英文篇名
A REVIEW OF GROUND SUBSIDENCE IN TAIPEI BASIN
作者
吳建民
摘要
臺北盆地人口密集,工商發達,地下水之利用日增,致發生地下水位劇降及地層下陷現象。作者於民國57年間從事台北防洪規劃,為推估將來地盤下陷,曾收集有關資料綜合整理,從土壤力學觀點推測沈陷量;推測方法用最簡單之一維單軸壓密理論,因方法過份簡單,未廣泛發表供有關人士參考。事過約20年,地工技術雜誌社約作者作一回顧,特將舊資料刊佈。此一問題國人已普遍注意,惟沿海地區抽水所致沈陷問題仍層出不窮,希能拋磚引玉,引起關心人士共同討論研究。
英文摘要
Ground subsidence which began in the mid-1950's due to ground-water overdraft in the Taipei Basin, has caused widespread concern for the past three decades. Withdrawals increased from 0.9 million m3 in 1957 to 435 million m3 in 1970. Piezometric heads declined at unprecedented rates during the 60's and early 70's. Well casings failed at alarming rates, and differential settlement caused numerous engineering problems. By 1985, 151 km2 or 62% of the basin area has subsided more than 0.5 meters, and maximum subsidence exceeded 2.15 m. The basin wide volume of subsidence totaled 231.3 million m3. This subsidence is one of the greatest environmental changes caused by man.
Importation of surface water to the heavily overdraft areas began in the mid-70's. As of 1987, after two decades of continued declining piezometric heads, many hundreds of supply wells were idle and piezometric heads were rising. Throughout the greater part of the basin, artesian pressures were recovering and the rates of the subsidence were reducing.
Basic data graphs, geological characteristics, predicted future subsidence using laboratory consolidation tests and its verification, generalized trend of piezometric head decline, and parameters for estimating subsidence under assumed hydrologic change, constitute a major part of this review describing the ground-water development and ground subsidence problems of the Taipei Basin.