复杂地质环境下超长深水钻孔灌注单桩承载性能

Single pile bearing performance of super-long deep water drilling in complicated geological environment

超长深水钻孔灌注桩荷载传递机理较为复杂,尤其是在复杂地质环境下,研究其承载性能对该类桩优化设计、施工具有重要作用。结合试桩自平衡静载试验资料,应用有限元软件GTS分析了超长深水钻孔灌注桩单桩在不同风化程度构造岩交替分布地层中的承载能力,其中土体本构关系采用Mohr-Coulomb模型,桩土界面设置接触单元,利用梁单元对桩进行数值模拟。结果表明:静载试验的Q-S曲线实测值和计算值吻合较好,桩的承载性能良好;桩端沉降在桩侧摩阻力发挥一定程度时开始显现,现场桩底沉渣清除较彻底;桩的轴力和桩侧摩阻力随深度变化受交替分布地层影响明显,并呈现一定规律。

The load transfer mechanism of super long deepwater bored pile is complicated, especially in complex geological environment,and its bearing performance has an important effect on the optimization design and construction of the pile.Based on the experimental data of self-balanced static load test,the load-bearing capacity of super-long deep water drilling single pile in different geostatistical tectonic-rock alternating strata is analyzed by finite element software GTS.Using Mohr-Coulomb model as constitutive relation of soil,and setting contact unit on the pile soil interface,the beam element is used to simulate the pile.The results show that the Q-S curve of the static load test is in good agreement with the calculated value,and the bearing capacity of the pile is good. The pile tip settlement begins to show a certain extent when the friction resistance of pile side is played. The axial force of pile and lateral friction of pile are obviously influenced by the change of depth,and show a certain rule.