超大直径空心独立复合桩是由空心桩、外围水泥搅拌桩和桩周注浆土体共同承载的新型桩基础。为确定该新型复合桩在安徽省江淮地区不同工况下的竖向极限承载力,引入等效弹性模量,提出了超大直径空心独立复合桩承载力计算方法;在此基础上,对比了数值计算和理论计算结果,提出能综合反映桩身尺寸影响的复合桩竖向极限承载力公式。研究结果表明:引入等效弹性模量这一概念将非均质的弹性模量等效为均质的弹性模量,将显著降低超大直径空心独立复合桩竖向极限承载力计算的复杂性,桩径和桩长对超大直径空心独立复合桩的竖向极限承载力产生较大影响;引入综合考虑桩径和桩长的影响因子D_L,使得改进的理论公式更加可靠。计算方法为今后类似工程的桩基承载力预估提供了理论参考。

The hollow independent composite pile with super-large diameter is a new type of pile foundation jointly carried by a hollow pile, an external cement mixing pile, and grouting soil around the pile. Numerical computation and theoretical calculation were performed in this paper to determine the vertical ultimate bearing capacity of this type of pile under different conditions in Jianghuai area of Anhui Province. Introducing the concept of equivalent elastic modulus to equate the non-homogeneous elastic modulus as the homogeneous elastic modulus will significantly reduce the complexity of calculating the vertical ultimate bearing capacity. Pile diameter and pile length have great impact on the vertical ultimate bearing capacity. The impact factor D_L which takes pile diameter and pile length into consideration makes the modified theoretical formula more reliable.