作者

編者的話

摘要

作者

董家鈞

摘要

地工人的「地工技術」，像是很多五、六年級生的「讀者文摘」或「電視週刊」，當收到雜誌時，總是迫不急待的，想要看看當期特定主題所帶來的新觀念與新技術，或是各類有趣的、重要的工程案例。要說「地工技術」是陪著許多地工同儕長大的一本雜誌，並不算是誇張的說法。對於本人而言，與這本雜誌千絲萬縷的關係，可能讓本人跟「地工技術」的情感，比一般的地工同儕多了一些些。藉本次贈言機會，抒發一下，並順道留下個人經歷過、與「地工技術」有關的記憶，期能引發地工同儕小小的共鳴。若發現跟過去贈言風格有所不同，也請資深讀者們見諒。
就讀大學期間，大地組教授們偶而會拿「地工技術」刊登文章作為補充教材，而那些補充教材可能就是許多地工人認識「地工技術」的開始。對一個20歲出頭的大學生而言，「地工技術」創刊前輩們的地位就像是“神”一樣的崇高，而基金會贊助人在學生們的眼中，也都是“非仙即佛”的學者、專家。碩士班期間，開始有機會寫作業或做專題，經常需要從「地工技術」的文章中找材料，因此，這本專業雜誌成為碩士生作業或專題報告重要的參考文獻，我們也開始比較有能力以比較系統性的方式閱讀本雜誌。碩士班畢業，開始準備大地技師考試，「地工技術」又成為重要的“武功秘笈”，特別是大地施工學這個科目，相信許多地工人都曾因為這本雜誌而多拿了幾十分。攻讀博士期間，本人第一次跟著教授投稿「地工技術」並被接受，於而立之年，看到自己的名字被刊登在「地工技術」文章第一頁，那種充滿榮譽感的悸動心情，到現在都還印象深刻。
畢業後於大地技師執業期間，本人還是維持著閱讀「地工技術」文章的習慣，工作上遇到的疑難雜症，常常可以從大地工程產、官、學界菁英所撰寫的文章中找到解方，或是引領找到答案的方向。相信許多不在大公司、沒有前輩引領的執業大地技師，應該會特別感到心有戚戚焉。另外，本人於執業期間正式加入地工技術基金會大家庭，成為許多地工人夢寐以求的基金會贊助人，並於35歲時開始“終生”免費收到「地工技術」，且享有每年獲邀參加地工基金會春酒的資格。
因生涯選擇，本人執業數年後轉職成為大學教授。這段期間開始受邀替「地工技術」審稿，體會到期刊文章同儕審查是怎麼一回事。接著在接近不惑之年，因緣際會擔任了「地工技術」專輯主編，更進一步了解到每期的「地工技術」出版之繁瑣、艱辛的過程，以及諸多“幕後的藏鏡人們”是多麼勞心、勞力的完成基金會交付之雜誌出版任務。
或許因為熱心參與基金會各類活動，在45歲時受主編邀請開始參與編輯委員會，並正式成為「地工技術」編輯群。在這個階段，認識到雜誌定位、執行方向、專輯主題產生方式，並開始了解經營一本雜誌有多少需努力克服之難題，以及認識到必須群策群力、考慮諸多面向後，才能產生重要決策。本人要特別感謝幾位總編輯、執行長與董事長看重，讓本人有機會擔任常務編輯，並於知天命之年時分別獲第十屆與第十二屆地工技術基金會董事會聘任為總編輯。在本人擔任總編輯這段期間，面臨諸多挑戰，包括整併編輯委員會與出版委員會、從實體雜誌走向電子化(編輯電子書)、以及長期支持雜誌之廣告主逐漸退休等等。萬幸的是，在基金會連續數屆的各委員會委員、主任委員、副執、執行長與董事長的通力合作下，這些問題大致上皆能獲得妥適之解決。
月初接獲「地工技術」雜誌靈魂人物李碧霞副執行長通知，總編輯與執行長推薦本人為 本期專輯「地工與地質模型不確定性之探討與應用」撰寫贈言，對即將年屆耳順之年的本人而言，這又進到一個與「地工技術」關係的新階段。能為「地工技術」撰寫贈言，都是受到各界敬重的人士與地工界的名師大儒，本人 獲邀，誠惶誠恐。推測受邀主因可能是近五年來，本人於產、官、學界到處爭取演講機會，推銷地質模型之不確定性量化及其對大地工程計畫風險之影響。因為擔心在贈言中再講太多，怕被嫌囉嗦，所以請讀者們自行閱讀本期專輯發表的多篇好文章。
驀然回首，與「地工技術」結緣已超過三十五年，從年輕學子到了可以寫贈言的這個階段，特別深深體會傳承的重要。這幾年很開心的看到許多年輕、優秀的地工夥伴，陸續加入地工技術基金會大家庭，並貢獻心力，燃燒自己，讓「地工技術」這本雜誌出版機器，可以繼續平順的轉動。本人衷心希望，退休後，還能每期收到「地工技術」，並坐在搖椅上開心閱讀著。

英文篇名

The Discussion of How to Present the Uncertainty of Engineering Geological Investigation Results

作者

丁禕、陳勉銘、許鈞傑、陸挽中

關鍵字

工程地質調查、不確定性、紀實性成果、分析性成果、地質模型。

摘要

我國規範土地利用開發或工程建設之法規眾多，儘管各法規所關注及規範之面向不同，但只要涉及土地與環境，皆要求在開發行為前，須進行地質調查以瞭解基地及周遭地區地質特性，及潛在之地質影響因素，提供充分地質資訊，以作為後續土地利用或工程規劃設計之基礎。爰此，需針對各法規特定需求，規劃合適之工程地質調查項目及方式。然而，凡調查必存在不確定性，本文研究工程地質調查中紀實性成果與分析性成果之不確定性類型與原因，並探討將各項地質調查成果建置為地質模型時，如何合理呈現各種不確定性。

英文摘要

In Taiwan, there are numerous regulations governing land development and engineering construction. Although these regulations focus on different aspects and areas, whenever land and the environment are involved, they all require geological investigations before development activities. These investigations aim to understand the geological characteristics of the site and its surrounding areas, as well as potential geological influencing factors. The purpose is to provide comprehensive geological information to serve as the foundation for subsequent land use or engineering planning and design. Given these specific requirements from various regulations, it becomes necessary to plan engineering geological investigation projects and methodologies appropriately. It is important to acknowledge that uncertainty is inherent in any investigation. This article discusses the types and reasons for uncertainty in both observational and analytical results in engineering geological investigations. Furthermore, it explores how to adequately represent these uncertainties when constructing geological models based on the outcomes of various geological investigations.

英文篇名

IAEG Guidelines for the Development and Application of Engineering Geological Models and Geological Model Uncertainty

作者

游中榮、詹佩臻

關鍵字

工程地質模型(EGM)、IAEG、不確定性

摘要

國際工程地質與環境協會(IAEG)在2019年制訂了「專案計畫工程地質模型之建構與應用指引」，其目的是根據工程的實際應用，提供簡潔、實用、易於理解和具專業水準之運用工程地質模型(EGM)的建議。EGM 是一個綜合、完整的認知框架，此框架是用來針對可能影響工程計畫及其工程特性的地質、地形和水文地質狀況等等條件，進行邏輯評估和解析。它代表對專案計畫中地質條件的理解，為整合工程地質知識提供框架，協助工程決策及評估潛在的大地工程風險。換句話說，建立EGM可以讓有經驗的專業人員預測專案計畫現場可能存在的情況、評估地下情況可能如何對專案計畫造成的不利影響。EGM包含建立假設模型(概念成分)及現場調查與監測(觀測成分)兩個要素，然而受限於地質的複雜變異性以及專案執行的種種考量，不論是在概念成分或是觀測成分，均會有相當程度的地質與地工不確定性，這些不確定性均會影響到工程專案所建立的EGM可靠度。地質模型是建立EGM的重要基礎，IAEG此份指引提供了一個建立EGM建議的作業流程，可以將建立地質模型的流程更明確化、減少建立地質模型的不確定性，並針對EGM進行適當的可靠度評估與審查，從而提升EGM的可靠度，降低工程專案風險。

英文摘要

In 2019, the International Association for Engineering Geology and the Environment (IAEG) established the ' Guidelines for the development and application of engineering geological models on projects,' aimed at providing concise, practical, easy-to-understand, and professionally sound recommendations for the use of Engineering Geological Model (EGM) based on engineering applications. EGM is a comprehensive cognitive framework used for logical assessment and analysis of geological, topographical, and hydrogeological conditions that may impact engineering projects and their engineering characteristics. It represents the understanding of geological conditions in a project and provides a framework for integrating engineering geological knowledge to assist in engineering decision-making and assessing potential geotechnical risks. EGM allows experienced professionals to predict potential site conditions for a project and evaluate how subsurface conditions might adversely affect the project. EGM consists of two components: the conceptual component, which includes building hypothesis models, and the observational component, which involves field investigations and monitoring. However, due to the complex variability in geology and various project considerations, both the conceptual and observational components exhibit a considerable degree of geological and geotechnical uncertainty. These uncertainties can affect the reliability of the EGM established for engineering projects. Geological Model is a fundamental basis for constructing an EGM. The guideline provided by IAEG offer an operational workflow for building EGM, making the process of constructing geological models clearer, reducing uncertainties associated with geological modeling, and allowing for appropriate reliability assessment and review of EGM to enhance their reliability and reduce engineering project risks.

英文篇名

Mapping Vs30 in Taipei Basin: Considering Stratigraphic and Geo-Property Spatial Variabilities

作者

盧育辰、林頤謙、董家鈞、簡宛瑩、洪汶宜、田永銘

關鍵字

地層模型不確定性、地工參數不確定性、空間變異性、隨機場、Vs30

摘要

本文提出一套考量地層層界與地工參數不確定性的地表下30公尺內之機率式平均剪力波速(Vs30)評估模式。本文係利用晚近開發的相依之地層及地工參數隨機場生成一系列地層以及與其相依的地工參數空間模型，並透過剪力波速(Vs)轉換式，將土壤孔隙比與垂直有效應力轉換為三維之Vs值空間分布，再將其轉換為Vs30平面圖，包括其平均值及不確定性。本文將研究成果與過去利用傳統方法獲得結果進行比較，以突顯本研究建議方法於呈現Vs30空間分布不確定性之優越性，以及地質模型對Vs30空間分布之重要性。

英文摘要

This paper proposed the probabilistic framework of “time-average shear wave velocity over the upper 30 m of ground surface” (Vs30) evaluation by considering the uncertainties of stratigraphic and geo-property models. The stratigraphy-and-geo-property dependent random field (SGDRF) is utilized to conduct a series of 3D stratigraphic and geo-property models based on borehole data herein. Then, a series of 3D spatial distributions of share wave velocity (Vs) can be obtained by substituting a series of 3D stratigraphic and geo-property models into the correlation model of Vs that consists of two geo-properties, i.e., void ratio and vertical effective stress. Through the travel-time relation, a series of spatial distributions of Vs30 can be transformed from a series of 3D Vs spatial distributions. The spatial distributions of the mean and standard deviation of Vs30 can be further obtained by counting a series of spatial distributions of Vs30. The simulation results are compared with the previous study, which demonstrates the superiority of the proposed method and the impact of geological knowledge on the evaluations of Vs30 and its uncertainty.

英文篇名

Development and Use of Geotechnical Performance Databases

作者

唐沖、方國光、卿建業

關鍵字

性能資料庫、載重試驗、預測競賽、隨機/認知不確定性、模型因數。

摘要

本文基於載重試驗資料庫、LCPC MOMIS數值模型校驗、國際預測競賽和ISSMGE調查報告“Are we overdesigning”，詳細分析了幾類地工結構性能預測的模型不確定性(包括基礎、邊坡與路堤、隧道與開挖、加勁擋土牆與土釘牆)。計算結果用模型因數(實測值/計算值)均值λ(偏差)和變異係數COV(離散程度)表示。最理想的模型因數是λ=1和COV=0。研究顯示：1.相關設計總體而言是偏安全的(承載力λ=1–3，沉陷λ0.6)高於承載力(COV

英文摘要

Based on performance databases, calibration of numerical model in LCPC MOMIS, results from thirty-four prediction events and ISSMGE global survey “Are we overdesigning”, the model uncertainty of predicting the performance of a variety of geotechnical systems is examined and characterized by the mean (λ, bias) and coefficient of variation (COV, dispersion) of model factor that is a ratio of measurement over prediction. The ideal model is characterized by λ=1 and COV = 0. It is demonstrated that 1. geotechnical analysis and design is generally on the safe side (stability: λ= 1–3 and deformation: λ< 1), 2. deformation or settlement prediction is of higher dispersion (COV>0.6) than capacity or stability analysis (COV < 0.6), 3. selection of relevant parameter values and analysis/design method depends heavily on engineer’s judgment that has the most significant effect on model factor statistics, 4. a sophisticated method does not necessarily give more accurate prediction than a simple model and the complexity of the model adopted should match the quality and quantity of data available, 5. engineer’s experience (from past stages of the same project or past projects at the same site, neighboring sites, or beyond) can effectively reduce the epistemic uncertainty. But Bayesian updating should complement engineering judgement where possible, because it makes better use of data and it addresses complex scenarios with greater logical consistency. Finally, three main characteristics of geotechnical practice are identified: site uniqueness, diverse norms and model imperfection.

英文篇名

Application of the Coupled Markov Chain in Soil Liquefaction Potential Evaluation

作者

盧之偉、李安叡、温修程、黃一平、曾俊傑

關鍵字

耦合馬可夫鏈、土壤剖面、隨機場、液化潛能。

摘要

關於區域性的液化潛能評估方法，現行的方式為先進行評估區域內各鑽孔之液化潛能評估，再以克利金(Kriging)方法內插計算鑽孔間之液化潛能指數，最終產出土壤液化潛勢地圖。然而，真實的地質結構是複雜且具不確定性的，這可能造成在設計、施工、營運的過程中發生誤判。故本研究使用耦合馬可夫鏈(Coupled Markov Chain，簡稱CMC)方法先進行地層剖面之產製與分析，將每個地質鑽孔之間的地層網格化，使地層變為數個虛擬鑽孔所組成，以均質及隨機場兩種方式進行土層參數之設定，最後進行液化潛能評估，並將其結果將於前述之傳統方式進行比較。本研究結果顯示，在本研究之鑽探資料範圍內，在使用CMC方法產製地層剖面之準確度高於傳統Kriging方法所得之結果。此外，於工程應用上，若採用CMC方法搭配隨機場土壤參數模型，建議可以計算該區域之出液化潛能平均值曲線後，並將變異係數(COV)設定為0.25，以保守估計液化潛能區間，此區間將包含傳統Kriging方法計算之液化潛能分析結果。

英文摘要

The evaluation of localized soil liquefaction potential is based primarily on the individual evaluation of the liquefaction potential in each borehole, followed by calculating the liquefaction potential index between boreholes through Kriging interpolation, and then plotting the liquefaction potential map. However, misjudgments in design, construction, and operation may occur due to the complexity and uncertainty of actual geologic structures. In this study, the coupled Markov chain (CMC) method was used to create and analyze stratigraphic profiles and to gridding the stratum between each borehole so that the stratum consists of several virtual boreholes. The soil layer parameters were established using homogenous and random field models, and the subsequent liquefaction potential evaluation results were compared with those derived using the Kriging method. The findings revealed that within the drilling data range in this study, the accuracy of the CMC model in generating stratigraphic profiles was greater than that of the Kriging method. Additionally, if the CMC method incorporated with random field parameters were to be used in engineering practice, we recommend that after calculating the curve of the mean, the COV should be set to 0.25 as a conservative estimation of the liquefaction potential interval that considers the evaluation results of the Kriging method.

英文篇名

Adaptive Kriging-Based Reliability Analysis for Slope Stability

作者

陳語晞、陳嘉村、J. Thedy、廖國偉

關鍵字

智慧訓練、坡地安全、不確定分析、反應曲面

摘要

本研究旨在找出對崩塌發生具有關鍵影響性的土壤參數或水文條件，本次檢測的隨機變數包含常見之地文與水文相關條件共七項；在邊坡運動過程上則使用可以模擬大規模變形物質點法來進行分析；又因邊坡為複雜系統，相關參數與模式的不確定性也需被合理量化，因此引入可靠度分析方法，利用MATLAB程式呼叫物質點法之分析結果，進一步建立克里金替代模型來進行失效機率的計算。最後透過對各參數進行敏感度分析，得出對於邊坡系統失效機率影響性最大的參數為土壤內摩擦角與凝聚力，本次結果與發展的分析技術可用以提供未來坡地防災管理參考。

英文摘要

This study aims to identify the soil parameters or hydrological conditions that have a critical influence on the occurrence of large-scale landslides. Seven common geotechnical and hydrological variables were included as random variables in this investigation. In the analysis of slope movement processes, Material Point Method which is capable of simulating large-scale deformations was employed. Given the complex nature of slopes, the uncertainties associated with relevant parameters and models needed to be adequately quantified. Therefore, a reliability analysis approach was introduced, utilizing MATLAB to interface with the material point modeling results. Subsequently, a Kriging surrogate model was established to compute the failure probability. Finally, through sensitivity analysis of each parameter, it was determined that the parameters with the greatest impact on the failure probability of the slope system are internal friction angle and cohesion. These findings along with the developed analytical techniques, can serve as valuable references for future slope disaster management efforts.

英文篇名

An Application of the Random Finite Element Method in Geotechnical Engineering

作者

梁維、葉馥瑄、蕭承熙、葛宇甯

關鍵字

隨機場有限元素法、PLAXIS2D、自動化分析

摘要

大地工程過去主要以定值法之極限平衡理論，輔以材料參數之參數分析，以達成考慮不確性於安全係數中。隨著有限元素法發展愈趨成熟，風險評估、可靠度分析設計須考慮土體參數的隨機變化，同時引入蒙地卡羅方法，對不同土層隨機場但相同邊界條件模型進行重複性分析，並透過機率法求得破壞機率，此分析過程重複且經需批量運算，因而顯示自動化控制之重要性。現今工程實務中以PLAXIS2D平台為主流，因此本研究以邊坡穩定性分析為例，於該平台下進行自動化隨機場邊坡分析，並對分析結果之安全係數進行機率統計與邊坡潛在破壞面進行歸類，藉此範例得以使隨機場與自動化方法更被廣泛地納入大地問題分析中。

英文摘要

A deterministic approach based on limit equilibrium theory has been adopted in conjunction with material parametric analysis to account for the uncertainty of the factor of safety in geotechnical engineering design and evaluation. With the advances of finite element method, risk assessment, and reliability design, the spatial variation of the soil properties can be quantified through random field theory and Monte Carlo simulation. Automation of this type of analysis becomes critical as it requires many simulations to obtain a probability of failure. The geotechnical finite element code PLAXIS2D has been frequently used in engineering practice for its intuitive and user-friendly interface. This paper incorporates an automation algorithm and random field assignment for the soil properties into the finite element code to perform slope stability analyses. Based on the random finite element method results, the safety factor is subjected to probabilistic slope stability analysis, and the potential failure surfaces of the slope are classified. We hope the developed methodology can be widely used in geotechnical engineering design and analysis.

英文篇名

Variance-Based Sensitivity Analysis for Soil Liquefaction Assessment

作者

宋佳霙、王瑞斌

關鍵字

土壤液化、大地參數、地質參數、敏感度。

摘要

本篇研究探討了大地工程和地質不確定性分別對土壤液化評估影響。研究以台北地區的土層數據進行敏感度分析。研究顯示，相較於大地工程不確定性，地質不確定性在土壤液化評估中影響較大。換句話說，不論在場址調查方面投入多少努力以獲取準確的大地工程參數，由於地質不確定性或地震動衰減中的自然隨機性，液化評估結果仍存在很大的不確定性。

英文摘要

This paper presents the study investigating the respective effect of geotechnical and geological uncertainties on soil liquefaction assessment. The study was on the basis of the data in Taipei, Taiwan. It shows that the geological uncertainty plays a dominant role on soil liquefaction assessment in comparison to geotechnical uncertainty. In other words, no matter how much efforts are spent on site investigation to obtain and make the geotechnical parameters as accurate as possible, the liquefaction assessment could be still subject to large uncertainty, due to the geological uncertainty or nature randomness in ground motion attenuation.

英文篇名

Study on the Uncertainty of Parameters in Site Specific Response Analysis for Taiwan Offshore Wind Farm

作者

陳湧文、江承家

關鍵字

特定場址地盤反應分析(SSRA)、土壤動態參數、土壤剪力波速。

摘要

離岸風電特定場址地盤反應分析(SSRA)之目的，係為評估設計地震歷時(反應譜)，於堅實地盤傳遞至風機位置所受之土層特性，以得到結構動力分析所需輸入之特定場址地震歷時(反應譜)。於地盤反應分析流程中，地質模型係依據場址調查結果進行建立，而輸入地震歷時則取自機率式地震危害度分析(PSHA)成果，整體分析流程之不確定性來源大致可分為：1.輸入地震、2.分析方式、3.土壤剪力波速、4.土壤動態參數。目前離岸風場地質調查較常採用圓錐貫入試驗(CPT)，然國內對於海床土壤及CPT試驗之相關研究較為缺乏，土壤分類及參數計算皆仰賴國外經驗公式。故本文主要係針對土壤剪力波速及土壤動態參數之不確定性進行探討，蒐集國內外文獻並就參數決定方式提出建議以降低不確定性，另說明土壤剪力波速計算方式對地盤反應分析之潛在影響，以供未來相關分析設計之參考。

英文摘要

The purpose of Site Specific Response Analysis (SSRA) is to assess the effect of the soil layer on design time series (response spectrum) transmitted from firm bedrock to offshore wind turbine location. The site specific time series (response spectrum) will be obtained for dynamic structural design use. In the process of ground response analysis, the geotechnical model is established by site investigation results; the seismic input is obtained from Probabilistic Seismic Hazard Analysis (PSHA) results. There are multiple sources of potential uncertainty in this analysis, including 1. soil shear wave velocity, 2. dynamic soil properties, 3. seismic input and 4. analysis method. The Cone Penetration Testing (CPT) is commonly used in site investigation. Since the research of seabed soil and CPT are insufficient in Taiwan, the soil property and parameter are evaluated by foreign empirical formula. Accordingly, this study focuses on the uncertainty of soil shear wave velocity and dynamic soil properties. The relevant data from domestic and international sources are compiled to provide recommendation for determining soil parameters. The potential influence on analyses from calculating shear wave velocity is also discussed in this study.

英文篇名

SPT-N Rod Energy Ratio and Its Effect on the Evaluation of Soil Liquefaction Potential

作者

黃富國、方健安、王淑娟、邵屏華、盧詩丁、邱禎龍、蘇泰維、謝有忠、王聖宗

關鍵字

標準貫入試驗、鑽桿能量比、土壤液化、液化潛能指數。

摘要

地震引致之土壤液化常造成建築物、橋梁及維生管線等基礎設施之嚴重損害。在以標準貫入試驗(SPT)之N值為基準的簡易液化評估法中，鑽桿能量比ER對液化潛能評估結果有很大的影響；但過去因ER資料較少而缺乏較有系統的研究，因此本研究乃蒐集過去幾年來，臺北市等九個縣市政府執行中級液化潛勢圖資計畫檢測所得之160個鑽孔，共1405筆之0~30m深度範圍的能量比ER數據，進行整理與迴歸分析，探討能量比ER與地層深度、土壤類別、SPT-N值、地下水位，及施作工班人員等因素之關係。並以臺北盆地為例，探討採用不同鑽桿能量比ER對液化潛能指數P_L之影響；此分析成果清楚顯示了液化潛能評估時，根據ER隨地表深度變化特性，進行SPT-N鑽桿能量比修正的重要性與必要性，尤其是近地表容易發生液化震損的範圍。

英文摘要

Seismic-induced soil liquefaction often causes significant damage to infrastructure such as buildings, bridges, and lifelines. It is essential to further study the potential of soil liquefaction. In the SPT-based method of liquefaction evaluation, the rod energy ratio (ER) of SPT-N has a large effect on the liquefaction potential. Therefore, 1405 data of ER from 160 boreholes had been collected and analyzed to explore the regression relationship of ER versus variable factors, such as depth, soil type, SPT-N value, water table, and person of drill. A case study of the Taipei Basin was conducted to investigate the influence of different ER on the liquefaction potential index of P_L. The results of the analysis clearly showed the importance and necessity of performing a correction for the SPT-N rod energy ratio based on the ER variation characteristics with depth when evaluating the liquefaction potential, especially in the shallow deposits where liquefaction damage is likely to occur.

英文篇名

Liquefaction Resistance Design for Raft Foundation (2023)

作者

謝旭昇、曾婷苓、林婷媚、黃于庭、盧之偉

關鍵字

液化、筏式基礎、地盤反力係數、容許承載力、地盤改良。

摘要

本文針對新版耐震設計規範及基礎設計規範有關土壤液化之相關條文，討論筏式基礎於土壤液化影響下之設計考量。新版與舊版設計規範皆可考量土壤液化後之殘餘強度，但新版規範可使用之折減係數遠低於舊版規範，因此基礎設計方式亦須相對調整。基本上仍以折減後之地盤反力係數及容許承載力，檢討筏式基礎是否符合結構需求。若筏式基礎之差異沉陷過大或承載力不足，則需考慮使用地盤改良消除液化潛能，或以地中壁、扶壁或基樁承擔部分或全部之結構荷重。本文以實際案例說明如何計算土壤液化後之地盤反力係數及容許承載力，同時亦簡要介紹土壤改良之設計方法，該方法著眼於提高改良後地盤之剪力波速以避免土壤產生液化。本文所提方法或許在理論上仍需更精進，但希望能多少解決新規範所造成之困惑。

英文摘要

This paper addresses some aspects regarding the raft foundation design under seismic condition. The previous and current design codes both allow the use of residual strength of liquefied soil for foundation design, however, the reduction factors stipulate in the current design code are much lower than the previous ones, and that requires the allowable bearing capacity and modulus of subgrade reaction for raft foundation design be adjusted to a much lower level accordingly. As a result of low bearing capacity and low spring constants, soil improvement or piles may be needed as part of the foundation system. Using design cases as background, this paper provides a systematic approach to calculate the allowable bearing capacity and modulus of subgrade reaction when liquefaction is of concern. A preliminary method for improvement design is also outlined in the example, which relies on increasing the shear wave velocity of improved ground to mitigate liquefaction potential. The design approaches sketched in this paper may have to be further theoretically refined, but it is hoped that these approaches can help to resolve some confusions related to the new design code.

作者

林錫宏、郭麗秋

摘要

林朝宗先生服務公職近40年，民國91年就任擔任經濟部中央地質調查所(以下簡稱地質調查所)所長，102年退休後，仍熱心推動各項地工及地質活動，疾呼專業工程地質的養成「從典型的地質學院教育做起」。112年7月12日這天一個輕鬆對話，看到一個專業、堅毅、果決的地質科學從業家，及其為地質後進建構的地質調查之路…。

作者

吳文傑、黃柏鈞、林榮潤、吳章諾

摘要