特高压输电线路桩基础低应变法检测适用性探讨

Study on the applicability of low strain method for pile foundat ion testing of ultra-high voltage transmission lines

特高压线路桩基础通常为直径在800mm以上大直径桩,低应变法在应用于特高压线路工程桩基础检测时存在一定局限性。通过现场试验分析了桩身尺寸、激振位置和测振位置对低应变法检测结果影响,探讨了低应变法对桩身缺陷识别的准确性。结果表明:特高压线路桩基础可以采用低应变法进行桩身完整性检测,其对桩长识别准确性较高,对桩身缺陷识别准确性相对声波透射法低。改变激振位置和测振位置会对桩身波速产生影响,桩身波速随激振点与测振点间距增大而增大。激振位置和测振位置的选择不必拘泥于国内外有关规范的规定,可根据现场实际情况灵活选择。研究成果可以为低应变法用于特高压线路工程桩基础检测提供参考和借鉴。

The low strain method has some limitations when applied to the pile foundation inspection of ultra-high voltage(UHV)line projects,as pile foundations are usually 800 mm in diameter or larger.Through the field test analysis of the pile body size,excitation position and location of vibration measurement on the low strain detection results,to discuss the accuracy of the low strain method of pile body defect identification.The results show that the low strain method can be used for pile integrity testing of UHV line pile foundations,and its accuracy is higher for pile length identification and lower for pile defects identification than the acoustic transmission method.The pile body wave speed increases with the distance between the excitation point and the survey point.The choice of excitation position and survey position need not be limited by the relevant domestic and international specifications,but can be chosen flexibly according to the actual situation.The research results can be used for the low strain method for ultra-high voltage line engineering pile foundation testing to provide reference and reference.