英文篇名
THE STUDY ON BEHAVIOUR OF HIGH EARTH-ROCK COFFERDAM IN THREE GORGES PROJECT
作者
包承綱
關鍵字
土石圍堰、風化花崗岩、應力應變分析、離心模型試驗
摘要
三峽工程二期上游圍堰最大高度82.5m,方量達700多萬m3。該圍堰在60m深水下施工,水下部分堰體由風化花崗岩(風化砂)在水中拋填而成,水上部分乾填,在堰體內打兩道混凝土防滲牆,要在一個枯水季完建並投入使用。無疑,這是一個難度很大的大型土石壩工程,也是三峽工程中幾項技術難點之一。
為了預測圍堰之性狀,近十餘年來進行了風化砂填料特性和60m水下拋填體密度研究,圍堰的應力應變分析,斷面結構的離心模型試驗,防滲牆塑性混凝土之研究,風化砂堰體、河床覆蓋層和淤積粉細砂層之動力穩定性研究,以及填料水下加密措施之現場研究等。由此得出該方案是可行的和可靠的。
英文摘要
The second stage upper stream cofferdam is a challenging structure in the Three Gorges Project. The height is about 83m, of which 60m are under water. The body of the cofferdam, with the total volume of 7,000,000 m3, is formed by tipping weathered granite material in deep water. Two concrete cutoff walls for preventing seepage erosion are set in the center of the body. All works should be finished in only 7 months. The structure is sophisticated in design and difficult to constrant.
For predicting the behaviur of this cofferdam, many research works have been done in the last decade. The topics include the investigations of the properties of weathered granite, the density of tipping material under 60m of water ( by centrifuge model test ), the plastic concrete for the cut -off wall, the numerical analysis of stress and strain, the ce1itrifuge model test for the section of cofferdam, the dyna mic stability analysis for the cofferdam body and its foundation together with the new sedimentary layer of fine sand, the field tests for strengthening the body under water, the monitoring facilities and so on.
The results show that the selected scheme is feasible and reliable.