作者

謝旭昇

摘要

據說營造廠有三件害怕的事情，一是深開挖，二是搭鷹架，三是交屋。深開挖忝為其首，尤其是都會區中的深開挖更是令人寢食難安，深怕會有想像不到的狀況產生。但根據莫非定律(Murphy′s Law)所言，凡有可能出錯的事情必然會出錯(Anything that can go wrong will go wrong)，都會區的深開挖也難逃莫非定律的魔咒，甚至不可能出錯的事情也會出錯。姑且不談由莫非定律主控的工程實務，純由學術研究的角度而言，深開挖是一個引人入勝的主題，複雜的土壤依時行為、三向度效應及多變的施工程序，乍看之下似乎可以用高階之土壤組成律配合高等數值分析程式解決之。但現場有太多牽一髮動全身的施工細節，致使分析結果與實際行為始終有所出入。施工細節的變化可能使開挖實際行為比預期結果來得好、變得差、或者完全脫離設計者或施工者的掌控。也因為施工細節的變化，每個深開挖工地都是獨一無二的，你必須帶著分析程式、走進工地、待在工地、注意所有的細節、看著每階段的變化、不斷的累積及修正開挖經驗，或許有一天你終會了解深開挖。
就主編所知，了解深開挖的前輩及同儕確實不少，邀稿應該不會困難。但邀稿就像深開挖工程一樣，有一些細節會造成預期外之變化。原本希望可以涵蓋各都會區之開挖案例，但有前輩高人對深開挖瞭若指掌但不想寫、有同儕業務鼎盛有心相助但無閒暇，也有寫完後束之高閣藏諸名山者，最終僅得七篇，涵蓋台北、台南及高雄三大都會區，尚缺台中、桃園、新竹、宜蘭等有大量開挖案例之都會區，誠屬可惜。
本期之七篇皆屬精彩之作。非常感謝台灣世曦陳聰海先生等人撰文探討高雄鐵路地下化之地工設計，該設計能有效控管施工風險，誠為中規中矩之作。大陸工程陳楷仁先生等人不吝分享高雄臨港地區深開挖工程之設計施工經驗，能有技術能力在高雄港邊進行大規模之開挖已屬不易，能全身而退者更屬難得。森城建設石朝松先生等人整理發表台北吳興街地表高程變化劇烈之開挖案例，支撐採非典型之配置方式，因地制宜，頗有可觀之處。磐工工程顧問郭晉榮先生等人縝密規畫基隆路一小型都更基地之深開挖，將舊連續壁之功能推展至極致，基地雖小，工夫至深。超偉工程顧問何政道先生經手之開挖設計何止上百，熟能生巧，為文探討扶壁及地中壁之配置，肯定有其獨到之見解。富國工程顧問周家瓊先生等人戮力於雙子星大樓之開挖工程，解決超大面積開挖之難題，並觀察得基地周遭隆起之特殊現象，此篇實屬難得之作。簡茂洲事務所簡茂洲先生為引領主編一窺深開挖堂奧之導師，其深開挖豐富之知識主編實難望其項背，簡先生撰文點出顛覆傳統認知之窄巷效應，顯見深開挖仍有諸多難解之謎團。本期另有兩篇精彩論著，一為邱俊翔、柯永彥先生等人有關剛性基腳之論述，兩位皆是地工界後起之秀，返璞歸真研究最基本之基腳行為，地工諸位先進何妨一讀? 另一篇為前田營造張桂才先生長期監測潛盾隧道環片土壓力、水壓力及內應力所整理之論述，凡此種種皆為難得之設計參考資料，開卷有益，也希望讀者一鼓作氣，一次完成全部九篇論文之研讀。
另本期贈言由陳正興教授執筆，陳教授為國家地震中心結構外審之審查委員，所審查指導之深開挖案例不知凡幾。舉凡各種類型的開挖、各種深度的開挖、各種地層的開挖、各種規模的開挖、各種光怪陸離的開挖，陳教授皆深有心得，所有開挖可能遭遇之問題也難逃陳教授之法眼，陳教授擔任本期之贈言人實為不二人選，於此特申謝忱。再次感謝贈言人、各篇作者、審稿者及基金會李碧霞、廖美嬌兩位小姐之辛勞，使地工技術140期終能如期付梓。
就如電影阿甘正傳的經典台詞：「人生就像一盒巧克力，你永遠不知道你會吃到什麼口味」，深開挖也差不多，你永遠不知道會碰到什麼狀況。編者不再贅言，就請各位讀者詳閱各篇，與諸位作者共同品嘗深開挖之酸甜苦辣。

作者

陳正興

摘要

本期地工技術專輯的主題為都會區深開挖工程，主編謝旭昇博士特要我寫贈言，主要的理由是我參與過很多的深開挖審查案，應有一些心得可分享，作為「贈言」實不敢當，請大家不妨看看作為參考。
回顧台灣深開挖工程的發展，三十年來的「地工技術」已刊載過無數案例，實為最完整的一部發展史。二、三十年來，台灣深開挖工程的設計、施工、監測與管理等方面均有驚人的進步，技術已達世界一流。就以開挖深度來論，台灣的深開挖工程已挖得非常深，例如北捷新蘆線道岔段的明挖深度已超過40公尺；民間建築案的地下室已挖至地下八層，開挖深度有達31.5公尺深者，而開挖20餘公尺者，比比皆是，已相當普遍；至於基樁工程施工最深者已達90公尺，而連續壁挖掘最深者亦達100公尺。再以施工困難度來論，台灣的深開挖工程「困難度」很高，幾個都會區都屬疏鬆軟弱的沖積土層，地下水位又高，施工困難度高，又大部份建案密度高基地小，往往緊鄰建物施築，稍有不慎，極易造成損鄰事件，甚或災變，台北高雄捷運的施工均曾發生數次大型災變，而民間建築案地下開挖之損鄰事件更是頻傳。

英文篇名

A Case Study on Deep Excavation of High-rise Building near Kaohsiung Harbor Area

作者

陳楷仁、謝致德、邢敏、黃東開

關鍵字

壁樁、扶壁、地中壁、現地抽水試驗、祛水

摘要

本文介紹位於鄰近高雄港地區深開挖實例，其地質以粉土質砂與厚層粉土質粘土互層為主，偶夾砂質粉土或粉質細砂層，地下水位高且受潮汐影響，增加深開挖所產生之大地工程問題與作業之難度。本案例為地下五層、地上41層鋼骨海景住宅，面對此區困難地質條件及特殊之地下水文特性，須從地工設計及施工層面提出解決方案以降低深開挖之風險。本案例基礎開挖採逆打工法施作，逆打鋼柱為矩形壁樁，擋土結構為連續壁，配合地中壁、扶壁之配置，及利用樓板與扶壁接合以提供臨時支撐之構想，抑制開挖期間擋土結構之側向變位與增加開挖之穩定性。為確認75m深壁樁之承載力，基地開挖前先進行壁樁載重試驗，以確認壁樁能承受上部結構吊裝荷重。此外，施工前重新檢視地質資料尋求可能存在之透水層，並進行現地抽水試驗以求得相關水理參數，以為加設深水井祛水之依據。本案例順利完成於困難
地質區域之深開挖工作，可為後續於高雄臨港地區其他案例施工之參考。

英文摘要

The site locates near Kaohsiung Harbor area, the characteristics of site geology is soft and loose soil with high and tide-influenced ground water table, The soil is mainly composed of slity sand, sandy silt and clayey silt stratum mixed with sandy silt layer. This paper illustrates an actual case on deep excavation for a high-rise building in seafront area.
The project is a 41-story high-rise building with 5-level basement, the basement was built by top-down construction method. Diaphragm wall with cross and buttress walls, which connected to the B4F slab, is adopted to reduce the
deflection of diaphragm wall and enhance the stability during excavation. The steel column embedded in 75-meter-long barrette piles were used to support the whole steel structure. A pile test for the barrette pile was conducted at site to
ensure adequate capacity. In addition, the bore hole data were reviewed to understand the possible permeable layer, and the pumping test was carried out at site to obtain the relevant hydraulic parameters in order to design additional deep
wells to deal with the ground water issues. This study would be a good reference for the design and construction of similar difficult project near Kaohsiung Harbor area in the future.

英文篇名

A Case of Deep Excavation with Ground Elevation Difference

作者

石朝松、程日晟、林婷媚

關鍵字

深開挖、地面高程差

摘要

近年都市精華地區建築物需求大，雖然大多已是高密度開發，仍然供不應求，以致於地價及房價快速攀升，而且居高不下，因此新的開發案早已由平地進到山麓地帶，是故出現地面高程差的基地深開挖，便無可避免。
本文藉由一地面高程差大之深開挖案例，說明當深開挖基地存在地面高程差時，在地層分佈、擋土結構、支撐系統等地工問題上的複雜性及變異性，在設計分析上較同一高程地面深開挖基地來得繁複許多。

英文摘要

The needs for urban building are especially big in recent years. Though most of the core areas have already been highly developed, it still cannot fulfill the needs and lead to the sky high costs of the land as well as building. Due to the scarcity and the high cost of the land, many new developing projects have spread from the plains into the foothills. And construction with deep excavation with ground elevation difference is inevitable.
This article uses a real case on the deep excavation with ground elevation difference to demonstrate the complexity and variability on design, analysis, and construction in the geotechnical engineering issues on stratigraphical distribution, retaining structures, strutting systems etc., compared to those projects on the same ground level.

英文篇名

Case Histories on the Narrow Lane Effects for Deep Excavations in Urban Area

作者

簡茂洲、簡子崴

關鍵字

深開挖、窄巷效應、壁體變位、地表沉陷

摘要

本文討論都會區深開挖工程一類較為異常之現象，即所謂之「窄巷效應」(Narrow lane effect)。窄巷效應乃是因都會區相鄰深開挖基地間往往僅有一巷之隔，兩基地開挖之主被動區交互重疊，且土壤受到兩次擋土及開挖作業之擾動，致使後施工開挖基地之擋土結構變位遠大於預期，且兩深開挖基地間窄巷之地表沉陷較經驗值亦超過甚多。就土壓力理論而言，兩基地間所夾之土壤為有限寬度之土體，且受巷道兩側擋土牆之束制，其作用於新建工程擋土牆之土壓力應低於理論主動土壓力，故新建工程窄巷側之擋土壁側向變位應低於預期，而壁體變位所引致之地表沉陷亦應低於預期。但有某些相鄰深開挖工程所表現之行為與預期狀況相反，窄巷側之壁體變位及地表沉陷皆遠超過其他側之數值。本文以實際案例呈現窄巷效應所造成之影響，希能提供學術研究及設計者對深開挖行為分析的新思考方向。

英文摘要

This paper presents a less known phenomenon in the field of deep excavation, namely, the narrow lane effect. The narrow lane effect describes the overlapping effects on the active and passive pressures of two adjacent deep excavation sites separated only by a narrow lane. As noted in the field, the lateral deformation of retaining wall and the associated ground settlement as a result of the narrow lane effect often exceed the empirical values by a large margin. It is a general belief that the soil mass sandwiched between two adjacent sites tends to yield less active pressure compared to that of an unconfined soil mass, and as a consequence, the resulting lateral wall deformation and ground settlement should be less than expected. However, the field behaviors of some deep excavations show the contrary, wall deformation and ground settlement on the narrow lane side are much higher than other sides free of the effects of adjacent basement. This paper presents case histories that exhibit narrow lane effects. It is hoped that these data serve as a good reference to designers and can be used by academic field as a basis for future researches.

英文篇名

Geotechnical Design of the TRA Kaohsiung Underground Railway in District DL01

作者

陳聰海、吳文隆、彭家德

關鍵字

鐵路地下化工程、明挖覆蓋工法、連續壁、圍堰

摘要

鐵路地下化為都市邁向現代化的重要指標，因都會區人口稠密、鄰房密集且腹地狹小，設計階段需特別考量施工之安全性及期程管控。國內鐵路地下化工程一般採明挖覆蓋工法施工，其工程特性為緊鄰營運中之臺鐵軌道，為確保連續壁槽溝穩定及深開挖安全，本工程採行：(1)橫交橋墩路口採CCP進行連續壁槽溝保護；(2)規劃小單元連續壁，縮短連續壁施工時間；(3)公、母單元均包覆帆布，降低連續壁包泥機率；(4)連續壁內預埋PVC管，以利超音波檢測壁體品質，並可據以評估是否於開挖前進行補強作業。此外，取消標準段中間樁及回撐，達到減少施工界面，縮短施工期程之目的。高雄鐵路地下化工程需穿越寬約75m愛河，過河段之隧道採用圍堰工法分三階段施工，因應主管機關汛期不得於河中施工之規定，設計河道版半逆打工法，以利汛期時可持續於河道版下方進行臺鐵隧道開挖作業。

英文摘要

Underground railway is an important index for a city step toward modernizing. Because of densely population, build-up area and small hinterland in urban area, the safety of construction and time management should be specially considered in design stage. Domestic underground railway in general is to adopt the cut and cover method, which is against the operating TRA railway. In order to protect guide ditch of diaphragm wall and to ensure safety of deep excavation, there
are some measures adopted including 1) using CCP to protect guide ditch of diaphragm wall at intersection and bridge pier; 2) working out small unit of diaphragm wall to shorten work schedule; 3) all panels covered with canvas to reduce interfacial adhesion between clay and diaphragm wall; 4) embedded PVC in diaphragm to help using ultrasonic testing the quality of diaphragm wall and in accordance with testing result to assess whether to strengthen the wall or not. Moreover, canceling post and re-strut can reduce construction interfaces to shorten the time schedule. TRA Kaohsiung underground railway project needs to pass through the 75m Love-river and the river-crossing section of tunnel is adopted the three stages of cofferdam construction method. To cope with the regulations of authority about avoiding construction in river during flood season, river slab of semi-top down construction method is designed, and it can be benefited at TRA tunnel excavation under river slab.

英文篇名

Case Study of Urban Renewal Excavation Utilizing Original Diaphgram Wall

作者

郭晉榮、林永光、洪菁隆、夏沛禹、張文海

關鍵字

建物更新、連續壁、地盤改良

摘要

本案例基地狹小，加上基地內存在一舊地下三層地下室結構及深25m之連續壁，建物更新時擋土措施之規劃及施工對工程人員是一大考驗，依本基地現況條件，如規劃施作新連續壁作為開挖擋土措施，工期相當耗時，且費用相當高。因此本案例利用舊有原地下三層的地下室結構(基礎深度14.2m)及舊連續壁(深25m、厚70cm)，配合地下室內側新建之H型鋼擋土排樁及基地內配置圓形密接地盤改良樁，並採用順打工法及部份樓版逆築連結舊連續壁及新設排樁之方式，來完成新建地上15層及地下四層(基礎深度21.5m)的新建築物。
本文之都市更新案例，基地面積僅約583平方公尺，舊建物為地上12層、地下3層之大樓，
基地周長約80m，基礎深度為14.2m，連續壁為厚度70cm、深度為25m。新建基地之地下室全
規劃於舊連續壁範圍內，基礎開挖深度為21.5m，擋土排樁為H414×405×18×28mm、長度為
34m。本文敘述說明於新舊基礎不同衝突處之開挖擋土工法規劃及設計上之考量，希望能提供
各位工程先進在遭遇類似工程時之參考。

英文摘要

This paper reports renovation of a building project, 12-story high added by a 3-story underground basement covering area of 583 m2 in Taipei. Perimeter of the planned site is 80m. The foundation depth and the slurry wall depth are 14.2m and 25m, respectively. In addition, the slurry wall thickness of this old building is 70cm. The new building foundation planned to sit inside the slurry wall area of the old building. New building is expected to excavate down to 21.5m, with drilled shafts H414×405×18×28mm installed down to 34m. The new foundation construction is firstly by taking advantage of the available basement structures of the old building and old slurry wall and by incorporating with the to-be-installed drilled shafts inside the basement and water tight cylindrical ground improvement piles to increase the strength of clay in the passive resistance zone. In addition, combining the top-down and bottom-up construction procedures by taking advantage of utilizing part of the floor slab to connect old slurry wall and newly installed drilled shafts to complete the building project.

英文篇名

Underground Construction of Taipei Twin Tower

作者

周家瓊、李守原、何樹根、黃一昌、林建宏、陳鴻濤、林聿羣

關鍵字

橫置連續壁、地中壁、扶壁、祛水、隆起

摘要

臺北市的都市發展遇到最大的瓶頸是建築用地不但取得困難且非常昂貴，大型的建築工程已非常少見，位於臺北車站特定專用區C1及D1用地的雙塔結構，為桃園國際機場聯外捷運系統臺北車站之聯開共構大樓，是近年少見的大面積開發，預計興建56層及76層之大樓各一棟，地下室跨越重慶北路東西兩側的街廓，開挖面積達25,775m2，深度27.1m。本案因為開挖面積大因而大量採用分區橫置連續壁、地中壁及扶壁；地下結構則採用鋼骨混凝土，開挖採用順打內支撐工法，因而地下鋼構需在層層支撐及分區連續壁的阻隔中吊裝；又因用地交付之時程不同，C1及D1之開挖時程不相同，增加了施工的複雜性及困難度。本文介紹本計畫地工設計之構想及
實際施工時遭遇的挑戰及克服方法，而地下室開挖過程中地表監測量得有隆起的特殊現象，因而本文一併介紹前述隆起之各項監測成果。

英文摘要

In Taipei City， a large area underground structure construction is seldom seen recently. The Twin Tower project is the one. Two high rise buildings, one is 56 floors and the other is 76 floors, were planned. They were planned to use one
basement which has 4 floors underground. This underground structure is also the starting station of Taoyuan airport rapid transit system and it has been constructed before the two towers. Because of the large excavation area, 25,775m2, the excavation and construction met a different problems from ordinary underground structure. This paper introduced the design and construction ideas. The hydraulic pressure released via dewatering in the Chingmei Gravel Layer are also introduced. When large amount of soil were removed in this case, monitoring data indicated that heavings occurred. This data was also introduced in this paper.

英文篇名

Efficiency of Installation with Cross Walls and Buttress Walls in Deep Excavation

作者

何政道、陳水龍、葉家佑

關鍵字

開挖、扶壁、地中壁、變位折減率、三向度有限元素法

摘要

在軟弱地層之深開挖工程，地中壁及扶壁經常被用來減少擋土壁體之側向變形量，目前已累積許多成功案例，顯示地中壁/扶壁的設置，對於抑制連續壁側向變位及開挖之穩定性皆有所貢獻。地中壁/扶壁之行為實際上屬於複雜之三向度問題，惟目前工程實務上，常簡化使用二向度之方式來分析，並無法有效模擬地中壁/扶壁與土壤之互制行為。本研究為了瞭解地中壁/扶壁間距對連續壁側向變位的影響，採用位於台北市深開挖16m之工程案例。以三向度有限元素法進行模擬，分析結果顯示與現場觀測資料頗為吻合，後續採用該模型進行一系列的研究。分析結果顯示，地中壁抑制連續壁側向變形之效果比扶壁好。本研究案例之扶壁變位折減率(DRR)約可達到50% (SBW/He=0.375)，地中壁變位折減率約可達到77.5% (SCW/He=0.55)。

英文摘要

Cross walls and buttress walls have been widely adopted, with many successful cases, in soft ground excavation work. The field instrumented displacement data indicated that cross walls and buttress walls could effectively reduce the lateral displacement of diaphragm wall and thus enhance the stability of the excavation work. The interaction between the soil/cross/buttress- and diaphragm walls is a three dimensional problem but in practice, due to the complexity of three-dimensional analysis, the problem is commonly simplified into a two-dimensional problem. This study aimed at examining the influence of the space of the cross/buttress walls on the displacement of diaphragm wall via a series of
three-dimensional FE analysis. The numerical procedure was first calibrated against the field data obtained from a 16m deep excavation real case in Taipei city. The FEM simulated results were consistent with the field monitored data. The
basic model was then used in the subsequent parametric study to evaluate the efficiency of buttress walls and cross walls in deep dxcavation. It was found that the cross walls were more efficient than the internal buttress walls on reducing the
displacement of the diaphragm wall. These results were evaluated and compared through the so-called displacement reduction ratio (DRR). The results indicated that the DRR of buttress walls and cross walls were 50% (for SBW/He=0.375)
and 77.5% (for SCW/He=0.55), respectively.

英文篇名

Analytical Rotational Performance Curve of a Rigid Footing

作者

邱俊翔、柯永彥、黃俊鴻、陳正興

關鍵字

獨立基腳、性能曲線、彎矩強度、降伏點

摘要

獨立基腳或擴展基礎之旋轉反應是工程設計之主要檢核項目之一，本文應用溫克基礎模式推導其受彎矩作用所產生旋轉角之無因次解析解，包括地盤情況為彈性土壤與完全彈塑性土壤兩種情況。根據解析解所得性能曲線之特性，藉以檢討現行設計規定之合理性，並建議簡化之性能設計曲線，供工程分析參考使用。研究結果顯示工程設計時獨立基腳之降伏點可取接觸面積減為50%之情況，性能曲線超過此點之斜率變得非常平緩，基礎彎矩強度隨旋轉角加大之增幅不大，而軸力為基腳彎矩強度之重要影響因子，其中小軸力之設計載重條件為較不利之情況。

英文摘要

The rocking response of a footing or spread foundation is essential to its stability and performance. The analytical dimensionless performance curves of a rigid footing are presented in this paper for the cases of elastic and elastoplastic
soils. Based on that, performance-based design criteria for the rotational response of a rigid footing are suggested for engineering applications. The rotational yield point of a footing shall be set at the condition when the foundation contact area has been reduced to 50% of the total foundation base area. Beyond this point, the slope of the performance curve becomes very gentle, so the moment resistance of the footing cannot increase much with respect to larger rotations. In addition, the axial force is an important factor influencing the rotational resistance of the footing, in which the case with low axial force is a disadvantage design condition.

英文篇名

Earth Pressure and Forces Acting on RC Lining of a Taipei MRT Shield Tunnel

作者

張桂才、余念梓、游澄發、王莉瑛

關鍵字

潛盾施工、RC 環片、背填灌漿、近接施工、自動化監測、環片土/水壓及內應力

摘要

本文探討台北捷運松山線CG590A施工標RC環片土/水壓及內應力監測結果，說明RC環片土/水壓計及鋼筋計裝設方式及配置，RC環片內應力分析方法，環片組裝及背填灌漿時，先行隧道受後行隧道近接施工，以及CG290及CG291子施工標隧道環片分別長達約400天及800天長期自動化監測作用於環片之土壓及內應力變化情形。

英文摘要

This paper study the earth pressure and member forces acting upon Taipei MRT shield tunnels RC lining based on real time monitoring results. Planning of installations of earth and water pressure cells , rebar strainmeters for RC lining,
as well as methodology for axial forces and bending moments calculated in RC lining, the monitoring results during the assembled of lining, back-fill grouting ,close proximity constructions and long term real time records about 400 days for CG290 projects and 800 days for CG291 projects were discussed.

作者

鄧源昌、黃俊鴻

摘要

阿里山森林鐵路為世界聞名之高山鐵路之一，有其重要之文化意義與保存價值。但在98 年莫拉克颱風之高降雨強度及長降雨延時侵襲下，造成阿里山鐵路數十個路段邊坡坍滑、路基流失，致使阿里山鐵、公路無法正常通行。後續相關復建工程隨即如火如荼的展開，復建工程中又以多林與二萬坪大規模崩塌地之整治與對應之鐵路隧道設計施工對策為特色。故地工技術基金會特於103 年4月17 日至18 日於阿里山地區舉辦本次研討會， 由台灣大學土木系林銘郎教授擔任領隊，並邀請嘉義大學森林暨自然資源學系李嶸泰教授及中興工程顧問公司劉弘祥工程師與蕭丁槐地質師擔任解說，參與學員一行共38 人。感謝主辦單位充分準備、解說老師除精闢闡述崩塌地與隧道之工程地質與介紹相關地工技術，亦在自然人文方面多加著墨，使各學員不僅工程知識滿載而歸，人文氣息更上層樓。