岩溶建筑地基强溶蚀带划分

Division of an intensive dissolution layer for building foundation in a karst terrain

强溶蚀带是岩溶地基中岩体溶蚀程度最高的深度范围,反映了场地岩溶发育的主要深度范围和岩溶地基处理难度,合理划分强溶蚀带对岩溶地基设计具有积极的工程实际意义。基于岩溶地基溶蚀程度深度分布特征,提出了强溶蚀带界限高程的确定方法,并结合具体的工程案例论证了强溶蚀带划分方法的先进合理性。结果表明:强溶蚀带不宜直接作为岩溶地基的主要持力层,其分布界限可根据溶蚀率深度分布曲线确定;在保证场地各勘察阶段具有足够的钻孔数量的前提下,同一场地在不同勘察阶段确定的强溶蚀带分布范围基本一致,这表明了其划分方法的合理性;在当前岩溶处置水平下,界限溶蚀率取25%作为强溶蚀带划分标准是合理的。

An intensity dissolution layer is the depth range of rock mass with the highest dissolution degree,and reflects the complexity degree of karst ground treatment. Therefore,rational division of the intensity dissolution layer plays an important role in the foundation design in a karst terrain. A method for dividing the intensity dissolution layer is proposed with the distribution of dissolution degree with depth,and its rationality and progressiveness is illustrated. Results show that the intensity dissolution layer should not be used directly as a main bearing layer for foundation in karst ground,and the boundary can be determined with the depth curve of dissolution ratio. The depth distribution range of the intensity dissolution layer is determined in different phase of geotechnical investigation with enough boreholes differing little from each other,illustrating the rationality of the dividing method of the intensity dissolution layer. Taking the boundary dissolution ratio of25% as the standard for dividing the intensity dissolution layer is in accordance with the present karst treatment technology.