基于BIC准则的基桩声波透射法管距修正研究

Research of the correction of distance between tubes in cross-hole sonic logging of pile based on BIC criterion

为减小声测管管距变化对基桩声波透射法完整性判定的影响,根据实际管距变化特点,提出采用BIC准则确定最小二乘法多项式拟合的阶数,对声测管管距进行拟合修正的具体方法。通过预设管距模拟试验数据,验证了该方法的准确性,并以某实际工程实测数据为例,进行分析拟合修正。修正后的数据能够消除声测管管斜对声速的影响,同时不影响桩身缺陷的判定,证明了声测管管距修正中利用BIC准则确定最小二乘法多项式拟合阶数方法的准确性和可行性。

In order to reduce the influence of the change of the distance between tubes on the judgment of the integrity of pile by cross-hole sonic logging, the specific method of fitting correction of the distance between tubes by using the BIC criterion to determine the order of least squares polynomial fitting is proposed according to the change characteristics of the actual distance between tubes.The accuracy of the method was verified by simulating test data with preset tube distances, and the analysis of the fitting correction was carried out with the actual measured data in an actual project, and the corrected data could eliminate the influence of the wave speed by the non-parallel of tubes, while not affecting the determination of pile defects.The accuracy and feasibility of using the BIC criterion to determine the order of polynomial fitting by the least squares method in the correction of the tubes distance is demonstrated.