本研究之目的在探討以敲擊回音法檢測錨筋長度之非破壞試驗的成效。工程技術不斷的發展，使錨筋類型之結構更廣泛地應用在工程加固及支撐上，如植筋、岩栓及地錨等，皆屬於此種結構。藉由埋入長條型之鋼桿與原結構體充分錨定，其高抵抗拉力之力學特性，穩固原結構體或作為兩種材料之連接構件。錨筋之埋設長度不足或錨固不完整時，可能使錨筋無法達到設計功能，使錨筋系統產生破壞。研究方法除了分析以敲擊回音試驗對現地埋設之錨筋長度與錨固完整性所得之檢測訊號外，同時以有限元素程式對錨筋結構之應力波動訊號作數值模擬分析，以驗證敲擊回音法之檢測成果。研究結果顯示，不同之錨筋長度與錨固完整性，在錨筋長度不同時，其應力波到之反射時間很明顯的產生差異；當錨筋錨固完整性不同時，對應力波之波形會產生特殊的反射。由數值分析所求得之結果，與敲擊回音試驗之檢測結果大致吻合，可見以敲擊回音法檢測錨筋之長度與錨固完整性確實可行。The purpose of this thesis is to investigate the application of the impact-echo method to evaluation of the embedded length of rock bolts. Rock bolts have been popularly applied to keeping steep slope stable. When the embedded length is insufficient, the function of rock bolts is questionable and this may cause the failure of the system. In this thesis, both numerical analyses and experimental studies were performed to understand the behavior of stress wave propagation in a rod with/without surrounding mortar. Signals caused by the arrivals of stress waves were analyzed in both the time and frequency domains. The results obtained from numerical analyses show that the spectral analysis is much easier than the time-domain waveform analysis especially in the case of steel rods surrounded by mortar. The apparent wave speed of the rock bolts is largely affected by the thickness and the wave speed of the surrounding mortar. The experimental results verify the numerical results. It has been proved that evaluating the embedded length of rock bolts using the impact-echo method is really feasible.總目錄
中文摘要Ⅰ
英文摘要Ⅱ
總目錄Ⅲ
本文目錄Ⅲ
表目錄Ⅴ
圖目錄Ⅵ
本文目錄
第一章 緒論1
第二章 應力波動理論與錨筋檢測文獻回顧3
2-1 應力波動理論3
2-1-1 混凝土之波傳原理3
2-1-2 幾何形狀對波速的影響4
2-1-3 敲擊回音試驗之波速檢測原理4
2-1-4 頻譜解析度的探討6
2-2 錨筋檢測之文獻回顧7
2-2-1 錨固長度之檢測7
2-2-2 錨固波速與錨固品質之檢測8
2-2-3 振動頻率與工作載重應力之檢測9
2-3 研究動機與目的9
第三章 數值模擬分析11
3-1 ANSYS/LS-DYNA模組11
3-2 參數設定11
3-3 錨筋模型分析之編號13
3-4 數值分析13
3-4-1 錨固層厚度與長度對波速影響13
3-4-2 錨固層材料性質對波速的影響14
3-4-3 錨固層百分比對波速的影響15
3-4-4 錨固層不完整對波速之影響17
3-4-5 現地模擬18
3-5 檢測錨固不完整位置之探討20
3-6 數值分析之結果探討21
第四章 試驗規劃23
4-1 試體規劃23
4-2 儀器設備24
第五章 試驗結果與討論26
5-1 位移接收器波速之量測26
5-1-1 位移接收器時間領域之量測26
5-1-2 位移接收器頻譜領域之量測28
5-2 加速規接收器波速之量測29
5-3 數值分析與現地試驗之比對30
第六章 結論與建議32
6-1 結論33
6-2 建議33
參考文獻3
