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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/917


    Title: 圓錐貫入試驗中砂土音射特性之研究;Study of Acoustic Emission Characteristics in Sand of Cone Penetration Test
    Authors: 葉逸彬;Yi-Pin Yeh
    Contributors: 土木工程研究所
    Keywords: 頻譜分析;錐尖阻抗;均方根音壓;音射發生率;frequency spectrum analysis;acoustic emission rate;root mean square of sound pressure;cone resistance
    Date: 2004-07-05
    Issue Date: 2009-09-18 17:15:30 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 圓錐貫入試驗由於操作簡單、迅速以及擷取資料具連續性,常應用於現地土層研判與土壤分類。本研究利用音射的量測技術,在錐尖加裝一微音器,探討圓錐貫入土體時,伴隨貫入過程所產生的音射。 本研究應用音射於圓錐貫入試驗中,利用圓形土槽與霣降儀等設備,在不同平均粒徑、相對密度和覆土應力條件下進行貫入試驗,同時量測錐尖阻抗與音射訊號。所得資料透過音射計數、均方根計算、快速傅立葉轉換等方法處理後,作一分析與探討。 研究結果顯示,均方根音壓與音射發生率隨平均粒徑變大有明顯增加的趨勢,錐尖阻抗則因平均粒徑的不同會有微小的影響。就不同相對密度與覆土應力條件下之結果顯示,錐尖阻抗會因相對密度或覆土應力之增加而增加,而均方根音壓則因相對密度而變化的幅度相當小,但仍會受到覆土應力的增加而提高,提高的趨勢不太明顯。不同加載方式的情況下,錐尖阻抗與均方根音壓雖有差距,但差距不大。此外,頻譜分析方面,西螺砂於不同試驗條件下,頻譜分布圖之趨勢都很相似,主要頻率分佈約在3~4kHz之間。 Cone Penetration Test (CPT) can be operated easily and quickly. CPT is usually applied in investigation of soil classification and soil layer verification. This research used the technique of sound measurement with a small microphone installed in the cone tip to measure the acoustic signal during the penetration of cone tip. One circular chamber and a movable sand pluviator were used to carry out a series of laboratory cone penetration tests under different relative densities and overburden pressures. The data waa recorded by data acquisition system, and acoustic emission (AE) rate, root mean squar (RMS) of sound pressure and frequency spectrum were analyzed. From the experimental results, the root mean square of sound pressure and AE rate increased with the increase of average grain size. The influences of average grain size on cone resistance ate small. Furthermore, it is shown that the cone resistance would be increased with the increase of relative density and overburden pressure. However, the root mean square of sound pressure is slightly varied with the change of relative density and overburden pressure. Then the difference between the root mean square of sound pressure and cone resistance under different pressure mode is not great. Besides, the analyses of frequency spectrum of Shiluo Sand showed that the major frequency distribution of these tests are located at the range of 3~4kHz.
    Appears in Collections:[土木工程研究所] 博碩士論文

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