| 姓名 | 莊棓景(Pou-Ching Chuang) | 電子郵件信箱 | s8711009@ms5.url.com.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 | 92學年第2學期 | |
| 論文名稱(中) | 沉泥質砂土中傾斜錐形擴座地錨之三向度分析 | |||
| 論文名稱(英) | Three Dimensional Analysis on the Inclined Blade-Underreamed Anchors in Silty Sand | |||
| 檔案 |
請遵守中華民國著作權法之相關規定，切勿任意重製、散佈、改作、轉貼、播送，以免觸法。 |
論文使用權限 | 校內外完全公開 | |
| 論文語文/頁數 | 中文/257 | |||
| 摘要(中) | 為探討沉泥質砂土中傾斜錐形擴座地錨之錨碇行為，本文使用SHSE模式(Strain Hardening-Softening
and Volume Expansion
Model)配合FLAC3D軟體進行傾斜錐形擴座地錨之三向度分析，並以現場試驗結果驗證數值分析結果之正確性。 由研究過程發現，傾斜錐形擴座地錨之錨碇力主要係來自摩擦力，面承力貢獻較少。在相對密度Dr＝30%的沉泥質砂土中，發揮尖峰摩擦力所需之位移量約為50%Dt(Dt：地錨鑽孔直徑)，達殘餘摩擦力之位移量約為100%Dt。本研究發現地錨的面承力並無明顯的尖峰值，經由降伏面承力之定義，可得知發揮地錨降伏面承力Qqy所需之位移量約為25%Dt，且不太受擴孔直徑與地錨傾斜角之影響。 無論是增加埋入深度、覆土深度、錨碇段長度或擴孔直徑皆可提升傾斜錐形擴座地錨之錨碇力，其中以增加錨碇段長度來增加錨碇力之效果最佳。由數值分析發現，不同傾斜角度下，地錨之面承力係數Nqu隨埋入深度或覆土深度的增加而減少，但不隨錨碇段長度的增加而改變。在不同傾斜角度下，改變埋入深度、覆土深度或錨碇段長度時，其尖峰摩擦力下之側向土壓力Kf均小於被動土壓係數，但大於靜止土壓力係數，且Kf值隨傾斜角度的增加而減少。由摩擦應力之分佈曲線得知，當地錨錨碇段長度達15m時，錨碇段周圍土壤並無明顯的漸進式降伏行為，因此在錨碇段15m範圍內，增加錨碇段長度可有效地增加錨碇力。此外，當受到現地環境所限制而無法增加錨碇段長度時，可利用增加擴孔直徑的方式提升錨碇力。 | |||
| 摘要(英) | A strain
hardening-softening and volume expansion model named “SHSE” and FLAC3D
software were quoted to study the anchorage behavior of inclined conical
anchors in silty sand. A field test program was conducted to verify the
applicability of the numerical program as well. It was found that the friction force dominates the anchorage capacity of a conical shaped anchor, the end resistance efforts not much contribution. Of anchors installed in silty sand with relative density Dr of 30%, an anchor displacement of 50% Dt (Dt is the diameter of borehole) is need for the shaft friction reaches peak value, shaft friction reaches residual state at an anchor displacement of about 100% Dt. No peak value of end resistance can be found in this study. According to the definition of yielding end-resistance, the yielding end-resistance develops at an anchor displacement of about 25% Dt. The underreamed diameter and inclination angle lightly affect on disolacement of yielding end-resistance. When embedded depth, overburden depth, fixed length or underreamed diameter of an anchor increased, the anchorage capacity also increased. Increasing fixed length should be the optimum method to increase the anchorage capacity. According to the numerical results, the end bearing coefficient Nqu decreases with overburden depth H and embedded depth Z underdifferent inclinatian angle α of an anchor. The Nqu cann’t be change by changing fixed length. The coefficient of lateral earth pressure Kf was less than the coefficient of passive earth pressure Kp; however, it was greater than the coefficient of earth paessure at rest K0. It can be seen from the friction stress distributes along fixed end, when fixed length is less than 15m, no progressive failure on friction resistance has been observed along the surface of the conical shaped anchor; therefore, the ultimate load could increases with fixed length. Besides, what if it may not to install a long conical shaped anchor due to the limitation of property boundary, increasing the underreamed diameter also could increase the ultimate load of an anchor. | |||
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