一阶变截面桩与等截面桩对比试验研究

Comparative Experimental Study Between First-Order Variable Di ameter Piles and Equal Diameter Piles

为研究一阶变截面桩在竖向荷载下的变形和承载特性,选取一组一阶变截面桩与等截面桩进行对比静载试验。试验分析对比了桩身轴力分布曲线、桩端应力及变截面处应力变化曲线、桩侧摩阻力沿桩身分布曲线和桩顶P-S曲线。结果表明:一阶变截面桩单位体积材料发挥效率更高,较等截面桩发挥效率提高约8%;变截面桩荷载传递仍然以侧摩阻力为主,当变截面处土层较弱时,随着荷载的增大变径处土层发生软化,变径处阻力趋于稳定,发挥作用有限。

In order to study the deformation and bearing characteristics of first-order variable diameter pile under vertical load,a set of first-order variable diameter piles and equal diameter piles were selected for comparative static load test. This test made an analysis by comparing the axial force distribution curve of the pile body,the stress at the pile end and the stress variation curve at the variable section,the pile side frictional resistance along the pile body distribution curve and the pile top P-S curve. The results showed that the first-order variable-section piles had higher efficiency per unit volume of material,8% higher than that of equal diameter piles. The load transfer of the variable-section piles was still dominated by the lateral friction. When the soil layer was weak at the variable section,it softened at the variable diameter as the load increased,and the resistance at the variable diameter tended to be stable,with limited function.