大面积荷载下超长水泥土搅拌桩承载性状的有限元分析

Finite Element Analysis of Bearing Property of Very Long Cement-Soil Mixed Columns Under Large Surface Loads

运用有限元分析程序,重点分析了荷载在超长水泥土搅拌桩桩身的传递规律,桩身强度、复合地基面积置换率、上部荷载作用面积、桩顶垫层刚度及桩径等参数对桩身附加应力的影响。计算结果表明,超长水泥土搅拌桩在桩身强度较高或大面积荷载情况下,桩顶荷载可以传递到桩体下部,水泥土搅拌桩的“有效桩长”概念宜进行调整;大面积荷载下宜采用刚度较大的垫层(如碎石或土工复合垫层),水泥土强度有保证时,宜采用低面积置换率等。

Finite element analysis software is applied to emphatically analyze the pattern of transmission of load along the body of very long cement-soil mixed columns and the influence of parameters like the strength of column shaft, area displacement ratio of a composite foundation, area of loading from the top, stiffness of cushion on top of columns and diameter of columns upon the additional stress in the column body. The result of the analysis indicates that when the strength of the very long cement soil mixed columns is very high or the load is applied on a vary large area, the loads from the top can be transmitted down to the lower part of the columns and it is advisable to modify the concept of ＂effective length＂ of cement-soil mixed columns. Cushion layer with higher rigidity （such as aggregate cushions or geosynthetics cushions） should be used when under the load of a large area. It is also advisable to adopt a lower area displacement ratio when the strength of the soil-cement mixture is warranted.