CN103696405B - Herringbone mud-rock flow water and stone separating system designing method - Google Patents

Abstract

The invention discloses a herringbone mud-rock flow water and stone separating system designing method. Structure of a herringbone mud-rock flow water and stone separating system is disclosed in the prior art, and no designing method of the system is disclosed yet, so that designing and application of the prevention and control system are limited. In engineering design of the herringbone mud-rock flow water and stone separating system, key parameters include span B of a water-stone separation grating, height H of the water-stone separation grating and length L of the water-stone separation grating. On the basis of basic parameters determined according to on-site inspection, experiments and mud-rock flow engineering investigation and design standards, a method for designing the span B, the height H and the length L of the water-stone separation grating in the engineering design method of the herringbone mud-rock flow water and stone separating system is provided. The herringbone mud-rock flow water and stone separating system designing method solves the technical problem that the herringbone mud-rock flow water and stone separating system cannot be accurately designed yet in engineering design, and is reliable in principle, scientific, simple and convenient in calculation process and adaptive to engineering construction requirements.

Description

Fish ridge mudstone flowing water stone piece-rate system method for designing

Technical field

The present invention relates to a kind of engineering design method, particularly relate to the method for designing of fish ridge mudstone flowing water stone piece-rate system, debris flow field, hydraulic engineering field.

Background technology

Mud-rock flow is formed at a kind of solid-liquid two-phase flow that the domatic or raceway groove in mountain area comprises water, stone and thin particulate matter.Due to debris flow occurrence suddenly and carry a large amount of stone and there is great destructive power, often form disaster.Mud-rock flow Control Engineering is one of mitigation means the most efficiently and effectively.

Applicant the patent No. be ZL201120352219.X, publication number is 202298575U, name is called the mudstone flowing water stone piece-rate system disclosing a kind of fish ridge in a kind of Chinese utility model patent of mudstone flowing water stone piece-rate system.Entire system is arranged on debris flow gully bed, and basic structure comprises drainage dam and is separated grid with the water stone across debris flow gully bed two sides.It is fish spine rack and panel construction that water stone is separated grid entirety, and form primarily of spine and girt strip, spine front end is immediately preceding drainage dam back side.System also can comprise dredging flow groove and stone stops long-pending field.This system can be further designed to multistage, along mud-rock flow raceway groove from the arrangement of upstream toward downstream spacing, and final composition fish ridge mudstone flowing water stone piece-rate system step by step.

Now still do not relate to this fish ridge mudstone flowing water stone piece-rate system method for designing open, limit this design preventing and treating system and application.

Referenced patents: Chengdu Inst. of Mountain Disaster and Environment, Ministry of Water Resources. a kind of mudstone flowing water stone piece-rate system: China, ZL201120352219.X [P] .2012-07-04.

Summary of the invention

Object of the present invention is exactly for the deficiencies in the prior art, and provide fish ridge mudstone flowing water stone piece-rate system method for designing, solving it still can not compared with the technical problem of careful design in engineering design.

The fish ridge mudstone flowing water stone piece-rate system that the present invention is directed to, is arranged on debris flow gully bed, comprises drainage dam, connects water stone be separated grid at drainage dam back side; Described water stone is separated grid across debris flow gully bed two sides, and anterior top and draining hole top, drainage dam are immediately.It is fish ridge structure that water stone is separated grid, and comprise the spine along mud-rock flow direction, spine both sides girt strip arranged side by side, girt strip base portion is fixed on support pier; Spine front end and draining hole top, drainage dam are immediately.Further, immediately dredging flow groove bottom drainage dam back side, dredging flow groove comprises the abutment wall arranged along debris flow gully bed both sides, arranges protection-apron bottom the ditch bed between abutment wall, and dredging flow groove afterbody arranges baffle wall style.Outside debris flow gully bed two sides, dredging flow groove two, stone is set and stops long-pending field.

Above-mentioned fish ridge mudstone flowing water stone piece-rate system is in engineering design, and critical parameter comprises water stone and is separated grid span B, water stone separation height of grid H, water stone separation grid length L.

For achieving the above object, technical scheme of the present invention is as follows:

Fish ridge mudstone flowing water stone piece-rate system method for designing, design water stone is separated grid span B, it is characterized in that: implement according to following steps:

Step S1: parameter is determined

Field investigation, according to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: the natural angle of respose of solid particle in mud-rock flow fish ridge mudstone flowing water stone piece-rate system build width B at the bottom of the raceway groove of position ', drainage dam draining hole width b,

Overflow degree of depth h when flowing through draining hole according to prior art determination mud-rock flow;

Step S2, water stone are separated grid span B and determine

Water stone is separated grid span B and determines according to formula 1 calculating:

B=hsin2 θ+b formula 1

In formula, B-water stone is separated grid span, m,

H-mud-rock flow flows through overflow degree of depth during draining hole, m, and step S1 determines,

θ-girt strip upper and lower two ends connecting line and mud-rock flow raceway groove base plane angle, ° equal

The natural angle of respose of solid particle in mud-rock flow

B-drainage dam draining hole width, m, step S1 determines.

The general principle that above-mentioned water stone is separated grid span B method for designing is: the first, span B affects the run duration of mud-rock flow on grid, thus affects water stone separating effect.If span B is too small, the run duration of mud-rock flow on grid is short, and part debris flow body has had little time water stone and has been separated and is just slipped to and stops long-pending field, causes water stone to be separated insufficient, affects structure result of use; If span B is excessive, mud-rock flow be slipped to stop long-pending field before just fully complete water stone be separated, cause construction investment to waste.So in engineering design, rational span B should be selected to make mud-rock flow under this span, just in time fully complete water stone and to be separated.Second; the desirable operational effect of structure is that solid particle that in mud-rock flow, particle diameter is greater than design particle separation diameter is split into as far as possible and stops long-pending field; and all the other debris flow bodies flow into dredging flow groove through grid as far as possible, so mud-rock flow fully completes the critical condition that water stone is separated on grid be: the solid particle that particle diameter is greater than design particle separation diameter equals the time of all the other debris flow bodies through grid along time of grid landing.And then; suppose that first mud-rock flow drops to grid surface through parabolic motion after draining hole flows out; then glide along grid surface; the debris flow body height of drop then flowed out from draining hole both sides is maximum; and this part debris flow body distance stops long-pending field recently, so the run duration of this part debris flow body on grid is the shortest.Be separated if this part debris flow body fully can complete water stone on grid, then all debris flow bodies all fully can complete the separation of water stone on grid.Comprehensive, the judgment condition of fitting span B is: the solid particle that particle diameter is greater than design particle separation diameter from the debris flow body that draining hole both sides are flowed out equals the time of all the other debris flow bodies through grid along the time of grid landing.

Based on above-mentioned principle analysis, only gravitate when supposing that mud-rock flow moves on grid, its flow depth equals mud-rock flow by the dark h of overflow during drainage dam, first, make parabolic motion under gravity after flowing out from drainage dam according to debris flow body, calculate vertical flow velocity v when mud-rock flow drops to grid surface _z; Secondly, according to be slipped to stop long-pending field solid particle with v _zsin θ is initial velocity, gsin θ be acceleration along grid landing, calculate the time t of solid particle along grid landing ₁; Again, be that the debris flow body of h is with v according to the degree of depth _zfor initial velocity, g be acceleration through grid, calculate the time t of debris flow body through grid ₂; Finally, t is utilized ₁=t ₂relation can obtain water outlet stone and be separated grid span B method for designing, i.e. formula 1.Wherein, overflow degree of depth h calculates according to method disclosed in bibliography 1 and determines; Drainage dam draining hole width b is determined by site inspection, foundation mud-rock flow engineering investigation and design specifications; Girt strip upper and lower two ends connecting line and mud-rock flow raceway groove base plane angle theta equal the solid particle natural angle of respose in mud-rock flow

According to pre-stage test result, the present invention is separated grid span B method for designing to the water stone in above-mentioned fish ridge mudstone flowing water stone piece-rate system method for designing and does further optimization, and specifically, water stone is separated grid span B and determines according to formula 2 calculating:

B=λ ₁(hsin2 θ+b) formula 2

In formula, λ ₁-grid span correction factor, value 1.48 ~ 1.61.

In the technical scheme optimized, introduce grid span correction factor λ ₁technical meaning be: because formula 1 obtains on the basis of hypothesis mud-rock flow only gravitate, but, when mud-rock flow moves on grid, except being subject to gravity, be also subject to frictional force, impact force, holding power etc., so this formula has certain error.In order to the error of cancelling 1, obtain the correction factor of formula 1 according to result of the test, so introduce λ ₁result of calculation can be made more accurate, more can meet engineering design requirements.Ordinary circumstance Under The Grille span correction factor λ ₁value 1.48 ~ 1.61, if mud-rock flow design discharge is larger, λ ₁value is larger.Further, in conditions permit situation, grid span correction factor λ ₁exact value should be determined through test.

Be separated grid span B method for designing based on above-mentioned water stone, the present invention further provides water stone and be separated height of grid H method for designing, its technical scheme is as follows:

A kind of fish ridge mudstone flowing water stone piece-rate system method for designing, is characterized in that: design water stone is separated height of grid H, completes on water stone separation grid span B basis,

Through experimental test determination basic parameter, comprising: in mud-rock flow particle diameter be greater than design particle separation diameter solid particle be separated to the ratio p stopping long-pending field ₁, particle diameter is less than design particle separation diameter in mud-rock flow solid particle is separated to the ratio p stopping long-pending field ₂, particle diameter is less than the solid particle ratio p of design particle separation diameter in mud-rock flow _d,

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: mud-rock flow bulk of solid matter concentration c before water stone is separated _v, mud-rock flow design discharge Q _c, the flow velocity v of mud-rock flow in dredging flow groove;

Water stone separation height of grid H simultaneous formula 3, formula 4, formula 5 calculate and determine:

H=H ₁+ H ₂formula 3

H ₁=0.5Btan θ formula 4

$H_2=\frac{Q_c^{\′}}{\mathrm{Bv}}$ Formula 5

In formula, H-water stone is separated height of grid, m,

H ₁the vertical height of plane on top to support pier on-girt strip, m,

B-water stone is separated grid span, m, calculates determine according to formula 1 or formula 2

θ-girt strip gradient, ° equals the mud-rock flow solid particle natural angle of respose ,

H ₂-support pier height, m,

The flow velocity of v-mud-rock flow in dredging flow groove, m/s,

Q _cthe letdown flow of '-dredging flow groove, m ³/ s, calculates according to formula 6 and determines,

Q _c'=(1-pc _v) Q _cformula 6

In formula, c _vmud-rock flow bulk of solid matter concentration before-water stone is separated,

Q _c-mud-rock flow design discharge, m ³/ s,

P-mud-rock flow solid matter is split into the ratio of stopping long-pending field, is calculated determine by formula 7,

P=(1-p _d) p ₁+ p _dp ₂formula 7

In formula, p _din-mud-rock flow, particle diameter is less than the solid particle ratio of design particle separation diameter,

P ₁in-mud-rock flow particle diameter be greater than design particle separation diameter solid particle be separated to the ratio of stopping long-pending field, span is 0.85 ~ 1.00,

P ₂in-mud-rock flow particle diameter be less than design particle separation diameter solid particle be separated to the ratio of stopping long-pending field, span is 0.25 ~ 0.35.

Above-mentioned water stone is separated height of grid H method for designing general principle and is: the first, and be fixed on support pier because water stone is separated grid by girt strip base portion, therefore water stone is separated the vertical height H that height of grid H is plane on top to support pier on girt strip ₁height H vertical with support pier ₂sum.The second, because girt strip gradient θ (i.e. girt strip upper and lower top line and the mud-rock flow raceway groove base plane angle gradient) equals the mud-rock flow solid particle natural angle of respose so H ₁be separated with water stone between grid span B and can be determined by trigonometric function relation.3rd, support pier height H ₂affect the conveyance capacity of dredging flow groove, therefore utilize dredging flow groove letdown flow Q _c' can inversion reckoning support pier height H ₂.Be clear water flow and solid matter flow sum according to debris flow and landslips, dredging flow groove letdown flow Q can be obtained _c' with piece-rate system design discharge Q _cbetween relation, i.e. formula expressed by (formula 8), wherein, ρ _cfor water stone is separated front mud-rock flow unit weight, kg/m ³, ρ _sfor mud-rock flow solid matter density, kg/m ³, the two is determined by experimental test, ρ _c' be mud-rock flow unit weight after the separation of water stone, kg/m ³, when supposing that mud-rock flow flows through water stone separation grid, be split into the material stopping long-pending field and be entirely made up of solid particle, then can obtain ρ _c' expression formula (formula 9), in formula, symbolic significance is the same.Simultaneous formula 8, formula 9 just can obtain the letdown flow Q of dredging flow groove _c' calculating formula, i.e. formula 6.

In said method, under general condition, in mud-rock flow particle diameter be greater than design particle separation diameter solid particle be separated to the ratio p stopping long-pending field ₁span is 0.85 ~ 1.00, if the solid particle that particle diameter is greater than design particle separation diameter is more regular, then and p ₁larger.In mud-rock flow particle diameter be less than design particle separation diameter solid particle be separated to the ratio p stopping long-pending field ₂span is 0.25 ~ 0.35, if particle diameter is greater than 0.5 times and is less than design particle separation diameter to obtain solid content more in mud-rock flow, then and p ₂larger.When conditions permit, p ₁, p ₂exact value all can be determined by test.

Be separated grid span B method for designing based on above-mentioned water stone, the present invention further provides water stone and be separated grid length L method for designing, its technical scheme is as follows:

A kind of fish ridge mudstone flowing water stone piece-rate system method for designing, is characterized in that: design water stone is separated grid length L, completes on water stone separation grid span B basis,

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: draining hole slope coefficient m;

Water stone is separated grid length L and determines according to formula 10 calculating:

$L=\frac{Q_c}{(b+\mathrm{mh})h}\·\sqrt{\frac{B}{g\sin \mathrm{\θ}\cos \mathrm{\θ}}}$ Formula 10

In formula, L-water stone is separated grid length, m,

Q _c-mud-rock flow design discharge, m ³/ s, determines according to design parameters,

B-drainage dam draining hole width, m, step S1 determines,

M-draining hole slope coefficient,

B-water stone is separated grid span, m,

G-acceleration of gravity, gets constant,

θ-girt strip gradient, °, equal the mud-rock flow solid particle natural angle of respose .

Above-mentioned water stone is separated grid length L method for designing general principle and is:

The first, about grill designs length.Water stone is separated grill designs length and depends on the largest motion distance of mud-rock flow on grid.As long as water stone is separated grid length equal the largest motion distance of mud-rock flow on grid; then can ensure that mud-rock flow all can be separated to both sides and stops long-pending field and can not fall into downstream raceway groove through being separated grid, the long construction investment that causes of reason grill designs is not wasted again simultaneously.

The second, about the definition of largest motion distance.Mud-rock flow water stone be separated grid moves time, the solid particle that most of particle diameter is greater than design particle separation diameter is slipped to along grid surface and stops long-pending field, and remainder flows into dredging flow groove through grid.The former run duration on grid is longer, and it is also larger along the move distance of grid length direction on grid.Simultaneously; be slipped in the solid particle stopping long-pending field, the solid particle flowed out from draining hole center and the distance of stopping between long-pending field maximum, under identical flow velocity; the run duration of these solid particles on grid surface is the longest, and its move distance along grid length direction is also just maximum.Therefore, water stone separation grill designs length should equal the move distance of these solid particles along grid length direction.

3rd, about the defining method of largest motion distance.Suppose that the solid particle flowed out from draining hole center only glides along grid surface under gravity, stop long-pending field until be slipped to.Flow velocity v then when solid particle flows out draining hole _x, water stone is separated grid span B, water stone be separated height of grid H or girt strip upper and lower two ends connecting line and mud-rock flow raceway groove base plane angle theta known when, these solid particles can be calculated at the move distance S of grid surface along grid length direction _max, thus obtain water outlet stone separation grid length L.S _maxsolid particle can be expressed as with flow velocity v _xat maximum duration t _maxthe distance of middle motion, i.e. S _max=v _xt _max(formula 11).V _xcan be by (formula 12) calculates and determines, wherein, and Q _cfor mud-rock flow design discharge (m ³/ s), A is that mud-rock flow is by area of passage (m during draining hole ²), b is draining hole bottom width (m), and m is draining hole slope coefficient, and h is overflow dark (m).

T _maxthe time that solid particle glides along grid surface with acceleration a=gsin θ, can be by (formula 13) calculates and determines, wherein, g is acceleration of gravity (m/s ²), θ is girt strip upper and lower two ends connecting line and mud-rock flow raceway groove base plane angle (°), and B is that water stone is separated grid span (m).

Can be obtained by formula 11, formula 12, formula 13 (formula 14), and obtain water stone separation grid L calculating formula, i.e. formula 10.

According to pre-stage test result, the present invention is separated grid length L method for designing to the water stone in above-mentioned fish ridge mudstone flowing water stone piece-rate system method for designing and does further optimization, and concrete technical scheme is:

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: mud-rock flow unit weight ρ before water stone is separated _c;

Water stone is separated grid span L and determines according to formula 15 calculating:

$L={\mathrm{\λ}}_2\·\frac{Q_c}{(b+\mathrm{mh})h}\·\sqrt{\frac{B}{g\sin \mathrm{\θ}\cos \mathrm{\θ}}}$ Formula 15

In formula, λ ₂-grid length correction coefficient, calculates according to formula 16 and determines;

λ ₂=2.131-0.0005 ρ _cformula 16

In formula, ρ _cmud-rock flow unit weight before-water stone is separated, kg/m ³.

In the technical scheme optimized, introduce grid length safety factor λ ₂technical meaning be: due to formula 10 be hypothesis mud-rock flow move on grid time only gravitate basis on obtain, this formula does not consider the frictional force between mud-rock flow and grid, so this formula has certain error, in order to eliminate error, the correction factor of formula 10 is obtained according to result of the test, so, introduce λ ₂result can be made more accurate, more can meet engineering design requirements.

Compared with prior art, the invention has the beneficial effects as follows: the method for designing providing fish ridge mudstone flowing water stone piece-rate system, is the concrete technical scheme selecting this debris flow structure to provide incorporation engineering condition complete design in Practical Project.

Bibliography 1: Lin Xueping. debris flow dam overfall conveyance capacity experimental study [D]. Chengdu: Chinese Academy of Sciences's Chengdu mountain region disaster and Environmental Research Institute, 2013

Accompanying drawing explanation

Fig. 1 is that water stone is separated grid span B, height H ₁, H ₂design diagram.

Fig. 2 is that water stone is separated grid length L design diagram.

Figure notation in accompanying drawing is respectively:

21 spine 22 girt strip 23 support piers

Detailed description of the invention

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are further described.

Embodiment one

As Fig. 1, by the preferred process of the present invention for certain debris flow gully designs a fish ridge mudstone flowing water stone piece-rate system.

1, water stone is separated grid span B design

Step S1, parameter are determined

Determine each basic parameter according to mud-rock flow engineering investigation and design specifications, test, comprising: the natural angle of respose of raceway groove bottom width B '=40m, mud-rock flow solid particle water stone piece-rate system design discharge Q _c=500m ³/ s, grid span correction factor λ ₁=1.6 (determining according to mud-rock flow design discharge size), drainage dam draining hole width b=10m, flow coefficient C=0.6.By Q _c=500m ³/ s, C=0.6, b=10m substitute into the dark h calculating formula of overflow in bibliography 1, obtain $h={\left(\frac{3Q}{2C\sqrt{2g}b}\right)}^{\frac{2}{3}}={\left(\frac{3\×500}{2\×0.6\sqrt{2\×10}\×10}\right)}^{\frac{2}{3}}=9.2m.$

Step S2, water stone are separated grid (2) span B and determine

By λ ₁=1.6, h=9.2m, θ=38 °, b=10m substitute into formula 2, have B=λ ₁(hsin2 θ+b)=1.6 × (9.2 × sin (38 × 2) °+10)=30.3m.

2, water stone separation grid spine and junction, drainage dam height H design

Field investigation and experimental test, determine that particle diameter is greater than the solid particle segregation ratio p of design particle separation diameter ₁=0.9, particle diameter is less than the solid particle segregation ratio p of design particle separation diameter ₂=0.3, in mud-rock flow, particle diameter is less than the solid particle ratio p of design particle separation diameter _d=0.8, water stone is separated front mud-rock flow solid matter volumetric concentration c _v=0.6, the flow velocity v=10m/s of mud-rock flow in dredging flow groove.

By p ₁=0.9, p ₂=0.3, p _d=0.8 substitution formula 7 has p=(1-0.8) × 0.9+0.8 × 0.3=0.42.

B=30.3m, θ=38 ° are substituted into formula 4, obtains H ₁=0.5Btan θ=0.5 × 30.3 × tan38 °=11.8m.

By c _v=0.6, p=0.42, Q _c=500m ³/ s substitutes into formula 6, has Q _c'=(1-0.6 × 0.42) 500=374m ³/ s.

By Q _c'=374m ³/ s, v=10m/s, B=30.3m substitute into formula 5, have $H_2=\frac{Q_c^{\′}}{\mathrm{Bv}}=\frac{374}{30.3\×10}=1.2m.$

By H ₁=11.8m, H ₂=1.2m substitutes into formula 3, has H=11.8+1.2=13m.

3, water stone is separated grid length L design

Field investigation and experimental test, determine that draining hole is designed to rectangle, mud-rock flow unit weight ρ before slope coefficient m=0, water stone are separated _c=1800kg/m ³.

By ρ _c=1800kg/m ³substitution formula 16 has λ ₂=2.131-0.0005 × 1800=1.23.

By Q _c=500m ³/ s, b=10m, h=9.2m, B=30.3m, θ=38 °, m=0 substitute into formula 15, have,

。

Claims (7)

1. fish ridge mudstone flowing water stone piece-rate system method for designing, for the design of fish ridge mudstone flowing water stone piece-rate system,

Described fish ridge mudstone flowing water stone piece-rate system is arranged on debris flow gully bed, comprises drainage dam, connects water stone be separated grid at drainage dam back side; Described water stone is separated grid across debris flow gully bed two sides, and the draining hole top on anterior top and drainage dam immediately; It is fish spine rack and panel construction that water stone is separated grid, and comprise the spine (21) along mud-rock flow direction, spine (21) both sides girt strip arranged side by side (22), girt strip (22) base portion is fixed on support pier (23);

It is characterized in that: design water stone is separated grid span B, implements according to following steps:

Step S1, parameter are determined

Field investigation, according to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: the natural angle of respose of solid particle in mud-rock flow fish ridge mudstone flowing water stone piece-rate system build width B at the bottom of the raceway groove of position ', drainage dam draining hole width b, overflow degree of depth h when flowing through draining hole according to prior art determination mud-rock flow;

Step S2, water stone are separated grid span B and determine

Water stone is separated grid span B and determines according to formula 1 calculating:

B=hsin2 θ+b formula 1

In formula, B-water stone is separated grid span, m,

H-mud-rock flow flows through overflow degree of depth during draining hole, m, and step S1 determines,

θ-girt strip (22) is two ends connecting line and mud-rock flow raceway groove base plane angle up and down, °, equal the natural angle of respose of solid particle in mud-rock flow

B-drainage dam draining hole width, m, step S1 determines.

2. method according to claim 1, is characterized in that: water stone is separated grid span B and determines according to formula 2 calculating:

B=λ ₁(hsin2 θ+b) formula 2

In formula, λ ₁-grid span correction factor, value 1.48 ~ 1.61.

3. method according to claim 2, is characterized in that: λ ₁value is determined through result of the test.

4. the method according to claim 1 or 2 or 3, is characterized in that:

Described fish ridge mudstone flowing water stone piece-rate system also includes dredging flow groove and stops long-pending field, immediately dredging flow groove bottom described drainage dam back side, and in debris flow gully bed two sides, dredging flow groove two arranged outside stone stops long-pending field;

Design water stone is separated height of grid H, completes on water stone separation grid span B basis,

Through experimental test determination basic parameter, comprising: in mud-rock flow particle diameter be greater than design particle separation diameter solid particle be separated to the ratio p stopping long-pending field ₁, particle diameter is less than design particle separation diameter in mud-rock flow solid particle is separated to the ratio p stopping long-pending field ₂, particle diameter is less than the solid particle ratio p of design particle separation diameter in mud-rock flow _d,

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: mud-rock flow bulk of solid matter concentration c before water stone is separated _v, mud-rock flow design discharge Q _c, the flow velocity v of mud-rock flow in dredging flow groove;

Water stone separation height of grid H simultaneous formula 3, formula 4, formula 5 calculate and determine:

H=H ₁+ H ₂formula 3

H ₁=0.5Btan θ formula 4

$H_2=\frac{Q_c^{\′}}{\mathrm{Bv}}$ Formula 5

In formula, H-water stone is separated height of grid, m,

H ₁the vertical height of plane on the upper top to support pier of-girt strip (22), m,

B-water stone is separated grid span, m, calculates determine according to formula 1 or formula 2,

θ-girt strip (22) is two ends connecting line and mud-rock flow raceway groove base plane angle up and down, °, equal the mud-rock flow solid particle natural angle of respose

H ₂-support pier (23) highly, m,

The flow velocity of v-mud-rock flow in dredging flow groove, m/s,

Q ' _cthe letdown flow of-dredging flow groove, m ³/ s, calculates according to formula 6 and determines,

Q ' _c=(1-pc _v) Q _cformula 6

In formula, c _vmud-rock flow bulk of solid matter concentration before-water stone is separated,

Q _c-mud-rock flow design discharge, m ³/ s,

P-mud-rock flow solid matter is split into the ratio of stopping long-pending field, is calculated determine by formula 7,

P=(1-p _d) p ₁+ p _dp ₂formula 7

In formula, p _din-mud-rock flow, particle diameter is less than the solid particle ratio of design particle separation diameter,

P ₁in-mud-rock flow particle diameter be greater than design particle separation diameter solid particle be separated to the ratio of stopping long-pending field, span is 0.85 ~ 1.00,

P ₂in-mud-rock flow particle diameter be less than design particle separation diameter solid particle be separated to the ratio of stopping long-pending field, span is 0.25 ~ 0.35.

5. method according to claim 4, is characterized in that: described p ₁, p ₂value is determined by result of the test.

6. the method according to claim 1 or 2 or 3, is characterized in that: design water stone is separated grid length L, completes on water stone separation grid span B basis,

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: draining hole slope coefficient m;

Water stone is separated grid length L and determines according to formula 10 calculating:

$L=\frac{Q_c}{(b+\mathrm{mh})h}\·\sqrt{\frac{B}{g\sin \mathrm{\θ}\cos \mathrm{\θ}}}$ Formula 10

In formula, L-water stone is separated grid length, m,

Q _c-mud-rock flow design discharge, m ³/ s, determines according to design parameters,

B-drainage dam draining hole width, m, step S1 determines,

M-draining hole slope coefficient,

B-water stone is separated grid span, m,

G-acceleration of gravity, gets constant,

θ-girt strip (22) is two ends connecting line and mud-rock flow raceway groove base plane angle up and down, °, equal the mud-rock flow solid particle natural angle of respose

7. method according to claim 6, is characterized in that:

According to mud-rock flow engineering investigation and design specifications determination basic parameter, comprising: mud-rock flow unit weight ρ before water stone is separated _c;

Water stone is separated grid span L and determines according to formula 15 calculating:

$L={\mathrm{\λ}}_2\·\frac{Q_c}{(b+\mathrm{mh})h}\·\sqrt{\frac{B}{g\sin \mathrm{\θ}\cos \mathrm{\θ}}}$ Formula 15

In formula, λ ₂-grid length correction coefficient, calculates according to formula 16 and determines;

λ ₂=2.131-0.0005 ρ _cformula 16

In formula, ρ _cmud-rock flow unit weight before-water stone is separated, kg/m ³.