| 姓名 | 楊舒慈(Shu-Tzu Yang) | 電子郵件信箱 | s9311610@mail.cyut.edu.tw | |
| 畢業系所 | 營建工程系碩士班(Department and Graduate Institute of Constrction Engineering) | |||
| 畢業學位 | 碩士(Master) | 畢業時期 | 94學年第2學期 | |
| 論文名稱(中) | 利用音波回音法檢測擋土結構物高度之可行性評估 | |||
| 論文名稱(英) | Evaluating the Height of Earth Retaining Structures with Sonic Echo Method | |||
| 檔案 |
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論文使用權限 | 校內外完全公開 | |
| 論文語文/頁數 | 中文/68 | |||
| 摘要(中) | 摘要 近年來有許多擋土結構物因使用年限或疏於維護及排水不良等問題，導致其功能降低，甚至失效，因而造成重大災害。由於這些擋土結構僅有一表面可接觸，且底版都埋設於地面下，故無法直接進行牆體尺寸之量測，當這些擋土牆出現缺陷時通常都不易被察覺，而使用傳統實驗則耗費時間和金錢。故如何利用非破壞檢測方式及數值模擬來檢測出擋土結構物的狀況與尺寸是非常值得探討和研究。 本研究探討能否將基樁之非破壞檢測的理論及技術應用到擋土結構物之檢測，運用ANSYS LS-DYNA二維平面應變模式與三維實體模式比較擋土結構物各部位尺寸對檢測訊號之影響，以評估利用音波回音法（Sonic Echo method）對於擋土結構物高度之可行性。 由本研究結果得到以下結論：利用ANSYS二維平面應變模式與三維實體模式數值模擬，得知音波回音法之檢測訊號會受到3D效應之影響。當接收器擺設位置離敲擊源愈遠時，可減少表面波的影響。而當擋土牆在埋入土壤中後，會造成檢測訊號的衰減，因而增加訊號判讀的困難度。整體而言，若能選擇適當之敲擊源與擺設接收器，以音波回音法評估擋土結構物之高度，仍具相當之可行性。 | |||
| 摘要(英) | ABSTRACT In recent years, failures of several earth retaining structures caused severe damage in property and loss of life in Taiwan. Therefore, evaluating the safety condition of existing earth retaining structures becomes an important task for the civil engineers. However, many of these retaining structures were built long time ago. The design drawing of these structures can no longer be found. It becomes necessary to access the dimensions of these retaining structures through non-destructive testing (NDT) techniques for their safety evaluation. The objective of this thesis is to investigate the feasibility of applying the sonic echo (SE) NDT technique for the evaluation of the height of existing earth retaining structures. Numerical modeling was performed to study the 3-dimensional effects on the measured signal using commercially available ANSYS LS-DYNA finite element software. Field tests were also performed on two earth retaining walls to verify the results from numerical modeling. Results of this study indicate that, in comparison to 1-dimensional structures such as piles, 3-dimensional effects reduce the intensity of signal reflected from the bottom of the structures, thus increase difficulty in determining the arrival time of the reflected wave. However, this difficulty can be overcome by selecting a suitable impact source and arranging the receiver properly. Therefore, it is concluded that the sonic echo method is a very promising technique for the evaluation of the height of existing earth retaining structures. | |||
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