厚壁蝶型弹簧用于基桩高应变测试的初步研究

Preliminary Study on Thick-wall Butterfly Spring Used for High Strain Test of Foundation Pile

针对基桩高应变动力试桩法应力测试环节中存在的混凝土非线性造成应力测试失真问题,借助有限元软件ABAQUS/Explicit对Ф500×Ф253×27×38-C3型厚壁碟簧进行仿真,计算分析了外力荷载下蝶型弹簧的变形和主应力,得到了厚壁蝶型弹簧初步满足受力变形的结论。基于此提出选取厚壁蝶型弹簧放置于桩顶作为高应变替打器,通过测试蝶型弹簧的变形来计算冲击碰撞过程中的应力,可以有效避免传统高应变测试过程中由于混凝土开裂或出现严重塑性变形导致力信号失真的情况。

In view of the distortion of stress test caused by concrete nonlinearity in high strain dynamic test method of foundation pile,tsimulates the thick wall butterfly spring of type Ф 500×Ф 253×27×38-C3 with the help of finite element software ABAQUS/Explicit,calculates and analyzes the deformation and principal stress of butterfly spring under external force load,and obtains the conclusion that the thick wall butterfly spring meets the stress deformation preliminarily.Based on this,the thick wall butterfly spring is selected to be placed on the top of the pile as a high strain displacement device,and the stress in the process of impact collision is calculated by testing the deformation of the butterfly spring,which can effectively avoid the distortion of stress signal caused by concrete cracking or severe plastic deformation in the traditional high strain testing process.