基于光纤监测钻孔灌注桩承载性能研究

Research on bearing capacity of bored pile based on optical fiber monitoring

为了研究湖州软土地区钻孔灌注桩侧摩阻力的发挥,采用光纤监测技术获取试桩在现场载荷试验中桩身轴力、桩侧摩阻力及桩顶沉降位移。通过对监测数据分析,结果表明:试验荷载下试桩为摩擦桩,摩擦桩的承载力提高主要由桩侧摩阻力决定,且随着桩顶荷载的增加各土层的侧摩阻力相应增加;上部的黏质粉土层侧摩阻力随着加载等级的增加相应增加并趋于极限,其他土层侧摩阻力也逐渐增加,其中桩承载力主要由中部粉质黏土层的侧摩阻力提供;在桩顶荷载较小的情况下,桩顶荷载由上部的土层侧摩阻力承担,轴力未传递到下部土层,下部土层对桩身侧摩阻力无发挥,桩端阻力为零。

In order to study the lateral friction of bored pile in Huzhou soft soil area,the optical fiber monitoring technology was used to obtain the pile axial force,pile side friction and pile top settlement displacement in the field load test.Through the analysis of the monitoring data,the results show that the test pile was friction pile under the test load,the bearing capacity of friction pile was mainly determined by the pile side friction resistance,and the side friction resistance of each soil layer increases with the increase of pile top load.The lateral friction resistance of the upper viscous silty soil layer gradually approached the limit with the increase of the loading grade,and the lateral friction resistance of the other strata rock and soil mass gradually increased with the increase of the loading grade.During the whole test process,the silty clay stratum in the middle gradually played the main role.When the pile top load was small,the pile top load was borne by the lateral friction of the upper soil layer,and the axial force was not transferred to the lower soil layer.The lower soil layer didn't exert the lateral friction of the pile,and the pile tip resistance was zero.