黄河铁谢工程弯道改造刍议

1、精品 料推荐discussion about transformation of curve conduit of yellow river tie xie projectliu you zhan( western he nan yellow river affairs bureau)abstract: tie xie project was passively built due to rush to deal with emergency, it is separated to two up-down bend in north gate dam (number 10 dam). unti

2、l last 70 centuries, stuff and descend projects were respectively built in up and down the dam. though the building of projects cannt transport downstream the 10 dam, it was suited to temporal water-sediment conditions, the river was in a perfect condition. after the “96.8”flooding, the tie xie proj

3、ect s inflow point ascend continually, since theproject didn t develop a integrate smooth bend and water-sediment conditions are changing, the disadvantage river conditions that lu cun project is near river began to appear. to settle tie xie project transport effectively, the emphases of project ben

4、d is how to improve 入溜 conditions ,make stuff project complete, make project a intact smooth bend and use riverbed dredge up to improve inflow, stream guidance and outflow conditions of riverbed project.key words: tie xie project; bend; fluctuating river; river regulation; yellow river1 the question

5、s put forwardyellow river tie xie project is between bai he and hui meng country ,meng jin county, 24km downstream xiaolangdi dam, south bank of yellow river, it is up to bai po project and down to lu cun project, 7.45km total lengths. tie xie project is in initial sections downstream yellow river,

6、it plays aimportant role in controlling flood and river circumstances. in a long time, because tie xie project s plane condition is not smooth, outlet flow is unsteady, often swings in about 2 km near lu cun project, this make the river circumstances by lu cun project is very unsteady and only its d

7、ownsection is near river after 1996. the long time unsteady of lu cun project must disturb river conditions downstreamand make the results of river improvement fail. since complex river boundaries of tie xie project, riveris restricted to bridge and beach and cannt adjust itself. meanwhile, with the

8、 construction of xiaolangdi, qixiayuan reservoir,taiao high speed yellow river road and so on, river regime have some new things and problems. so speeding at constructing river regulation, rebuildingtie xie project, building smooth and plan flow guidance bend to make them suited to new water-sedimen

9、t boundary conditons are keys of this river reach regulation and emergent needs of downstream wandering river regulation.2 .basic conditions of river way2.1 characteristics of river waythe reach of yellow river tie xie project is reach that is transited from mountain areas river to fluvial plain. in

10、 mountain areas, water flow diffuses and velocity is slow, sand-cobble bed load which are brought from upper ravine river bed can be deposited in river section, so sand-cobble river island that has several flow branches distributary is developed upper yellow river road bridge, luo yang. river island

11、 is constituted of scree and rude sand, it is in the north center of river bed and is1m-5m taller than river bed, its top is sandy roam and bottom is round gravel and scree. generally, river bed is covered by sand-cobble, grain diameter from 20 to 200 mm, the width of river is 2500m, width of main r

12、iver channel is 500-700m, slope of river bed is 0.5 0.7 , the depth of scree down luo yang bridge is gradually increased, its riverbed is consist of rude sand, beach is unsteady and slope of river way is 0.265 .2.2 characteristic of water-sedimentaccordingto xiaolangdi hydraulic station datum, the a

13、verage annual discharge of the river1精品 料推荐regime is 378.38 hundred million3m from 1956 to 1995, the sediment discharge is 11.4 hundred milliontons. average discharge is 200 hundred million353% of total discharges,m in flood seasons, ismean annual discharge is 1300 m3 /s. the virtual changes of sedi

14、mentamounts are high,30 hundred million tons if the sand are much and 10 hundred million if it is little, average sedimentconcentration is 33.9kg/ m3.sediment concentrationfloodin 1996, the most highthere were high3sediment concentration is 941 kg/ m .until sluice in xiaolangdi reservoir october,199

15、9, downstream water-sediment changed obviouslyin the affluence of the reservoir. the main features are: the flux is obviously slower, the scope of flux fluctuation decreased, discharge is nearly equal in flood and unflood seasons, runoff amount decreasedmore obvious in flood seasons; sediment amount

16、s decreased obviously, mean annual sediment concentration is 1.97 kg/m3 from 1999 to 2002, sediment runoff is 10615 ten thousand tons. mean sediment concentration is 0.292 kg/m 3 in 2000, annual sediment runoff is 442 ten thousand tons; mean sediment concentration is 1.43kg/m 3 in 2001, annual sedim

17、ent runoff is 2213 ten thousand tons, meansediment concentration is 4.18 kg/ m 3, annual sediment runoff is 7960 ten thousand tons.2.3 erosion and deposition of river bedin natural condition, the erosion and deposition of tie xie river regime is high. according tomeasurement data, section of tie xie

18、 deposited 7000 m 2 from 1934 to 1952 and 4290 m 2 from 1952 to1960. after sanmenxia reservior worked, river regime eroded obviously. tie xie sections water leveldecreased obviously from 1960 to 1965, it decreased 3.36m when the flux is 3000m3/s. tie xie riversection continued to erode after 1965 an

19、d reach the biggest value 20000 m2 in 1968. sanmenxiareservior discharged sediment to open bottom holes in 1970, tie xie river section quickly deposited and reach its biggest 5000m 2 in 1973. sanmenxia reservior sluiced and discharged sediment in 1974, tie xie section began to erode, the accumulated

20、 erosion exceeded 10000m2 from 1976. later, from1977 to 1999, with the changes of water-sediment, tie xie section eroded and deposited regulations,but the extent is little,tie xie section is eroded about 9000m 2 contrasted to before sanmenxiareservior worked from xiaolangdi reservoir worked in octob

21、er,1999. after xiaolangdi reservoir worked, riverbed s erosion is obvious, average erosion depth is about 2.5 3.0m, the main channel of tie xie section depth decreased.3 project construction and river evolvement3.1 historical riverthe river way that tie xie project is in has 4000 years old, its left

22、 bank is qing feng ling and theright is mang mountain, the wander is restricted to the regions. the main changes of river section is inbig floodtime,in history, flood brought a great deal scree bed load out of gorges and depositedsuddenly,thatmade branch river eroded or deposited fiercely and change

23、d theriver regime.sand-cobble river bed is steady when the flow is medium or little and the river regimeis not changedacutely. between 1933 and 1958, the river was separated south and north branches after it outflowedbai po. the south and north branches river could be streamed during many years, the

24、 main streamflowed the north river way between bai he and bai po, and the river regimedinn t change muchcompared with that in 1933, after the flood in 1958, north river disappeared, the river outflowed tiexie and went into zhao gou wan near lu cun and tie hu, forming the current river regime . thetr

25、anslation extent of main flow positions was was bigger in bai he and bai po projects, so tie xieproject was instable that made downstream river regimedisordered.between 1960 and 1964, tie xie project inflowed and the conditions near river improved a little,but tie xie couldn tflow well. to block up

26、the bunch channel between bai po and zhi shu town, baipo bunch channel project was built up in 1969, north river went south and the stream decreased2精品 料推荐gradually, this limited the problems that the yellow river north bank collapsed continually. later, bai he and bai pos inflows were regulated mor

27、e , tie xie project standed by river and the inflow condition was improved intensively, the lu cun began to go incurvate during several years and each embayment descend and collapsed. lu cun project was began to built in 1971. high sediment concentration flood block up the river in 1973, tie xie out

28、flowed and the north branch deposited, south branch increased to 80%, 21-31 dam of lun cun standed by river.3.2 tie xie block up embayment and descendbecause tie xie project was built to deal with the emergencies, the whole vulnerable spot was not developed a full embayment, the north dam could be s

29、eparated up and down embayments looked fromthe plane. river regimedescended when the big flood came, the outflow was smooth by the northdam and was suited with the down lun cun and hua yuan zheng project. river regimewent up whenthe flood was small, small embayment reached river up north dam and str

30、eamed to tao wan up the lun cun project. the rebuildment of tie xie project was made to block up embayment up 1200m north dam, that comprised down north dam vulnerable spot a smooth embayment, controlling the water consistent with the river regime . number 1-5 dam were blocked up and down extended b

31、etween 1973 and 1986. number 1-5 dam head was in the line with the 31battlement and the north dam head, the down project head was in the with the guidance line, the extension line of dam head was face to the number 10 dam head.afternumber 1and 2 the blocked embayment was builtin the spring of 1974,

32、due to theembayments top flow widely, number 10 dam streamed badly, and lu cun project flowed down, huayuan town project went out of river in 1975.tie xie project s inflow condition was stable,the river regime changed little, up embayment and down river regime had the chances of adjusting itself, lu

33、cun project s flow lengths gradually increased, due to water and sediment were rich this period of time. the river regime gradually tended to smooth, at the most time main stream made a trajectory buckettype energy dissipation to the river channel north side of tie xie project, by the influence of c

34、obble island, the river was separated to two branches ,the 80% main stream went the north, from up lu cun project to embayment of lu cun project, lu cun project was nearly by the river. down of 21dam huayuan town project began to go by river and the river regimegradually went stable. until the flood

35、time in 1996, the river section was in a healthy condition.3.3 appearance and development of disadvantage river regimeafter the 96.8 flood came, tie xie projects flow point went up, the flow angle was partially big,the main flow went up blocked dam s upstream surface at a big flow angle due to the n

36、umber 1 damsstream guidance, the project bended and the flow point ascended, this made the main stream bended on the opposite of number 12 dam, the main channel of tie xie section nearby shifted south, though tie xie project was by the river the entire year, the river went out of vulnerable spot and

37、 extended number 5dam, the outflow went south center or glissaded, this made the south branch river developed down luo yang road bridge, north branch river shrunk, this made lu cun project descended continually, the flow dam section diminished quickly, river regime s disadvantage conditions.afterthe

38、 96.8 flood,since the yellowriver s downstream did not flowinundation,in thecondition of small flow low sediment concentration, small flow river regime was influenced seriously by sand-cobble marginal and channel bar. the river regime transformed very slowly, the disadvantage river regime lasted for

39、 long. the most serious condition was the length was only 400m by the river, 90% of stream guidance went out of river from number 32 dam in 1999. the river collapsed and shaped concave to wen men bank immigrant settlement protection embankment after the river went out lu cun, this threatened protect

40、ion embankment and influenced river regime down lu cun. though number3精品 料推荐5 and 15 submerged dam were built down tie xie project in 2000 and 2003, dam by the river of lu cun ascended gradually, lu cun project that was near the river was all along in 24-36 dam, thedisadvantage river regime was hold

41、 back temporally.4 the reason why changes of river regime4.1 the direct reason of changes of river regime was upper bends early over flowanalysing historical and current tie xie regime data, the change of upper bend over flow positionwas the direct reasons of tie xie project river regime.from the197

42、0s on, tie xie project was upperbend overflow at the most time, outflow reached to upper and medium head when the upper bend was overflowed by blocked bend and number 10 dam, the river regime was in a favorable condition. whenthe upper bend was overflowedby number 1-3 dam, the number 12dam was to fa

43、ce bank and thecobble of depth of burial was superficial, that lead to the outflow could not reached the lu cun project and went bend here, the river regime was in a unhealthy condition. the disadvantage river regime was caused by blocked project s upper ones when blocked project 1 and 2 were constr

44、ucted in the spring of 1974 and the disadvantage river regime after the flood in 1996. the differences were upper outflow was changed by men by building the blocked project 1-2 dam, and the upper outflow did not changed much, in additionally to rich water and sediment, the river regime had chanced t

45、o adjust itself.4.2 tie xie project did not develop a complete smooth bendblocked bend and down extend project that were rebuilt through tie xie project could not makethe whole vulnerable spot a smooth bend , it was hard to arrange the river regime. then, because upper inflow condition was stable, t

46、he emphasis was how to make dam 10 a smooth bend and the upper onesof project was omitted. the first battlement lay crossly, the space between each battlement and the angle of dam flow were different, viewing from in a plane, dam 1 protruded into the river, wasbounded to dam 1.when the outflow point

47、 was vary, the influence to the backward river regime was different. the initial flow point of vulnerable spot was dam 1-2, blocked bay 1-4 streamed smoothly,the upper bend of several dam flow smoothly, flowed through blocked bay projectand dam 10, thedam of lu cun project was long, the degrees of f

48、low increased gradually and the flow guidance was ideal. the initial flow spot of vulnerable spot ascended to revetment 4,bai he inflow went to revetment4 before bank stand bend, the main stream guided to tie xie channel bar through dam 1 and then went up to blocked bay s face at a big angel, the da

49、m sent flow out and the outflow went south to the end of lu cun project.4.3 the influence of“96.8”flood and water-sediment of upriverafter the “96.8”flood, tie xieproject s flow point ascended, inflow angle went partially bigger,the big one was sent to southeast by dam 1-3, blocked dam 5 did not str

50、eam that lead to thedisadvantage of the lu cun project was stand by the river. after the“96.8”flood, water and sedimentthat were from upriver decreased obviously, and the were not big flood in the flood season especially after the xiao lang di project worked that made rinsing discharged, but long te

51、rm condition that small river regime make tie xie project flow point ascend did not change, and gradually intensify, revetment bank gradually collapsed and retreated. tie xie flow condition were not improved and the disadvantage river regime lasted.4.4 influence analysis of sand and cobble river bed

52、 to river regimethe upper of tie xie project had a channel bar, under the center there were not flood plain, the beach head was erode when big inundation and the effect was not obvious. meanwhile, the river channel existed small cobble beach, and the influence to the river regime was in the variety

53、with the flux. after the 96.8 flood, especially xiao lang di reservoir worked, water diminished from upriver, tie xie channel bar cobble restricted bai po outflow and tie xie project went on ascended, the changes of4精品 料推荐river regime did not enhance the capability of vulnerable spot flow.after the

54、steam went out of luo yang road bridge, the river way extended quickly and the slope ofriver minished quickly, the beach between tie xie and lu cun transformed at a unregular rule, therewere several branches riverin the channel. before 1996, the upriver s water was richand wasinfluenced little by sa

55、nd-cobble beach, the river regime was normal at a global view. after the 96.8flood, the disadvantage river regime was developed. though two submerged dam were built in 2000and 2003 at the end of tie xie project, sand-cobble riverbed, especially the appearance of cobble beachand the riverbed s genera

56、l down-cutting between tie xie and lu cun, main stream was blocked off bycobble beach after submerged dam, it still steamed in the down south river and did not influence thewhole river regime, lu cun project that was near river was not improved fundamentally.5 countermeasure and step of bend transformation5.1 make project inflow under dam 1the main problem of tie xie project was inflow could not reach lu cun project effectively, analyzing the reasons of river regime s changes, tie xie project inflowed ascended continually was the one of main reasons. in the current water and sediment cond