本研究在探討張應變對扁絲織布過濾特性之影響，使用GTBR、GTBS、GTG及GTW等四種扁絲織布，其中GTBR、GTBS、GTG以線寬相同之絲線經緯向交織而成，GTW之經線由粗細不同有規則排列編織而成，且較細絲線呈現皺摺。分別對四種織布於未伸張及張應變2.5%、5%、7.5%、10%時，進行變水頭透水速率量測、濕篩法開孔徑量測及改良式ASTM D5102之GR試驗儀；以連續變換水力坡降進行土壤-地工織物系統坡降比試驗，以探討織物於未伸張及張應變下之坡降比值及滲流量變化。試驗結果以織物有效開孔徑、透水速率變化、GR值、系統滲流量及土層滲透係數進行比較與討論。 織物開孔徑量測與透水速率試驗結果顯示，三種經緯向絲線線寬相同交織而成之織布的開孔徑皆隨張應變增加而增加，有效開孔徑與張應變呈凹口向上之曲線關係，另一種由粗細不同經線有規則排列編織而成之織布(織布W)的開孔徑隨張應變增加而降低，有效開孔徑與張應變呈凹口向下之曲線關係。 織物開孔徑(O95、O50、O15)與透水速率之相關性結果顯示，GTBR、GTBS及GTG於張應變7.5 %以內，隨張應變增加的改變幅度相似，超過張應變7.5 %以後，透水速率改變幅度比開孔徑(O95、O50、O15)來的大；GTW之織物開孔徑與透水速率隨張應變之改變幅度無直接相關性。 坡降比試驗結果顯示，在低水力坡降時，四種織布皆隨張應變增加而無明顯的GR值改變，在中、高水力坡降時，GTBR及GTBS之GR值皆隨張應變增加而逐漸降低；GTG於前半段GR值隨張應變增加而逐漸升高，後半段隨張應變增加而逐漸降低；織布W之GR值隨張應變增加而增加，到張應變7.5 %阻塞情形會再下降，之後會隨張應變增加而阻塞。系統滲流量隨水力坡降增加有逐漸增加的現象，土層滲透係數k12及k23隨試驗延時增加有逐漸降低的現象。 The influence of tensile strain on the filtration characteristics of slit-film woven geotextiles were investigated in this study. Apparatus have been designed and built for determining pore size distribution, measuring flow rate through plain geotextile, and conducting a gradient ratio test. A unidirectional strained geotextile specimen was secured by clamping a pair of steel ring on the specimen; three experiments were carried out collaborated with the clamping specimen. Four geotextiles, designated as BR, BS, G and were employed to carry out the experiments. The geotextile were stretched to 2.5%, 5%, 7.5% and 10% strains prior to installation in apparatus. The experimental results show: (1) The AOS of the BR, BS and G geotextiles were Increase with the increase in tensile strain, but the W geotextile had opposite trend. (2) The BR, BS, and G geotextiles have similar relationships between the opening size, seepage rate and the tensile strain for the geotextiles submitted to less than 7.5% tensile strain. Geotextile W showed no clear correlation between the opening size, seepage rate and the tensile strain. (3) Tensile strain has insignificant effect on the GR value for the four tested geotextiles when the soil-geotextile system was subjected to low hydraulic gradient water flow.
