塑膠管長期管剛性加速試驗

論文摘要內容：本研究選擇本國地下管線常用之塑膠管分別為PE波紋管、PVC及ABS推進管進行長期管剛性試驗(long-term pipe stiffness, LTPS)並使用加速過程法(Rate Process Method, RPM)進行加速管剛性試驗，選擇管徑為300 mm管線。長期管剛性試驗以ASTM D2412進行試驗，以各試驗管材的傳統管剛性試驗(Conventional Pipe Stiffness, CPS)所得之初始管剛性（IPS），並以初始管剛性荷重以百分比由高至低逐漸下降，作為試驗之荷載，每組試驗達管材內徑5.00 %變形率後終止。加速管剛性試驗，係以管材熱變形溫度為原則增加試驗之溫度並於於高溫烘箱中進行試驗，加速管材隨時間之變形率，以縮短試驗時間。傳統管管剛性結果為1905 kN/m/m、1233 kN/m/m，244 kN/m/m，分別為PVC管、ABS管，PE波紋管。長期管剛性試驗結果顯示，以相同管徑300 mm管材在相同百分比荷載下比較管剛性與變形率之關係，結果變形率與管剛性強度相反，推斷變形率與管剛性並非呈線性遞減，結果可知，塑膠管的變形行為受到其材質、管徑、荷載等條件影響。由RPM試驗結果得知300 mmABS(II)在同樣70％IPS荷載下，試驗溫度由40℃提高至80℃試驗完成時間為由432小時縮短至0.28小時，由此可知提高試驗的溫度能有效的加速管材變形速率，在達到相同變形率條件下，試驗溫度與試驗間成對數反比之關係。試驗結果顯示，管材之管剛性於時間對數座標上其遞減趨勢大致呈反S曲線，並以不同溫度之試驗結果參考Bragaw建議之函數並建立各管材推估公式，公式由常數A、溫度T與應力P組成，常數項控制各溫度推估曲線在對數座標圖上之斜率與間距，其溫度T為絕對溫度加上試驗溫度，最後求得logtf為各溫度與應力於到達管內徑5%變形量之時間，其推估結果顯示各溫度與應力到達5%之時間在對數座標圖上的趨勢有相似且平移之情況。本研究亦使用指數函數e模擬管材變形趨勢，其公式中D(t)到達管內徑5%變形量之時間，Ds與Df分別為模擬管材變形之起始點與終點其常數亦控制其管材變型曲線之斜率緩急，其模擬試驗中之管材變形量之趨勢相當吻合，並且能推估到達管內徑5%變形量之時間。利用函數用於推估管徑300mm PVC及ABS管與PE波紋管於各溫度下之LTPS的變形趨勢並得到了良好的結果。證明可應用RPM法作為推估塑膠管長期管剛性折減之加速推估機制，並可建置塑膠管加速長期管剛性推估模式。關鍵字：長期管剛性試驗(LTPS)、加速過程法(RPM)、塑膠管

關鍵字

長期管剛性試驗(LTPS) ；加速過程法(RPM) ；塑膠管

並列摘要

The Contents of Abstract in this thesis: Conventional long-term and Rate Process Method (RPM) procedures were used to investigate the long term pipe stiffness of plastic pipes. HDPE corrugated drainage pipe, PVC and ASB jacking pipes were used in the study. The nominal diameter of the test pipes is 300 mm. ASTM D2412 standard test method with the parallel-plate loading mechanism was used in the study. The load associated with 5% pipe diameter deflection according to the standard test method was determined as the Conventional Pipe Stiffness (CPS) for each test pipes. Long term pipe stiffness tests were performed under various percentage of the CPS load for each test pipes. Each test was terminated as the pipe deflection reaching 5% of its diameter. The associated loading and time were used to calculate the time dependent long-term pipe stiffness value (LTPS) for the test pipes. High temperature procedure was used in the accelerated pipe stiffness tests to predict the long term load deflection relationship of plastic pipes in order to reduce the time for the tests. The results of the study indicted that the conventional pipe stiffness of the test pipes are 1905 kN/m/m, 1234 kN/m/m, and 244 kN/m/m for PVC, ASB, and HDPE-C pipes, respectively. HDPE-Corrugated and PVC pipes showed the highest and lowest pipe deflection rate under constant load compared with others. The pipe deflection would decrease as increasing the pipe stiffness. Generally, S-type long-term pipe deflection curve on a semi-log time scale was observed. Logarithm can be used to formulate the pipe deflection versus time under constant load. Long-term pipe stiffness (LTPS) decreased as the time elapsed on a semi-log scale. LTPS is a function of pipe material properties, pipe geometry, SDR value, and external loading conditions. The results of high temperature RPM indicated that the required time to reach 5% pipe diameter deflection decreased as the temperature increased on a semi-log time scale. Bragaw’s equations were formulated the long-term pipe stiffness with time, temperature, and Conventional Pipe Stiffness (CPS) for the test plastic pipes. Keywords: Long-term pipe stiffness, Rate Process Method (RPM), Plastic pipe.

並列關鍵字

Long-term pipe stiffness ； Rate Process Method (RPM) ； Plastic pipe

參考文獻

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