岩石地基上独立基础抗剪及其经济性分析

Shear calculation and economy analysis of independent foundation on rock subgrade

岩石地基上独立基础的抗剪验算存在较多争议,结合地基基础设计规范及相关地方标准,对不同地基承载力下的独立基础进行了计算,分析表明在地基承载力小于1200kPa时基础厚度由冲切控制,承载力大于1200kPa时基础厚度由抗剪切控制,必须进行抗剪验算,独立基础抗剪切所需厚度与抗冲切所需厚度之比最大可达到4倍。同时还进行了独立基础的经济性分析,计算表明无论基础厚度如何,独立基础总造价随着地基承载力呈非线性下降关系,同时基础中混凝土的造价占比可达70%~85%,从经济性角度出发,独立基础最首要控制的是混凝土的用量而不是配筋率。

There are many disputes about the shear check calculation of Independent Foundation on rock subgrade.Combining with the Code for Design of Building Foundation and the relevant local standards,the Independent Foundations under different foundation bearing capacity are calculated,the analysis indicates that the thickness of foundation is controlled by punching resistance when the bearing capacity of foundation is less than 1200 k Pa and by shear strength when the bearing capacity is more than 1200 kPa,the ratio of the required shear thickness to the punching shear thickness of the Independent Foundation can reach 4 times.At the same time,the economic analysis of the Independent Foundation shows that the total cost of the independent foundation decreases non-linearly with the bearing capacity of the foundation regardless of the thickness of the foundation,and the cost of concrete in the foundation can reach 70%~85%,the primary control of the Independent Foundation is the most important thing in order to the control the cost.