含樁帽模型群樁之完整性檢測

現今的社會中，非破壞檢測(Non-Destructive Testing, NDT)技術已成功的被應用於新建單樁的完整性檢測，但對於既有含樁帽基樁之完整性檢測經驗仍然缺乏，主因在於受到樁帽效應的影響；既有的基樁時常以含樁帽群樁之方式呈現，因此使檢測訊號變得複雜，導致完整性檢測之困難。為解決老舊橋梁的安全性檢測所產生之問題，因此促成本研究之動機。本研究利用音波回音法(Sonic Echo, SE)、脈波反應法(Impulse Response, IR)及超震波法(Ultra Seismic, US)對含樁帽模型群樁進行完整性檢測。試驗用之模型群樁已在其內部預設大小、位置、型式不同之缺陷，探討此三種常用基樁完整性檢測技術在含樁帽效應下是否能準確的判斷出缺陷大小、位置與型式，並探討以脈波反應法中力學導納曲線的初始直線斜率判斷基樁完整性之可行性。由試驗結果得知：在樁帽效應影響下，SE法與IR法仍能區分完整樁及斷樁，惟所獲得樁長或斷樁位置之誤差較不含樁帽支模型樁明顯增大，且訊號判讀更加困難，而US法在接收器位置擺設恰當之情況下，亦可明確判斷完整樁與斷樁；在脈波反應法中的初始直線斜率判斷基樁完整性是可行的，但仍需做深入探討。

關鍵字

超震波；脈波反應；音波回音；完整性檢測

並列摘要

The non-destructive testing (NDT) methods have been successfully applied to the integrity testing for newly-built pile. But experience with integrity testing of piles with pile cap is still lacking. The main reason is the effect of pile cap. The existing piles are often presented in the form of group pile with pile cap, thus making the testing signal very complex, and causing difficulties for integrity testing. In this study, sonic echo (SE) method, impulse response (IR) method and ultra-seismic (US) method were used for integrity testing of model piles with pile cap. The model piles contain defects of various size, location, and type. The objective of this study is to investigate the feasibility of these three NDT methods in detecting the defects in the model piles. Results of these tests indicate that: even with the influence of the pile cap, SE method and IR method can still distinguish between intact pile and piles with major defects, but error in pile length are greater than piles without pile cap. Furthermore, the signal is more difficult to interpret. If the receiver is placed properly, the US method can clearly determine the intact pile and broken pile.