变截面与等截面管桩复合地基承载特性对比研究

为探讨阶梯型变截面管桩复合地基的承载特性及优点,进行了2组等截面管桩复合地基和3组阶梯形变截面管桩复合地基承载性状的室内大比例模型对比试验。试验结果表明:在相同荷载作用下,阶梯形变截面管桩及其复合地基的沉降明显低于等截面管桩及其复合地基的沉降。在管桩材料用量及所处的地质条件相同的情况下,阶梯形变截面管桩单桩刚度明显大于等截面管桩的单桩刚度。阶梯形变截面管桩桩身强度能较好地与桩身轴力变化规律协调。因此,采用阶梯形变截面管桩能充分利用桩身强度,降低桩基造价。

Comparative Research of Bearing Characteristics of the Composite Foundation with Variable Section and Uniform Section Pipe-Piles

To study the ladder-shaped variable section pipe-pile composite foundation load-bearing characteristics, conducted on indoor large scale model contrast experiments the bearing properties of two groups of uniform section pipe pile composite foundation and three groups of ladder-shaped variable cross-section pipe pile composite foundation. The conclusions show that: under the same loading, the settlement of ladder-shaped variable cross-section pipe pile and its composite foundation is obviously less than that of uniform section pipe pile. On the condition that the amount of pipe pile materials and geological conditions are the same, the single pile stiffness of ladder-shaped variable cross-section is significantly greater than the stiffness of uniform section single pile. The strength of ladder-shaped variable cross-section pipe pile is coordinated with the variation of axial force of pile shaft. Therefore, adopting ladder-shaped variable cross-section pipe pile makes full use of pile strength and reduces the cost of the pile.