-10℃冻土为隧道钻挖机提供无阻通道.pdfVIP

工程簡訊 01/2012 (第十期 Issue No. 10) -10℃凍土為隧道鑽挖機提供無阻通道 -10oC℃ underground to pave way for smooth access of Tunnel Boring Machine 以 凍 土 法 來 鞏 固 隧 道。 Construction of the tunnel was supported by ground freezing. 為配合西港島綫的隧道工程，工程團隊於離地面25米的上環 the eastbound tunnel, which were left in place temporary support 地底，將泥土冷卻至零下10度，以準備為隧道鑽挖機提供無 for remedial work to the foundations of a nearby building in the 阻通道。 mid-1980’s. As these steel frames would be in the path of the TBM, removal was considered essential to safely complete the TBM drive 西港島綫在使用隧道鑽挖機由上環至西營盤進行鑽挖工程 in this critical section. 前，由於鄰近隧道的大廈在八十年代進行樁柱維修工程時遺 留了鐵架，阻礙了東行隧道的挖掘，工程團隊需建造一條長27 Before the excavation of the eastbound tunnel started, a 27-metre long 2-metre diameter tunnel was constructed with the use 米和直徑2米的隧道，以移走遺留於地底的鐵架。 of ground freezing technology to provide access for removing 受到該處的軟土地質及高地下水位的地理環境限制，使用凍 the obstructions. Ground freezing was considered as the most 土法來鞏固該處的地層是最合適及安全的方法。在進行凍土 appropriate and safe method due to the geological constraints 工程前，工程團隊於上環站設立了冷卻循環系統，透過只有零 including disturbed ground and the high ground water table. 下27度的冷卻劑 — 氯化鈣（即鹽水），揼入預先安裝在隧道 A cooling circulation system was set up at Sheung Wan Station. 旁的一系列喉管，讓泥土冷卻成冰，然後冷卻劑返回循環冷卻 A calcium chloride solution, simple salt water which remains in 系統，再次進行冷卻過程，經過數星期後形成了1.5米厚的冰 its liquid