基層材料對地工皂土毯導水度之影響

Abstract

地工皂土毯(Geosynthetic clay liners, GCLs)為一種新近發展出之地工合成材料，它在歐美國家已經被廣泛應用在廢棄物掩埋場中，主要因為它有兩大優點：一是工廠生產品質良好穩定；二是施工容易。 本研究目的在了解地工皂土毯在礫石基層上之滲透性，使用自行設計之滲透儀以礫石為基層去求得針軋型(Needle-punched)與黏合型(Adhesive-bonded)地工皂土毯的滲透性，試驗完後量測其厚度與基重之變化量進而了解皂土受擠壓之改變情形。 實驗結果顯示隨著有效應力的增大，地工皂土毯的阻水性越好；隨著基層材料粒徑的增大，皂土受擠壓產生的變化越大，此外黏合型地工皂土毯受擠壓的影響比較小。

Geosynthetic clay liners (GCLs) are a group of recently developed geosynthetic materials. GCLs have been used in landfills in the United States and European countries. GCLs have two major advantages: consistency in quality and ease of installation. The objective of this research is to study the hydraulic performance of GCLs on soils containing gravels. The hydraulic conductivity of needle-punched and adhesive-bonded geotextile-supported GCLs placed on gravel was measured using specially designed permeameter. Measurements of local thickness and mass per unit area of the specimens were taken after each test to quantify the migration of bentonite. Test results show that the hydraulic conductivity of both GCLs decreased with increasing confining stress. In general, migration of bentonite increased with increasing gravel size. Variation of thickness and migration of bentonite were generally less for the needle-punched product.