桩基静载过程中OFDR温度补偿试验研究

Experimental Study on Temperature Compensation Based on OFDRTechnology in Static Load Test of Pile Foundation

桩基静载试验是一种准确、可靠的桩基承载力测试试验,通过静载试验中桩身变形的测试,有利于分析桩基变形和承载特性.在桩基静载试验过程中,采用光频域反射(OFDR)技术开展桩基变形测试,考虑到温度的影响,对OFDR技术测得应变结果进行了温度补偿.结果显示:在本次试验中,用于温度补偿的温度传感光纤应变值随着桩顶上部加载出现了较大的变化,其原因是光纤传感器与钢筋笼之间绑扎过于紧密.对比进行温度补偿和不进行温度补偿的桩身应变数据,发现不做温度补偿造成的影响不能忽略,因此应变传感光纤测试结果必须进行温度补偿.研究结果可为桩基变形高精度监测提供科学参考.

The static load test of pile foundation is an accurate and reliable test of bearing capacity of pile foundation.The test of pile deformation in static load test is useful to analyze the deformation and bearing characteristics of pile foundation.In the process of pile foundation static load test,the optical frequency domain reflection(OFDR)technology is used to measure pile foundation deformation.Considering the influence of temperature,the strain results measured by OFDR technology are temperature compensated.The results show that:in this test,the strain value of temperature sensing optic fiber sensor used for temperature compensation has changed greatly with the load on the top of the pile,which is due to the tight binding between the optic fiber sensor and the reinforcement cage.Comparing the pile strain data with and without temperature compensation,it is found that the impact caused by without temperature compensation cannot be ignored,the strain sensing optic fiber test result must be temperature compensated.The results can provide scientific reference for high-precision monitoring of pile foundation deformation.