桩侧注浆嵌岩抗拔桩承载性状原位试验研究

Field tests of the performance of side-grouting uplift rock-socketed piles

为了研究桩侧注浆抗拔桩的承载性能,基于桩侧注浆嵌岩抗拔桩的现场足尺载试验,对比分析桩侧注浆和未加固浆荷载-位移变化规律,分析桩身轴力传递规律与桩侧阻力发挥性状,并采用双曲线、指数函数和幂函数分别对试桩荷载-位移曲线进行拟合分析。试验结果表明,桩侧注浆可显著提高嵌岩抗拔桩的极限承载力,采用指数函数对桩侧注浆嵌岩抗拔桩的荷载位移曲线拟合吻合较好;注浆与未注浆嵌岩抗拔桩的桩身轴力均随深度逐渐减少,桩端处轴力始终为0;桩侧阻力的发挥是一个异步过程,而桩侧注浆能够有效改善桩侧土层摩阻力,增强了桩周土体侧阻力发挥效应。

To investigate grouting effects of side-grouting piles of uplift rock-socketed piles,in-situ static load tests were conducted on the basis of side-grouting rock-socketed pile.The response of load-displacement of grouting and un-grouting uplift rock-socketed piles was performed.The behaviors of axial force transfer and skin friction of piles are researched.Moreover,the hyperbolic function,exponential function and power function are used of fit the load-displacement curves of the test piles,respectively.The results show that the side-grouting can greatly improve the bearing capacity of rock-socketed piles,and that the exponential function can be used fit the curves well.The axial force of side-grouting and non-grouting rock-socketed pile both decrease gradually with depth and the measured end axial forces of piles are near zero.The side friction is an asynchronous process,and the side-grouting can be effectively improved the side friction and the effect of the side friction of the pile.