土石壩的評(píng)估和修復(fù)畢業(yè)設(shè)計(jì)外文翻譯-其他專(zhuān)業(yè)-預(yù)覽頁(yè)
【正文】 study is presented as an introduction to the engineering challenges of embankment rehabilitation, with particular reference to the Croton Dam Project. Case Study The Croton Dam Project is located on the Muskegon River in Michigan. The project is owned and operated by the Consumer Power Company. The project structures include two earth embankments, a gated spillway, and a concrete and masonry powerhouse. The earth embankments of this project were constructed of sand with concrete 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。本文旨在通過(guò)對(duì)克羅頓堤壩進(jìn)行的的案例分析，介紹大壩評(píng)估和修復(fù)過(guò)程中會(huì)遇到的技術(shù)難題。大壩建造工程，尤其是土質(zhì)結(jié)構(gòu)工程，在許多方 面已經(jīng)取得進(jìn)步并將繼續(xù)改進(jìn)，特別是在節(jié)約資源和可接受風(fēng)險(xiǎn)水平的測(cè)定方面更是需要改進(jìn)。因此，如果沒(méi)有統(tǒng)一的設(shè)計(jì)規(guī)范，很難制定出一套嚴(yán)格的對(duì)建成大壩的評(píng)估制度。在業(yè)主同意施工后，工程師應(yīng)該檢測(cè)幾個(gè)關(guān)鍵因素，這些因素相關(guān)的，結(jié)合適當(dāng)?shù)撵o態(tài)和動(dòng)態(tài)穩(wěn)定性的計(jì)算結(jié)果，就形成了評(píng)估報(bào)告的基礎(chǔ)。失穩(wěn)則會(huì)導(dǎo)致壩體開(kāi)裂，反過(guò)來(lái)會(huì)導(dǎo)致滲漏和腐蝕。如果擔(dān)心快速水位下降情況下的上流坡面的穩(wěn)定性會(huì)下降，那么深入分析或監(jiān)測(cè)產(chǎn)生的孔隙水的壓力或微調(diào)水庫(kù)的操作方式會(huì)消除（對(duì)于失穩(wěn)）的顧慮。然而，單靠這一解決措施，大壩修復(fù)程度收效甚微。在大壩修復(fù)過(guò)程中，必須高度重視建成大壩的安全問(wèn)題。接下來(lái)的文章里，將對(duì)克羅頓大壩工程維護(hù)案例進(jìn)行分析，以此來(lái)介紹大壩修復(fù)過(guò)程中可能遇到的問(wèn)題。工程中的土石壩屬于砂石混凝土心墻壩。對(duì)克爾頓壩左側(cè)下游斜坡進(jìn)行的震后穩(wěn)定性評(píng)估是聯(lián)邦能源監(jiān)管委員會(huì)的 1993 年的監(jiān)測(cè)項(xiàng)目第 12 部分中的一部分。然后進(jìn)行一維動(dòng)態(tài)分析，以確定設(shè)計(jì)地震烈度引起的應(yīng)力。 抗震評(píng)價(jià) 在分析中考慮了兩種失敗模式，即大壩失穩(wěn)和大壩過(guò)度變形，緊接著又進(jìn)行了如下分析：（ 1）震后瞬時(shí)的孔隙水壓力測(cè)定；（ 2)震后松散地基表面評(píng)估；（ 3）震后對(duì)大壩填土中的疏松砂巖層的液化程度分析；（ 4）震后砂巖層液化產(chǎn) 生的影響。因此，可以得出結(jié)論：在地震發(fā)生后由于液化引起的沉降超過(guò) （ 英尺），將引起邊坡的失穩(wěn)，最終將導(dǎo)致堤壩發(fā)生顯著的永久變形。第一，進(jìn)行對(duì)大壩下游左側(cè)斜坡的穩(wěn)定性測(cè)試。根據(jù)這個(gè)值，進(jìn)行反算來(lái)確定最小慣入標(biāo)準(zhǔn)值。
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