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1、<p>  附錄Ⅱ 外文資料及翻譯</p><p>  Straight to the source of seepage</p><p>  Jim Swaisgood, Jerry Montgomery and Val Kofoed report on the investigative work undertaken to discover the source of se

2、epage at River Reservoir dam in the US.</p><p>  Water seeping through an earthen embankment suggests a number of possible circumstances, and none of them are good. At best, the reservoir owner is losing a v

3、aluable commodity. The worst case scenario is that the seepage may be the precursor of dam failure. The first step in addressing a problem with seepage is as obvious as it is difficult: pinpointing its source. In the pas

4、t, procedures for determining the exact location and nature of seepage points have been both costly and time consuming. Of</p><p>  River Reservoir dam is an arched earthen structure on the headwaters of the

5、 Little Colorado River. It is located about 24km southwest of Eagar, Arizona, US, and is owned and operated by Round Valley Water Users Association (RVWUA). Based on very limited engineering, the dam was constructed by s

6、ettlers in 1896 of local materials and without a clay core. Due to recurring sloughing problems, the dam received significant modifications on at least four separate occasions. The embankment consists of c</p><

7、;p>  In 1996 additional riprap was installed to reduce the original slope of the upstream and downstream faces. A review of the early inspection reports revealed that the left abutment drain was constructed using tabu

8、lar rocks to create a box-shaped opening over the rock foundation. However, the contacts between these rocks were neither sealed nor grouted. There has been much speculation regarding the original purpose of this drain.

9、Most investigators believe that it was constructed to carry away wat</p><p>  In late March 2004 an unusual amount of water was observed to be seeping from the left-abutment weir box. This seepage contained

10、significantly higher than normal silt content. The path of the seepage was thought to be related to the supposed spring, its associated clay pipe, and the stone-box drainage system. Investigators feared the possibility o

11、f imminent dam failure. Emergency personnel were mobilised to the site to monitor and address the situation. RVWUA immediately contacted the State of A</p><p>  Aquatrack technology</p><p>  The

12、 manner in which the investigative work was done can only be fully appreciated when understanding how Willowstick’s AquaTrack technology works. AquaTrack uses a low voltage, low amperage, audio-frequency electrical curre

13、nt to energise the groundwater or seepage in question. Electrodes are placed strategically in wells, springs or surface water so as to induce electricity to flow through the groundwater system of interest. Because ground

14、water is a conductor, the electrical current will follow </p><p>  The AquaTrack instrument measures the voltage from each of the three sensors located at each measurement station. The measured values corres

15、pond to the strength of the magnetic field. For quality control, a base station is established within the survey area. The field strength at the base station is measured at the beginning, middle, and end of each field da

16、y. This data is used to identify any changes in the background magnetic field, such as diurnal drift. The magnetic field measurements collec</p><p>  In the case of the River Reservoir dam investigation, one

17、 electrode was installed in the lake approximately 244m south of the western abutment and a second was placed in the left abutment weir box, where the high silt content was observed (about 43m downstream of the crest of

18、the dam). These two electrodes were connected by heavy gauge wire and linked to a 400Hz power generator. An electrical current was then induced between the two electrodes. One hundred and seven magnetic measurements were

19、 th</p><p>  Mapping seepage</p><p>  Armed with this data, Willowstick produced maps of the preferential flow paths that existed between the reservoir and the left abutment weir box and its ass

20、ociated drainage system. This information was integral to the comprehensive remedy developed by the geotechnical engineers at TCB. Willowstick personnel mobilised rapidly on short notice and performed the investigation w

21、ork over a two day period. Preliminary maps were generated on an overnight basis. The final report was presented to TCB with</p><p>  The location of the leak was confirmed through dye tests performed immedi

22、ately after the magnetic field survey. Three different fluorescent dyes were used for the tracer work, fluorescein (green), eosine (yellow), and rhodamine WT (red). The rhodamine was placed in the middle section of the d

23、am near the old tabular-stone drain.</p><p>  Repair of the embankment began in August 2005 with the excavation of a V-notch cut. This was designed to expose and remove the alleged open stone drain that had

24、been assumed to exist as evidenced by the interpretation of historical records, the AquaTrack survey results and dye studies. Other investigatory techniques such as probing and exploration borings also contributed to the

25、 interpretation results. In September of the same year, the foundation level was reached and the excavator encountered </p><p>  At a distance of approximately 32m upstream from the downstream exit of the dr

26、ain, the opening was blocked with a grouted rock mass that had been constructed in an effort to seal the opening. Based on historical records, this seal was attempted prior to 1920, but was not effective. Just downstream

27、 from the seal, a drain channel was found to enter the main drainage tunnel at a sharp angle from the left abutment. This pathway was developed in a natural soil and rock channel under a log platform th</p><p&

28、gt;<b>  滲透水根源探究</b></p><p>  吉姆Swaisgood,蒙哥馬利和杰里-Kofoed關(guān)于開展調(diào)查工作以發(fā)現(xiàn)在美國(guó)的河水庫(kù)大壩滲水根源。 </p><p>  水流通過土堤滲透表明一些可能的情況,沒有一種情況是好的跡象。最好的情況就是水庫(kù)管理局失去了寶貴的商品,最壞的情況就是滲漏可能導(dǎo)致大壩失事。解決滲透問題第一步就是確定它的來源,困難那么

29、明顯。在過去,確定其精確位置和自然滲透點(diǎn)的方法步驟都很費(fèi)時(shí)費(fèi)錢。當(dāng)然,當(dāng)大壩的失事是瞬時(shí)的,那將以花費(fèi)更多的時(shí)間和金錢為代價(jià)的。工程師確定滲漏源的效率和速度可能在及時(shí)確定和由于沒有及時(shí)確定所導(dǎo)致的失事災(zāi)難是不同的。</p><p>  河水庫(kù)大壩是小科羅拉多源頭的土質(zhì)結(jié)構(gòu)拱壩。它位于美國(guó)亞利桑那埃哥達(dá)西南大約24千米處,是由圓谷水用水協(xié)會(huì)(KVWVA)所擁有和經(jīng)營(yíng)的。由于工程施工受到限制,大壩是1896年當(dāng)?shù)鼐用?/p>

30、用當(dāng)?shù)夭牧辖ㄔ?,而沒有采用粘土心墻。由于壩表土質(zhì)經(jīng)常剝落,大壩至少四次大的整修。壩堤是由長(zhǎng)335米,最大高程為21.3米的亞粘土碓石殼體構(gòu)成,且座落在玄武巖上部。</p><p>  在1996年,為了減小上游厚石坡度和下游坡面,大壩增建了額外的拋石體。早期的推測(cè)報(bào)告表明左岸壩肩排水孔利用tabular巖構(gòu)成,在巖基處形成了一個(gè)“盒”開孔。然而,這些巖石間的連接縫既沒有止水密封也沒有進(jìn)行灌漿。關(guān)于這個(gè)排水孔厚度的

31、用途,引出很多猜測(cè)。大多數(shù)調(diào)查者相信這個(gè)排水孔是用來排除常年存在于左岸壩肩內(nèi)部的積水。還有一種猜測(cè)是這個(gè)排水孔是為水庫(kù)暫時(shí)的節(jié)點(diǎn)。在2004年3月,在左岸壩肩檢測(cè)到一些不同尋常的滲水流,這比滲水流的一般水流含沙量要高。滲水路徑是被認(rèn)為與原先假定的水流有關(guān),它跟粘土管涌和“盒”形基巖排水系統(tǒng)有關(guān)。調(diào)查人員們擔(dān)心大壩會(huì)瞬間失事的可能性,緊急出動(dòng)人員到現(xiàn)場(chǎng)處理情況。KVWVA立即聯(lián)絡(luò)亞利亞那州,州政府同意撥款資助調(diào)查和后續(xù)修補(bǔ)工作。KVWVA

32、同時(shí)也爭(zhēng)取工程公司和Braden(TCB)公司(其與Willowstick共同合作)。TCB和Willowstick在調(diào)查和處理滲透日益嚴(yán)重情況方面有能力幫助KVWVA。</p><p>  Aquatrack科技</p><p>  當(dāng)了解Willow Stick's AquaTrach科技如何工作時(shí),調(diào)查工作就能唯一充分了解。AquaTrack公司利用低電壓,低電流,自動(dòng)頻率電

33、流去注入有滲漏問題的地下水。把電絲安置在壩體,地表水用來誘發(fā)電流,從而電流通過地下水系統(tǒng)。由于地表水時(shí)導(dǎo)體,電流會(huì)沿著導(dǎo)線間的地下水流動(dòng)。當(dāng)它通過地下水時(shí),產(chǎn)生一個(gè)磁場(chǎng),利用極敏感的磁性接收器,可識(shí)別和檢測(cè)出來自地表的磁場(chǎng)。磁性接收器測(cè)量特殊磁場(chǎng),過濾干擾,然后放大信號(hào)。在一段時(shí)間內(nèi)反復(fù)測(cè)量可以確保穩(wěn)定的結(jié)果。</p><p>  該設(shè)備用于測(cè)量磁場(chǎng),包括三個(gè)傳感器面向正交方向,一個(gè)用于收集,過濾和處理傳感器數(shù)據(jù)

34、的數(shù)據(jù)。一個(gè)全球定位系統(tǒng)用于確定和描繪場(chǎng)區(qū)測(cè)量,和一個(gè)窗型手提電腦存儲(chǔ)GPS和磁場(chǎng)數(shù)相。這種設(shè)備裝在一個(gè)標(biāo)桿。可以手工以每站進(jìn)行測(cè)量。</p><p>  AquaTrack設(shè)備測(cè)量位于每個(gè)測(cè)量站中的來自三個(gè)傳感器的電壓。為了質(zhì)量控制,在測(cè)量區(qū)設(shè)置了一個(gè)底部站點(diǎn)。在每一個(gè)磁場(chǎng)日的開始、中間和結(jié)束,在底部站點(diǎn)進(jìn)行測(cè)量。</p><p>  這些數(shù)據(jù)用來識(shí)別在地下磁場(chǎng)中任何變化,例如浮移。數(shù)據(jù)

35、的質(zhì)量通過檢查在虛擬時(shí)間內(nèi)信號(hào)噪音的比率來保證。數(shù)據(jù)的波動(dòng)時(shí)由于自然的和人造現(xiàn)象被移動(dòng)。水平和垂直方向的磁場(chǎng)被放大,進(jìn)一步測(cè)量地下漏流系統(tǒng)和方向被確定。調(diào)查數(shù)據(jù)后來正?;?,顯示磁場(chǎng)延伸的相對(duì)高低。高電流相應(yīng)于相對(duì)高磁場(chǎng),并代表地下水上升。在River Reservior大壩調(diào)查中,一個(gè)電絲被安放在離西北壩肩南224m的湖中,第二個(gè)電絲被安放在左岸壩肩。這兩個(gè)電絲在上游和下游壩邊坡和壩頂測(cè)量103個(gè)數(shù)據(jù)。另外20個(gè)測(cè)量是在水庫(kù)里的庫(kù)上進(jìn)行

36、的。在測(cè)量工作完成后,收集到的數(shù)據(jù)被送回到實(shí)驗(yàn)室里進(jìn)行解釋。被測(cè)量到的數(shù)據(jù)被處理,繪制,還有其他相關(guān)水文信息。調(diào)查的結(jié)果在水平和垂直方向存在很大的滲透。</p><p><b>  滲透測(cè)繪</b></p><p>  利用這些數(shù)據(jù),Willowstick繪制了存在于水庫(kù)和左岸壩肩的水流路徑。還有與之相關(guān)的排水系統(tǒng)。這一信是TCB工程師調(diào)查工作,歷時(shí)2天。在一夜間就繪

37、制出初步基礎(chǔ)地圖,最后在數(shù)周內(nèi)提交報(bào)告,完成這項(xiàng)工作。通過染色檢查確立了滲漏地點(diǎn),三個(gè)不同的熒光染料被用于跟蹤工作。紅色被放置在接近大壩tabular巖石排水孔中部。</p><p>  2005 年8月開始進(jìn)行了一個(gè)五次切斷的河堤修復(fù)。這是為了消除所謂的公開揭示和石料流失,它被認(rèn)為是作出史料解釋存在的證據(jù),依據(jù)Aquatrack調(diào)查結(jié)果和研究。其他調(diào)查,如發(fā)現(xiàn)和勘探鉆孔技術(shù)也有助于解釋結(jié)果。同年九月,該基礎(chǔ)達(dá)成

38、了水平, 被懷疑在同一地點(diǎn)遇到開放隧道的挖掘。挖掘顯示的排水系統(tǒng)建筑,包括了0.3m寬0.6m高的排水管,已成為爆破玄武巖和底部、頂部基石的雙層巖石組成。</p><p>  從上游到下游距離大約32米地方的排水口出口,開放已凍結(jié)的灌漿巖石以開放的印記為人們努力所建。根據(jù)史料記載,1920年之前,這個(gè)印記是未知的,但并非有效。僅下游從印記、排水渠道發(fā)現(xiàn)從左橋臺(tái)進(jìn)入主要排水整角隧道。這條途徑被應(yīng)用于低于平臺(tái)的天然土

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