CN1238408A - Low dam for eliminating potential energy by drainage and its construction method - Google Patents

Abstract

A low dam for eliminating potential energy by drainage and storing water for irrigation is constructed by laying stone with mortar. In the dam body, there is a concrete frame. The tail dam is lower than river bed. The elevation angle of drainage lip is 30-35 deg. The upper limit (t3) and lower limit (t1) of water depth meet the relationship: t1 less than Ht + a less than t3, where Ht is normal water depth and a is height of tail dam. Its advantages are low investment, low cost of engineering, long service life, and ensuring irrigation.

Description

Low dam for eliminating potential energy by drainage and construction method thereof

The present invention relates to the hydraulic engineering technical field, exactly it is a kind of low dam for eliminating potential energy by drainage and construction method thereof.

China is the abundant country of a water resource, made full use of water resource and can bring great benefit to national economy, if but utilize bad life and the national economy that causes flooding also can give the people to bring severe impairment and make good use of the just bound dam and sluice-gate of water resource, only just there is more than 2500 of small-sized dam and sluice-gate in Liaoning Province, belong to weir mostly, it is the overfall dam of 1～3 meter of height of dam, wherein belong to provisional engineering (sandstone dam, bavin masonry dam etc.) nearly 1900, nearly 600 the provisional barrage weirs of various permanent dam and sluice-gate are because integral dam is poor, no energy dissipating measure or energy dissipating measure are too simple and easy, damaged or destroyed by flood often occurs, want have 1 year damaged or destroyed by flood, repair 1～3 time; Nonvolatil barrage weir, multiple dam type had been researched and developed in each provinces and regions in recent years.Include light-duty dam as 1 font plate dam, L type dam, h type dam, assembling man-like shelf template dam, assembling multi arch dam etc.; The gravity dam is arranged as stone masonry or concrete broad crested weir, practical weir, broken line weir and assembling face dam etc.; The weir of making of plastic cement has rubber dam, diaphragm drag-line dam etc.Remove Liaoning institute of water-saving section in the above-mentioned dam type at the successful rubber dam of the research eighties,, do not exist to block water and the erosion damage problem, but cost is higher, easily aged deterioration in energy emptying flood period; Introduce the assembling face dam of research in the nineties, be designed to submerged bucket dissipator, but exist the downstream, dam to wash away problem in flood period, and globality is relatively poor, damaged or destroyed by flood is more serious in the great flood in nineteen ninety-five Liaoning.The barrage weir of other patterns all is to adopt disspation through hydraudic jimp, energy dissipater such as absorption basin and apron, engineering quantity is big, construction is complicated, cost is higher, and damaged or destroyed by flood often appears according to behind the nineteen ninety-five flood, Liaoning institute of water-saving section is to the investigation of the whole province's barrage (lock) damaged or destroyed by flood situation: dam (lock) body of the permanent barrage of the whole province (lock), accounting for about 20% of whole damaged or destroyed by floods appears, accounting for more than 60% of damaged or destroyed by flood in various degree appears, absorption basin generally destroys and the at first damaged or destroyed by flood of absorption basin and downstream erosion control measure, is the basic reason of dam (lock) body damaged or destroyed by flood.Therefore, change energy dissipating form and energy-dissipating structure, become barrage (lock) and built problem demanding prompt solution

The purpose of this invention is to provide a kind of low dam for eliminating potential energy by drainage and construction method thereof, height of dam is 1～3 meter, and discharge per unit width is 7m ³/ s.m, bailing bucket underflow speed 5-6m/s.Not only save engineering quantity, and can resist bigger flood.

The objective of the invention is to be achieved by the following scheme, it forms dam body by stone masonry, in concrete frame is arranged, it is characterized in that: the tail dam will be lower than the riverbed, bailing lip angle θ is 30 °～35 °, upper limit depth of water t ₃, lower limit depth of water t ₁Between should satisfy relational expression:

t ₁＜H _t+ | a| (t ₃, H _tBe normal depth of flow, a is a tail bank height.A shrinkage joint should be arranged along the dam length direction every 18～22 meters, a sand washing port is established for 8～12 meters in every interval, and wide 1.0～3.0 meters low dam for eliminating potential energy by drainage sections design of sand washing port is carried out according to the following procedure: dam crest press the design of WES curve; Dam slope M determines dam slope M value (available interpolation method) according to design height of dam P according to the form below;

Height of dam P (m)	????1	????1.5	????2.0	????2.5
					Dam slope 1: M	?1∶13	?1∶11	?1∶09	?1∶07

Anti-arc radius R presses table 6 according to design discharge per unit width q, determines anti-arc radius R value (available interpolation method);

Design discharge per unit width q (m 3/s.m?)	??3	???5	???7
				Anti-arc radius R (m)	?1.5	?2.0	?2.5

The high a of tail bank is elevation of primary election between-0.2 meter～-0.5 generally, determines by the fluidised form checking computations at last; The dark h of tail Kan Xiayouhechuanchong _eBy dashing the dark h of calculating _e〉=h _DAfter the section preliminary design is finished, check by following form and formula,

Project discharge per unit width (m 3/sm	?E o	k o	?ψ	h c	?k	?t 1	t 3	?H t+｜a｜
									????0.5
????1.0
									????q If
????q The school

$k_o=\frac{q_i}{\sqrt{g}{E}_{\mathrm{oi}}^{1.5}}\&RightArrow;\mathrm{\&psi;}=1.06-2.58k_o\&RightArrow;h_c=\frac{q_i}{\mathrm{\&psi;}\sqrt{{2\mathrm{gE}}_{\mathrm{oi}}}}$ $\&RightArrow;k=\frac{q_i}{\sqrt{g}{E}_i^{1.5}}{\&RightArrow;t}_i=h_e\frac{0.3+0.625k}{k}\&RightArrow;{\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="A9811398000091.png"\; state="\{\{state\}\}">t</figure-callout>}}_3=t_1+$ $h_c\frac{0.28-0.7k}{k-0.03}$

Advantage of the present invention is to have the stronger ability of resisting flood, and than disspation through hydraudic jimp barrage small investment, engineering cost is low, and service life is long, saves overhead cost.The bucket typed stilling barrage has stronger anti-damaged or destroyed by flood and cuts latent irrigation ability, therefore can improve the fraction of pouring water, and can do some non-irrigated modify-water fields more, guarantees the irrigation water requirement, guarantees the irrigated land high and stable yields.Thereby the present invention not only direct economic benefit is outstanding, and indirect economic effect is obvious, if apply in engineerings such as the small-sized barrage in the whole nation, its benefit is very considerable.

Below in conjunction with drawings and Examples the present invention is done further detailed description.

Fig. 1 is a structural representation of the present invention.

1 is concrete frame among the figure, and 2 is dam body, and 3 is stone masonry, and a is the bank height, H _tBe downstream normal depth of flow, t ₃Be the upper limit depth of water, t ₁Be the lower limit depth of water, h _DDark for washing away, h _cFor shrinking the depth of water, h _eKey-wall is dark, and P is a height of dam.

The underwater bed of low dam for eliminating potential energy by drainage is mainly sand grains, and low dam for eliminating potential energy by drainage is to be built on the soft basis of sandy gravel.Design according to specified conditions.At first tackle dam slope design, for low dam for eliminating potential energy by drainage, the water levels of upstream and downstream difference is little, often flooded if the dam slope design is steeper at overflow in flood season dam crest by the level of tail water, then main flow will break away from dam facing, form oppositely to revolve in bailing bucket to roll, and cause below the tail bank and wash away, and sand grains brought in the bailing bucket, cause dam facing wearing and tearing in the bailing bucket.Dam slope can be more suddenly during height of dam, and dam slope should delay and considers and save the dam body engineering quantity as far as possible that the syntagmatic of optimizing is seen before and stated height of dam and dam slope table when the dam was low.The excessive engineering quantity that then increases of anti-arc radius R, extremely uneconomical.The syntagmatic of optimizing is seen before and is stated anti-arc radius and design discharge per unit width coordination table.Bailing lip angle θ should select between 30 °～35 °.Tail bank height a should be equal to or less than underwater bed, generally should be between-0.2 meter～0.5 meter the selection of tail bank height relevant with stream gradient, stream gradient is steep more, then the absolute value of the high a of bank should be big more.Chiltern washes away horseshoe bend or the people is the river course of adopting the easy incision of sand, and the absolute value that bank is high also should be bigger than normal.Determining of the high a value of bank should be by the checking computations of the fluidised form waterpower in design decision.Determining of dam crest according to depth of water H before the design weir _d(generally meeting peak flood flow by 5 years one calculates), pressing the definite of WES curve design dam slope M should be according to design height of dam P, and it is definite to table look-up.Anti-arc radius R is according to design discharge per unit width q (generally by 5 years one chance Calculation of Flood), and it is definite to table look-up.Tail bank buried depth h _eGenerally should be greater than 2.0 meters, at last by dashing the dark h of calculating _e〉=h _DWith the dam crest is the origin of coordinates, sets up rectangular coordinate system, determines the parameter of section.After low dam for eliminating potential energy by drainage section preliminary design is finished, should carry out fluidised form and dash dark checking computations, with checking high a of tail bank and tail bank buried depth h _eWhether value is reasonable, if improperly should in time adjust fluidised form checking computations and undertaken by aforementioned formula, when satisfying t ₁(H _t+ | a| (t ₃The time, can think to reach designing requirement, if downstream normal depth of flow H _tDo not satisfy this relational expression, then need suppose tail bank elevation again, draft section, calculate again, till satisfying this condition.Dash in the dark checking computations if the h that takes _e〉=h _DPromptly think to reach designing requirement, otherwise should be by h _DValue revises h again _eCan construct after design is finished, note suitably arranging shrinkage joint and sand washing port along the dam length direction.Dam body adopts the stone masonry entity structure more, and overfull dam surface adopts high grade particulate concrete more, and thickness is about 10cm, and stone-laying body and being connected of concrete layer should be left the hair stubble, should brushing concrete bonding agent during discontinuous construction, and the concrete surface layer label with sand washing port in the bailing bucket should be not less than C ₃₀, and suitably increase thickness, to adapt to gravel abrasion and freeze proof needs.During height of dam P＞2.0m, the concrete layer planted agent of bailing bucket buries temperature steel underground.Have and cut the low dam for eliminating potential energy by drainage of diving and requiring, should in stone masonry is built by laying bricks or stones, the wide concrete cutoff wall of 0.1～0.2m together be set downwards, perhaps geomembrane anti-seepage layer is set along the upstream dam facing along dam crest; Tail bank downstream face should be hung the thick steel bar concrete surface layer of 0.2m, in case Hui Tao during super design flood.The bank protections of the abutment wall of dam end, aileron and dyke etc., method for designing is carried out routinely.

Claims (3)

1, low dam for eliminating potential energy by drainage and construction method thereof, it forms dam body by stone masonry, in concrete frame is arranged, it is characterized in that: the tail dam will be lower than the riverbed, bailing lip angle θ is 30 °～35 °, upper limit depth of water t ₃, lower limit depth of water t ₁Between should satisfy relational expression:

t ₁(H _t+ | a| (t ₃, H _tBe normal depth of flow, a is a tail bank height.

2, low dam for eliminating potential energy by drainage according to claim 1 and construction method thereof is characterized in that: a shrinkage joint should be arranged along the dam length direction every 18～22 meters, a sand washing port is established for 8～12 meters in every interval, and sand washing port is wide 1.0～3.0 meters.

3, low dam for eliminating potential energy by drainage according to claim 1 and construction method thereof is characterized in that: the design of low dam for eliminating potential energy by drainage section is carried out according to the following procedure: dam crest is pressed the design of WES curve; Dam slope M determines dam slope M value (available interpolation method) according to design height of dam P according to the form below; Height of dam P (m) ???1 ???1.5 ???2.0 ???2.5 Dam slope 1: M ?1∶13 ?1∶11 ?1∶09 ?1∶07 Anti-arc radius R presses table 6 according to design discharge per unit width q, determines anti-arc radius R value (available interpolation method); Design discharge per unit width q (m ³/s.m) ???3 ???5 ???7 Anti-arc radius R (m) 1.5 ?2.0 ?2.5 The high a of tail bank is elevation of primary election between-0.2 meter～-0.5 generally, determines by the fluidised form checking computations at last; Tail bank buried depth h _eBy dashing the dark h of calculating _e〉=h _DAfter the section preliminary design is finished, check by following form and formula, Project discharge per unit width (m ³/sm ?E _o k _o ?ψ hc ?k ?t ₁ ?t ₃ ?H _t+｜a｜ ????0.5 ????1.0 ????q _If ????q _{The school} $k_o=\frac{q_i}{\sqrt{g}{E}_{\mathrm{oi}}^{1.5}}\&RightArrow;\mathrm{\&psi;}=1.06-2.58k_o\&RightArrow;h_c=\frac{q_i}{\mathrm{\&psi;}\sqrt{2g{E}_{\mathrm{oi}}}}$ $\&RightArrow;k=\frac{q_i}{\sqrt{g}{E}_i^{1.5}}\&RightArrow;t_i=h_e\frac{0.3+0.625k}{k}\&RightArrow;t_3=t_1+$ $h_c=\frac{0.28-0.7k}{k-0.03}$

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