【正文】 te core walls. The embankments were built using a modified hydraulic fill method. This method consisted of dumping the sand and then sluicing the sand into the desired location. Croton Dam is classified as a ??highhazard‘‘ dam and is in earthquake zone 1. As part of the FERC Part 12 Inspection (FERC 1993), an evaluation of the seismic stability was performed for the downstream slope of the left embankment at Croton Dam. The Croton Dam embankment was analyzed in the following manner. Soil parameters were chosen based on standard peration (N) values and laboratory tests, and a seismic study was carried out to obtain the design earthquake. Using the chosen soil properties, a static finiteelement study was conducted to evaluate the existing state of stress in the embankment. Then a onedimensional dynamic analysis was conducted to determine the stress induced by the design earthquake shaking. The available strength was pared with expected maximum earthquake conditions so that the stability of the embankment during and immediately after an earthquake could be evaluated. The evaluation showed that the embankment had a strong potential to liquefy and fail during the design earthquake. The minimum soil strength required to eliminate the liquefaction potential was then determined, and a remendation was made to strengthen the embankment soils by insitu densification. Seismic Evaluation Two modes of failure were considered in the analyses—namely, loss of stability and excessive deformations of the embankment. The following analyses were carried out in succession: (1) Determination of pore water pressure buildup immediately following the design earthquake。 more and more owners are ing to realize that the cost of restoring their facilities is taking up a significant fraction of their operating budgets. Rehabilitation is, therefore, being a major growth industry for the future. In embankment dam engineering, neither the foundation nor the fills are premanufactured to standards or codes, and their performance correspondingly is never 100% predictable. Dam engineering—in particular, that related to earth structures—has evolved on many fronts and continues to do so, particularly in the context of the economical use of resources and the determination of acceptable levels of risk. Because of this, therefore, there remains a wide variety of opinion and practice among engineers working in the field. Many aspects of designing and constructing dams will probably always fall within that group of engineering problems for which there are no universally accepted or uniquely correct procedures. In spite of advances in related technologies, however, it is likely that the building of embankments and therefore their maintenance, monitoring, and assessment will remain an empirical process. It is, therefore, difficult to conceive of a set of rigorous assessment procedures for existing dams, if there are no design codes. Many agencies (the . Army Corps of Engineers, USBR, Tennessee Valley Authority, FERC, etc.) have developed checklists for field inspections, for example, and suggested formats and topics for assessment reporting. However, these cannot be taken as procedures。 附錄一 外文翻譯 英文原文 Assessment and Rehabilitation of Embankment Dams Nasim Uddin, ., Abstract: A series of observations, studies, and analyses to be made in the field and in the office are presented to gain a proper understanding of how an embankment dam fits into its geologic setting and how it interacts with the presence of the reservoir it impounds. It is intended to provide an introduction to the engineering challenges of assessment and rehabilitation of embankments, with particular reference to a Croton Dam embankment. DOI: (ASCE)08873828(2021)16:4(176) CE Database keywords: Rehabilitation。 they serve as guidelines, reminders, and examples of what to look for and report on, but they serve as no substitute for an experienced, interested, and observant engineering eye. Several key factors should be examined by the engineer in the context of the mandate agreed upon with the dam owner, and these together with relevant and appropriate putations of static and dynamic stability form the basis of the assessment. It is only sensible for an engineer to mit to the evaluation of the condition of, or the assessment of, an existing and operating dam if he/she is familiar and fortable with the design and construction of such things and furthermore has demonstrated his/her understanding and experience. Rehabilitation Measures The main factors affecting the performance of an embankment dam are (1)seepage。 (2) estimation of strength for the loose foundation layer during and immediately following the earthquake。 引言 水利或其他工程上的許多大型設(shè)備，已經(jīng)非常陳舊且磨損嚴(yán)重；更多的業(yè)主逐漸意識到維護(hù)設(shè)施的費用在運營成本里所占的比重越來越大。因此在該領(lǐng)域，仍存在多種改進(jìn)意見和實踐方法。許多機(jī)構(gòu)（美國陸軍工程兵團(tuán)，田納西流域管理局，聯(lián)邦能源監(jiān)管委員會等）已經(jīng)開發(fā)出用于實地檢測的核對表，例 如，可 行的評估報告和主題。如果工程師熟悉并習(xí)慣于設(shè)計建造大壩，并且對該領(lǐng)域有足夠的了解且有豐富的工程實踐經(jīng)驗，這種評估報告則是工程師們所能提交的唯一合理的報告。為提高大壩的穩(wěn)定性，防止?jié)B漏管涌所采取的措施取決于溢出點位置（地基還是壩體），滲流量及其臨界值。最后加高土壩通常是相對簡單的填充操作，尤其是加高程度相對較小的填充操作更為簡 單。通常，需結(jié)合多種解決措施，如安裝一個帶減壓系統(tǒng)的截流器。大壩因維護(hù)措施不完備而遭受重大損失的例子是很常見的。 案例研究 克羅頓大壩工程坐落于密歇根州境內(nèi)的馬斯基根河上。土石壩的填筑采用改進(jìn)的水力沖填方法。按以下方式對克羅頓堤壩進(jìn)行分析。將堤壩的現(xiàn)有強(qiáng)度與預(yù)期最大地震影響進(jìn)行比較，這樣就可以對堤壩在地震期間以及震后瞬時的穩(wěn) 定性進(jìn)行評估。 液化影響評價 根據(jù)修正的后的標(biāo)準(zhǔn)貫入試驗值的平均值和循環(huán)應(yīng)力比，在總共沉降的（ 15 英尺）松散圖層中 ，由于液化產(chǎn)生的沉降為 （ 英尺）。 堤防整治 基于上述分析結(jié)果，建議通過現(xiàn)場壓實的方法加固大壩。使用不同的強(qiáng)度和幾何參數(shù)以確定最小剪力強(qiáng)度和最小的土壤加強(qiáng)帶。第三，基于最小土壤加強(qiáng)帶和最大土壤加強(qiáng)帶的數(shù)值重新評估沙礫的液化潛能，以顯示假設(shè)大壩加固到最低值，那時在壩體左側(cè)下游坡面的潛在液化危險是否被消除。 6a*CZ7H$dq8Kqqf HVZFedswSyXTyamp。 qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkum amp。 qYpEh5pDx2zVkum amp。 qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkum amp。 QA9wkxFyeQ^! dj sXuyUP2kNXpRWXm Aamp。 gTXRm 6X4NGpP$vSTTamp。 qYpEh5pDx2zVkumamp。qYpEh5pDx2zVkumamp。qYpEh5pDx2zVkumamp。 qYpEh5pDx2zVkum amp。 QA9wkxFyeQ^! djsXuyUP2kNXpRWXm Aamp。 gTXRm 6X4NGpP$vSTTamp。 gTXRm 6X4NGpP$vSTTamp。 gTXRm 6X4NGpP$vSTTamp。gTXRm 6X4NGpP$vSTTamp。gTXRm 6X4NGpP$vSTTamp。 gTX