基于光纤布拉格光栅传感技术的不同桩径静压桩贯入特性研究

Penetration Characteristics of Jacked Piles with Different Pile Diameters Based on Fiber Bragg Grating Sensing Technology

为了探索光纤布拉格光栅(FBG)传感技术在针对不同桩径静压桩贯入特性测试中的适用性,分别采用拉伸试验机、砂标法标定FBG应变传感器、FBG压力传感器,传感器线性度及测试精度较好,并配合不同桩径的模型桩在大尺寸模型箱中进行了室内静压沉桩试验。试验结果表明:FBG传感技术能够较好地满足不同桩径静压桩贯入特性的测试要求,所用传感器具有较高的线性度、灵敏性,经验证测试数据可靠,传感器安装方法可行;所用传感器能够对模型桩贯入过程中的压桩力、桩端阻力、侧摩阻力、桩身轴力、单位侧摩阻力进行动态、精准的监测,较为直观地反映了不同桩径的模型桩在静压过程中的贯入特性差异及变化规律。

To explore the applicability of the fiber Bragg grating(FBG)sensing technology in the penetration characteristics of jacked piles with different pile diameters,FBG strain and pressure sensors were calibrated using a tensile testing machine and sand calibration method,respectively.The linearity and testing accuracy of sensors are found to be good.Further,the jacked pile test of the test model with sensors was conducted in a large model box.Experiment results indicate that the requirement for FBG sensing technology to test the penetration characteristics of jacked piles with different pile diameters can be satisfied.FBG sensors demonstrate high linearity and sensitivity;moreover,the test data are reliable,and the installation method of the sensor is feasible.During the penetration process,FBG sensors can dynamically and accurately monitor the pile driving force,pile end resistance,side friction resistance,pile axial force,and unit side friction.Moreover,they can reflect the differences and change rules of penetration characteristics of the model piles with different pile diameters in the process of isostatic pressing.