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所謂萬丈高樓平地起,因此結構物是否穩固,有賴於良好承載基礎之支撐,而基礎型式之研選與結構載重、用地大小、地形、地質、地下水位及周圍環境等各項條件息息相關,一般工程常採用之基礎型式包括:(1)直接基礎(2)筏式基礎(3)樁基礎(4)沉箱基礎(5)井式基礎(6)壁式基礎等六種類型,本期以較特殊之井式基礎、沉箱及壁式基礎為主題,內容精采可期。
井式基礎之結構型式類似大尺寸的樁基礎,通常以人工或小型機械開挖的方式鑿井,再於井中施築基礎結構,具有可採用小型機具施工、基礎面積小、開挖工法可順應地形等特點。由於開挖期間必須保持井壁安定,避免因坍方造成工安事故,一般會選擇在地質狀況較好,地下水位較深之地層施築,以降低施工風險,但實際地質狀況往往比預估情況複雜,因此開挖期間常有湧水湧砂之情況發生,必須因時因地制宜,調整施工對策,施工深具挑戰性。國內相關工程案例如機場捷運高架橋段、高速公路五楊高架橋段及台電連接站鐵塔基礎等。
沉箱,是以沉降的方式利用自重或其他外力將施作結構下沉至設計深度,然而為順利讓結構沉入地下,施工中必須加載或超挖,因此基礎常有傾斜或偏心等情況,而超挖更容易造成工區附近地層下陷,施工控制精度較差,過去常用於河川地或高灘地等較無鄰近構造物之區域,國內相關工程案例如機場捷運高架橋段及台電潛盾隧道工作井等。近年來都會區沉箱施工,為改善上述傳統沉箱施工的缺點,已有多起採用壓入式沉箱工法之案例,所謂「壓入沉箱工法」之優勢在於可減少施工用地及開挖對鄰近結構物之影響,其特徵為先利用油壓千斤頂之反作用力,使沉箱底端刃口強制貫入土壤足夠深度後,再挖掘沉箱內積土。如此即可減低傳統自重式沉箱超挖容易帶來之砂湧等問題,除可降低對週遭土壤之擾動外,整體施工精度亦大為提升,國內相關工程案例如台北捷運聯絡通道逃生井及台電大林高港潛盾隧道工作井等。
壁式基礎是以連續壁單元作為結構體支承之基礎構造,其功能與大口徑基樁類似,但在造型上有別於傳統鑽掘式基樁之圓柱體,由於壁式基礎斷面較傳統基樁更具彈性,配合上部載重可提供更經濟設計,節省工程經費。國內壁式基礎主要運用於橋樑基礎及建築基礎,尤其是近年來高層建築基礎之使用有越來越多之趨勢,但由於壁樁之承載行為與傳統鑽掘式圓形基樁可能有所不同,因此壁樁之現地試樁成果及行為之探討,就相形重要了,本專輯收錄相關論文頗值得參考。 本期共蒐錄10篇論文,內容涵蓋橋樑沉箱基礎、潛盾隧道工作井採用之壓入式沉箱工法、橋樑及連接站之井式基礎及高層建築採用之壁樁,內容豐富多元,且各篇作者皆為相關領域之專家,所提之案例也都屬案例中之經典,內容精采豐富,深具參考價值,值得各位讀者細細品讀。
第一篇為台灣大學陳正興博士等人所發表之「沉箱基礎設計規範之評析與側向阻抗之簡化分析模式」,本文首先檢討國內常用日本沉箱規範分析模式之合理性,繼而探討沉箱之側向阻抗問題,以理論模式分析沉箱周邊土壤對沉箱彎矩阻抗之貢獻,顯示可將沉箱之分析模式近似簡化為僅考慮沉箱周邊土壤之水平反力,此簡化模型之力學分析變得相當簡單,方便於工程初步分析時計算使用,此分析模式簡單明瞭,值得初步分析時參考使用。
第二篇為廖惠生先生等人所發表之「都會區連接站井式基礎兼直井施工案例之探討」,本案例特色包括採用索道替代施工便道降低對周遭環境影響;採昇井工法施作排碴孔,將直井擴挖及整地之剩餘土石方,藉由排碴孔排出;捨棄施工快速炸藥開炸工法,採用機械開挖降低施工噪音及振動對居民之影響;另外,採用直井與通風機房結構襯砌「併行施工」方式,有效縮短施工工期。由於民意高漲、環保意識抬頭,加上居民對生活品質要求越來越高,在都會區內之工程施工往往動輒得咎,也常常因為抗爭,使工程無法順利進行,本案例相關對策可提供未來都會區施工之參考。
第三篇為陳道生先生等人所發表之「井式基礎於中壢台地之設計與施工案例探討」,本案例位於中壢台地,地層為透水性高之卵礫石層,其下方為膠結不良之軟弱岩盤,基礎開挖施工採用鋼支保加噴凝土保護,實際施工時遭遇漏水湧砂等問題造成工程無法順利進行,經檢討地質特性及近接狀況後,分別採用灌漿改良、隔幕排樁及加強導水等工程對策,值得未來類似工程之參考。
第四篇為孫漢豪先生等人所發表之「曲流地形之道路受莫拉克風災重建案例探討」,本案例位於高雄市茂林區高132線上,道路因受莫拉克風災強降雨之影響而柔腸寸斷,主要重建包括邊坡整治及橋樑重建等工作,其中橋樑重建部份,分別依不同條件採用井式基礎及沉箱基礎施作。另外,在重建後佈設監測儀器,除可了解道路完工後受降雨及地震之影響外,同時其監測數據可作為公部門道路管制之參考,值得後續災後重建之參考。
第五篇為為曾孝欽先生等人所發表之「壓入式沉箱工法於潛盾工作井之應用」,本案例為台電潛盾工作井,因開挖較深且鄰近建物,因此採用壓入式沉箱工法,可減少施工用地及開挖對鄰近結構物之影響,並免除內支撐對潛盾施工之干擾。本文主要針對壓入式沉箱工法規劃設計、施工管理重點加以介紹,並藉由監測結果探討本工法對周遭地層之影響,內容精采豐富,值得都會區沉箱施工參考應用。
第六篇為為徐明志先生等人所發表之「矩形壁樁極限載重試驗案例分析與探討」,近年來國內採用連續壁單元作為承載上部結構之載重基礎,以替代大口徑場鑄圓樁之案例已日漸普遍。然矩形壁樁與傳統圓樁之斷面形狀及施工方式均不同,本文彙整多組壁樁載重試驗結果,及比較有、無施作樁底灌漿壁樁間樁頭試驗曲線之差異,並建議分析方法與歸納評估之簡化線性模式,可作為後續壁樁試樁分析模型之參考。
第七篇為邱德夫先生等人所發表之「建築物壁式基礎案例探討」,本工程位於熱鬧的精華商圈,並緊鄰主要道路及高架捷運站,為增加施工安全並減少鄰近地表及建物之變形,除施作連續壁做為擋土設施之外,另採用扶壁、地中壁及地盤改良等多種輔助設施,其中地中壁同時也做為日後建築結構物之承載使用,必須承載上構所傳遞之壓力、側向力,以及上浮力。壁式基礎在都會區高層建築使用有越來越多之趨勢,尤其在大深度開挖及對變形較敏感之近接施工,此篇之使用對策、分析模式及監測結果,值得進一步參考。
第八篇為吳文隆先生等人所發表之「國內井式基礎設計與施工案例介紹」,本文詳細說明井式基礎之設計與施工重點,讀者可參考上述原則,依據所在案例之地層特性、結構需求、經濟性及施工性等綜合進行評估,選擇結構物適合之基礎型式。文中並列舉三個經典案例,可供後續相關工程於基礎型式研選及設計施工之參考。
第九篇為陳鴻濤先生等人所發表之「超高層大樓壁樁前期載重試驗內容與成果之應用-以機場捷運臺北站(A1站)共構聯合開發大樓工程為例」,本文為提供後續聯開大樓深基礎設計所需之參數,於連續壁及壁樁工程中先行進行2組壁樁前期載重試驗及1組前期拉拔試驗。文中針對載重試驗之規劃、儀器配置、數據分析與設計參數整理進行介紹,並說明壁樁前期載重試驗成果之應用。
最後一篇為台北科技大學倪至寬博士等人所發表之「路塹橋墩深開挖與PLAXIS 3D模擬分析」,本文根據蒐集傾度管監測數據,並搭配高速公路裂縫位置,進而研判邊坡潛在滑動面的位置,以決定較佳開挖擋土工法。另外,以有限元素軟體與監測結果進行回饋分析比較,驗證地盤力學參數的適用性,可作為後續類似案例分析之參考。
本期專輯特別敦請曹壽民董事長贈言,曹壽民董事長曾任教於台灣大學土木系,並曾擔任台北市交通局局長與不分區立法委員,目前擔任中興工程顧問公司董事長,為國內土木工程界極少數經歷跨足產、官、學、政的人,經歷完整豐富,也在各職務上表現優異,足為土木工程界的典範。回想學生時代,因受地工技術雜誌啟發,引發對大地工程的興趣,進而跨入大地工程領域,這些年來,也從單純讀者、作者、到主編的角色,是一直陪伴我們成長的刊物,相信這是多數地工人共同的經驗。本期承蒙編輯委員會邀請擔任主編工作,個人雖覺才疏學淺,但因盛情難卻,僅能抱持誠徨誠恐態度,盡力而為。所幸地工界就像個大家庭一樣充滿溫暖,在邀稿期間有人一口答應賜稿,有人熱心推薦專家學者,始能順利完成本期之邀稿工作,讓本期內容更加多元充實。
最後,編者衷心感謝所有作者朋友在百忙之中提供精采文章,讓本期地工技術得以充實圓滿。另也特別感謝萬鼎公司余明山協理在主編期間指導,及各位審稿委員提供寶貴意見與悉心指正,當然還有李碧霞及廖美嬌兩位小姐在專輯主編上提供之寳貴經驗,讓本期文章內容更臻完備,特此一併誌謝。
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首先謝謝「財團法人地工技術研究發展基金會」俞董事長造訪中興,並面邀贈言,盛情難卻,不敢不從。回想大學時修習趙國華老師講授之「土壤力學」,因個人悟性不高,努力不夠,經補考後才過關;今日卻要贈言「地工技術」專業期刊,既慚愧又惶恐,自忖大概是老天爺要懲罰我年輕時的懶散與荒疏,所謂天意不可違,只有勉力為之。
「中興工程顧問公司」成立於1994年,其前身「中興工程顧問社」成立於1970年,以提供水利工程與水力發電的技術服務起家,曾參與國內重要水庫如曾文、翡翠、南化、霧社、明潭等之設計工作。由於壩基、引水隧道、導水隧道與電廠均為地下工程,其成敗與地工技術關係密切,因此40餘年來,中興工程顧問社與中興工程顧問公司在地工技術的研究與應用方面,一直投注經費與心力,期能維持國際水準的專業能力,進而確保相關重大工程的品質與安全。
回顧過去,1972年蔣經國先生出任行政院長,面對退出聯合國、中日斷交、美國總統尼克森訪問中國大陸等多項外交挫敗,重新思考國家發展的方向,決定從「反攻大陸」變成「建設台灣」,於是在1973年提出「十大建設」,從此展開紮根台灣的工作。經過長期的努力,台灣西部人口密集地區的基礎建設已大致就緒。近年來,為了均衡城鄉發展與促進觀光產業,國家的建設重點逐漸轉移至台灣東部地區與山區,相關重大建設有蘇花改、花東鐵路電氣化、台9線南迴公路拓寬改善、南迴鐵路電氣化與國道4號等工程。由於東部地區屬於變質岩,地質條件複雜且敏感,而山區工程必須穿山越嶺,地工挑戰嚴峻,因此大地工程專業人員成為上述工程能否如期如質完成的關鍵因素;益顯地工技術的精進更為重要,貴刊的發揮空間更加寬廣。
衷心感謝地工方面的前輩先進與專家學者多年來的指導與愛護,使得中興工程顧問公司能夠追隨各位,跟上時代;未來仍請大家繼續鞭策與賜教,期能與時俱進,服務社會,造福人民。
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Review for Design Specifications of Caisson Foundations and the Simplified Model for Lateral Response Analysis |
陳正興、柯永彥、邱俊翔 |
沉箱基礎、設計規範、側向阻抗、簡化分析模式。 |
本文回顧日本之沉箱設計規範,檢討評析常用分析模式之合理性,繼則探討沉箱之側向阻抗問題,以理論模式分析沉箱周邊土壤對沉箱彎矩阻抗之貢獻,顯示可將沉箱之分析模式近似簡化為僅考慮沉箱周邊土壤之水平反力,此簡化模型之力學分析變得相當簡單,可直接推導得在彈性土壤與完全彈塑性土壤中沉箱側向反應之解析解,方便於工程初步分析時計算使用。 |
The commonly used design specifications of caisson foundation were reviewed in this paper. The model that simulates lateral resistance of a caisson foundation contributed from various soil springs connected to the caisson was investigated analytically and numerically. Results showed that the resistance comes majorly from the horizontal subgrade reactions in front/back of the caisson. Based on that, modeling for the lateral response of a caisson can be approximately simplified to only considering the horizontal soil reactions sarrounding the caisson, which makes the mechanis analysis much easier. This simplified model can then be utilized to directly implement the analytical solutions of the lateral response of a rigid caisson embedded in the elastic soils and in the perfectly elasto-plastic soils, which are useful for preliminary analysis in engineering parctice. |
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A Case Study of Shaft Foundation Doubled as Vent Shaft for Cable Connection Station in Metropolitan Area |
廖惠生、江承家、蔡英聖 |
井式基礎、直井、索道、昇井工法、新奧工法。 |
本工程連接站位於台北都會區邊緣的山坡地且屬保護林區,因此規劃臨時索道配合昇井工法,做為機具運輸及後續擴挖之排碴孔,使後續機械擴挖之棄土,利用洞道運棄,免除開路與車輛運送污染減少對環境衝擊。本文即針對此都會區連接站基礎設計及施工案例加以介紹,主要內容包括通風機房擴挖段施工、索道施作、昇井工法施作、直井擴挖及結構體施作等。 |
In this case, the cable connection station locates at Taipei metropolis, which located on a slope land and of protected forest areas. For the machine tools transportation and the mud hole as waste soil dump, the Raise Boring Method with temporary cableway is applied to reduce the environment impact. This paper introduces the design and construction of foundation for cable connection station, including the Raise Boring Method, cableway installation, shaft reaming, the excavation expansion construction of fan room and the structure construction task. |
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Case Study of Design and Construction of Well Foundation on Jhongli Terrace |
陳道生、張志勇、蔡旻君 |
井式基礎、卵礫石層、軟岩、地盤改良。 |
本文簡述中壢台地之地質特性,以高架橋梁工程為例檢討基礎之研選原則。基於施工用地限制與載重條件之考量,採用井式基礎並探討井基設計流程與施工方式。然因中壢台地卵礫石層透水性高,其下方軟弱岩盤膠結不良,造成井基開挖時遭遇地下水掏刷地層及湧水之情形,本文案例採用灌漿改良、隔幕排樁、加強導水等改善對策以順利構築井基,相關處置經驗可供工程界參考。 |
In this article, the geological properties of Jhongli Terrace are reviewed and rule of selecting foundation type for bridges herein is proposed. Because of the limitation of construction area and high loading requirement of bridges, well foundation is recommended. Design and construction procedures of well foundation are also reviewed. Due to the high permeability of gravel layer and loose deposit of weak rock, scouring and gushing water occurred during excavation, engineer adopt measures such as grouting, cut-off pile, and drainage system to accomplish the construction of well foundation. The purpose for the article is to provide a helpful reference on similar ground condition. |
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A Case Study of Meandering Road Rebuilt after Typhoon Morakot |
孫漢豪、郄爾敏 |
莫拉克、曲流地形、蜿蜒度。 |
位於高雄市茂林區的高132線係沿濁口溪向上游興建的道路,因濁口溪蜿蜒度高使曲流地形顯著,風景優美,一直是高雄市著名的地理景觀觀光勝地。民國98年遭受莫拉克颱風強降雨侵襲道路的上、下邊坡因而柔腸寸斷;經詳細調查作業後,探討其破壞原因與機制,再依其特性予以分段設計,以避免重覆致災。就地工角度探討,重建工程主要區分為野溪沖刷、順向坡及板岩潛移破壞等三大類,採不同的修復工法。其中部份路段受限於重建經費或困難度過高,無法以甲類修復者,則採簡易修復方式辦理。 山區道路常在同一地點發生重覆致災現象,本重建工程於設計階段即注意此一現象,在部份路段規劃設置了監測儀器,以瞭解完工後道路受降雨或地震等的影響,同時當中央氣象局發佈豪大雨特報時,監測數據尚可提供公部門做為管制道路之參考。全線重建修復迄今已超過三年,道路狀況良好,期間曾遭遇民國101年6月12日強降雨,雖部份路段有發生較大的變位,但無道路中斷的狀況。採簡易修復搭配監測系統的理念,可作為山區道路新建或重建之參考。
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Kao-132 line in Maolin, Kaohsiung city was constructed along the upstream of Jhoukou River. The landscape is eminent because of its meandering form and has been a well-known tourist resort. In 2009, the typhoon Morakot severely damaged the road. After detailed forensic investigation and reconnaissance study, the future disaster-induced damage can be minimized by using various design methods. From the geotechnical point of view, the rebuilt can be categorized with different causes of failure, including trench erosion, dip slope and slate creep. For roads that are restricted by available funding and construction feasibility, simple repair is recommended. Since the disasters usually happen repeatedly in the same areas, monitoring devices were installed in sections of road in order to study the rainfall and seismic effects to the road after construction. When sever rainstorm warning is issued from the Central Weather Bureau, the monitoring data can provide agencies reference information for traffic control. The rebuilt has been completed for more than 3 years and the road has been maintained in good condition. The sever rainstorm on June 12, 2013 did not cause much damage except a few large displacement. From this case study, the concept of simple repair with monitoring system is a viable option for new construction and rebuilt of mountain roads.
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Application of Caisson Method to Shafts for Shield Tunneling |
曾孝欽、陳達政、三井 隆 |
壓入式沉箱、潛盾工作井、砂礫石層。 |
目前潛盾工作井深開挖之設計以連續壁配合架設型鋼內支撐工法最為常見,然隨著都會區迅速發展,潛盾工作井設置於侷限用地或緊鄰既有結構物旁之情況也愈顯普遍。工作井採用「壓入沉箱工法」之優勢,在於可減少施工用地及開挖對鄰近結構物之影響,並免除內支撐對潛盾施工之干擾,達成適度減體減量之目的。壓入式沉箱工法應用在台灣工程之案例越來越多,惟挖掘深度超過40m之大尺寸沉箱工作井案例仍為罕見,本文將以台灣電力股份有限公司「大林~高港345kV電纜線路第二工區潛盾洞道暨高港冷卻機房統包工程」之潛盾工作井為例,介紹大尺寸壓入式沉箱工法於規劃設計、施工管理之考量重點,以及藉由監測結果探討本工法對周遭地層之影響。 |
To meet the tight schedule of construction, a caisson method that uses anchors to provide reaction forces can be introduced for the launching shaft in shield tunneling. The method does not require an interior bracing system to provide excavation stability that always becomes obstruction during assemblage and trial operation of shield machine. Compared to traditional one that uses dead weights to descend each caisson section, the method can reach higher criteria for verticality. The induced surface settlement can be significantly reduced, resulting in less effect on adjacent structures or facilities. This paper describes a case history in Kaohsiung City where a launching shaft with 18 m in diameter and 40 m in depth is constructed using the caisson method. Key consideration in planning, design, and construction management is illustrated. According to monitoring results, the method is proved to be time and cost effective for a tight-schedule project. |
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Case Study for Ultimate Load Test of Walled-type Pile |
徐明志、高秋振、鄺柏軒、俞清瀚、陳正興 |
壁樁、極限載重試驗、樁底灌漿、t-z曲線、q-w曲線、樁勁度。 |
近年來國內採用連續壁單元作為承載上部結構垂直載重基礎,以替代大口徑場鑄圓樁之案例已日漸普遍,然矩形壁樁與傳統圓樁之斷面形狀及施工方式均不同,且目前可供參考達極限破壞載重之試驗案例不多,故壁樁之承載及變形行為宜進一步深入探討。本文彙整新北市華中橋西側重劃區內6組壁樁之下壓載重試驗結果,首先分析各試驗壁樁於不同地層之t-z曲線及樁底卵礫石層之q-w曲線,並比較有、無施作樁底灌漿壁樁間樁頭荷重-位移(Q~S)曲線及q-w曲線之差異;繼則評估繪製本案例各土層之代表性t-z及q-w曲線,據以提出其簡化線性勁度模式,用來計算不同尺寸壁樁之樁頭荷重-位移曲線(即性能曲線);然後建議樁頭之等值雙直線基樁垂直承載勁度(Kv),供樁筏複合基礎之土壤-結構互制分析使用。本案例研究結果顯示,採用t-z及q-w曲線法可合理模擬矩形壁樁之荷重-位移行為與其性能表現;且本文所採用之分析方法與歸納評估之簡化線性模式,可應用於其他地區試樁作類似之分析,以擷取合理適用之分析模型。 |
The units of diaphragm wall, also called as walled-type piles or rectangular piles, were designed as foundations to support the vertical loadings of superstructures common recently in Taiwan. However, the cross-sections and construction methods of walled-type piles were rather different from those of conventional larger-diameter circular bored piles and the available test results of walled-type piles loaded to ultimate failure were still few, thus the bearing behaviors of walled-type piles should be investigated. Results of six compressive load tests of walled-type piles, which fully instrumented and installed in New Taipei City, are studied in this paper. First the characteristics of t-z curves of various alluvial soils and q-w curves of gravel layer are evaluated, and the differences of load-deflection (Q~S) curves and q-w curves for piles with or without base grouting are discussed. Then the representative nonlinear t-z curves and q-w curves for various soil strata are summarized; in addition, the simplified linear models for representative t-z curves and q-w curves together with the corresponding parameters of stiffness and strength are proposed. Accordingly the load-deflection curves, which designated as the “performance curves”, for walled-type piles with various cross-section and lengths are simulated. Besides, the bilinear models for load-deflection curves as well as the corresponding equivalent stiffness are suggested for the analysis of soil-structure interaction of pile-raft foundation. Results of this case study indicates that the simulation method employing the t-z and q-w curves can be used to estimate the bearing behavior of walled-type piles very well; the simplified linear models and analysis methods proposed are suggested to be utilized in interpreting the results of pile load tests conducted in the other sites, thus the applicable analysis models can be established. |
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Study of a Construction Case with Buttresses and Cross Wall Foundation |
邱德夫、許達馨、張福全 |
地中壁、扶壁、壁樁。 |
本文藉由臺北市緊鄰主要道路及重要結構物之建築案例,說明於深開挖工程中,為增加施工之安全並減少鄰損,採用扶壁、地中壁及地盤改良做為抑制擋土連續壁變形之輔助方案,而地中壁也做為日後建築結構物之承載壁樁使用。設計時除利用RIDO及Plaxis程式分析擋土壁之變形外,更以ETABS軟體評估土壤與結構之互制行為。 本案例目前已開挖至大底,根據監測結果,壁體變形量與分析結果相當一致,顯示設計階段之假設及參數選擇相當合理,而地中壁及扶壁亦發揮其抑制變形效果,後續結構物持續興建以及監測成果十分值得期待。
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A construction case located in Taipei which is adjacent to main road and important structures is introduced in this paper. In order to increase construction safety and reduce the risk in the deep excavation projects, cross walls, buttresses and ground treatment are used aside from retaining diaphragm wall. The cross walls are also served as the foundation for the building while completing excavation. Two commercial software including RIDO and Plaxis are used to analyze the deformation behavior of retaining wall as well as adjacent ground. Besides, ETABES is used to simulate the interaction of structure and cross walls. The excavation has reached the designed depth so far. Based on the monitoring results, the deformation of retaining wall is quite consistent with analyzing results which shows the assumptions and parameters used in the analysis are reasonable. Also, cross walls, buttresses and ground treatment are helpful to control the deformation. Due to the good agreement, the follow-up construction of building and persistent monitoring are expected.
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Case Study on Design and Construction of the Vertical Shaft Excavation |
吳文隆、蕭秋安、楊智堯 |
井式基礎、設計、施工。 |
為因應國內經濟發展之需要,既有公路及軌道等交通公共建設已逐漸不敷使用,必須新建或拓寬以容納日益增加之需求。然而,可供使用土地逐漸減少以及社會對於施工環境保護的重視,使得上述工程必須考量各種環境因素,選擇適當之工法或基礎型式以因應各種環境限制條件。一般基礎型式大致多為直接基礎及樁基礎,而在用地受限及坡度較陡峭,大型機具無法施工的條件下,井式基礎提供較佳之施工性並可縮小基礎尺寸,降低基礎開挖面積。然而,井式基礎在設計及施工時亦有其限制及必需注意重點,本文彙整井式基礎之設計與施工重點,並以實際案例介紹,提供後續相關工程於基礎型式研選時之參考。 |
For the needs of domestic economic development, the public transportation construction have been not enough gradually. However, the available land for the construction is reducing, and the demand of the environment protection is increasing. So that these projects must consider a variety of environmental factors, and select the appropriate foundation type to various environmental constraints. In the past, the foundation type is usually selected the spread footing type and pile foundation. But for the space-constrained and steeper slopes areas, the large construction equipment is hard to work. In such case, the well foundation is the another better choice. However, there are also some limited and considerations of the design and construction of well foundation. This article presents the case studies on design and construction of well foundation for the reference of the future construction works. |
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Taiwan Taoyuan International Airport Access MRT System A1 Station & C1/D1 Relevant Development Building Pile Foundation Preliminary Loading Test Content and Application |
陳鴻濤、陳俊宏、林建華、林恒次 |
自動化測讀儀器、軸力與摩擦力分佈、t-z及q-z曲線、回饋分析。 |
台灣桃園國際機場捷運線 A1車站與C1基地56層及D1基地76層聯合開發大樓共構,為提供後續聯開大樓深基礎設計所需之參數,規劃於連續壁及壁樁工程中先行進行2組壁樁前期載重試驗及1組前期拉拔試驗。 本次前期載重試驗主樁尺寸為1.3m x 2.7m x 52m,利用電子式荷重計、電子位移計、鋼筋應力計、樁體變位計、自動化測讀設備等儀器,於每階段加載時所規定之時間擷取試驗數據資料,配合各儀器所埋設位置,計算每一節樁身分段之軸力傳遞與摩擦力分佈狀況,以及每一地層之摩擦應力發揮與變位關係之t-z曲線、承載層反力發揮與變位關係之q-z曲線等成果,提供作為進行不同尺寸壁樁承載力與載重-沉陷量關係之回饋分析計算之用。 本文將針對2組載重試驗之規劃、儀器配置、數據分析與設計參數整理進行介紹,並以C1/D1聯合開發大樓深基礎設計為例,說明壁樁前期載重試驗成果之應用。
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Taiwan Taoyuan international airport access MRT system A1 station and relevant development building is located on Parcel C1, D1. In order to provide the design parameter of high building’s deep foundation, performing preliminary loading test in diaphragm wall and pile engineering contract. The scale of test pile is 1.3mx2.7mx52m, the automatic electric instruments including load cell, LVDT, installed in testing pile reinforcing bar stress transducer, telltale etc. had been measured by computer and data logger at indicated time for every step of loading. The load transfer and friction development of pile and stratum t-z & q-z curve may be calculated using the data from every instrument. The result of loading test could be applied in feedback analysis for different scale of pile bearing capacity and settlement analysis for C1/D1 relevant development building pile foundation.
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Vertical Shaft Construction and PLAXIS 3D Simulation |
倪至寬、鄭郁翰 |
高架橋、竹削井式擋土工法、掛網噴漿、土釘、PLAXIS 3D。 |
國道1號五股至楊梅段拓寬之新建工程,其中泰山林口路段,因為上邊坡側為高速公路不適開挖,所以在下邊坡處進行橋墩基礎開挖,使用三種不同的開挖擋土工法,分別為型鋼襯板擋土工法、土釘逐階降挖擋土工法與竹削井式擋土工法。 本文針對土釘逐階降挖擋土工法與竹削井式擋土工法,蒐集傾度管監測數據,彙整後繪製不同開挖階段之傾度管側向變位及側向變位速率圖形,搭配高速公路裂縫位置,進而研判邊坡潛在滑動面的位置,最後依據傾度管的變位、開挖壁面的穩定性、高速公路裂縫與滑動面的產生以及工期長短,以決定較佳開挖擋土工法。然後,以非線性有限元素法軟體PLAXIS 3D,模擬土釘逐階降挖擋土工法之每一階開挖過程,以數值回饋分析結果與現地傾度管變位比對,驗證地盤力學參數的適用性,最後,以PLAXIS 3D使用相同的土壤與材料參數,模擬竹削井式擋土工法的開挖過程,擋土壁位移分析結果與傾度管的變位也吻合,驗證竹削井式擋土工法開挖過程邊坡穩定的優越性。
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A new viaduct was constructed to relieve the congesting traffic flow on National Expressway No. 1,from Wugu to Yangmei. Three difference excavation methods were used to install the bridge pier foundation along the slope of embankment for National Expressway, such as braced cut with soldier beam retaining wall, open rectangular excavation with shotcrete wall and soil nail retaining system, and vertical round shaft excavation with shotcrete wall and horizontal beams. Monitoring results of inclinometers located near the bridge pier foundations during foundation excavation were used to investigate the soil movement of upslope after each stage of excavation. In addition, the possibility of potential sliding failure was also analyzed due to the appearance of several parallel tensile cracks on the expressway pavement. The advantage and disadvantage of these excavation methods are evaluated based on the monitoring results and construction records. Then a nonlinear 3-dimensional finite element software, PLAXIS 3D, are used to verify the soil engineering properties so that the calculated and measured inclinometer deflections are well matched. Finally this finite element method with the same calibrated material parameters is used to simulate vertical round shaft excavation with shotcrete wall and horizontal beams. The calculated deflection of inclinometer matched very well to the measurement on the site. The monitoring results and numerical results also demonstrate the superiority of vertical round shaft excavation over the other two excavation methods in this formation of clayey gravel with cobble.
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汪安邦 |
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捷運松山站為臺北捷運松山線的端點站(圖一),位於臺鐵松山火車站後站廣場前之八德路四段(路寬30m)下方,介於松山路與虎林街之間,為全長319.7m,寬23.6 m,開挖深度約21.2m的地下兩層島式月台車站(圖二);為提供營運列車換軌調度須要,車站前方並設置橫渡線,開挖深度約20.3m。如圖三,工址北側緊鄰慈祐宮、基隆河河濱公園、饒河街觀光夜市及松山國小;南側則連通臺鐵松山火車站及五分埔成衣批發中心等學校、交通、商業與信仰等人潮密集區域。 |
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李璟芳、黃韋凱、冀樹勇 |
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一、前言 隨著地形測繪技術日新月異,數值地形的精度亦逐年提升,從早期以航測技術產製之廣域數值地形(5-40 m精度),已逐漸演進至利用空載光達(airborne LiDAR)之全波形回波濾除地表植被與建物,並產製高精度(0.5-1 m精度)數值地表模型(digital surface model, DSM)與高程模型(digital elevation model)。受惠於高精度地形蓬勃發展與地理資訊系統(GIS)軟體的普及,著眼於工程地質、坡地防災、遙測判釋或智慧城市建模等目的,依據目的需求所研製之各類立體明暗彩繪圖也逐漸推陳出新。立體圖資工具之精進,除了可提升專家判斷相關潛在地質災害之正確性,同時也降低了地形判釋門檻與分析時間,並將原本二維平面圖地形轉化為三維立體化地貌之視覺呈現。
二、圖資產製原理與方法 彩繪明暗圖一詞最早由李錫堤(1996)提出,其以不同日照方向、觀測角度及彩度色階賦予二維數值地形模型(digital terrain model, DTM)不同垂直高度的顏色,以突顯地形上之局部地表起伏特徵(如圖1(a)),為了加強地表崎嶇之明暗度(illumination)表現,其考量散射效應以增顯數值地形立體感,並採用蘭勃式定律(Lambert’s law)處理地表的反射光強度,依據不同高程值給定不同RGB色彩值(如綠色代表標高0 m;黃色代表標高250 m;紅色代表標高5000 m),完成後之立體彩繪明暗圖除可同時呈現山區地形之陰影效果外,同時也可藉由顏色差異區別地貌高程差異(圖一(b))。Yokoyama (2002)則提出地表開度(surface openness)概念分別對地形隆起與凹陷之特徵進行地上開度(negative openness)與地下開度(positive openness)光照陰影分析(圖二(a)),並假設光源自物體垂直正上方以全方位照射。地上開度主要強調山脊線而降低山谷色調(圖二(b)),而地下開度則突顯山谷模糊山脊(圖二(c))。根據此原則,其率先提出尾根谷度= (地上開度值 - 地下開度值)/2,意即將兩張不同開度灰階光照圖相減後進行套疊(稱為尾根谷度圖),融合結果將使山脊與丘陵地形因開度值較高呈現明亮色澤,反之,山谷與窪地處則相對略顯色澤深暗。另Chiba(2008)則將尾根谷度圖進一步以坡度之關係配合彩度色階來表現立體地形之緩傾程度,目的在於使陡峭地形呈現較深彩度,而緩坡或水平面則以淺淡的彩度展示。至於坡度彩度圖之顏色選擇上,則選定對人眼具有較佳辨識度之紅色,並稱之為赤色立體地圖(red relief image map)。該類地圖已於日本進行廣泛應用,並於日本、台灣及美國等國家陸續取得專利(台灣目前由專責測繪公司提供服務)。如2014/3/22於美國華盛頓州發生Oso大規模崩塌災害後(圖三(a)),日本亞細亞測繪公司即以美方開放資料之1m精度光達數值地形進行立體地圖產製,並提供圖資予相關官方或學術單位進行研析。針對Oso之坡地崩塌災害,中興工程顧問社亦以明暗數值地形,融合坡度圖與特定光源陰影圖產製之立體彩繪明暗圖(圖三(b)),其優點為產製迅速,不受既有專利限制,同時可達到凸顯局部地形特徵與地質災害判釋成效。 三、圖資應用 在立體彩繪明暗圖之應用上,目前以火山地形(如錐狀火山口、熔岩流分布範圍)、舊(具潛在危險)崩塌地、土石流集水區蝕溝、森林茂密區隱沒斷層帶或歷史古蹟點位判釋最為常見(李錫堤,1996、Huangerud, 2014、Lin et al., 2013)。以大地工程較為相關之坡面災害而言,如圖四(a)所示,為美國地質調查所(USGS)利用立體明暗圖針對Oso災害區周邊所圈繪之舊崩塌堆積滑動塊體分布圖,圖中(a)-(d)分別表示不同年代所發生之崩滑堆積塊體((a)較年輕;(d)較古老),本災害發生後即有專家學者根據立體明暗圖,研判該崩塌災害為兩次崩塌所形成,該論述亦於災後地表振動訊號分析及現場調查被證實,顯示三維立體圖資確可協助釐清各崩塌塊體之土砂量體與破壞運移順序,並提供工程權責單位進行河道清疏及坡面治理參考。圖四(b)為利用立體彩繪明暗圖(坡度圖與高程模型套疊),探討茂密森林區內之隱沒斷層線通過對於地形貌演育之影響,藉由室內立體地圖之研判,可協助確認地工構造物周緣是否存在不利之地質構造,並縮短野外大範圍調查時程,可將節省時間針對重點區位進行詳細調查。美國科羅拉多州地質調查所則進一步整合平面地質圖與立體地圖進行套疊(圖四(c)),以三維彩繪陰影地質圖提供相關工程開發及工址選擇之參考。其他應用如地質構造線圈繪、水庫集水區蓄水量體評估(配合水深測量)、海岸沙丘、河道灘線測量與土石流下游沖積扇地貌評估等,未來透過各類新興測量工具之引進與立體地圖研製技術的更新,相信將必可提供工程師及研究人員於地形(質)圖資分析使用上的新選擇。
參考文獻 李錫堤(1996),“數值地形的彩繪明暗製圖及應用”,地工技術,第56期,第69-84頁。 横山隆三、白沢道生、菊池祐(1999),開度による地形特徴の表示,写真測量とリモートセンシング, 38(4), pp.26-34. 日本亞細亞測繪公司http://www.ajiko.co.jp/en/recent_activations02.html. Yokoyama R., Shirasawa M. and Pike R. J. (2002) , “Visualizing topography by openness: a new application of image processing to digital elevation models”, photogrammetric engineering & remote sensing, 68(3), pp.257-265. Chiba T., Kaneta S. I. and Suzuki Y. (2008), “Red relief image map: new visualization method for three dimensional data”, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 37(B),pp.1071-1076. Lin Z., Kaneda H., Mukoyama S., Asada N. and Chiba T. (2013), “Detection of subtle tectonic– geomorphic features in densely forested mountains by very high-resolution airborne LiDAR survey”, Geomorphology, 182, pp.104-115. Haugerud R. A. (2014), “Preliminary Interpretation of Pre-2014 Landslide Deposits in the Vicinity of Oso, Washington”, U.S. Geological Survey, pp.4. Colorado Geological survey, http://coloradogeologicalsurvey.org.
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