混凝土層狀結構內層接合不同材料之轉換函數反應

Chaoyang University of Technology Institutional Repository > 理工學院 > 營建工程系 > 博碩士論文 > Item 310901800/28052

Please use this identifier to cite or link to this item: http://ir.lib.cyut.edu.tw:8080/handle/310901800/28052

Title:	混凝土層狀結構內層接合不同材料之轉換函數反應 Using the Simulated Transfer Function Obtained from theImpact-Echo Method to Evaluate the Material Properties of Substrate Layer for a Laminate Concrete Structure
Authors:	黃愛惠 Huang, Ai-Hui
Contributors:	營建工程系碩士班鄭家齊 Chia-Chi Cheng
Keywords:	轉換函數;聲阻係數 none
Date:	2004-12-31
Issue Date:	2016-01-23 14:18:20 (UTC+8)
Abstract:	本研究為探討混凝土層狀結構內層接合不同材料之轉換函數反應，由於敲擊回音法檢測時所得到之反應頻譜，各尖峰振幅值會隨注入的能量與地面接觸時間不同而有相當大之差異，所以實驗的結果需使用轉換函數才能作定量之評估。利用材料聲阻係數的改變可推斷在混凝土層後是否有掏空、積水、或地層變動破碎的現象或是推斷地質狀況。發展這種非破壞檢測的方法，對於不適合鑽心的隧道砌襯、採礦豎坑以及河海壩堤防的評估有一定的價值。本研究是由下列兩方向加以討論：(一) 探討實際檢測不同聲阻係數比值之複合版(下層為環氧樹脂、石膏或低強度水泥砂漿)與轉換振幅值之關係。(二) 由數值模擬複合版不同聲阻係數比值與下層厚度推導聲阻係數與轉換振幅的關係。實驗結果顯示，不同次敲擊於同一試體所得之頻譜，其介面深度尖峰振幅值可能相差甚遠，經過轉換後，其轉換振幅值相當接近，證明經過轉換後，同一界面反射所得之轉換函數頻譜中振幅值能夠穩定。將實驗結果代入先前發展之版厚振幅值與版厚關係式，可得到版厚尖峰振幅為1.571。實驗所得之版厚尖峰振幅1.39，所得之尖峰振幅誤差為11.5％。數值模擬推導出Z2/Z1比值與轉換振幅值之關係式，可用來預測上層為10公分版厚，Z2/Z1比值之轉換振幅。實驗與數值模擬之結果振幅強度順序均為環氧樹脂>石膏>低強度水泥砂漿，呈現極高之相關性。 This dissertation is a study for using the simulated transfer function obtained from the impact-echo method to evaluate the material properties of substrate layer for a laminate concrete structure. The peak amplitude in impact-echo spectrum may be varied by the energy and the contact time produced by the impact force. The experimental result needs to be transformed into transfer function for quantitative evaluation. The different acoustic impedance (Z) in substrate layer such as air, earth or water may lead to different spectral amplitude corresponding to concrete layer. Thus it is possible to non-destructively evaluate the substrate geological state for tunnel, mining pit or dike which is unfit for coring. The purpose of this study is as following. 1. Explore the connection between the experimental spectral amplitude corresponding to the interface of a composite concrete plate in transfer function and acoustic impedances for different substrate layers such as epoxy, gypsum and low-strength concrete.2. Using numerical simulation to study the relationship between ratio of acoustic impedance for substrate and concrete layer (Z2/Z1) and the spectral amplitude corresponding to the interface in transfer function. The thickness of substrate layer is also concerned as a variable. The experimental results show, for various tests applying on the same specimen, the spectral amplitude corresponding to depth of the interface may differ greatly. After transformation, the amplitudes in the transfer functions become stable. Take the experimental parameters into the previously developed equation for relating peak-amplitude to the thickness of a pure concrete plate without substrate layer. The predicted amplitude for the 10 cm-thick plate is 1.571, which has 11.5% error to the average experimental amplitude, 1.39. The relation between Z2/Z1 ratio and spectral amplitude corresponding to the interface in transfer function developed by numerical model can be used for predicting the experimental results for composite plates. Comparing the numerical and experimental results of composite plates with epoxy, gypsum, low strength mortar substrates, the order of spectral amplitudes values are epoxy >Gypsum > low strength mortar. The correlation is high.
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