黃河鐵謝工程彎道改造芻議

1、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). Until las

2、t 70 centuries, stuff and descend projects were respectively built in up and down the dam. Though the building of projects cann't 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 pro

3、ject 's inflow point ascend continually, since the project 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

4、 project bend 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

5、the questions 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 Ye

6、llow river, it plays a important role in controlling flood and river circumstances. In a long time, because Tie xie project'splane 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 unstead

7、y and only its downsection is near river after 1996. the long time unsteady of Lu cun project must disturb river conditions downstream and make the results of river improvement fail. Since complex river boundaries of Tie xie project, river is restricted to bridge and beach and cann't adjust itse

8、lf. Meanwhile, with the 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 suit

9、ed to new water-sediment 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 riv

10、er to fluvial plain. In 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,

11、 Luo Yang. River island 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

12、 2500m, width of main river 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-sedimentAccording to Xiaolang di hydra

13、ulic station datum, the average annual discharge of the river3regime is 378.38 hundred million m from 1956 to 1995, the sediment discharge is 11.4 hundred million3 tons. Average discharge is 200 hundred million m in flood seasons, is 53% of total discharges,3 mean annual discharge is 1300 m/s. the v

14、irtual changes of sedimentamounts are high,30 hundred million tons if the sand are much and 10 hundred million if it is little, average sediment3.concentration is 33.9kg/ m there were high sediment concentration flood in 1996, the most high3 sediment concentration is 941 kg/ m .Until sluice in Xiaol

15、angdi reservoir October,1999, downstream water-sediment changed obviously in 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 decreased more obvious in f

16、lood seasons; sediment amounts decreased obviously, mean annual sediment concentration is 1.97 kg/m3 from 1999 to 2002, sediment runoff is 10615 ten thousand tons. Mean 3sediment concentration is 0.292 kg/m in 2000, annual sediment runoff is 442 ten thousand tons; mean3sediment concentration is 1.43

17、kg/m in 2001, annual sediment runoff is 2213 ten thousand tons, mean3, sediment concentration is 4.18 kg/ m3, 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 to 22 meas

18、urement data, section of Tie xie deposited 7000 m from 1934 to 1952 and 4290 m from 1952 to 1960. After Sanmenxia Reservior worked, river regime eroded obviously. Tie xie section 's water level decreased obviously from 1960 to 1965, it decreased 3.36m when the flux is 3000m 3/s. Tie xie river 2s

19、ection continued to erode after 1965 and reach the biggest value 20000 m in 1968. Sanmenxia Reservior 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

20、section began to erode, the accumulated erosion exceeded 10000m2 from 1976. later, from 1977 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 Sanmenxia Reservior worke

21、d from Xiaolangdi reservoir worked in October,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 Ti

22、e xie project is in has 4000 years old, its left bank is Qing feng ling and the right is Mang mountain, the wander is restricted to the regions. The main changes of river section is in big flood time, in history, flood brought a great deal scree bed load out of gorges and deposited suddenly, that ma

23、de branch river eroded or deposited fiercely and changed the river 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 outflowed Bai po. The south and nor

24、th branches river could be streamed during many years, the main stream flowed the north river way between Bai he and Bai po, and the river regime dinn 't change much compared with that in 1933, after the flood in 1958, north river disappeared, the river outflowed Tie xie and went into Zhao gou w

25、an near Lu cun and Tie hu, forming the current river regime . The translation extent of main flow positions was was bigger in Bai he and Bai po projects, so Tie xie project was instable that made downstream river regime disordered.Between 1960 and 1964, Tie xie project inflowed and the conditions ne

26、ar river improved a little, but Tie xie couldn 't flow well. To block up the bunch channel between Bai po and Zhi shu town, Bai po bunch channel project was built up in 1969, north river went south and the stream decreased gradually, this limited the problems that the Yellow river north bank col

27、lapsed continually. Later, Bai he and Bai po 's inflows were regulated more , 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 1

28、971. high sediment concentration flood block up the river in 1973, Tie xie outflowed 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 whol

29、e vulnerable spot was not developed a full embayment, the north dam could be separated up and down embayments looked from the plane. River regime descended when the big flood came, the outflow was smooth by the north dam and was suited with the down Lun cun and Hua yuan zheng project. River regimewe

30、nt up whenthe flood was small, small embayment reached river up north dam and streamed 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 cons

31、istent with the river regime . Number 1-5 dam were blocked up and down extended between 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 d

32、am head.After number 1and 2 the blocked embayment was built in the spring of 1974, due to the embayment's top flow widely, number 10 dam streamed badly, and Lu cun project flowed down, Hua yuan town project went out of river in 1975.Tie xie project 's inflow condition was stable,the river re

33、gime changed little, up embayment and down river regime had the chances of adjusting itself, Lu 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 bu

34、cket type energy dissipation to the river channel north side of Tie xie project, by the influence of cobble 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 21da

35、m Hua yuan town project began to go by river and the river regimegradually went stable. Until the floodtime 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 project 's flow point went up, the flow

36、angle was partially big, the main flow went up blocked dam 's upstream surface at a big flow angle due to the number 1 dam s stream 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 nea

37、rby shifted south, though Tie xie project was by the river the entire year, the river went out of vulnerable spot and 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 pr

38、oject descended continually, the flow dam section diminished quickly, river regime 's disadvantage conditions.After the 96.8 flood, since the Yellow river 's downstream did not flow inundation, in the condition of small flow low sediment concentration, small flow river regime was influenced

39、seriously by sand-cobble marginal and channel bar. The river regime transformed very slowly, the disadvantage river regime lasted for 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 a

40、nd shaped concave to Wen men bank immigrant settlement protection embankment after the river went out Lu cun, this threatened protection embankment and influenced river regime down Lu cun. Though number 5 and 15 submerged dam were built down Tie xie project in 2000 and 2003, dam by the river of Lu c

41、un ascended gradually, Lu cun project that was near the river was all along in 24-36 dam, the disadvantage river regime was hold back temporally.4 the reason why changes of river regime4.1 the direct reason of changes of river regime was upper bend 's early over flowAnalysing historical and curr

42、ent Tie xie regime data, the change of upper bend over flow position was the direct reasons of Tie xie project river regime.From the1970s 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 numbe

43、r 10 dam, the river regime was in a favorable condition. When the upper bend was overflowed by number 1-3 dam, the number 12dam was to face bank and the cobble 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 i

44、n a unhealthy condition. The disadvantage river regime was caused by blocked project 's upper ones when blocked project 1 and 2 were constructed 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

45、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 to 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 coul

46、d not make the whole vulnerable spot a smooth bend , it was hard to arrange the river regime. Then, because upper inflow condition was stable, the emphasis was how to make dam 10 a smooth bend and the upper ones of project was omitted. The first battlement lay crossly, the space between each battlem

47、ent and the angle of dam flow were different, viewing from in a plane, dam 1 protruded into the river, was bounded to dam 1.when the outflow point 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 smoot

48、hly, 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 flow increased gradually and the flow guidance was ideal. The initial flow spot of vulnerable spot ascended to revetment 4,Bai he inflow went to revetment

49、 4 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 dam 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 “9

50、6.8”flood, tie xie project s f'low point ascended, inflow angle went partially bigger, the big one was sent to southeast by dam 1-3, blocked dam 5 did not stream that lead to the disadvantage of the lu cun project was stand by the river. After the“96.8”flood, water and sedimentthat were from upr

51、iver 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 term condition that small river regime make Tie xie project flow point ascend did not change, and gradually intensify, revetment bank gradu

52、ally 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 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 whe

53、n 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 with the flux. After the 96.8 flood, especially Xiao lang di reservoir worked, water diminished from upriver, Tie xie channel bar cobble

54、restricted Bai po outflow and Tie xie project went on ascended, the changes of river regime did not enhance the capability of vulnerable spot flow.After the steam went out of Luo yang road bridge, the river way extended quickly and the slope of river minished quickly, the beach between Tie xie and L

55、u cun transformed at a unregular rule, there were several branches river in the channel. Before 1996, the upriver 's water was rich and was influenced little by sand-cobble beach, the river regime was normal at a global view. After the 96.8 flood, the disadvantage river regime was developed. Tho

56、ugh two submerged dam were built in 2000 and 2003 at the end of Tie xie project, sand-cobble riverbed, especially the appearance of cobble beach and the riverbed 's general down-cutting between Tie xie and Lu cun, main stream was blocked off by cobble beach after submerged dam, it still steamed

57、in the down south river and did not influence the whole 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 eff

58、ectively, 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 condition, to solve the inflow ascend was to eliminate the Tie xie channel bar 's influence to inflow. Channel bar was main

59、ly influenced by small river regime, digging north branch river of Tie xie channel bar and made small went north branch river into blocked project. A submerge dam was built before revetment 4 of main river channel to make main stream above medium water across revetment 4, inflow under dam 1, small water stream went Tie xie north branch of channel bar and the blocked bay was smooth.5.2 transformed the project to basic smooth bendTie xie project was incomplete and the upper bend was not a smooth bend, from the 70s,80s on, the blocked project was built, this