应用圆孔柱扩张理论对预制管桩的挤土效应分析

假定预制管桩在沉桩时的挤土过程是一个有初始孔径的圆柱形孔的扩张过程，初始孔径等于管桩的内径，最终孔径等于管桩外径，应用前人提出的圆孔扩张理论对管桩进行弹塑性分析，得到塑性区半径、土体位移等解析表达式，也对实际工程中常遇到的土塞效应对该理论应用的影响进行了讨论，并对某电厂扩建工程中预制管桩施工引起的土体位移进行计算，通过现场监测，验证了上述解析表达式的合理性，得出可以参考该组解析解来预测预制管桩施工的挤土效应的结论。

Analysis of pile driving effect of precast tubular pile using cylindrical cavity expansion theory

Based on the suppositon of the process of pile driving of Precast Pressure Hollow Pile as the expansion process of cylindrical cavity expansion with initialized aperture and terminal aperture which are respectively equal to inner diameter and external diameter,the expressions of radius of plastical zone,soil displacement are deduced using cylindrical cavity expansion theory;the discussion of plugging effect which appear in the tubular pile costruction offenly is also made.The soil displacements are figured out provoked in the process of precast tubular pile costruction in an electric power plant extend program using the expressions;and the conclusion is come out by checking with data obtained from field monitoring that these expressions are appropriate and could be utilized to forcast the effect of precast tubular pile driving.