基于FBG传感技术的砂土中管桩土塞效应测试

为了探索光纤光栅传感技术在双壁开口管桩贯入过程中土塞效应的适用性,采用增敏微型光纤光栅传感器,在大尺寸模型试验箱中进行了静力压桩下双壁开口模型管桩的土塞效应测试。试验模型管桩高为1 065mm,厚度为20mm,模型材料选用铝管,管桩贯入到密实状态的砂土中。沿内、外管对称布置26个光纤光栅测点,通过改变桩靴形式,采集贯入过程土塞高度和应变数据,分析了不同桩靴形式下管桩的土塞高度、桩内和外侧摩阻力等贯入特性,研究了静压作用下管桩的土塞效应。结果表明,光纤光栅适用于双壁开口管桩的土塞效应测试要求,能准确体现管桩的应变大小及桩内、外侧摩阻力等贯入特性。

Test Research on Plugging Effect of Open Pipe Pile in Sand Based on FBG Sensing Technology

In order to explore the applicability of fiber grating sensing technology in the process of pipe pile penetration for sandy soil, plugging effect test of the double-walled opening model pipe pile under static pressure pile is tested in a large-scale model test chamber, using a sensitized micro-fiber grating sensor. The height of the experimental model pipe pile is 1065 mm, and the thickness is 20 mm. Moreover, the material of model tubes is aluminum and the pipe pile penetrates into the compact sand. 26 fiber Bragg grating (FBG) measuring points are arranged symmetrically along the internal and external pipes. The plugging height and strain data are collected by changing the shape of the pile shoe. The plug height, medial and lateral friction and other penetrating characteristics of the pipe pile are analyzed, and the plugging effect under static load is studied. The results show that FBG is suitable for the test of plugging effect of double-walled open pipe piles, which can accurately reflect the strain of pipe piles and penetration characteristics of the medial and lateral friction.