了比较,说明了地基处理方案的合理性,为高层建筑复杂岩溶地基处理提供了较好的借鉴。
Foundation design of high-rise buildings in karst region is always the difficult point of ground treatment in a construction project. The karst foundation has the properties that many soil caves and caverns are found; rock surface is greatly undulating; ground water there is unpredictable and so on. These complex conditions in karst area to some extent make the foundation design of high-rise buildings extremely challenged. In this paper, a foundation design of high-rise buildings on cobbly soil karst ground is introduced in which the abundant and reliable data were obtained through the loading test of undisturbed soil, ramming-reamed pile composite foundation, punching pile composite foundation and other in-situ tests. According to the scientific analysis of test results, thickness of covering layer and development of karst, the scheme of ground treatment with multiple types of pile below raft foundation is adopted at last. This scheme can not only satisfy the requests of the load and the settlement, but also consider the risks of the cave collapse and the differential settlement, which is even more economical. And the calculated settlement was made to be compared with actual observations to illustrate the rationality of the chosen scheme. It will be a good reference for handling ground treatment of high-rise buildings in complex karst region.