CN103306236B - 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 of groundwater reservoir is constructed at the ancient coombe of underground palaeostream

Technical field

The present invention utilizes special formation, landform and the groundwater condition in the ancient coombe riverbed of underground palaeostream, constructs groundwater dam, tackles and the diving contained in underground reservoir, and build up the method for groundwater reservoir, belong to hydraulic engineering construction field.

Background technology

Since last century the eighties, the extreme natural calamities such as the sandstorm that domestic and international media occur China and drought have carried out a large amount of reports and comment, wherein have report to 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 are because of drought lack of water, and a large amount of groundwater absorbing source, causes groundwater table to decline rapidly, thus it is sagging to cause ground to ftracture, 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 no a set of more perfect systems approach, can for underground palaeostream ancient coombe riverbed geology, landform and the feature in aquifer thereof and the nourishment condition at water source, solve the antiseepage problem to the various different water cut rock-soil layer in underground, and the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude, recharges moisturizing to groundwater reservoir, improves the problems such as the continuation that reservoir supplies water.

Summary of the invention

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

The present invention realizes the technical scheme that above-mentioned purpose takes: the method for constructing groundwater reservoir at the ancient coombe of underground palaeostream, comprises the steps:

(1) to the prospecting of underground palaeostream, ancient coombe, concrete prospecting step is as follows:

(A) place name of the ancient coombe of underground palaeostream, stratum, the origin cause of formation, trend, length, underground reservoir thickness and subsurface level and ground level is reconnoitred;

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

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

(D) base area lower storage reservoir reservoir area geology orographic condition, selects buried channel broader and longer, milder, has the stratum in thicker aquifer, to ensure that groundwater reservoir has larger reservoir capacity; Absolute altitude lower storage reservoir controlling water level design elevation above Ground in dividing ridge, both sides, riverbed, underground in reservoir area, after ensureing that reservoir builds up retaining, storehouse Nei Shui can not toward storehouse external leakage; Comparatively grow area at karst, groundwater reservoir reservoir area is selected more weak at Karst Development, and the more complete section of basement rock, in case storehouse seepage;

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

(A) selection of dam type, adopts the dam body type of underground overfall dam;

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

1., first to planning to build the existing work in ground in groundwater reservoir reservoir area, agriculture, woods, to herd and the requirement of movable total load to below ground soil layer bearing stratum bearing capacity of house and the various industry of road is assessed, tentatively determine to cross soil thickness between water overflow profile head from ground to groundwater reservoir dam crest, i.e. the soil thickness of reserved area load contentedly; Then measure the wet season in groundwater reservoir reservoir area and superlatively descend water level elevation and ordinary water level absolute altitude, the less maintenance of groundwater table absolute altitude change lasts maximum duration, in moon number;

2., the design of backup land area load bearing stratum soil thickness, backup land area load bearing stratum soil layer floor level is made with superlatively descending water level elevation, to guarantee after groundwater reservoir builds up, groundwater reservoir water level is to ground, reservoir area and the original environmental ecology of periphery, and various facility does not affect;

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

4., dam crest overflow design of section, water overflow section is crossed for dam crest so that the section between groundwater reservoir peak level absolute altitude and ordinary water level absolute altitude is high, guarantee that wet season maximum water flow can successfully pass through from dam crest spillwag chute, can not rise because of water level flood period, affect upper soil horizon and produce softening or sag;

(C) design of underground overflow dam body, adopt Percussion Piles to be built into diaphragm wall antiseepage dam body, underground overfall dam agent structure is Large-size rebar concrete campshed, is close to mutually between stake, and it is that long 1/3 of stake is long that reinforced concrete pile enters rock; Row's minor diameter element concrete stake is set up, with percolating water between imperial anti-reinforced concrete pile near the position, contact triangle place between every two reinforced concrete piles at steel bar concrete campshed upstream side; Utilize punching pile machine in work progress, the upper and lower impact pore-forming of block stamp, compacted for hole wall periphery rock-soil layer, improves rock-soil layer compactness, angle of internal friction and modulus of deformation;

(3) groundwater reservoir reservoir area antiseepage design of dam body, two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude is higher than groundwater reservoir controlling water level design elevation, and after ensureing that groundwater reservoir builds up retaining, reservoir area water can not toward storehouse external leakage; For section, local, reservoir area ground water divide absolute altitude lower than the location of groundwater reservoir controlling water level absolute altitude, construct antiseepage dam, groundwater reservoir reservoir area; Reservoir area antiseepage dam body, 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 steel bar concrete campshed, stake footpath Φ 800-1000mm, stake to hold in rock stratum or underground impervious clay blanket 1/3 long; Stake heights of roofs is greater than groundwater reservoir controlling water level design elevation 2.0-3.0m;

(B) design of antiseepage campshed, antiseepage stake is laid in inside the reservoir of steel bar concrete campshed, is close to the triangle place of the Contact of reinforced concrete pile, leaks to prevent space between reinforced concrete pile;

(4) Stability Assessment of groundwater reservoir dam body, is checked by the shear strength calculating dam body;

(5) according to the design of step (2), construct to groundwater reservoir dam body, employing punching pile machine is construction machinery, first arranges the construction of reinforced concrete pile, arranges the construction of dam body element concrete stake after the week;

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

(7) survey and draw groundwater reservoir longitudinal plan, calculate the dried up amount of average mark of 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, draw groundwater reservoir water level and water retention capacity graph of relation, with this curve map for the guide that draws water with water and foundation, act out one's plan scientific consumption of water; Establishing a bite water level observation well at reservoir dam upstream side, is the permanent observation well of observed stage in reservoir; Before drawing water, first observed stage, understands the existing water yield situation of reservoir, then draws water at regular time and quantity according to plan; After drawing water, time of pumping up to only founding shelves with draw water front and back water level and pump-out record; After drawing water at every turn, increase and measure water level number of times, grasp cycle and the elapsed time of water level rezime; Before water level not yet recovers, excess is forbidden to be drawn water;

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

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

(B) from storehouse, dig canal diversion, water source outside storehouse is drawn and recharges moisturizing to groundwater reservoir;

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

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

1., when dam body be in sand bed or sandy gravel stratum, husky and grain size of gravel is less, few containing shale, water content is little, and when underground water does not have a bearing capacity phenomenon, antiseepage campshed should adopt water under high pressure mud rotary churning pile; Antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed, antiseepage campshed and steel bar concrete campshed parallel to each other, 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 underground impervious wall dam body;

2., when dam body is at powder soil horizon, farinose argillic horizon, mud or miscellaneous fill layer, 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 steel bar concrete campshed, overlap between antiseepage stake 100mm, sequential production, stake is held into impervious stratum 0.5-1.0m, and stake heights of roofs is greater than groundwater reservoir controlling water level design elevation 2-3m;

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

4., when dam body is at fine sand layer or sandy gravel stratum, layer of gravel is thicker, and particle diameter is comparatively large, and underground water is very abundant, there is very large bearing capacity, when side by side in lower storage reservoir storehouse, water lateral pressure is larger, antiseepage stake adopts plain concrete stake, and antiseepage campshed will be close to steel bar concrete campshed, the construction of steel bar concrete campshed is front, the construction of antiseepage campshed is rear, and the stake of antiseepage campshed is held into underground impervious stratum 0.5-1.0m, and stake is long equal with steel bar concrete campshed length.

Compared with prior art, the beneficial effect had is as follows in the present invention:

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

(2) SEA LEVEL VARIATION in reservoir, can ensure the ground of reservoir area and the original industry of periphery, agricultural, animal husbandry, forestry and the environmental ecology such as house, road unaffected, and better Conservation and development can be obtained.

(3) dam body strength and stability is high.

(4) set up the scientific utilization pattern of pondage, make benefit reasonable maximization, groundwater reservoir can obtain the running of continuation.

Accompanying drawing explanation

Fig. 1 is electric profiling exploration line arrangement diagram, wherein, and 1, well point, 2, electric profiling line, 3, underground palaeostream passage.

Fig. 2 is the different water level elevation sectional drawing of three, groundwater reservoir reservoir area well, wherein, and 4,3 well numberings, the water level grade line of 5,3 wells, the spacing L of 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, dam crest overflow section height h ₂, 10, groundwater reservoir dam body, 11, groundwater reservoir wet season extreme high water elevation line, 12, groundwater reservoir ordinary water level elevation 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, wherein, " 0-0 " for groundwater reservoir controlling water level design elevation, length be L0, " a-a ", " b-b ", " c-c " and " d-d " are 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.

Detailed description of the invention

Inventor is for the sense of duty of occupation and interest, from the eighties initial stage in last century, just start the research of underground palaeostream, ancient coombe being constructed to groundwater reservoir, to underground palaeostream ancient coombe riverbed geology, landform and the feature in aquifer thereof and the nourishment condition at water source, to the anti-permeation method of the various different water cut rock-soil layer in underground, the type selecting of groundwater dam, the design of height of dam and dam crest overflow section absolute altitude, and moisturizing is recharged to groundwater reservoir, improve the problems such as the continuation of reservoir water supply, all carry out research and experiment targetedly.

Through years of researches and experiment, from theory to specifically to the prospecting of engineering, design, construction, and to technical barriers such as the separation methods of underground water-bearing rock soil moisture in layer, comprehensively create a set of feasible method.Simultaneously in research and experiment process, feel groundwater reservoir engineering and ground hydraulic engineering construction, although they are two kinds of different theories, exploit condition is different from utilizing water source mode, but their construction program, requirement are consistent with object, being all the problem of water consumption in order to solve the mankind each other, can saying it is " reaching the same goal by different routes ".Therefore the author is to hydraulic engineering construction, and this subject of hydro science, has therefrom realized a new intension, has thought and construction groundwater reservoir should be called " underground hydro science ", ground hydraulic engineering theoretically, should be called " ground hydro science ".Hydro science is general name, includes " ground hydro science " and " underground hydro science " two different subjects.Thus created a name part and status to groundwater reservoir in theory.

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

Method of constructing groundwater reservoir at the ancient coombe of underground palaeostream of the present invention, specific design and enforcement are carried out in accordance with the following steps:

1, the feature of underground palaeostream, ancient coombe stratum and underground water

(1) landform unit

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

(2) origin cause of formation on stratum

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

(3) feature of underground water

Alluvium in the Quaternary Period in ancient stream channel or ancient coombe, from ground from top to bottom, sequentially, common is silty clay, silt, silty sand, sand, gravel etc. in rock-soil layer distribution.But ground, some sections cover by the poor cohesive soil crust layer of one deck water permeability, following each aquifer becomes the infiltration lane of underground water.Underground water source is primarily of water source, upstream and the supply of ambient atmosphere rainwater.Water source is abundanter, and the impact that groundwater table is subject to season is larger.

2, to the prospecting of underground palaeostream, ancient coombe

The formation of underground palaeostream, ancient coombe is more complicated, and stratum is also more complicated, and they are hidden in underground all deeply, is difficult to particular location, trend, length and its aquifer thickness etc. of finding out them from ground.To the understanding of these conditions, very important to constructing groundwater reservoir.

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

The main method of current China prospecting has:

(1) interrelated data of underground palaeostream, ancient coombe can be found from national region geologic structure diagram and hydrogeologic map.As place name, stratum, the origin cause of formation, trend, length, underground reservoir thickness, and subsurface level and ground level etc.

(2) application of remote sensing satellite prospecting data.Remote sensing satellite prospecting is more advanced exploratory techniques in modern age, all fine to prospecting effert such as underground palaeostream, ancient coombe diving passage trend, length, aquifer thickness.Interrelated data can be found in scientific research, design departments such as Di Kuang, oil, traffic, water power and territories.

(3) solution is explored from the underground water well point that forefathers are ready-made.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 electric profiling becomes mutually a bit of extension to move towards once discovery underground reservoir continuously, namely progressively extend and explore with increase electric profiling, continue recourse its trend, length, demand always to cradle, the tributary terminal of upstream.

2. electrical sounding.When electric profiling exploration measure ancient stream channel, ancient coombe underground latent water passage the preliminary data such as trend, width, aquifer thickness after, then to verify with resistivity soun ding.The thickness of main checking underground reservoir and buried depth, and the absolute altitude in impermeable rock soil layer face bottom aquifer.

(4) geological drilling is current comparatively accurate, the most conventional exploitation method.With it, several exploration results such as above remote sensing satellite and electrical prospecting are checked, mainly qualification of dive water layer thickness and aquifer bottom rock-soil layer character and water permeability over the ground, and impervious layer scar absolute altitude etc.

(B) underground water source Conditions Evaluation

(1) obtain on a large amount of performance basis in above several exploration, also will find out the type of nourishment source, upstream further, mainly be divided into air rainwater and snowmelt runoff etc.

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

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

1. groundwater reservoir hydraulic slope and estimation supply diving flow is measured.

Plan to build the storehouse inland lot of groundwater reservoir, drill 2-3 underground water well, at regular intervals between each well.Then the water level elevation of each well is measured.Finally draw the hydraulic gradient figure in groundwater reservoir, as shown in Figure 2.

Underground, reservoir area hydraulic gradient calculates, and design formulas is as follows:

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

The diving flow rate calculation formula in reservoir area is entered, Darcy formula from upstream:

$Q=K\·\frac{h}{l}\·W$

In formula:

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

L---underground water is at 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 parameter (rice/day)

What 2. calculate groundwater reservoir extreme high water crosses water maximum stream flow.

That counts out peak level crosses water cross sectional area W _high(m ²)

The highest flood discharge is:

3. the water flow Q of groundwater reservoir ordinary water level (in storehouse, SEA LEVEL VARIATION is few, last moon number many) is calculated _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. the water flow Q of lowest water level is calculated _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) narrower " Hu Kou " section is selected.

(2) bottom riverbed, underground be impermeable rock soil layer, both sides are symmetrical shape is " U " font.

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

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

(1) select buried channel broader and longer, milder, have the stratum in thicker aquifer.To ensure that groundwater reservoir has larger reservoir capacity.

(2) in reservoir area, dividing ridge, both sides, riverbed, underground absolute altitude is higher than groundwater reservoir controlling water level design elevation, and after ensureing that reservoir builds up retaining, storehouse Nei Shui can not toward storehouse external leakage.

(3) comparatively grow area at karst, groundwater reservoir reservoir area will be selected at Karst Development more weak as far as possible, the more complete section of basement rock, in case storehouse seepage.

3, to underground palaeostream, ancient coombe, groundwater reservoir design of dam body

A, the specific condition constructing groundwater reservoir and requirement

1. at underground palaeostream, ancient coombe building groundwater reservoir, dam body is buried in underground, utilizes dam body to tackle and the underground latent water contained in alluvium in the Quaternary Period, so form groundwater reservoir.

2. after groundwater reservoir builds up; SEA LEVEL VARIATION in reservoir, unaffected to ground, ensure in the ground of reservoir area and the original industry of periphery, agricultural, animal husbandry, forestry and the environmental ecology such as house, road; unaffected, and the requirement of better Conservation and devel-opment can be obtained.

3., after groundwater reservoir builds up, to utilization and the benefit of pondage, the running of continuation can be obtained.

The selection of B, dam type

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

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

Meet some specific condition constructing groundwater reservoir, height of dam and dam crest overflow section two schemes designed of groundwater reservoir be together with difficulty.But as long as the natural law of underground water can be understood fully, just can make the design scheme of the science of meeting.

Main method is:

1., first understand and plan to build the existing work in ground in groundwater reservoir reservoir area, agriculture, woods, to herd and the requirement of the various industry activity such as house, road total load to below ground soil layer bearing stratum bearing capacity is assessed.Tentatively determine to cross soil thickness between water overflow profile head (i.e. the soil thickness of reserved area load contentedly) from ground to groundwater reservoir dam crest.

Then measure the wet season in groundwater reservoir reservoir area and superlatively descend water level elevation and ordinary water level absolute altitude (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.

Backup land area load bearing stratum soil layer floor level is made with superlatively descending water level elevation.To guarantee after groundwater reservoir builds up, groundwater reservoir water level is to ground, reservoir area and the original environmental ecology of periphery, and various facility does not affect.H as shown in Figure 3 ₁.

3., dam crest elevation design

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

4., dam crest overflow design of section

Water overflow section is crossed for dam crest so that the section between groundwater reservoir peak level absolute altitude and ordinary water level absolute altitude is high.Guarantee the wet season, maximum water flow can successfully pass through from dam crest spillwag chute, can not rise, affect upper soil horizon and produce softening or sag because of water level flood period.H as shown in Figure 3 ₂.

The design of D, underground overflow dam body

1., because of underground palaeostream, ancient coombe underground alluvial deposit in Quaternary Period sand, gravel, boulder bed loosely, difficulty of construction is large, and Percussion Piles should be adopted to be built into diaphragm wall antiseepage dam body.

2., underground overfall dam agent structure is Large-size rebar concrete campshed, is close to mutually between stake.It is that long 1/3 of stake is long that reinforced concrete pile enters rock.

3., at steel bar concrete campshed upstream side row's minor diameter element concrete stake is set up, with percolating water between imperial anti-reinforced concrete pile near the position, contact triangle place between every two reinforced concrete piles.

4., utilize punching pile machine in work progress, the upper and lower impact pore-forming of block stamp is compacted for hole wall periphery rock-soil layer, improve the physical mechanical index such as rock-soil layer compactness, angle of internal friction and modulus of deformation, substantially increase the overturning or slip resistance analysis to dam body and the equicohesive feature of shearing resistance, for dam structure design scheme provide better, more economize according to and condition.

Obtain the data that physical mechanical index two changes such as dam body (pile foundation) construction front and back rock-soil layer compactness, angle of internal friction and modulus of deformation are different, by carrying out twice dynamic sounding detection to pile body periphery both sides rock-soil layer before and after pile body construction, two different data can be obtained.

5., dam body links the underground dam body formed by punching steel bar concrete campshed, and the Liang Ge side, upstream and downstream of dam body, forms vertical line from dam crest to base of dam, does not need to do straight line again or profile design of taking out stitches, as shown in Figure 2.

6., because overflow segment absolute altitude difference in groundwater reservoir dam crest upstream and downstream is less, it is comparatively slow that water seepage velocity is crossed in aquifer, less to scour at rear apron of the dam power, therefore to after dam crest and dam, do not need to make curve shape design, as shown in Figure 3.

4, groundwater reservoir reservoir area antiseepage design of dam body

Two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude is higher than groundwater reservoir controlling water level design elevation, and after ensureing that groundwater reservoir builds up retaining, reservoir area water can not toward storehouse external leakage.For section, local, reservoir area ground water divide absolute altitude lower than the location of groundwater reservoir controlling water level absolute altitude, underground anti-seepage dam must be constructed, be called antiseepage dam, groundwater reservoir reservoir area.Reservoir area antiseepage dam body, is made up of steel bar concrete campshed and antiseepage campshed.

The design of A, steel bar concrete campshed

Based on considering that being in descend lower location, dividing ridge constructs antiseepage dam, dam body can be subject to the lateral pressure impact of water in groundwater reservoir, and therefore antiseepage dam body need use the reinforced concrete pile of antiskid and overturning or slip resistance analysis for agent structure.

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

The design of B, antiseepage campshed

Antiseepage stake is laid in inside the reservoir of steel bar concrete campshed, is close to the triangle place of the Contact of reinforced concrete pile, leaks to prevent space between reinforced concrete pile.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. sand bed, sandy gravel stratum, is in.When husky, grain size of gravel is less, less containing shale, water content is less in addition, and underground water does not have the conditions such as bearing capacity phenomenon, and antiseepage stake should adopt water under high pressure mud churning consolidation campshed method.Antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed.Antiseepage campshed and steel bar concrete campshed parallel to each other, 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 underground impervious wall dam body.As shown in Figure 7.

2., at mixing soft layers such as powder soil horizon, farinose argillic horizon, mud, miscellaneous fill layers.Antiseepage campshed should adopt two row's deep-mixed pile consolidation methods.Two row's antiseepage campsheds are laid in the reservoir medial surface of steel bar concrete campshed, and be close to mutually with steel bar concrete campshed, require to overlap 100mm between antiseepage stake, require sequential production, impervious stratum 0.5-1.0m (or on bedrock surface) is held in stake.Stake heights of roofs is greater than groundwater reservoir controlling water level design elevation 2-3m.As shown in Figure 6.

3., at powder soil horizon, sandy gravel stratum, when underground water is abundanter, but when underground water does not have a pressure-bearing property, antiseepage stake then adopts the plain concrete deposited row of piles pile driving construction scheme of boring.The stake of element concrete is laid in the reservoir medial surface of reinforced concrete pile, is close to steel bar concrete campshed.Stake is held into underground impervious stratum 0.5-1.0m, and stake is long consistent with 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 comparatively large, and underground water is very abundant, has very large bearing capacity, and when side by side in lower storage reservoir storehouse, water lateral pressure is larger, antiseepage stake will adopt Percussion Piles element concrete campshed scheme.Antiseepage campshed will be close to steel bar concrete campshed.The construction of steel bar concrete campshed is front, and the construction of antiseepage campshed is rear.The stake of antiseepage campshed is held into underground impervious stratum 0.5-1.0m, and stake is long equal with steel bar concrete campshed length.As shown in Figure 5.

5, the stability calculation of groundwater reservoir dam body

In underground during the selection to dam type of ancient coombe, ground, ancient stream channel layer building groundwater reservoir, type that we all select " underground overfall dam "." the underground anti-seepage dam " selected on antiseepage dam, groundwater reservoir reservoir area, although two kinds of dam type differences, purposes is different, and the agent structure on dam is similar.

Because above two kinds of dam type building conditions requirement is special, complex geologic conditions.When considering design of dam body and constructure scheme, have employed corresponding measure, certain humidification has been obtained to the stable of dam body, simultaneously because groundwater reservoir project scale is less, therefore the dam stabilization of above two kinds of dam types is assessed, the checking computations of toppling making dam body can not be needed, only do the shear strength checking computations of dam body.

Shear strength formula is:

$K=\frac{\mathrm{f\ΣW}}{\mathrm{\ΣP}}$

In formula:

K-by shear Strength Calculation factor against sliding (by table adopt)

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

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

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

6, groundwater reservoir dam construction

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

2., reinforced concrete pile first arranges construction.Stake the general 800-1000mm in footpath, stake end embed batholith (or impermeable rock soil layer), the degree of depth be stake long 1/3, the arrangement of reinforcement of stake is determined by design.

3., pile body construction pore-creating time easy collapse hole, note adding appropriate clay, cement, or adopt casing execute brill.

4., reinforced concrete pile top mark is high determines reserved negative pile length by design.

5., the concrete stake of dam body element, complete the rear week construction of construction at steel bar concrete campshed.Element concrete campshed is laid in steel bar concrete campshed upstream side, and the contact triangle place between reinforced concrete pile two is close in plain concrete stake position.Stake footpath Φ 600-800mm.Stake is held into batholith 0.5m, concrete strength C15-C20.As shown in Figure 5.

7, the construction on groundwater reservoir reservoir area antiseepage dam

Reservoir area antiseepage dam body, is made up of steel bar concrete campshed and antiseepage campshed.

(1) construction of steel bar concrete campshed

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

2., laying is close to mutually between reinforced concrete pile.

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

4., reinforced concrete pile diameter of phi 800-1000mm, stake hold into underground impervious stratum deeply for stake long 1/3, enter 0.5m in horizon d, concrete strength is C20-C25.

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

(2) construction of antiseepage campshed

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

According to above 4th article of B design, antiseepage consolidation method has water under high pressure mud rotary churning pile, deep-mixed pile, plain concrete deposited stake and the plain concrete deposited stake of punching etc. 4 kinds of holing.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., first from dam site to reservoir tail, carry out riverbed geological drilling, and be depicted as groundwater reservoir longitudinal plan.As shown in Figure 8.Then according to underground, reservoir area bed configuration different level point, draw and calculate several cross sectional area.As the cross-sectional drawing of A-A, B-B, C-C, be respectively Fig. 9, Figure 10 and Figure 11.

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

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

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

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

2. groundwater reservoir water-bearing rock soil layer volume (V, is counted out _{total sand})

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

C, calculating groundwater reservoir water retention capacity

Design formulas:

V _{total water}=V _{total sand}× V _par

In formula:

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

V _{total sand}------groundwater reservoir aquifer cumulative volume (m ³)

V _par---integrated multilayer aquifer is every cubic metre of average (V isolating the water yield on average _par) (m ³)

The separation method of D, underground reservoir water content

Groundwater reservoir mentioned herein builds groundwater reservoir in underground reservoir, says accurately and should be called in " 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 be made up of multiple DIFFERENT SOIL layer.Because of the difference of the condition such as lithology, particle diameter size, grating, density in every layer of aquifer, water content has very large difference.

For the water content Separation Research of underground reservoir, people create several method for many years:

(1), sample letter oven drying method;

(2), centrifuge partition method;

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

The testing sequence of analog measurement method:

1., first understand fully that planning to build below groundwater reservoir controlling water level design elevation has how many layers of aquifer, the rock and soil properties in every layer of aquifer by geological drilling data, and distribution sequence, the key elements such as soil layer construction particle diameter, density, every layer of soil thickness.

2., the making of analog measurement device.Batchmeter can be made into cuboid, its volume V=abc, a=length, b=width, c=height.Make batchmeter inner hollow body and amass 2.0-3.0 (m ³).Plate can with plank or iron sheet.Be drain water steel net plate at the batchmeter other end, before steel net plate, be close to one piece of movable water impermeable sheet.Be catch basin after barrier sheet, establish bottom catch basin one can the drain tube holes of open and close.

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

4., machinery of sampling, the bucket drill bit of rotary pile-digging machine can be selected to construct.Bucket diameter of phi 1.0-2.0 (m).Or adopt the sampling of manual digging pile construction method.

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

6., sample (underground reservoir) is put into batchmeter after, first specimen surface is paved whole, then local use water source, injects batchmeter.After specimen surface stable level is saturation state, namely measure batchmeter aquifer volume V (m in the saturated condition ³).Drain tube holes bottom finally unlatching activity water-stop sheet and catch basin, after water drains in device to be batched, calculates in batchmeter the volume V being separated water outlet _water(m ³), be the water content volume V of every cubic metre of saturated aqueous rock-soil layer _water(m ³).

7. integrated multilayer aquifer on average every cubic metre of average V isolating the water yield, is finally calculated _par(m ³).

E, evaluation to several separation achievement of underground reservoir water content.

From the V of above three kinds of separation method gained _watervalue contrast, oven drying method is larger than centrifuge partition method, and analog measurement method is minimum.Namely oven drying method > centrifuge partition method > simulates measurement Law.

Although oven drying method and the isolated water yield V of centrifuge partition method _waterbe worth larger.All through oven drying method and the isolated aquifer of centrifuge method, become loose dry sand, dry ground.But the means of underground reservoir being drawn water from current reality and equipment, mainly adopt underground large diameter water well and the small-bore well of machine drill, with means and the equipment of pumping for water pump, to the water yield that saturated aquifer every cubic metre can be drawn, also do not reach oven drying method and centrifuge isolated water yield from every cubic metre of saturated aquifer far away.But, when well water pumping stops after certain hour, the diving of upstream namely slowly from aquifer osmotic flow supplement, make the water content in aquifer obtain reinstatement again.This change procedure, is similar to the nature of seepage action of ground water with the separation process of analog measurement method.In addition, separation process and the water yield separated and the effect of analog measurement method, be similar to utilizing the effect of well water pumping at present, the assessment for groundwater reservoir water retention capacity has more directive significance and Practical significance.

F, groundwater reservoir water retention capacity calculated examples

(1) for Fig. 8-Figure 11

1, set dam body to reservoir tail each water level isohypse length as:

" 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, set groundwater reservoir several cross sections width as

1. AA cross section is as Fig. 9.

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

2. BB cross section is as Figure 10.

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

3. CC cross section is as Figure 11.

L’ ₀＝30m；L’ ₁＝20m；L’ ₂＝10m

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

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

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

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

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

2., V is calculated with same computational methods _{2 is husky}, V _{3 is husky}, V _{4 is husky}.

V _{2 is husky}=71175 (m ³)

V _{3 is husky}=47025 (m ³)

V _{4 is husky}=34425 (m ³)

(3) groundwater reservoir aquifer cumulative volume is

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

＝101250+71175+47025+34425＝253875(m ³)

(4) groundwater reservoir retaining total amount is:

V _{total water}=V _{total sand}× V _par=253875 × 0.25=63469 (m ³)

Wherein:

V _{1 water}=V _{1 is husky}× V _par=101250 × 0.25=25312 (m ³)

V _{2 water}=V _{2 is husky}× V _par=71175 × 0.25=17794 (m ³)

V _{3 water}=V _{3 is husky}× V _par=47025 × 0.25=11756 (m ³)

V _{4 water}=V _{4 is husky}× V _par=34425 × 0.25=8606 (m ³)

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

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

A, (4) point see 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 water level elevation

“0”＝63469(m ³)

“a”＝38157(m ³)

“b”＝20363(m ³)

“c”＝8607(m ³)

“d”＝0.0(m ³)

2., be the guide and foundation that draw water with water with " water level and pondage curve map ", to act out one's plan, scientific consumption of water, overcome blindness.

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

4., draw water at every turn after, increase and measure water level number of times, grasp cycle and the elapsed time of water level rezime.

5., before water level not yet recovers, forbid excess to be drawn water, forbidden the wrong-doing doing " taking off pool and fishing ".

6., draw water before, first observed stage, understands reservoir existing water yield situation.Then draw water at regular time and quantity according to plan.After drawing water, time of pumping up to only recording vertical shelves with draw water front and back water level, pump-out etc.

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

10, groundwater reservoir recharges make-up water measure

In dry season, some groundwater reservoirs there will be lowest water level and last the long period, have impact on the continuation of reservoir water running.Therefore, when building groundwater reservoir, just should consider the matters building and recharge moisturizing engineering simultaneously.

A, recharge moisturizing engineering and have following several method:

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

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

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

2. on mountain, upstream, the molten water of Gao Ling earth's surface ice and snow;

3. earth's surface Junichiro Koizumi water burst.

(2) from storehouse, canal diversion is dug.Water source outside storehouse is attracted and recharges moisturizing to groundwater reservoir.

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

B, several design and construction recharging moisturizing engineering

1. the above cabinet that catchments, open grave, storehouse engineering, be communicated with groundwater reservoir with water-drawing channel.These catchworks scrape out cuboid toward underground from ground, the degree of depth is greater than top width, backfill coarse sand and gravel in hole, sand gravel aspect low 500-1000mm more near coal-mine than ground, then fill out clay thickness 500-1000mm last time in sand gravel aspect, argillic horizon maintains an equal level with near coal-mine ground level after compacting.To reduce moisture evaporation and to affect traffic above-ground.But sump is when backfilling clay, the water inlet that make-up water source flows into sump be reserved.

2. dig a well from storehouse or hole, the underground channel of water-drawing channel, also will backfill coarse sand and layer of gravel, and backfill argillic horizon 500-1000mm, fair with ground level after compacting.Object and effect are also to reduce moisture evaporation and affecting traffic above-ground.

11, to the protection of groundwater reservoir

1. the firsthand information such as exploration, design, construction of groundwater reservoir, found shelves and preserve for a long time.

2. on the ground, place constructing groundwater reservoir, the position on the spot such as dam body, edge, reservoir area, storehouse tail be marked, and set board declare protect.

3. forbid the various large-scale streets and buildings basis exceeding reserved soil layer bearing stratum permitted bearing capacity across ground, reservoir area.As being left with no alternative, then adopting bridge span Vietnamese side formula, pass through from reservoir area hemisphere.

Claims (2)

1. construct the method for groundwater reservoir at the ancient coombe of underground palaeostream, it is characterized in that, comprise the steps:

(1) to the prospecting of underground palaeostream, ancient coombe, concrete prospecting step is as follows:

(A) place name of the ancient coombe of underground palaeostream, stratum, the origin cause of formation, trend, length, underground reservoir thickness and subsurface level and ground level is reconnoitred;

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

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

(D) base area lower storage reservoir reservoir area geology orographic condition, selects buried channel broader and longer, milder, has the stratum in thicker aquifer, to ensure that groundwater reservoir has larger reservoir capacity; Absolute altitude lower storage reservoir controlling water level design elevation above Ground in dividing ridge, both sides, riverbed, underground in reservoir area, after ensureing that reservoir builds up retaining, storehouse Nei Shui can not toward storehouse external leakage; Comparatively grow area at karst, groundwater reservoir reservoir area is selected more weak at Karst Development, and the more complete section of basement rock, in case storehouse seepage;

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

(A) selection of dam type, adopts the dam body type of underground overfall dam;

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

1., first to planning to build the existing work in ground in groundwater reservoir reservoir area, agriculture, woods, to herd and the requirement of movable total load to below ground soil layer bearing stratum bearing capacity of house and the various industry of road is assessed, tentatively determine to cross soil thickness between water overflow profile head from ground to groundwater reservoir dam crest, i.e. the soil thickness of reserved area load contentedly; Then measure the wet season in groundwater reservoir reservoir area and superlatively descend water level elevation and ordinary water level absolute altitude, the less maintenance of groundwater table absolute altitude change lasts maximum duration, in moon number;

2., the design of backup land area load bearing stratum soil thickness, backup land area load bearing stratum soil layer floor level is made with superlatively descending water level elevation, to guarantee after groundwater reservoir builds up, groundwater reservoir water level is to ground, reservoir area and the original environmental ecology of periphery, and various facility does not affect;

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

4., dam crest overflow design of section, water overflow section is crossed for dam crest so that the section between groundwater reservoir peak level absolute altitude and ordinary water level absolute altitude is high, guarantee that wet season maximum water flow can successfully pass through from dam crest spillwag chute, can not rise because of water level flood period, affect upper soil horizon and produce softening or sag;

(C) design of underground overflow dam body, adopt Percussion Piles to be built into diaphragm wall antiseepage dam body, underground overfall dam agent structure is Large-size rebar concrete campshed, is close to mutually between stake, and it is that long 1/3 of stake is long that reinforced concrete pile enters rock; Row's minor diameter element concrete stake is set up, with percolating water between imperial anti-reinforced concrete pile near the position, contact triangle place between every two reinforced concrete piles at steel bar concrete campshed upstream side; Utilize punching pile machine in work progress, the upper and lower impact pore-forming of block stamp, compacted for hole wall periphery rock-soil layer, improves rock-soil layer compactness, angle of internal friction and modulus of deformation;

(3) groundwater reservoir reservoir area antiseepage design of dam body, two sides, riverbed, groundwater reservoir reservoir area ground water divide absolute altitude is higher than groundwater reservoir controlling water level design elevation, and after ensureing that groundwater reservoir builds up retaining, reservoir area water can not toward storehouse external leakage; For section, local, reservoir area ground water divide absolute altitude lower than the location of groundwater reservoir controlling water level absolute altitude, construct antiseepage dam, groundwater reservoir reservoir area; Reservoir area antiseepage dam body, 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 steel bar concrete campshed, stake footpath Φ 800-1000mm, stake to hold in rock stratum or underground impervious clay blanket 1/3 long; Stake heights of roofs is greater than groundwater reservoir controlling water level design elevation 2.0-3.0m;

(B) design of antiseepage campshed, antiseepage stake is laid in inside the reservoir of steel bar concrete campshed, is close to the triangle place of the Contact of reinforced concrete pile, leaks to prevent space between reinforced concrete pile;

(4) Stability Assessment of groundwater reservoir dam body, is checked by the shear strength calculating dam body;

(5) according to the design of step (2), construct to groundwater reservoir dam body, employing punching pile machine is construction machinery, first arranges the construction of reinforced concrete pile, arranges the construction of dam body element concrete stake after the week;

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

(7) survey and draw groundwater reservoir longitudinal plan, calculate the dried up amount of average mark of 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, draw groundwater reservoir water level and water retention capacity graph of relation, with this curve map for the guide that draws water with water and foundation, act out one's plan scientific consumption of water; Establishing a bite water level observation well at reservoir dam upstream side, is the permanent observation well of observed stage in reservoir; Before drawing water, first observed stage, understands the existing water yield situation of reservoir, then draws water at regular time and quantity according to plan; After drawing water, time of pumping up to only founding shelves with draw water front and back water level and pump-out record; After drawing water at every turn, increase and measure water level number of times, grasp cycle and the elapsed time of water level rezime; Before water level not yet recovers, excess is forbidden to be drawn water;

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

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

(B) from storehouse, dig canal diversion, water source outside storehouse is drawn and recharges moisturizing to groundwater reservoir;

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

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

1., when dam body be in sand bed or sandy gravel stratum, husky and grain size of gravel is less, few containing shale, water content is little, and when underground water does not have a bearing capacity phenomenon, antiseepage campshed should adopt water under high pressure mud rotary churning pile; Antiseepage campshed is laid in the reservoir medial surface of steel bar concrete campshed, antiseepage campshed and steel bar concrete campshed parallel to each other, 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 underground impervious wall dam body;

2., when dam body is at powder soil horizon, farinose argillic horizon, mud or miscellaneous fill layer, 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 steel bar concrete campshed, overlap between antiseepage stake 100mm, sequential production, stake is held into impervious stratum 0.5-1.0m, and stake heights of roofs is greater than groundwater reservoir controlling water level design elevation 2-3m;

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

4., when dam body is at fine sand layer or sandy gravel stratum, layer of gravel is thicker, and particle diameter is comparatively large, and underground water is very abundant, there is very large bearing capacity, when side by side in lower storage reservoir storehouse, water lateral pressure is larger, antiseepage stake adopts plain concrete stake, and antiseepage campshed will be close to steel bar concrete campshed, the construction of steel bar concrete campshed is front, the construction of antiseepage campshed is rear, and the stake of antiseepage campshed is held into underground impervious stratum 0.5-1.0m, and stake is long equal with steel bar concrete campshed length.