CN103306236A - Method for constructing underground reservoir in ancient gully of ancient underground river channel - Google Patents

Abstract

The invention relates to a method for constructing an underground reservoir in an ancient gully of an ancient underground river channel. The method comprises the following steps: investigating the ancient gully of the ancient underground river channel, designing an underground reservoir dam body, designing an anti-seepage dam body in the reservoir area of the underground reservoir, carrying out stability assessment on the underground reservoir dam body, constructing the underground reservoir dam body, constructing the anti-seepage dam body in the reservoir area of the underground reservoir, surveying and mapping a longitudinal profile of the underground reservoir and calculating the volume of a water-bearing rock-soil layer of the underground reservoir, the water storage capacity of the underground reservoir and the average water separation quantity of an underground water-bearing layer; scientifically utilizing the water storage capacity of the underground reservoir and carrying out recharge and water replenishment on the underground reservoir. The method has the beneficial effect that aiming at the riverbed geology and the landform of the ancient gully of the ancient underground river channel, the characteristics of the water-bearing layer of the ancient gully of the ancient underground river channel as well as the supply conditions of a water source, the anti-seepage problem of various different water-bearing rock-soil layers and problems about the type selection of an underground water dam, the design of dam height and dam crest overflow section elevation, the recharge and the water replenishment of the underground reservoir and the improvement of water supply continuity of the reservoir can be systematically solved.

Description

The method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel

Technical field

The present invention is special formation, landform and the groundwater condition that utilizes in the ancient coombe riverbed, underground ancient stream channel, constructs groundwater dam, tackles and the diving of containing in the underground reservoir, and builds up the method for groundwater reservoir, belongs to the hydraulic engineering construction field.

Background technology

Since the last century the eighties, extreme natural calamities such as medium sandstorm that China is taken place both at home and abroad and drought have been carried out a large amount of reports and comment, wherein have to report and point out that China has been accounted for 1/3rd of territory total area by the area of desertification.In China, many provinces and cities draw underground water source in a large number because of the drought lack of water, cause groundwater table to descend rapidly, thereby cause that the ground cracking sink, and causes very big economic loss and casualties to country.Because the contradiction of water requirement and water supply capacity strengthens year by year, increasing people puts in the research of groundwater reservoir.

At present, still there is not a cover than the perfect system method, can be at ancient coombe riverbed, underground ancient stream channel geology, landform and the characteristics in aquifer and the nourishment condition at water source, solution is to the antiseepage problem of underground various different water cut rock-soil layers, and the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude to the moisturizing of recharging of groundwater reservoir, improves the problems such as continuation that reservoir supplies water.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, a kind of method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel is provided, at ancient coombe riverbed, underground ancient stream channel geology, landform and the characteristics in aquifer and the nourishment condition at water source, systematically solve the antiseepage problem of various different water cut rock-soil layers, and the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude is to the problem of recharging moisturizing and raising reservoir water supply continuation of groundwater reservoir.

The present invention realizes that the technical scheme that above-mentioned purpose is taked is: the method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel comprises the steps:

(1) to the prospecting of underground ancient stream channel, ancient coombe, it is as follows specifically to reconnoitre step:

(A) place name, stratum, the origin cause of formation, trend, length, underground reservoir thickness and underground absolute altitude and the ground level of the ancient coombe in the underground ancient stream channel of prospecting;

(B) evaluation of subterranean water condition, on the basis of step (A), further find out the type of nourishment source, upstream, understand variation of groundwater level in local annual rainfall, atmospheric evaporation amount and the storehouse, comprise wet season extreme high water absolute altitude, dry season lowest water level absolute altitude and last with the ordinary water level absolute altitude and last; Measure the groundwater reservoir hydraulic slope, estimation supply diving flow, water maximum stream flow, the water flow of groundwater reservoir ordinary water level and the water flow of lowest water level excessively of calculating groundwater reservoir extreme high water;

(C) the geology orographic condition on base area lower storage reservoir dam site basis is selected narrower Hu Kou section, and bottom, underground riverbed is the impermeable rock soil layer, and both sides are " U " font for the shape of symmetry; Dam body basis rock-soil layer is complete hard, the rock-soil layer of impermeability;

(D) base area lower storage reservoir reservoir area geology orographic condition selects the buried channel broader and long, and is milder, and the stratum in thicker aquifer is arranged, and to guarantee groundwater reservoir bigger reservoir capacity arranged; Absolute altitude lower storage reservoir control water level design elevation above Ground in dividing ridge, both sides, underground riverbed in the reservoir area, after guaranteeing that reservoir builds up retaining, storehouse Nei Shui can not be toward the storehouse external leakage; Grow the area at karst, the groundwater reservoir reservoir area is chosen in a little less than the karst growth, and the section that basement rock is more complete is in case the storehouse seepage;

(2) design groundwater reservoir dam body, concrete steps are as follows:

(A) the dam body type of underground overfall dam is adopted in the selection of dam type;

(B) the underground height of dam of design and dam crest overflow section, concrete grammar is as follows:

1., at first to planning to build the existing worker in ground in the groundwater reservoir reservoir area, farming, woods, herding and the movable total load of house and the various industries of road is assessed the requirement of below ground soil layer bearing stratum bearing capacity, preliminary determine to cross soil thickness between the water overflow section top from ground to groundwater reservoir dam crest, namely reserve the soil thickness of area load contentedly; Measure in the groundwater reservoir reservoir area wet season then and superlatively descend water level elevation and ordinary water level absolute altitude, the groundwater table absolute altitude changes less maintenance and lasts maximum duration, in moon number;

2., the design of backup land area load bearing stratum soil thickness, make backup land area load bearing stratum soil layer base plate absolute altitude with superlatively descending water level elevation, to guarantee that after groundwater reservoir builds up the groundwater reservoir water level is to ground, reservoir area and peripheral original environmental ecology, and various facility is unaffected;

3., the dam crest absolute altitude designs, and is groundwater reservoir dam crest design elevation with the ordinary water level absolute altitude, guarantees the normality of groundwater reservoir water retention capacity and the continuation of benefit;

4., dam crest overflow design of section, be that dam crest is crossed water overflow section with the section height between groundwater reservoir peak level absolute altitude and the ordinary water level absolute altitude, guarantee that maximum water flow of wet season can successfully pass through from the dam crest spillwag chute, can not influence upper soil horizon and produce phenomenons such as softening or sagging because of water level rising flood period;

(C) design of underground overflow dam body adopts the punching stake to be built into diaphragm wall antiseepage dam body, and underground overfall dam agent structure is major diameter steel bar concrete campshed, is close to mutually between the stake, and it is long for long 1/3 of stake that reinforced concrete pile is gone into rock; Set up the plain concrete stake of row's minor diameter at steel bar concrete campshed upstream side near the position, contact triangle place between per two reinforced concrete piles, to drive percolating water between the anti-reinforced concrete pile; Utilize punching stake machine in work progress, on the block stamp, on to impact pore-creating compacted hole wall periphery rock-soil layer, improve rock-soil layer compactness, angle of internal friction and modulus of deformation;

(3) groundwater reservoir reservoir area antiseepage dam body design, two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude be lower storage reservoir control water level design elevation above Ground, and after guaranteeing that groundwater reservoir builds up retaining, reservoir area water can not be toward the storehouse external leakage; Be lower than the location that groundwater reservoir is controlled water level elevation for local section, reservoir area ground water divide absolute altitude, construct antiseepage dam, groundwater reservoir reservoir area; Antiseepage dam body in reservoir area is made up of steel bar concrete campshed and antiseepage campshed; The design following steps (A) of steel bar concrete campshed, the design following steps (B) of antiseepage campshed:

(A) design of steel bar concrete campshed is close to mutually between the steel bar concrete campshed, stake footpath Φ 800-1000mm, stake end go in rock stratum or the underground impervious clay blanket 1/3 long; The stake heights of roofs is effectively controlled water level design elevation 2.0-3.0m greater than groundwater reservoir;

(B) design of antiseepage campshed, antiseepage stake are laid in the reservoir inboard of steel bar concrete campshed, are close to the triangle place that contacts between the reinforced concrete pile, to prevent that the space leaks between the reinforced concrete pile;

(4) the stable assessment of groundwater reservoir dam body checks by the shear strength of calculating dam body;

(5) according to the design of step (2), the groundwater reservoir dam body is constructed, adopting punching stake machine or rotary pile-digging machine is construction machinery, arranges the construction of reinforced concrete pile earlier, arranges the construction of the plain concrete stake of dam body after the week;

(6) according to the design of step (3), constructed in antiseepage dam, groundwater reservoir reservoir area;

(7) mapping groundwater reservoir longitudinal plan, the dried up amount of average mark of calculating groundwater reservoir water-bearing rock soil layer volume, groundwater reservoir water retention capacity and underground reservoir;

(8) to the scientific utilization of groundwater reservoir water retention capacity, drawing groundwater reservoir water level and water retention capacity graph of relation, is guide and the foundation that water draws water with this curve map, the science that acts out one's plan water; Establish a bite water level observation well at the reservoir dam upstream side, be the permanent observation well of observed stage in the reservoir; Before drawing water, first observed stage is understood the existing water yield situation of reservoir, draws water at regular time and quantity according to plan then; After drawing water, time of pumping up to end and draw water before and after water level and the upright shelves of pump-out record; After drawing water at every turn, increase and measure the water level number of times, grasp the cycle of water level recovery and last the time; Before water level does not recover as yet, forbid excess to be drawn water;

(9) in dry season, when groundwater reservoir lowest water level occurs and lasts the long period, carry out groundwater reservoir and recharge the moisturizing measure; The moisturizing measure is as follows:

(A) in the groundwater reservoir upstream or the tributary build catchment cabinet, catchment open grave or the storehouse of catchmenting, then these water storages are introduced in groundwater reservoirs;

(B) outside the storehouse, dig the canal diversion, water source outside the storehouse is drawn to groundwater reservoir recharge moisturizing;

(C) moisturizing is recharged in the diversion of digging a well outside the storehouse;

The described antiseepage campshed of step (3) comprises deep-mixed pile, water under high pressure mud rotary churning pile or plain concrete stake,

1., be in sand bed or sandy gravel stratum when dam body, husky and the gravel particle diameter is less, it is few to contain shale, and water content is little, and when underground water did not have the bearing capacity phenomenon, the antiseepage campshed should adopt water under high pressure mud to revolve stake; The antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed, and antiseepage campshed and steel bar concrete campshed are parallel to each other, and spacing 300mm utilizes the diffusion of water under high pressure mud rotary churning pile, and steel bar concrete campshed and cement paste rotary churning pile are consolidated into a width of cloth underground impervious wall dam body;

2., when dam body during at powder soil horizon, farinose argillic horizon, mud or miscellaneous fill layer, the antiseepage campshed adopts deep-mixed pile, two row's antiseepage campsheds are laid in the reservoir medial surface of steel bar concrete campshed, be close to mutually with the steel bar concrete campshed, drive mutually between the antiseepage stake and meet 100mm, construction continuously, the stake end is gone into waterproof soil layer 0.5-1.0m, and the stake heights of roofs is greater than groundwater reservoir control water level design elevation 2-3m;

3., when dam body at powder soil horizon or sandy gravel stratum, underground water is abundanter, but underground water is not when having pressure-bearing property, plain concrete stake is adopted in the antiseepage stake, and plain concrete stake is laid in the reservoir medial surface of reinforced concrete pile, is close to the steel bar concrete campshed, the stake end is gone into underground waterproof soil layer 0.5-1.0m, and stake is long consistent with the steel bar concrete campshed;

4., when dam body at fine sand layer or sandy gravel stratum, layer of gravel is thicker, and particle diameter is bigger, and underground water is very abundant, has very big bearing capacity, when side by side the water lateral pressure was big in the lower storage reservoir storehouse, plain concrete stake was adopted in the antiseepage stake, and the antiseepage campshed will be close to the steel bar concrete campshed, the construction of steel bar concrete campshed is preceding, antiseepage campshed construction after, the stake of antiseepage campshed is held into underground waterproof soil layer 0.5-1.0m, stake long with steel bar concrete campshed equal in length.

The present invention compared with prior art, the beneficial effect that has is as follows:

(1) at ancient coombe riverbed, underground ancient stream channel geology, landform and the characteristics in aquifer and the nourishment condition at water source, can systematically solve the antiseepage problem of various different water cut rock-soil layers, and the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude is to the problem of recharging moisturizing and raising reservoir water supply continuation of groundwater reservoir.

(2) SEA LEVEL VARIATION in the reservoir, can guarantee on the ground of reservoir area and environmental ecology such as peripheral original industry, agricultural, animal husbandry, forestry and house, road unaffected, and can obtain better protection and development.

(3) dam body intensity and stability are high.

(4) set up the scientific utilization pattern of pondage, benefit is rationally maximized, groundwater reservoir can obtain the running of continuation.

Description of drawings

Fig. 1 is electric profiling exploration line arrangement diagram, wherein, and 1, the well point, 2, the electric profiling line, 3, underground ancient stream channel passage.

Fig. 2 is the different water level elevation sectional drawings of three wells in groundwater reservoir reservoir area, wherein, and 4,3 well numberings, the water level grade line of 5,3 wells, distance L between 6,3 wells ₁, L ₂

Fig. 3 is groundwater reservoir overfall dam and reservoir longitudinal plan, wherein, and 7, ground level, 8, backup land area load bearing stratum thickness h ₁, 9, the high h of dam crest overflow section ₂, 10, the groundwater reservoir dam body, 11, groundwater reservoir wet season extreme high water absolute altitude line, 12, groundwater reservoir ordinary water level absolute altitude line.

Fig. 4 is water level and pondage graph of relation.

Fig. 5 is dam body reinforced concrete pile and plain concrete stake plane of arrangement figure, wherein, and 13, be reinforced concrete pile, 14, plain concrete stake.

Fig. 6 is groundwater reservoir reservoir area antiseepage reinforced concrete pile and deep-mixed pile plan view, wherein, and 15, deep-mixed pile.

Fig. 7 is reservoir area reinforced concrete pile and water under high pressure mud rotary churning pile plan view, wherein, and 16, water under high pressure mud rotary churning pile.

Fig. 8 is groundwater reservoir reservoir area longitudinal plan, and wherein, " 0-0 " is groundwater reservoir control water level design elevation, and length is L0, and " a-a ", " b-b ", " c-c " and " d-d " are the reservoir level isohypse, and length is respectively L ₁, L ₂, L ₃And L ₄

Fig. 9 is the AA cross sectional area figure of Fig. 8.

Figure 10 is the BB cross sectional area figure of Fig. 8.

Figure 11 is the CC cross sectional area figure of Fig. 8.

Figure 12 is underground water-bearing rock soil moisture in layer analog measurement device sectional drawing, wherein, and 17, batchmeter sand sample groove, 18, movable water-stop sheet, 19, steel mesh seepage plate, 20, dust-collecting bucket.

The specific embodiment

The inventor is for the sense of duty and the interest of occupation, from the eighties initial stage in last century, just begin research that underground ancient stream channel, ancient coombe are constructed groundwater reservoir, to ancient coombe riverbed, underground ancient stream channel geology, landform and the characteristics in aquifer and the nourishment condition at water source, anti-permeation method to underground various different water cut rock-soil layers, the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude, and to the moisturizing of recharging of groundwater reservoir, improve the problems such as continuation that reservoir supplies water, all carried out research and experiment targetedly.

Through years of researches and experiment, from theory to specifically to prospecting, design, the construction of engineering, and to the technical barriers such as separation method of underground water-bearing rock soil moisture in layer, comprehensively create the feasible method of a cover.Simultaneously in the research and experiment process, feel groundwater reservoir engineering and ground hydraulic engineering construction, though they are two kinds of different theories, the exploitation condition with utilize the water source mode different, but their construction program, requirement are consistent with purpose, all be in order to solve human problem of water consumption, can say so " reaching the same goal by different routes " each other.Therefore the author is to hydraulic engineering construction, and this subject of hydro science, therefrom realized a new intension, thinks should be called " underground hydro science " theoretically by the construction groundwater reservoir that the ground hydraulic engineering should be called " ground hydro science ".Hydro science is general name, includes two different subjects of " ground hydro science " and " underground hydro science ".Thereby a name part and status have been created to groundwater reservoir in theory.

Below in conjunction with specific embodiment technical scheme of the present invention is described further.

The method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel of the present invention, specific design and enforcement are carried out according to following steps:

1, underground ancient stream channel, ancient coombe stratum and phreatic feature

(1) landform unit

Underground ancient stream channel, ancient coombe stratum belong to alluvial plain and the estuarine delta unit of stream deposition landforms.

(2) origin cause of formation on stratum

Because the alluvial plain of stream deposition landforms and estuarine delta period, be subjected to the effect of river middle and upper reaches current, cover in the little stream that materials such as a large amount of sand, gravel form river valley haugh, low-lying land or early stage, becomes dark creek or covered conduit, is called underground ancient stream channel or ancient coombe.The alluvial deposit of these ancient stream channels or ancient coombe is alluvial formation in the Quaternary Period.

(3) phreatic characteristics

Alluvium in the Quaternary Period in ancient stream channel or the ancient coombe, from ground from top to bottom, rock-soil layer distributes in regular turn, sees to be silty clay, silt, silty sand, sand, gravel etc. more.But the ground, section that has is covered by the relatively poor cohesive soil crust layer of one deck water permeability, and each following aquifer becomes phreatic infiltration lane.Underground water source is mainly by water source, upstream and the supply of ambient atmosphere rainwater.The water source is abundanter, and the influence that groundwater table is subjected to season is bigger.

2, to the prospecting of underground ancient stream channel, ancient coombe

The formation of underground ancient stream channel, ancient coombe is complicated, and the stratum is also complicated, and they all be hidden in deeply underground, be difficult to find out from ground they particular location, trend, length, with and aquifer thickness etc.To the understanding of these conditions, very important to constructing groundwater reservoir.

(A) to underground ancient stream channel, the prospecting of ancient coombe diving passage

The main method of current China prospecting has:

(1) can find the interrelated data of underground ancient stream channel, ancient coombe on national region geological structure figure and the hydrogeologic map.As place name, stratum, the origin cause of formation, trend, length, underground reservoir thickness, and underground absolute altitude and ground level etc.

(2) application of remote sensing satellite prospecting data.The remote sensing satellite prospecting is advanced prospecting technology in modern age, and is all fine to prospecting effects such as underground ancient stream channel, ancient coombe diving passage trend, length, aquifer thickness.Can find interrelated data in scientific research, design departments such as Di Kuang, oil, traffic, water power and territories.

(3) explore solution from the ready-made underground water well point of forefathers.As shown in Figure 1, specific procedure is:

1. electric profiling prospecting.Centered by well point, respectively lay several electric profiling exploration line at the four direction of well.When in a single day electric profiling finds that underground reservoir becomes mutually continuously a bit of extension to move towards, namely progressively extend and increase the electric profiling exploration, continue recourse its trend, length, demand till cradle, the tributary terminal point of upstream always.

2. electrical sounding.Measure the preliminary datas such as trend, width, aquifer thickness of the underground latent water passage of ancient stream channel, ancient coombe when electric profiling exploration after, verify with resistivity soun ding again.Thickness and the buried depth of main checking underground reservoir, and the absolute altitude of bottom, aquifer impermeable rock soil layer face.

(4) geological drilling is more accurate now, exploitation method commonly used the most directly perceived.To the check of several exploration achievements such as above remote sensing satellite and electrical prospecting, mainly be the evaluation of dive water layer thickness and aquifer bottom rock-soil layer character and water permeability over the ground with it, and impervious layer scar absolute altitude etc.

(B) underground water source condition assessment

(1) obtains on a large amount of achievements basis in above several explorations, also will further find out the type of nourishment source, upstream, mainly be divided into atmosphere rainwater and ice and snow melt water etc.

(2) understand data such as local annual rainfall and atmospheric evaporation amount.

(3) understand variation of groundwater level in the storehouse.As 1. wet season extreme high water absolute altitude; 2. dry season lowest water level absolute altitude and last (moon); 3. ordinary water level absolute altitude and last (moon).For groundwater reservoir dam crest overflow section and the design of recharging moisturizing provide reliable foundation.

1. measure groundwater reservoir hydraulic slope and estimation supply diving flow.

Plan to build the storehouse inland lot of groundwater reservoir, drilling 2-3 underground water well, at regular intervals between each well.Measure the water level elevation of each well then.Draw the hydraulic gradient figure in the groundwater reservoir at last, as shown in Figure 2.

The underground hydraulic gradient in reservoir area is calculated, and design formulas is as follows:

$i=\frac{h}{l}$

Go into the diving flow design formulas in the reservoir area from the upstream, Darcy formula:

$Q=K\·\frac{h}{l}\·W$

In the formula:

The head loss (m) of h---underground water on seepage flow approach L length

L---underground water is in seepage flow approach L length (m)

(the m of water cross sectional area excessively of W---seepage action of ground water ²)

K---transmission coefficient reflects various ground water permeability parameters (rice/day)

2. calculate the water maximum stream flow excessively of groundwater reservoir extreme high water.

Count out the W of water cross sectional area excessively of peak level _High(m ²)

The highest flood discharge is:

3. calculate the water flow Q of groundwater reservoir ordinary water level (SEA LEVEL VARIATION is few in the storehouse, last moon number many) _Often（m ₃）

Count out ordinary water level and cross water cross sectional area W _Often（m ²）

The water flow of ordinary water level is:

4. calculate the water flow Q of lowest water level _Low(m ³)

The water cross sectional area excessively of lowest water level is W _Low(m ²)

The water flow of lowest water level is:

(C) the geology orographic condition on groundwater reservoir dam site basis.

(1) selects narrower " Hu Kou " section.

(2) bottom, underground riverbed is the impermeable rock soil layer, and both sides are " U " font for the shape of symmetry.

(3) dam body basis rock-soil layer is complete harder, the rock-soil layer of impermeability.

(D) groundwater reservoir reservoir area geology, orographic condition.

(1) select the buried channel broader and long, milder, the stratum in thicker aquifer is arranged.To guarantee that groundwater reservoir has bigger reservoir capacity.

(2) absolute altitude lower storage reservoir control water level design elevation above Ground in dividing ridge, both sides, underground riverbed in the reservoir area, after guaranteeing that reservoir builds up retaining, storehouse Nei Shui can not be toward the storehouse external leakage.

(3) grow the area at karst, the groundwater reservoir reservoir area will be chosen in a little less than the karst growth as far as possible, and the section that basement rock is more complete is in case the storehouse seepage.

3, to underground ancient stream channel, ancient coombe, the design of groundwater reservoir dam body

A, the specific condition of constructing groundwater reservoir and requirement

1. in underground ancient stream channel, ancient coombe building groundwater reservoir, dam body is buried in underground, utilizes dam body interception and the underground latent water of containing in the alluvium in the Quaternary Period, so form groundwater reservoir.

2. after groundwater reservoir builds up; SEA LEVEL VARIATION in the reservoir, unaffected to ground, guarantee on the ground of reservoir area and environmental ecology such as peripheral original industry, agricultural, animal husbandry, forestry and house, road; unaffected, and can obtain the requirement of better protection and development.

3. after groundwater reservoir built up, utilization and benefit to pondage can obtain the running of continuation.

The selection of B, dam type

Based on the condition of the stratum characteristic of building dam alluvial deposit in the residing Quaternary Period and building groundwater reservoir with require specially, in the ancient stream channel, the selection of ancient coombe subsurface formations building reservoir dam type, should adopt the dam body type of " underground overfall dam ".

The design of C, underground height of dam and dam crest overflow section

Satisfy some specific condition of constructing groundwater reservoir, the height of dam of groundwater reservoir is difficulties with the scheme of two designs of dam crest overflow section.As long as but can understand fully the phreatic natural law, just can make the design scheme of the science of meeting.

Main method is:

1., at first understand and plan to build the existing worker in ground in the groundwater reservoir reservoir area, farming, woods, herd and various industry activity total loads such as house, road are assessed the requirement of below ground soil layer bearing stratum bearing capacity.Preliminary determine to cross soil thickness (namely reserving the soil thickness of area load contentedly) between the water overflow section top from ground to groundwater reservoir dam crest.

Measure in the groundwater reservoir reservoir area wet season then and superlatively descend water level elevation and ordinary water level absolute altitude (the groundwater table absolute altitude changes less maintenance and lasts maximum duration, in moon number).

2., the design of backup land area load bearing stratum soil thickness.

Make backup land area load bearing stratum soil layer base plate absolute altitude with superlatively descending water level elevation.To guarantee that after groundwater reservoir builds up the groundwater reservoir water level is to ground, reservoir area and peripheral original environmental ecology, and various facility is unaffected.See h shown in Figure 3 ₁

3., dam crest absolute altitude design

Be groundwater reservoir dam crest design elevation with the ordinary water level absolute altitude.Guarantee the normality of groundwater reservoir water retention capacity and the continuation of benefit.

4., dam crest overflow design of section

Be that dam crest is crossed water overflow section with the section height between groundwater reservoir peak level absolute altitude and the ordinary water level absolute altitude.Guarantee the wet season, maximum water flow can successfully pass through from the dam crest spillwag chute, can not influence upper soil horizon and produce phenomenons such as softening or sagging because of water level rising flood period.H as shown in Figure 3 ₂

The design of D, underground overflow dam body

1., looser because of underground ancient stream channel, ancient coombe alluvial deposit sand in the underground Quaternary Period, gravel, boulder bed, difficulty of construction is big, should adopt the punching stake to be built into diaphragm wall antiseepage dam body.

2., underground overfall dam agent structure is major diameter steel bar concrete campshed, be close to mutually between the stake.Reinforced concrete pile go into rock for stake long 1/3 long.

3., set up the plain concrete stake of row's minor diameter at steel bar concrete campshed upstream side near the position, contact triangle place between per two reinforced concrete piles, to drive percolating water between the anti-reinforced concrete pile.

4., utilize punching stake machine in work progress, on the block stamp, on to impact pore-creating compacted hole wall periphery rock-soil layer, improve physical property mechanical index such as rock-soil layer compactness, angle of internal friction and modulus of deformation, overturning or slip resistance analysis and the equicohesive characteristics of shearing resistance to dam body have been improved greatly, the foundation and the condition that provide better, more economized for the dam structure design scheme.

Obtain two of physical property mechanical index such as dam body (pile foundation) construction front and back rock-soil layer compactness, angle of internal friction and modulus of deformation and change different data, can detect by before and after the pile body construction pile body periphery both sides rock-soil layer being carried out twice dynamic sounding, can obtain two different data.

5., dam body links the underground dam body forms by punching steel bar concrete campshed, two sides, the upstream and downstream of dam body have formed vertical line from dam crest to base of dam, do not need to do the designs of straight line or the shape of taking out stitches, as shown in Figure 2 again.

6., because groundwater reservoir dam crest upstream and downstream overflow segment absolute altitude differs less, and it is slower that the water seepage velocity is crossed in the aquifer, less to scouring force behind the dam, therefore to behind dam crest and the dam, need not make curve shape design, as shown in Figure 3.

4, groundwater reservoir reservoir area antiseepage dam body design

Two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude is lower storage reservoir control water level design elevation above Ground, and after guaranteeing that groundwater reservoir builds up retaining, reservoir area water can not be toward the storehouse external leakage.Be lower than the location that groundwater reservoir is controlled water level elevation for local section, reservoir area ground water divide absolute altitude, must construct underground antiseepage dam, be called antiseepage dam, groundwater reservoir reservoir area.Antiseepage dam body in reservoir area is made up of steel bar concrete campshed and antiseepage campshed.

The design of A, steel bar concrete campshed

Construct the antiseepage dam based on considering to be in than location, dividing ridge under the lowland, dam body can be subjected to the lateral pressure influence of water in the groundwater reservoir, so the antiseepage dam body need use the reinforced concrete pile of antiskid and overturning or slip resistance analysis to be agent structure.

The steel bar concrete campshed is close to mutually between the stake, stake footpath Φ 800-1000mm, stake end go in rock stratum or the underground impervious clay blanket 1/3 long.The stake heights of roofs is effectively controlled water level design elevation 2.0-3.0m greater than groundwater reservoir, and the reinforcing bar preparation needs to determine by design.

The design of B, antiseepage campshed

The antiseepage stake is laid in the reservoir inboard of steel bar concrete campshed, is close to the triangle place that contacts between the reinforced concrete pile, to prevent that the space leaks between the reinforced concrete pile.The antiseepage campshed has deep-mixed pile, water under high pressure mud rotary churning pile, plain concrete stake etc.According to different soil layer properties and different saturation states, select different antiseepage consolidation methods.

1., be in sand bed, sandy gravel stratum.When husky, the gravel particle diameter is less, it is less to contain shale, water content is less in addition, and underground water do not have conditions such as bearing capacity phenomenon, the antiseepage stake should be adopted the fixed campshed method of water under high pressure mud churning.The antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed.Antiseepage campshed and steel bar concrete campshed are parallel to each other, and spacing 300mm utilizes the diffusion of water under high pressure mud rotary churning pile, and steel bar concrete campshed and cement paste rotary churning pile are consolidated into a width of cloth underground impervious wall dam body.As shown in Figure 7.

2., mix soft layer at powder soil horizon, farinose argillic horizon, mud, miscellaneous fill layer etc.The antiseepage campshed should adopt two row's deep-mixed pile consolidation methods.Two row antiseepage campsheds are laid in the reservoir medial surface of steel bar concrete campshed, are close to mutually with the steel bar concrete campshed, require between the antiseepage stake to drive mutually to meet 100mm, require construction continuously, the stake end go into waterproof soil layer 0.5-1.0m(or to bedrock surface).The stake heights of roofs is greater than groundwater reservoir control water level design elevation 2-3m.As shown in Figure 6.

3., at powder soil horizon, sandy gravel stratum, abundanter when underground water, but underground water is not when having pressure-bearing property, the plain concrete deposited row of piles pile driving construction scheme of boring is then adopted in the antiseepage stake.Plain concrete stake is laid in the reservoir medial surface of reinforced concrete pile, is close to the steel bar concrete campshed.The stake end is gone into underground waterproof soil layer 0.5-1.0m, and stake is long consistent with the steel bar concrete campshed.As shown in Figure 5.

4., thicker at fine sand layer, sandy gravel stratum, layer of gravel, and particle diameter is bigger, underground water is very abundant, has very big bearing capacity, when side by side the water lateral pressure was big in the lower storage reservoir storehouse, the antiseepage stake will be adopted the plain concrete campshed of punching stake scheme.The antiseepage campshed will be close to the steel bar concrete campshed.Steel bar concrete campshed construction is preceding, the construction of antiseepage campshed after.The stake of antiseepage campshed is held into underground waterproof soil layer 0.5-1.0m, the long and steel bar concrete campshed equal in length of stake.As shown in Figure 5.

5, the stability calculation of groundwater reservoir dam body

During to the selection of dam type, we all select " underground overfall dam " type for use at underground ancient coombe, ancient stream channel ground layer building groundwater reservoir." the underground antiseepage dam " selected for use on antiseepage dam, groundwater reservoir reservoir area, though two kinds of dam type differences, the purposes difference, the agent structure on the dam is similar.

Because it is special that above two kinds of dam type building conditions require, the geological conditions complexity.When considering dam body design and construction scheme, adopted corresponding measure, stablizing of dam body obtained certain humidification, less because of the groundwater reservoir project scale simultaneously, so to the stable assessment of the dam body of above two kinds of dam types, can not need do the checking computations of toppling of dam body, only do the shear strength checking computations of dam body.

The shear strength formula is:

In the formula: $K=\frac{\mathrm{f\ΣW}}{\mathrm{\ΣP}}$

K-by the antiskid buckling safety factor of shear Strength Calculation (adopting by table)

The shearing resistance friction factor of f-dam body and dam foundation rock contact surface

∑ W-act on the dam body all loads to the normal direction score value (comprising uplift pressure) of slip plane

∑ P-act on the dam body all loads to the tangential score value (comprising uplift pressure KN) of slip plane

6, groundwater reservoir dam body construction

1., construction machinery.Mainly be to adopt punching stake machine, rotary pile-digging machine.

2., reinforced concrete pile is arranged construction earlier.The general 800-1000mm in stake footpath, the stake end embeds batholith (or impermeable rock soil layer), the degree of depth be stake long 1/3, the arrangement of reinforcement of stake is definite by design.

3., the hole of when pile body construction pore-creating, collapsing easily, note adding an amount of clay, cement, or adopt casing to execute brill.

4., the reinforced concrete pile top mark is high determines to reserve negative pile length by design.

5., the plain concrete stake of dam body, finish the back week construction of construction at the steel bar concrete campshed.Plain concrete campshed is laid in steel bar concrete campshed upstream side, and the contact triangle place between two of the reinforced concrete piles is close in plain concrete stake position.Stake footpath Φ 600-800mm.The stake end is gone into batholith 0.5m, concrete strength C15-C20.As shown in Figure 5.

7, the construction on groundwater reservoir reservoir area antiseepage dam

Antiseepage dam body in reservoir area is made up of steel bar concrete campshed and antiseepage campshed.

(1) construction of steel bar concrete campshed

1., the steel bar concrete campshed carries out before being arranged in the construction of antiseepage campshed.

2., be close to laying between the reinforced concrete pile mutually.

3., select to be fit to the stake machine of execution conditions according to the underground watershed soil layer property in reservoir area and groundwater state, as pile-driving machine, punching stake machine, rotary pile-digging machine etc.

4., reinforced concrete pile diameter of phi 800-1000mm, stake end go into underground waterproof soil layer deeply for stake long 1/3, go into 0.5m in the horizon d, concrete strength is C20-C25.

5., the reinforcing cage arrangement of reinforcement is fixed by designing requirement, stake is long to be determined by a design elevation.

(2) construction of antiseepage campshed

Antiseepage campshed in reservoir area is selected different antiseepage consolidation methods according to different soil layer properties and different saturation states.

According to above the 4th B design, the antiseepage consolidation method has water under high pressure mud rotary churning pile, 4 kinds of deep-mixed pile, the plain concrete deposited stake of boring and the plain concrete deposited stakes of punching etc.Relevant construction aspect, in design, existing explanation does not need to go to live in the household of one's in-laws on getting married here.

8, the computational methods of groundwater reservoir water retention capacity

A, mapping groundwater reservoir longitudinal plan

1., at first from dam site to the reservoir tail, carry out the riverbed geological drilling, and be depicted as the groundwater reservoir longitudinal plan.As shown in Figure 8.Then according to the underground bed configuration different level point in reservoir area, draw and calculate several cross sectional areas.As the cross-sectional drawing of A-A, B-B, C-C, be respectively Fig. 9, Figure 10 and Figure 11.

2., calculate dam body to each different water level isohypse (L of reservoir tail ₀, L ₁, L ₃, L ₄) length, with and average length (L _Flat).As shown in Figure 8.

B, calculating groundwater reservoir water-bearing rock soil layer volume

1., count out the volume of water-bearing rock soil layer between groundwater reservoir water level 0-a, a-b, b-c, the c-d

In kind count out a-b(V _{2 sand}), b-c(V _{3 sand}), c-d(V _{4 sand})

2., count out groundwater reservoir water-bearing rock soil layer volume (V _{Total husky})

(V _{Total husky})=V _{1 sand}+ V _{2 sand}+ V _{3 sand}+ V _{4 sand}(4)

C, calculating groundwater reservoir water retention capacity

Design formulas:

V _{Total water}=V _{Total husky}* V _Par

In the formula:

V _{Total water}---groundwater reservoir retaining total amount (m ³)

V _{Total husky}---groundwater reservoir aquifer cumulative volume (m ³)

V _Par---the average every cubic metre of average (V that isolates the water yield in integrated multilayer aquifer _Par) (m ³)

The separation method of D, underground reservoir water content

The said groundwater reservoir of this paper is to build groundwater reservoir in underground reservoir, says accurately to be called " underground reservoir storehouse ".The water retention capacity of groundwater reservoir refers to the water yield (m contained from underground reservoir ³).

The aquifer of groundwater reservoir, the mixing stratum of being formed by multiple DIFFERENT SOIL layer.Because of the difference of conditions such as the lithology in every layer of aquifer, particle diameter size, grating, density, water content has very big difference.

For the water content separate study of underground reservoir, people have created several method for many years:

(1), sample letter oven drying method;

(2), centrifuge partition method;

(3), the author recommends to adopt the analog measurement method.

The testing sequence of analog measurement method:

1., at first understand fully below planning to build groundwater reservoir controls the water level design elevation what layer aquifer are arranged, the rock and soil properties in every layer of aquifer, and distribution sequence, key elements such as soil layer construction particle diameter, density, every layer of soil thickness by the geological drilling data.

2., the making of analog measurement device.Batchmeter can be made into cuboid, its volume V=abc, a=length, b=width, c=height.Make the long-pending 2.0-3.0(m of batchmeter inner hollow body ³).Plate can be with plank or iron sheet.Be the drain water steel net plate at the batchmeter other end, before steel net plate, be close to a movable water impermeable sheet.Be catch basin behind the barrier sheet, but the draining pore of an open and close is established in the catch basin bottom.

3., after batchmeter completes, lay the gradient of batchmeter then in the ratio of the hydraulic gradient of groundwater reservoir.The discharge ends of batchmeter makes it be similar to riverbed phreatic natural grade seepage flow situation towards the inclination toe.

4., sampling machinery, the bucket drill bit construction that can select rotary pile-digging machine for use.Bucket diameter of phi 1.0-2.0(m).Or adopt the manual digging pile construction method to sample.

5., sampling and test sequence, from top to down, stratified sampling and test, test result record wants sequence to distinguish, must not confusion.

6., sample (underground reservoir) put into batchmeter after, earlier specimen surface is paved wholely, utilize the water source then on the spot, inject batchmeter.After the specimen surface stable level is saturation state, namely measure the volume V (m of batchmeter aquifer under saturation state ³).The draining pore of the water-stop sheet of unlatching activity at last and catch basin bottom, treat that water drains in the batchmeter after, calculate the volume V that separates water outlet in the batchmeter _Water(m ³), be the water content volume V of every cubic metre of saturated aqueous rock-soil layer _Water(m ³).

7., calculate the average every cubic metre of average V that isolates the water yield in integrated multilayer aquifer at last _Par(m ³).

E, to the evaluation of several separation achievements of underground aquifer water content.

V from above three kinds of separation method gained _WaterValue is to recently seeing, oven drying method is bigger than centrifuge partition method, analog measurement method minimum.It is oven drying method＞centrifuge partition method＞simulate measurement Law.

Though oven drying method and the isolated water yield V of centrifuge partition method _WaterBe worth bigger.All aquifers of separating with centrifuge method through oven drying method have become loose dried sand, dry ground.But the means and the equipment that are drawn water in underground aquifer from current reality, mainly be to adopt underground heavy caliber well and the small-bore well of machine drill, the means and the equipment that draw water with water pump, to the every cubic metre of water yield that can draw of saturated aqueous layer, also do not reach oven drying method and the centrifuge isolated water yield from every cubic metre of saturated aqueous layer far away.But, when well draw water stop certain hour after, the diving of upstream namely slowly from the aquifer osmotic flow replenish, make the water content in aquifer obtain again to restore to the original state.This change procedure more is similar to the nature of seepage action of ground water with the separation process of analog measurement method.In addition, the separation process of analog measurement method and the water yield of separating and effect, approximate with the effect of utilizing well to draw water at present, have more directive significance and Practical significance for the assessment of groundwater reservoir water retention capacity.

F, groundwater reservoir water retention capacity calculated examples

(1) be example with Fig. 8-Figure 11

1, establishing dam body to each water level isohypse length of reservoir tail is:

" 0 " water level isohypse length L ₀=1200m

" a " water level isohypse length L ₁=1050m

" b " water level isohypse length L ₂=900m

" c " water level isohypse length L ₃=750m

" d " water level isohypse length L ₄=600m

2, establishing the several cross sections of groundwater reservoir width is

1. AA cross section such as Fig. 9.

L’ ₀＝70m；L’ ₁＝60m；L’ ₂＝53m；L’ ₃＝40m；L’ ₄＝20m

2. BB cross section such as Figure 10.

L’ ₀＝50m；L’ ₁＝40m；L’ ₂＝36m；L’ ₃＝32m；L’ ₄＝10m

3. CC cross section such as Figure 11.

L’ ₀＝30m；L’ ₁＝20m；L’ ₂＝10m

3, the spacing of establishing between every grade of water level 0-a, a-b, b-c, the c-d is 2.0(m).

4, establish analog measurement method integrated multilayer aquifer and isolate water yield average V for average every cubic metre _Par=0.25(m ³)

(2) calculate volume (V in aquifer between water level 0-a, a-b, b-c, the c-d _{1 sand}, V _{2 sand}, V _{3 sand}, V _{4 sand}).

1., volume V in aquifer between 0-1 _{1 sand}

V _{1 sand}=W _{1 is flat}* L _{1 is flat}=90 * 1125=101250(m ³)

2., calculate V with same computational methods _{2 sand}, V _{3 sand}, V _{4 sand}

V _{2 sand}=71175(m ³)

V _{3 sand}=47025(m ³)

V _{4 sand}=34425(m ³)

(3) groundwater reservoir aquifer cumulative volume is

V _{Total husky}=V _{1 sand}+ V _{2 sand}+ V _{3 sand}+ V _{4 sand}

＝101250+71175+47025+34425＝253875（m ³）

(4) groundwater reservoir retaining total amount is:

V _{Total water}=V _{Total husky}* V _Par=253875 * 0.25=63469(m ³)

Wherein:

V _{1 water}=V _{1 sand}* V _Par=101250 * 0.25=25312(m ³)

V _{2 water}=V _{2 sand}* V _Par=71175 * 0.25=17794(m ³)

V _{3 water}=V _{3 sand}* V _Par=47025 * 0.25=11756(m ³)

V _{4 water}=V _{4 sand}* V _Par=34425 * 0.25=8606(m ³)

9, to the scientific utilization of groundwater reservoir water retention capacity

1., draw groundwater reservoir water level and water retention capacity graph of relation, as shown in Figure 4.

A, referring to (4) point of Fig. 8 and step 8.

B, known groundwater reservoir water retention capacity are V _{Total water}=63469(m ³)

Because groundwater reservoir water retention capacity total amount is " 0 " water level elevation reservoir filling total amount.

Then the pondage volume of each water level elevation is:

“0”＝63469（m ³）

The pondage of " a " water level elevation is:

63469-V _{1 water}=63469-25312=38157(m ³)

The pondage of " b " water level elevation is:

38157-V _{2 water}=38157-17794=20363(m ³)

The pondage of " b " water level elevation is:

20363-V _{3 water}=20363-11756=8607(m ³)

The pondage of " d " water level elevation is:

8607-V _{4 water}=8607-8607=0

C, drafting water level and pondage graph of relation

Be depicted as " water level and pondage graph of relation " with the relative reservoir filling value of following several water level elevations

“0”＝63469（m ³）

“a”＝38157（m ³）

“b”＝20363（m ³）

“c”＝8607（m ³）

“d”＝0.0（m ³）

2., be guide and the foundation that water draws water with " water level and pondage curve map ", act out one's plan, the science water, overcome blindness.

3., establish a bite water level observation well at the reservoir dam upstream side, be the permanent observation well of observed stage in the reservoir.

4., at every turn after drawing water, increase and measure the water level number of times, grasp the cycle of water level recovery and last the time.

5., before water level recovers as yet, forbid excess to be drawn water, forbidden to do the wrong-doing of " taking off the pool and fishing ".

6., draw water before, first observed stage is understood the existing water yield situation of reservoir.Draw water at regular time and quantity according to plan then.After drawing water, to record upright shelves to time of pumping up to ending with draw water front and back water level, pump-out etc.

7., reservoir has the personal management, draw water electricity consumption and plant equipment special messenger are responsible for.

10, groundwater reservoir recharges the moisturizing measure

In dry season, the groundwater reservoir that has lowest water level can occur and last the long period, has influenced the continuation of reservoir with water running.Therefore, when the building groundwater reservoir, just should consider simultaneously to make up the matters of recharging the moisturizing engineering.

A, recharge the moisturizing engineering following several method arranged:

(1) in the groundwater reservoir upstream, the tributary builds catchment cabinet, open grave, storehouse.Then these water storages are introduced in the groundwater reservoir.

This is equal possession, water source face water resource partly, flows in the ground, upstream of groundwater reservoir.Main water source is:

1. in the groundwater reservoir reservoir area with the amount of rainfall of the ground collective area of reservoir upstream;

2. on the mountain, upstream, the molten water of Gao Ling face of land ice and snow;

3. face of land Junichiro Koizumi water burst.

(2) outside the storehouse, dig the canal diversion.Water source outside the storehouse attracted to groundwater reservoir recharge moisturizing.

(3) moisturizing is recharged in the diversion of digging a well outside the storehouse.

B, several design and construction that recharges the moisturizing engineering

1. the Yi Shang cabinet that catchments, open grave, storehouse engineering are communicated with groundwater reservoir with water-drawing channel.These catchworks begin from ground toward the underground cuboid that scrapes out, the degree of depth is cheated interior backfill coarse sand and gravel greater than top width, and the sand gravel aspect is than the near coal-mine low 500-1000mm in ground, fill out clay bed thickness 500-1000mm last time in the sand gravel aspect then, argillic horizon maintains an equal level with near coal-mine ground level after tamping.To reduce water evaporates and to influence traffic above-ground.But sump will be reserved the water inlet that the supplementing water source and course is gone into sump when the backfill clay.

2. the underground hole channel of well-digging or water-drawing channel outside the storehouse is also wanted backfill coarse sand and layer of gravel, and backfill argillic horizon 500-1000mm, and the compacting back maintains an equal level with ground level.Purpose and effect also are in order to reduce water evaporates and to influence traffic above-ground.

11, to the protection of groundwater reservoir

1. firsthand information such as the exploration of groundwater reservoir, design, construction will found a grade long preservation.

2. on the ground, place of constructing groundwater reservoir, mark position on the spot such as dam body, edge, reservoir area, storehouse tail, and the declaration of tree board grants asylum.

3. forbidding surpass to reserve the soil layer bearing stratum allows the various large-scale road of bearing capacity and building foundation across ground, reservoir area.As be left with no alternative, then adopt bridge span Vietnamese side formula, pass through from the reservoir area hemisphere.

Claims (2)

1. the method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel is characterized in that, comprises the steps:

(1) to the prospecting of underground ancient stream channel, ancient coombe, it is as follows specifically to reconnoitre step:

(A) place name, stratum, the origin cause of formation, trend, length, underground reservoir thickness and underground absolute altitude and the ground level of the ancient coombe in the underground ancient stream channel of prospecting;

(B) evaluation of subterranean water condition, on the basis of step (A), further find out the type of nourishment source, upstream, understand variation of groundwater level in local annual rainfall, atmospheric evaporation amount and the storehouse, comprise wet season extreme high water absolute altitude, dry season lowest water level absolute altitude and last with the ordinary water level absolute altitude and last; Measure the groundwater reservoir hydraulic slope, estimation supply diving flow, water maximum stream flow, the water flow of groundwater reservoir ordinary water level and the water flow of lowest water level excessively of calculating groundwater reservoir extreme high water;

(C) the geology orographic condition on base area lower storage reservoir dam site basis is selected narrower Hu Kou section, and bottom, underground riverbed is the impermeable rock soil layer, and both sides are " U " font for the shape of symmetry; Dam body basis rock-soil layer is the rock-soil layer of complete hard, impermeability;

(D) base area lower storage reservoir reservoir area geology orographic condition selects the buried channel broader and long, and is milder, and the stratum in thicker aquifer is arranged, and to guarantee groundwater reservoir bigger reservoir capacity arranged; Absolute altitude lower storage reservoir control water level design elevation above Ground in dividing ridge, both sides, underground riverbed in the reservoir area, after guaranteeing that reservoir builds up retaining, storehouse Nei Shui can not be toward the storehouse external leakage; Grow the area at karst, the groundwater reservoir reservoir area is chosen in a little less than the karst growth, and the section that basement rock is more complete is in case the storehouse seepage;

(2) design groundwater reservoir dam body, concrete steps are as follows:

(A) the dam body type of underground overfall dam is adopted in the selection of dam type;

(B) the underground height of dam of design and dam crest overflow section, concrete grammar is as follows:

1., at first to planning to build the existing worker in ground in the groundwater reservoir reservoir area, farming, woods, herding and the movable total load of house and the various industries of road is assessed the requirement of below ground soil layer bearing stratum bearing capacity, preliminary determine to cross soil thickness between the water overflow section top from ground to groundwater reservoir dam crest, namely reserve the soil thickness of area load contentedly; Measure in the groundwater reservoir reservoir area wet season then and superlatively descend water level elevation and ordinary water level absolute altitude, the groundwater table absolute altitude changes less maintenance and lasts maximum duration, in moon number;

2., the design of backup land area load bearing stratum soil thickness, make backup land area load bearing stratum soil layer base plate absolute altitude with superlatively descending water level elevation, to guarantee that after groundwater reservoir builds up the groundwater reservoir water level is to ground, reservoir area and peripheral original environmental ecology, and various facility is unaffected;

3., the dam crest absolute altitude designs, and is groundwater reservoir dam crest design elevation with the ordinary water level absolute altitude, guarantees the normality of groundwater reservoir water retention capacity and the continuation of benefit;

4., dam crest overflow design of section, be that dam crest is crossed water overflow section with the section height between groundwater reservoir peak level absolute altitude and the ordinary water level absolute altitude, guarantee that maximum water flow of wet season can successfully pass through from the dam crest spillwag chute, can not influence upper soil horizon and produce phenomenons such as softening or sagging because of water level rising flood period;

(C) design of underground overflow dam body adopts the punching stake to be built into diaphragm wall antiseepage dam body, and underground overfall dam agent structure is major diameter steel bar concrete campshed, is close to mutually between the stake, and it is long for long 1/3 of stake that reinforced concrete pile is gone into rock; Set up the plain concrete stake of row's minor diameter at steel bar concrete campshed upstream side near the position, contact triangle place between per two reinforced concrete piles, to drive percolating water between the anti-reinforced concrete pile; Utilize punching stake machine in work progress, on the block stamp, on to impact pore-creating compacted hole wall periphery rock-soil layer, improve rock-soil layer compactness, angle of internal friction and modulus of deformation;

(3) groundwater reservoir reservoir area antiseepage dam body design, two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude be lower storage reservoir control water level design elevation above Ground, and after guaranteeing that groundwater reservoir builds up retaining, reservoir area water can not be toward the storehouse external leakage; Be lower than the location that groundwater reservoir is controlled water level elevation for local section, reservoir area ground water divide absolute altitude, construct antiseepage dam, groundwater reservoir reservoir area; Antiseepage dam body in reservoir area is made up of steel bar concrete campshed and antiseepage campshed; The design following steps (A) of steel bar concrete campshed, the design following steps (B) of antiseepage campshed:

(A) design of steel bar concrete campshed is close to mutually between the steel bar concrete campshed, stake footpath Φ 800-1000mm, stake end go in rock stratum or the underground impervious clay blanket 1/3 long; The stake heights of roofs is effectively controlled water level design elevation 2.0-3.0m greater than groundwater reservoir;

(B) design of antiseepage campshed, antiseepage stake are laid in the reservoir inboard of steel bar concrete campshed, are close to the triangle place that contacts between the reinforced concrete pile, to prevent that the space leaks between the reinforced concrete pile;

(4) the stable assessment of groundwater reservoir dam body checks by the shear strength of calculating dam body;

(5) according to the design of step (2), the groundwater reservoir dam body is constructed, adopting punching stake machine or rotary pile-digging machine is construction machinery, arranges the construction of reinforced concrete pile earlier, arranges the construction of the plain concrete stake of dam body after the week;

(6) according to the design of step (3), constructed in antiseepage dam, groundwater reservoir reservoir area;

(7) mapping groundwater reservoir longitudinal plan, the dried up amount of average mark of calculating groundwater reservoir water-bearing rock soil layer volume, groundwater reservoir water retention capacity and underground reservoir;

(8) to the scientific utilization of groundwater reservoir water retention capacity, drawing groundwater reservoir water level and water retention capacity graph of relation, is guide and the foundation that water draws water with this curve map, the science that acts out one's plan water; Establish a bite water level observation well at the reservoir dam upstream side, be the permanent observation well of observed stage in the reservoir; Before drawing water, first observed stage is understood the existing water yield situation of reservoir, draws water at regular time and quantity according to plan then; After drawing water, time of pumping up to end and draw water before and after water level and the upright shelves of pump-out record; After drawing water at every turn, increase and measure the water level number of times, grasp the cycle of water level recovery and last the time; Before water level does not recover as yet, forbid excess to be drawn water;

(9) in dry season, when groundwater reservoir lowest water level occurs and lasts the long period, carry out groundwater reservoir and recharge the moisturizing measure; The moisturizing measure is as follows:

(A) in the groundwater reservoir upstream or the tributary build catchment cabinet, catchment open grave or the storehouse of catchmenting, then these water storages are introduced in groundwater reservoirs;

(B) outside the storehouse, dig the canal diversion, water source outside the storehouse is drawn to groundwater reservoir recharge moisturizing;

(C) moisturizing is recharged in the diversion of digging a well outside the storehouse.

2. the method that ancient coombe is constructed groundwater reservoir in underground ancient stream channel according to claim 1 is characterized in that the described antiseepage campshed of step (3) comprises deep-mixed pile, water under high pressure mud rotary churning pile or plain concrete stake,

1., be in sand bed or sandy gravel stratum when dam body, husky and the gravel particle diameter is less, it is few to contain shale, and water content is little, and when underground water did not have the bearing capacity phenomenon, the antiseepage campshed should adopt water under high pressure mud to revolve stake; The antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed, and antiseepage campshed and steel bar concrete campshed are parallel to each other, and spacing 300mm utilizes the diffusion of water under high pressure mud rotary churning pile, and steel bar concrete campshed and cement paste rotary churning pile are consolidated into a width of cloth underground impervious wall dam body;

2., when dam body during at powder soil horizon, farinose argillic horizon, mud or miscellaneous fill layer, the antiseepage campshed adopts deep-mixed pile, two row's antiseepage campsheds are laid in the reservoir medial surface of steel bar concrete campshed, be close to mutually with the steel bar concrete campshed, drive mutually between the antiseepage stake and meet 100mm, construction continuously, the stake end is gone into waterproof soil layer 0.5-1.0m, and the stake heights of roofs is greater than groundwater reservoir control water level design elevation 2-3m;

3., when dam body at powder soil horizon or sandy gravel stratum, underground water is abundanter, but underground water is not when having pressure-bearing property, plain concrete stake is adopted in the antiseepage stake, and plain concrete stake is laid in the reservoir medial surface of reinforced concrete pile, is close to the steel bar concrete campshed, the stake end is gone into underground waterproof soil layer 0.5-1.0m, and stake is long consistent with the steel bar concrete campshed;

4., when dam body at fine sand layer or sandy gravel stratum, layer of gravel is thicker, and particle diameter is bigger, and underground water is very abundant, has very big bearing capacity, when side by side the water lateral pressure was big in the lower storage reservoir storehouse, plain concrete stake was adopted in the antiseepage stake, and the antiseepage campshed will be close to the steel bar concrete campshed, the construction of steel bar concrete campshed is preceding, antiseepage campshed construction after, the stake of antiseepage campshed is held into underground waterproof soil layer 0.5-1.0m, stake long with steel bar concrete campshed equal in length.

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