|Abstract: ||摘要:台灣地區之工業廢料與都市垃圾,隨著經濟 與都市人口之迅速成長與日俱增.由於台灣地 狹人稠,對於這些廢料與垃圾若處置不當,將造 成嚴重之環境汙染.垃圾掩埋場之滲出水或廢 料貯存池之滲漏,常為土壤與地下水汙染之主 要來源.根據許多研究顯示,有機與無機化學物 質會改變黏土之性質.作為垃圾掩埋場或廢料 貯存池之襯砌層(Liner),以避免垃圾滲出水或廢 料接觸其他潔淨物質.夯實黏土層常會因垃圾 掩埋場滲出水之侵襲而增加其水力傳導度.酸 和鹼也會溶解黏土中之礦物質,使其水力傳導 度產生很大變化.如此,黏土襯砌層受化學廢料 侵襲時,其是否能維持不透水之特性,就頗為大地工程師所關切.夯實黏土層在垃圾掩埋場滲 出水作用下,其他工程性質是否亦會受到影響, 值得吾人深入研究探討.若欲評估夯實黏土層 受化學廢料侵襲時所可能產生之影響,並進而 謀求防範之道,非得對黏土與廢料間之互制作 用做一通徹之研究,方能盡其功.本研究擬以土 壤化學之觀點,就黏土顆粒表面電性、陽離子 交換、電化雙層理論等,配合實驗結果之比較, 對黏土與化學廢料間之互制作用做深入之探討 ,期能尋得防止夯實黏土層受化學廢料侵襲之 穩固方法,以防止土壤與地下水受到嚴重汙染.|
abstract:Permeabilities are measured on compacted clays that are permeated with different permeants in rigid-wall and flexible-wall permeaters. The clay samples permeated in the rigid-wall permeater are also tested with scanning electron microscopy (SEM). For flexible-wall permeater, chemical liquids yield lower permeability than tap water. However, for rigid-wall permeater, chemical liquids yield higher permeability than tap water. The high permeability produced by chemical liquids with rigid-wall permeater is caused by a reduction in the thickness of the diffuse double layer that surrounds clay particles. When the double layer shrinks, the particles of soil tend to pull closer together, i.e., to form shrinkage cracks and increase permeability. They may also tend to form more permeable flocculent structure. These phenomena can be verified with SEM. Under confining pressure, these shrinkage cracks may be closed up, and the development of flocculation may be limited, resulted in decrease of permeability. In addition to applying confining pressure, the stabilization scheme of admixture such as flyash is studied. It is found that the added flyash can significantly reduce and stabilize permeability of chemical attacked soil.