岩石地基承载力取值原则探讨

Discussion on valuing principle of bearing capacity of rock foundation

《水利水电工程地质勘察规范》（GB50487-2008）规定：坚硬岩、半坚硬岩石地基承载力可按岩石单轴饱和抗压强度折减后取值,坚硬岩取岩石单轴抗压强度的1/25~1/20,中硬岩取岩石单轴抗压强度的1/20~1/10。综合分析各行业的研究成果,认为该取值原则偏于保守,仅仅考虑单轴抗压强度的影响比较片面,会在实际工程中造成不必要的浪费。结合水电工程的特点和不同行业的研究成果,提出以岩体完整性和岩石强度相结合的基岩承载力取值原则,建议及时修改规范相关条文,以便更加切合工程实际。

It is regulated in Code for Engineering Geological Investigation of Water Resources and Hydropower that the bearing capacity of hard rock and medium hard rock foundation can be valued by the reduced saturated uniaxial compressive strength. The bearing capacity of hard rock foundation is valued at 1 /25 to 1 /20 of the uniaxial compressive strength of the rock and that of medium hard rock is 1 /20 to 1 /10 of the uniaxial compressive strength. Based on the comprehensive analysis of the research results of different fields,the original valuing principle is deemed as conservative because it is unilateral to only consider the influence of uniaxial compressive strength,which may cause waste in practice. According to the characteristics of hydropower projects and research results of different fields,the valuing principle of bearing capacity of rock foundation which considers both the integrity and strength of the rock is proposed and it is advised that related specifications of the Code should be revised to meet the need of engineering practice of the current time.