Comb-shaped debris flow prevention and control system and calculation method for slag yards stacked along rivers

Abstract

The present invention discloses a comb-shaped debris flow prevention and control system and calculation method for slag yards piled along rivers. In the system of the present invention, a retaining dam and a grid frame retaining structure are arranged in the debris flow channel and upstream of the waste slag body. The water inlet end of a bottom slag drain pipe is arranged at the bottom of the retaining dam. One end of the grid frame is connected to the retaining dam, and the other end is buried in the soil layer. Then, a bottom slag drain pipe is arranged to penetrate through the entire waste slag body, and a number of water diversion pipes arranged in a comb shape are arranged on the riverside side of the drainage section of the bottom slag drain pipe. When a debris flow occurs, the boulders in the debris flow can be intercepted by the grid frame, the water in the debris flow flows through the grid frame into the bottom slag drain pipe, and is discharged into the water channel through the water diversion pipes, achieving the beneficial effect of separating water and stones in the debris flow, weakening the carrying and spreading ability of the debris flow, and reducing the impact and destructive power of the debris flow. The calculation method in the present invention can help save the project investment of the system and assist in preventing and controlling debris flows with beneficial effects.

Description

Technical Field

[0001] The invention relates to the technical field of geological disaster prevention and control, and in particular to a comb-shaped debris flow prevention and control system and a calculation method for a slag dump along a river. Background Art

[0002] When building railway or highway tunnels and bridges, a large amount of waste is needed. The location of the waste dump is restricted by the harsh conditions of topography and geology. The waste dump can only be located in the debris flow channel or along the river bank. If the amount of waste is large and the conditions are severely restricted, the waste dump will be located in the debris flow channel and along the river bank. If a waste dump is built in this area, if a debris flow occurs, the debris flow will impact the waste into the river, and even form a barrier lake, which will seriously damage the local environment.

[0003] In order to prevent and control debris flow, the traditional existing technology is to build blocking structures, diversion structures, etc. However, due to the limitation of the waste dump, the building of blocking structures can intercept sand and gravel, but the flood will still impact the waste dump, and the waste will be used as debris flow source material, causing a second debris flow disaster. The diversion structure is restricted by the terrain and cannot find a suitable location for diversion.

[0004] Therefore, in view of the above situation, it is necessary to provide a new concept of debris flow prevention and control measures to solve the problem of debris flow prevention and control in waste dumps located in debris flow channels and along rivers. Summary of the invention

[0005] In response to the problems of the prior art, the present invention provides a comb-shaped debris flow prevention and control system and calculation method for slag dumps along rivers, which can prevent and control the secondary natural disasters caused by the impact of debris flows on riverside slag dumps. It can not only meet the requirements of engineering slag disposal, but also prevent and control debris flows, protect the production and living safety near the river and downstream of the debris flow channel, and also reduce and save engineering investment.

[0006] In order to achieve the purpose of the above invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a comb-shaped debris flow prevention and control calculation method for a slag yard stacked along a river. This method is based on a comb-shaped prevention and control system for a slag yard stacked along a river. The system includes a waste slag body, a retaining structure, a bottom drain pipe for the slag, and a water diversion pipe; the retaining structure is arranged in the debris flow channel and is located upstream of the waste slag body. The retaining structure includes a retaining dam and a grid framework. The inlet end of the bottom drain pipe for the slag is arranged at the bottom of the retaining dam. The grid framework is inclined. One end of the grid framework is connected to the retaining dam, and the other end is buried in the soil layer. The space enclosed by the grid framework and the retaining dam communicates with the inlet end of the bottom drain pipe for the slag; the bottom drain pipe for the slag penetrates through the entire waste slag body. The bottom drain pipe for the slag is divided into section A and section B. Section A is a water collection section, and section B is a water discharge section; several water diversion pipes are connected to the riverside side of section B of the bottom drain pipe for the slag, and the water diversion pipes are arranged in a comb shape;

[0008] The method includes the following steps:

[0009] S10. Determine the amount of waste slag according to the project scale and determine the position of the waste slag body;

[0010] S20. Calculate the debris flow discharge according to previous debris flow experience data or rainfall data and determine the water surface height of the debris flow runoff flowing through the debris flow channel;

[0011] S30. Determine the elevation of the retaining dam according to the water surface elevation of the debris flow runoff. The elevation of the top of the retaining dam exceeds the water surface elevation of the debris flow runoff by more than 3 m; Measure the elevation H of the part of the bottom drain pipe for the slag at the junction of section A and section B of the bottom drain pipe for the slag A , and the elevation H of the end of the bottom drain pipe for the slag downstream of section B of the bottom drain pipe for the slag B ;

[0012] S40. Establish a calculation model based on the diameter of the bottom drain pipe for the slag, the roughness coefficient of the bottom drain pipe for the slag, the water discharge flow rate per unit length of the water diversion pipe, and the length of section B of the bottom drain pipe for the slag, specifically as follows:

[0013] The area E of the cross-section of the bottom drain pipe for the slag is:

[0014] E = πA 2 / 4;

[0015] The wetted perimeter k of the bottom drain pipe for the slag is:

[0016] k = πA;

[0017] The hydraulic radius F is:

[0018] F = C / k = A / 4;

[0019] In the above formula, A is the diameter of the bottom drain pipe for the slag; E is the cross-sectional area of the bottom drain pipe for the slag;

[0020] Select the Chezy formula applicable to the pipeline:

[0021] Q = Ev;

[0022]

[0023] Wherein, Q is the flow rate of the water flowing through the slag bottom drain pipe; v is the flow velocity of the water flowing through the slag bottom drain pipe; g is the acceleration due to gravity; y is the flow coefficient; λ is the friction coefficient along the way; C is the Chezy coefficient, and the Chezy coefficient is based on the pipeline flow and is calculated using the following formula:

[0024] C = n -1 F 1 / 6 ;

[0025] In the formula, n is the roughness of the slag bottom drain pipe, taking 0.014; F is the hydraulic radius;

[0026] Since the longitudinal coverage range of the waste residue body is more than 100 m, the local head loss and the velocity head loss are ignored, and the head loss of the water flowing through the slag bottom drain pipe is:

[0027]

[0028] Let the discharge modulus be:

[0029]

[0030] In the formula, L is the length of the slag bottom drain pipe through which the water flows; h f is the head loss of the water flowing through the slag bottom drain pipe with a length of L;

[0031] Define the water surface elevation at the retaining dam when debris flow occurs as H 0 , the elevation of the slag bottom drain pipe at the junction of section A and section B of the slag bottom drain pipe is H A , the elevation of the slag bottom drain pipe at the downstream end of section B of the slag bottom drain pipe is H B , the length L of section A of the slag bottom drain pipe A , the length L of section B of the slag bottom drain pipe B , and the point at a distance z from the junction of section A and section B of the slag bottom drain pipe is point Z;

[0032] According to the Bernoulli equation, it can be obtained that the equivalent elevation H 1 of the water flowing to the junction of section A and section B of the slag bottom drain pipe is:

[0033]

[0034] The flow rate Q at the cross-section of point Z at a distance z from the junction of section A and section B of the slag bottom drain pipez is:

[0035] Q Z = Q B +(L B -z)q;

[0036] In the formula, q is the drainage flow rate of the water diversion pipe per unit length, and the value can be measured by experiments; Q B is the drainage flow rate at the downstream end of section B of the slag bottom drain pipe, and can be taken as 0 in the extreme case;

[0037] Since the flow rate is in a constantly changing state during the flow in section B of the slag bottom drain pipe, the water flow belongs to variable flow and non-uniform flow. However, within a small flow section dz, considering the flow rate as constant and as uniform flow, the head loss h fB along the flow path within the dz flow section is constructed, and the calculus model is:

[0038]

[0039] Integrating the head loss h fB of the small flow section for section B of the slag bottom drain pipe, the head loss h fB along the flow path of the water flow in section B of the slag bottom drain pipe is obtained as:

[0040]

[0041] Under normal circumstances, when the water in the slag bottom drain pipe does not all drain into the river through the water diversion pipe and a part of the water flow flows out through the end of the slag bottom drain pipe, that is, Q B ≠0, a design calculation model based on the diameter of the slag bottom drain pipe, the roughness coefficient of the slag bottom drain pipe, the drainage flow rate q of the water diversion pipe per unit length, and the length L B of section B of the slag bottom drain pipe is established as:

[0042]

[0043] In the extreme case, when all the water in the slag bottom drain pipe drains into the river through the water diversion pipe, that is, Q B = 0, a design calculation model based on the diameter of the slag bottom drain pipe, the roughness coefficient of the slag bottom drain pipe, the drainage flow rate q of the water diversion pipe per unit length, and the length L B of section B of the slag bottom drain pipe is established as:

[0044]

[0045] Where:

[0046] The beneficial effect of the calculation method for preventing and controlling comb-shaped debris flow for the slag yard stacked along the river of the present invention is:

[0047] 1. This calculation method is based on a comb-shaped debris flow prevention and control system for slag dumps along the river. The system can separate water and rocks in the debris flow by building a waste dump in the debris flow channel near the river, using a slag bottom drainage pipe, a water diversion pipe connected to the B section (discharge section) of the slag bottom drainage pipe, and a blocking structure composed of a blocking dam and a grid frame. The water flow is discharged into the river channel through the water diversion pipe, weakening the carrying and diffusion capacity of the debris flow, using the waste dump body and the blocking structure 8 to resist the impact kinetic energy of the rocks in the debris flow, and leaving the rocks in the debris flow upstream of the waste dump body, completely decomposing the debris flow, playing a role in preventing and controlling the debris flow, avoiding the debris flow impacting the waste dump body to form secondary disasters, avoiding the formation of a barrier lake, and preventing the ecological environment from being polluted. Therefore, the calculation method of the present invention can help prevent and control the debris flow.

[0048] 2. The proposed method is based on the diameter of the slag bottom drainage pipe, the roughness of the slag bottom drainage pipe, the water discharge flow rate per unit length of the water diversion pipe q and the length of the B section of the slag bottom drainage pipe L. B The design calculation model can reasonably select the design parameters of each component of the waste dump according to different terrain conditions and different debris flow scales, so as to achieve the purpose of saving project investment.

[0049] The present invention also provides a comb-shaped debris flow prevention and control system for slag dumps along rivers, comprising a slag body, a retaining structure, a slag bottom drainage pipe, a water diversion pipe, and a slag bottom blind ditch; a drainage ditch is arranged on the top of the slag body to intercept water flowing down from the surrounding mountains, the retaining structure is arranged in the debris flow channel and is located upstream of the slag body, the retaining structure comprises a retaining dam and a grid frame, a water inlet end of the slag bottom drainage pipe is arranged at the bottom of the retaining dam, the grid frame is inclined, one end of the grid frame is connected to the retaining dam, and the other end is buried in the soil layer, the space enclosed by the grid frame and the retaining dam is connected to the water inlet end of the slag bottom drainage pipe, and the grid frame is used to prevent and control the blocks in the debris flow The water inlet end of the slag bottom drainage pipe is blocked; the slag bottom drainage pipe runs through the entire abandoned slag body, and is used to discharge the water in the debris flow channel that passes through the grid skeleton into the downstream of the debris flow channel or the river channel. The slag bottom drainage pipe is divided into section A and section B, and section A is a water collection section, and section B is a water discharge section; the slag bottom blind ditch is arranged at intervals of 10-20m at the bottom of the abandoned slag body, and holes are provided on the wall of the slag bottom drainage pipe, so that the water in the abandoned slag body can flow into the slag bottom drainage pipe through the slag bottom blind ditch and the holes of the slag bottom drainage pipe; the river side of section B of the slag bottom drainage pipe is connected to a plurality of the water diversion pipes, and the water diversion pipes are arranged in a comb shape, and are used to introduce the water in the slag bottom drainage pipe into the river channel for discharge.

[0050] In one embodiment, a filter layer is arranged around the slag bottom drainage pipe, which can prevent the slag of the abandoned slag body from passing through the holes of the slag bottom drainage pipe and entering the slag bottom drainage pipe.

[0051] In one embodiment, the filter layer is composed of pebbles.

[0052] In one embodiment, the grid framework adopts a reinforced concrete structure. By setting the grid framework to adopt a reinforced concrete structure, the grid framework can have higher hardness and strength and is not easily damaged by the boulders in the debris flow.

[0053] In one embodiment, a retaining wall is provided on one side of the waste residue body close to the river channel. This design can, on the one hand, prevent the soil and waste of the waste residue body from flowing into the river channel, and on the other hand, prevent the waste residue body from collapsing by itself.

[0054] In one embodiment, drainage holes are provided on the retaining wall part corresponding to the B section of the bottom slag drain pipe. This design helps to discharge the water in the waste residue body into the river channel through the drainage holes.

[0055] In one embodiment, one end of the water inlet pipe connected to the bottom slag drain pipe is higher than the end of the water inlet pipe far from the bottom slag drain pipe. This design helps the water inlet pipe to better discharge the water in the bottom slag drain pipe into the river channel.

[0056] In one embodiment, the retaining structure further includes a buffer structure. The buffer structure includes a baffle plate located on the side of the retaining dam facing away from the waste residue body and a buffer layer connecting the baffle plate and the retaining dam. The baffle plate is located above the grid framework. The buffer structure can buffer the impact force of the boulders in the debris flow on the retaining dam, so that the retaining dam is not easily damaged by the boulders in the debris flow and can extend the service life of the retaining dam.

[0057] In one embodiment, the buffer layer is composed of buffer springs.

[0058] The beneficial effects of the comb-shaped debris flow prevention and control system for the slag yard stacked along the river of the present invention are as follows: By setting a blocking structure in the debris flow channel and upstream of the waste slag body, the blocking structure includes a blocking dam and a grid framework. The water inlet end of the bottom drain pipe is arranged at the bottom of the blocking dam. The grid framework is inclined. One end of the grid framework is connected to the blocking dam, and the other end is buried in the soil layer. The space enclosed by the grid framework and the blocking dam is communicated with the water inlet end of the bottom drain pipe. Then, by setting the bottom drain pipe to penetrate through the entire waste slag body, and arranging a number of water diversion pipes arranged in a comb shape on the riverside side of the drainage section (section B) of the bottom drain pipe. When a debris flow occurs, the boulders in the debris flow can be intercepted by the grid framework, and the water in the debris flow passes through the grid framework and flows into the bottom drain pipe. When the water in the bottom drain pipe flows through the drainage end (section B), it can be discharged into the water channel through the water diversion pipes, achieving the beneficial effect of separating water and stones in the debris flow, that is, the boulders are left on the upstream of the waste slag body, and the water in the debris flow is discharged into the river through the bottom drain pipe and the water diversion pipes, completely decomposing the debris flow, weakening the carrying and spreading ability of the debris flow, reducing the impact and destructive power of the debris flow, protecting the ecological environment, and achieving the beneficial effect of preventing the secondary natural disasters caused by the impact of the riverside waste slag yard by the debris flow, which can not only meet the requirements of engineering waste slag, but also protect the production and living safety near the river and downstream of the debris flow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present invention will be further described below with reference to the drawings and embodiments.

[0060] Figure 1 is a plan view of the comb-shaped debris flow prevention and control system for the slag yard stacked along the river according to an embodiment of the present invention;

[0061] Figure 2 is Figure 1 a schematic cross-sectional view of D-D of the part where the waste slag body is located in

[0062] Figure 3 is Figure 1 a schematic cross-sectional view of C-C of the part where the waste slag body is located in

[0063] Figure 4 is Figure 1 a schematic cross-sectional view of the blocking structure in

[0064] Figure 5 is Figure 1 a schematic cross-sectional and longitudinal-sectional view of the blocking structure in

[0065] Figure 6 is a schematic diagram of the calculation model of the drainage flow rate of the water diversion pipe per unit length and the length of section B of the bottom drain pipe in the comb-shaped debris flow prevention and control calculation method of the present invention for the slag yard stacked along the river;

[0066] Figure 7Schematic cross-section of the retaining structure in another embodiment.

[0067] Reference numerals:

[0068] 1 - waste dump; 2 - debris flow channel; 3 - river channel; 4 - bottom drain pipe of the slag; 5 - water diversion pipe; 6 - retaining wall; 7 - bottom blind ditch of the slag; 8 - retaining structure; 9 - filter layer; 10 - drainage gutter; 11 - block stone; 81 - grid framework; 82 - retaining dam; 83 - buffer structure; 831 - retaining plate; 832 - buffer layer. Detailed implementation manners

[0069] The following is only a preferred embodiment of the present invention and does not limit the protection scope of the present invention accordingly.

[0070] It should be noted that when an element is referred to as "connected to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0071] Embodiment 1

[0072] This embodiment discloses a calculation method for preventing and controlling comb-shaped debris flows in a slag yard stacked along a river. This method is based on a comb-shaped debris flow prevention and control system for a slag yard stacked along a river, such as Figures 1 to 5As shown in the figure, the system includes a waste dump 1, a retaining structure 8, a drain pipe 4 at the bottom of the slag, and a water diversion pipe 5; the retaining structure 8 is arranged in the debris flow channel 2 and upstream of the waste dump 1. The retaining structure 8 includes a retaining dam 82 and a grid framework 81. The inlet end of the drain pipe 4 at the bottom of the slag is arranged at the bottom of the retaining dam 82. The grid framework 81 is inclined. One end of the grid framework 81 is connected to the retaining dam 82, and the other end is buried in the soil layer. The space enclosed by the grid framework 81 and the retaining dam 82 is communicated with the inlet end of the drain pipe 4 at the bottom of the slag. The grid framework 81 is used to prevent the boulders in the debris flow from falling into the space enclosed by the retaining dam 82 and the grid framework 81, so as to prevent the boulders 11 in the debris flow from blocking the inlet end of the drain pipe 4 at the bottom of the slag; the drain pipe 4 at the bottom of the slag runs through the entire waste dump 1 and can be used to discharge the water passing through the grid framework 81 in the debris flow channel 2 to the downstream of the debris flow channel 2 or the river channel 3. The drain pipe 4 at the bottom of the slag is divided into section A and section B. Section A is the water collecting section, and section B is the water discharging section; several water diversion pipes 5 are connected to the riverside side of section B of the drain pipe 4 at the bottom of the slag. The water diversion pipes 5 are arranged in a comb shape and are used to introduce the water in the drain pipe 4 at the bottom of the slag into the river channel 3 for discharge. Therefore, the specific calculation method for preventing and controlling comb-shaped debris flow in the slag yard along the river includes the following steps:

[0073] S10. Determine the amount of waste slag according to the project scale, and then determine the position of the waste dump 1.

[0074] S20. Calculate the debris flow discharge according to the previous debris flow experience data or rainfall data to obtain the water surface height of the debris flow runoff flowing through the debris flow channel 2.

[0075] S30. Determine the elevation of the retaining dam 82 according to the water surface elevation of the debris flow runoff. The elevation of the top of the retaining dam 82 exceeds the water surface elevation of the debris flow runoff by more than 3m; measure the elevation H A of the part of the drain pipe 4 at the bottom of the slag at the junction of section A and section B of the drain pipe 4 at the bottom of the slag, and the elevation H B of the end of section B of the drain pipe 4 at the bottom of the slag downstream.

[0076] S40. Establish a calculation model based on the diameter of the drain pipe 4 at the bottom of the slag, the roughness coefficient of the drain pipe 4 at the bottom of the slag, the water discharge flow rate per unit length of the water diversion pipe 5, and the length of section B of the drain pipe 4 at the bottom of the slag, specifically as follows:

[0077] The area E of the cross-section of the drain pipe 4 at the bottom of the slag is:

[0078] E = πA 2 / 4;

[0079] The wetted perimeter k of the drain pipe 4 at the bottom of the slag is:

[0080] k = πA;

[0081] The hydraulic radius F is:

[0082] F = C / k = A / 4;

[0083] In the above formula, A is the diameter of the bottom slag drain pipe 4; E is the cross-sectional area of the bottom slag drain pipe 4.

[0084] Select the Chezy formula applicable to the pipeline:

[0085] Q = Ev;

[0086]

[0087] Among them, Q is the flow rate of the water flow through the bottom slag drain pipe 4; v is the flow velocity of the water flow through the bottom slag drain pipe 4; g is the acceleration of gravity; y is the discharge coefficient; λ is the friction factor along the length; C is the Chezy coefficient, and the Chezy coefficient is calculated according to the following formula for pipe flow:

[0088] C = n -1 F 1 / 6 ;

[0089] In the formula, n is the roughness coefficient of the bottom slag drain pipe 4, taking 0.014; F is the hydraulic radius;

[0090] Since the longitudinal coverage range of the waste slag body 1 is more than 100 m, the local head loss and the velocity head loss are ignored, and the head loss of the water flow through the bottom slag drain pipe 4 is:

[0091]

[0092] Let the discharge modulus be:

[0093]

[0094] In the formula, L is the length of the water flow through the bottom slag drain pipe 4; h f is the head loss of the water flow through the bottom slag drain pipe 4 with a length of L;

[0095] Define the water surface elevation at the retaining dam 82 when the debris flow occurs as H 0 , the elevation of the bottom slag drain pipe 4 at the junction of section A and section B of the bottom slag drain pipe 4 is H A , the elevation of the bottom slag drain pipe 4 at the downstream end of section B of the bottom slag drain pipe 4 is H B , the length L of section A of the bottom slag drain pipe 4 A , the length L of section B of the bottom slag drain pipe 4 B , the point at a distance z from the junction of section A and section B of the bottom slag drain pipe 4 is point Z;

[0096] According to the Bernoulli equation, the equivalent elevation H 1 of the water flow reaching the junction of section A and section B of the bottom slag drain pipe 4 is:

[0097]

[0098] Such as Figure 6As shown, the flow rate Q at the cross-section Z, which is at a distance z from the junction of section A and section B of the slag bottom drain pipe 4 z is:

[0099] Q Z = Q B +(L B -z)q;

[0100] In the formula, q is the drainage flow rate per unit length of the water diversion pipe 5, and its value can be measured by experiments; Q B is the drainage flow rate at the downstream end of section B of the slag bottom drain pipe 4, which can be taken as 0 in the extreme case;

[0101] Since the flow rate is in a constantly changing state during the flow in section B of the slag bottom drain pipe 4, the water flow belongs to variable flow and non-uniform flow. However, within a small flow section dz, considering the flow rate remains unchanged and as a uniform flow, a calculus model of the head loss h fB along the path in the dz flow section is constructed as:

[0102]

[0103] Integrating the head loss h fB of the small flow section for section B of the slag bottom drain pipe 4, the head loss h fB along the path of the water flow in section B of the slag bottom drain pipe 4 is obtained as:

[0104]

[0105]

[0106] Among them, under normal circumstances: when not all the water in the slag bottom drain pipe 4 is discharged into the river 3 through the water diversion pipe 5, and a part of the water flow flows out through the end of the slag bottom drain pipe 4, that is, Q B ≠0, a design calculation model based on the diameter of the slag bottom drain pipe 4, the roughness of the slag bottom drain pipe 4, the drainage flow rate q per unit length of the water diversion pipe 5, and the length L B of section B of the slag bottom drain pipe 4 is established as:

[0107]

[0108] In the extreme case: when all the water in the slag bottom drain pipe 4 is discharged into the river 3 through the water diversion pipe 5, that is, Q B = 0, a design calculation model based on the diameter of the slag bottom drain pipe 4, the roughness of the slag bottom drain pipe 4, the drainage flow rate q per unit length of the water diversion pipe 5, and the length L B of section B of the slag bottom drain pipe 4 is established as:

[0109]

[0110] Among them:

[0111] The comb-shaped debris flow prevention and control calculation method for the slag yard stacked along the river of the present invention has the following beneficial effects:

[0112] 1. This calculation method is based on the comb-shaped debris flow prevention and control system for the slag yard stacked along the river. The system builds a waste slag yard in the debris flow gully 2 near the river. By using the bottom drain pipe 4 of the slag, the water diversion pipe 5 connecting the B section (discharge section) of the bottom drain pipe 4 of the slag, and the retaining structure 8 composed of the retaining dam and the grid framework 81, it can separate the water and stones in the debris flow. The water flows through the water diversion pipe 5 and is discharged into the river 3, weakening the carrying and spreading ability of the debris flow. The waste slag body 1 and the retaining structure 8 are used to resist the impact kinetic energy of the boulders in the debris flow, and the boulders in the debris flow are left upstream of the waste slag body 1, completely decomposing the debris flow, playing a role in preventing and controlling the debris flow, avoiding the formation of secondary disasters caused by the debris flow impacting the waste slag body 1, avoiding the formation of a barrier lake, and preventing the ecological environment from being polluted. Therefore, the calculation method of the present invention can assist in preventing and controlling the debris flow.

[0113] 2. By proposing a design calculation model based on the diameter of the bottom drain pipe 4 of the slag, the roughness coefficient of the bottom drain pipe 4 of the slag, the water discharge flow rate q per unit length of the water diversion pipe 5, and the length L of the B section of the bottom drain pipe 4 of the slag B the design parameters of each component of the waste slag yard can be reasonably selected according to different terrain conditions and different debris flow scales, achieving the purpose of saving project investment.

[0114] Embodiment 2

[0115] This embodiment discloses a comb-shaped debris flow prevention and control system for the slag yard stacked along the river, which adopts the comb-shaped debris flow prevention and control calculation method for the slag yard stacked along the river described in Embodiment 1, as Figures 1 to 5As shown in the figure, the comb-shaped debris flow prevention and control system for the slag yard stacked along the river includes a waste residue body 1, a retaining structure 8, a bottom drain pipe 4 for the slag, a water diversion pipe 5, and a bottom blind ditch 7 for the slag; a drainage gutter 10 is arranged at the top of the waste residue body 1 to intercept the water flowing down from the surrounding mountains. The retaining structure 8 is arranged in the debris flow channel 2 and upstream of the waste residue body 1. The retaining structure 8 includes a retaining dam 82 and a grid framework 81. The inlet end of the bottom drain pipe 4 for the slag is arranged at the bottom of the retaining dam 82. The grid framework 81 is inclined. One end of the grid framework 81 is connected to the retaining dam 82, and the other end is buried in the soil layer. The space enclosed by the grid framework 81 and the retaining dam 82 communicates with the inlet end of the bottom drain pipe 4 for the slag. The grid framework 81 is used to prevent the boulders 11 in the debris flow from blocking the inlet end of the bottom drain pipe 4 for the slag; the bottom drain pipe 4 for the slag penetrates through the entire waste residue body 1 and can be used to drain the water passing through the grid framework 81 in the debris flow channel 2 into the downstream of the debris flow channel 2 or the river channel 3. The bottom drain pipe 4 for the slag is divided into section A and section B. Section A is the water collection section, and section B is the water discharge section; a bottom blind ditch 7 for the slag is arranged at the bottom of the waste residue body 1 every 10 - 20 m. There are holes on the pipe wall of the bottom drain pipe 4 for the slag, so that the water in the waste residue body 1 can flow into the bottom drain pipe 4 through the bottom blind ditch 7 and the holes of the bottom drain pipe 4 for the slag; several water diversion pipes 5 are connected to the riverside side of section B of the bottom drain pipe 4 for the slag. The water diversion pipes 5 are arranged in a comb shape and are used to introduce the water in the bottom drain pipe 4 into the river channel 3 for drainage. Among them, the position of the waste residue body 1, the elevation of the retaining dam 82, the length of section A of the bottom drain pipe 4 for the slag, the length of section B of the bottom drain pipe 4 for the slag, the number and diameter of the water diversion pipes 5, and the drainage flow rate Q at the downstream end of section B of the bottom drain pipe 4 for the slag B are all determined by the comb-shaped debris flow prevention and control calculation method for the slag yard stacked along the river described in Embodiment 1.

[0116] In the present invention, a retaining structure 8 is provided in the debris flow channel 2 and upstream of the waste residue body 1. The retaining structure 8 includes a retaining dam 82 and a grid framework 81. The water inlet end of the bottom drain pipe 4 is provided at the bottom of the retaining dam 82. The grid framework 81 is inclined. One end of the grid framework 81 is connected to the retaining dam 82, and the other end is buried in the soil layer. The space enclosed by the grid framework 81 and the retaining dam 82 communicates with the water inlet end of the bottom drain pipe 4. Then, by arranging the bottom drain pipe 4 to penetrate through the entire waste residue body 1, and a number of comb-shaped arranged water diversion pipes 5 are provided on the riverside side of the drainage section (section B) of the bottom drain pipe 4. When a debris flow occurs, the boulders 11 in the debris flow can be intercepted by the grid framework 81, and the water in the debris flow flows through the grid framework 81 and into the bottom drain pipe 4. When the water in the bottom drain pipe 4 flows through the drainage end (section B), it can be discharged into the water channel 3 through the water diversion pipes 5, achieving the beneficial effect of separating water and stones in the debris flow, that is, the boulders are left upstream of the waste residue body 1, and the water in the debris flow is discharged into the river channel 3 through the bottom drain pipe 4 and the water diversion pipes 5, completely decomposing the debris flow, weakening the carrying and spreading ability of the debris flow, reducing the impact and destructive power of the debris flow, protecting the ecological environment, and achieving the beneficial effect of preventing secondary natural disasters caused by the impact of the riverside-type waste residue site by the debris flow, which can not only meet the requirements of engineering waste residue, but also protect the safety of production and life near the river channel 3 and downstream of the debris flow channel 2.

[0117] In addition, for the comb-shaped debris flow prevention system for the slag yard stacked along the river of the present invention, by adopting the comb-shaped debris flow prevention calculation method described in Embodiment 1, it is possible to reasonably select the design parameters of each component of the waste residue site according to different terrain conditions and different debris flow scales, and achieve the purpose of saving project investment.

[0118] Furthermore, an anti-filter layer 9 is arranged around the bottom drain pipe 4. The anti-filter layer 9 can prevent the soil of the waste residue body 1 from passing through the holes of the bottom drain pipe 4 and entering the bottom drain pipe 4. Preferably, the anti-filter layer 9 is composed of pebbles.

[0119] In this embodiment, the grid framework 81 is preferably made of a reinforced concrete structure so that the grid framework 81 has a high impact resistance and is not easily damaged by the boulders in the debris flow.

[0120] A retaining wall 6 is provided on the side of the waste residue body 1 close to the river channel 3. This design can, on the one hand, prevent the soil of the waste residue body 1 from flowing into the river channel 3, and on the other hand, prevent the waste residue body 1 from collapsing by itself. In other embodiments, drainage holes can be provided on the part of the retaining wall 6 corresponding to the B section of the bottom drain pipe 4 to assist the bottom drain pipe 4 in discharging the water in the waste residue body 1 into the river channel 3. In order to prevent the drainage holes from being blocked, an anti-filter layer 9 can also be provided on the side of this part of the retaining wall 6 facing the waste residue body 1.

[0121] In order to enable the water diversion pipe 5 to better drain the water in the slag bottom drain pipe 4, the end of the water diversion pipe 5 connected to the slag bottom drain pipe 4 is higher than the end of the water diversion pipe 5 away from the slag bottom drain pipe 4.

[0122] In other feasible embodiments, such as Figure 7 As shown, the retaining structure 8 further includes a buffer structure 83. The buffer structure 83 includes a baffle plate 831 located on the side of the retaining dam 82 facing away from the waste slag body 1 and a buffer layer 832 connecting the baffle plate 831 and the retaining dam 82. The baffle plate 831 is located above the grid framework 81. The buffer structure 83 can buffer the impact force of the boulders in the debris flow on the retaining dam 82, so that the retaining dam 82 is not easily damaged by the boulders in the debris flow, and the service life of the retaining dam 82 can be extended. In this embodiment, the buffer layer 832 is composed of buffer springs.

[0123] The above content is only the preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation to the present invention.

Claims

1. A comb-shaped debris flow prevention and control calculation method for slag yards piled along rivers, characterized in that, this method is based on a comb-shaped prevention and control system for slag yards piled along rivers, and the system includes waste rock bodies, retaining structures, bottom drain pipes of the slag yard and water diversion pipes; the retaining structure is arranged in the debris flow channel and upstream of the waste rock body, and the retaining structure includes a retaining dam and a grid framework. The water inlet end of the bottom drain pipe of the slag yard is arranged at the bottom of the retaining dam. The grid framework is inclined. One end of the grid framework is connected to the retaining dam, and the other end is buried in the soil layer. The space surrounded by the grid framework and the retaining dam communicates with the water inlet end of the bottom drain pipe of the slag yard; the bottom drain pipe of the slag yard penetrates through the entire waste rock body, and the bottom drain pipe is divided into section A and section B. Section A is the water collection section, and section B is the water discharge section; several water diversion pipes are connected to the riverside side of section B of the bottom drain pipe of the slag yard, and the water diversion pipes are arranged in a comb shape; this method includes the following steps: S10. Determine the amount of waste rock according to the project scale and determine the position of the waste rock body; S20. Calculate the debris flow discharge according to previous debris flow experience data or rainfall data and determine the water surface height of the debris flow runoff flowing through the debris flow channel; S30. Determine the elevation of the retaining dam according to the water surface elevation of the debris flow runoff. The elevation of the top of the retaining dam exceeds the water surface elevation of the debris flow runoff by more than 3 m, and measure the elevation H of the part of the bottom slag drain pipe at the junction of section A and section B of the bottom slag drain pipe A , and the elevation H of the end of the bottom slag drain pipe downstream of section B B ; S40. Establish a calculation model based on the diameter of the bottom drain pipe of the slag yard, the roughness coefficient of the bottom drain pipe of the slag yard, the water discharge flow rate per unit length of the water diversion pipe and the length of section B of the bottom drain pipe of the slag yard, specifically as follows: The cross-sectional area E of the bottom drain pipe of the slag yard is: E = πA 2 / 4; The wetted perimeter k of the bottom drain pipe of the slag yard is: k = πA; The hydraulic radius F is: F = C / k = A / 4; In the above formula, A is the diameter of the bottom drain pipe of the slag yard; E is the cross-sectional area of the bottom drain pipe of the slag yard; Select the Chezy formula applicable to pipelines: Q = Ev; Among them, Q is the flow rate of the water flow through the bottom drain pipe of the slag yard; v is the flow velocity of the water flow through the bottom drain pipe of the slag yard; g is the acceleration of gravity; y is the discharge coefficient; λ is the friction factor; C is the Chezy coefficient, and the Chezy coefficient is based on pipe flow and is calculated by the following formula: C = n -1 F 1 / 6 ; In the formula, n is the roughness coefficient of the bottom drain pipe of the slag yard, taking 0.014; F is the hydraulic radius; Since the longitudinal coverage range of the waste rock body is more than 100 m, the local head loss and the velocity head loss are ignored, and the head loss of the water flow through the bottom drain pipe of the slag yard is: Let the discharge modulus be: where L is the length of the slag bottom drain pipe through which the flow passes; h f is the head loss of the water flow passing through the slag bottom drain pipe with a length of L; Define the water surface elevation at the retaining dam during debris flow occurrence as H 0 , the elevation of the bottom slag drain pipe at the junction of section A and section B is H A , the elevation of the bottom slag drain pipe at the downstream end of section B is H B , the length L of section A of the bottom slag drain pipe A , the length L of section B of the bottom slag drain pipe B , and the point at a distance z from the junction of section A and section B of the bottom slag drain pipe is point Z; According to Bernoulli's equation, the equivalent elevation H of the water flow at the junction of section A and section B of the slag bottom drain pipe can be obtained. 1 It is: The flow rate Q at the cross-section of point Z which is at a distance z from the junction of section A and section B of the slag bottom drain pipe z is as follows: Q Z = Q B +(L B - z)q; where q is the drainage flow rate per unit length of the water diversion pipe, and the value is measured by experiments; Q B is the drainage flow rate at the downstream end of section B of the slag bottom drain pipe, and is taken as 0 in the extreme case; Since the flow rate is in a constantly changing state during the flow in section B of the slag bottom drain pipe, the water flow is a variable flow and a non-uniform flow. However, within a tiny flow section dz, considering the flow rate remains unchanged and regarding it as a uniform flow, a calculus model of the head loss h along the path within the dz flow section is constructed. fB is: The head loss h of a tiny flow segment fB Integrate the B section of the slag bottom drain pipe to obtain the frictional head loss h of the water flow in the B section of the slag bottom drain pipe fB It is as follows: Under normal circumstances, when not all of the water in the slag bottom drain pipe is discharged into the river through the water diversion pipe, and a part of the water flow flows out through the end of the slag bottom drain pipe, i.e., Q B ≠0, a design calculation model based on the diameter of the slag bottom drain pipe, the roughness coefficient of the slag bottom drain pipe, the water discharge flow rate q per unit length of the water diversion pipe, and the length L of section B of the slag bottom drain pipe B is established as follows: In the extreme case, when all the water in the slag bottom drain pipe is discharged into the river through the water diversion pipe, i.e., Q B = 0, a design calculation model based on the diameter of the slag bottom drain pipe, the roughness coefficient of the slag bottom drain pipe, the water discharge flow rate q per unit length of the water diversion pipe, and the length L of the B section of the slag bottom drain pipe B is as follows: Wherein:

2. A comb-shaped debris flow prevention and control system for slag yards piled along rivers, characterized in that, Adopt a comb-shaped debris flow prevention and control calculation method for a slag yard stacked along a river as described in claim 1. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river includes a waste slag body, a retaining structure, a bottom drain pipe for the slag, a water diversion pipe, and a bottom blind ditch for the slag; a drainage gutter is arranged at the top of the waste slag body for intercepting the water flowing down from the surrounding mountains. The retaining structure is arranged in the debris flow channel and upstream of the waste slag body. The retaining structure includes a retaining dam and a grid framework. The inlet end of the bottom drain pipe for the slag is arranged at the bottom of the retaining dam. The grid framework is inclined. One end of the grid framework is connected to the retaining dam, and the other end is buried in the soil layer. The space enclosed by the grid framework and the retaining dam communicates with the inlet end of the bottom drain pipe for the slag. The grid framework is used to prevent the boulders in the debris flow from blocking the inlet end of the bottom drain pipe for the slag; the bottom drain pipe for the slag penetrates through the entire waste slag body and is used to discharge the water passing through the grid framework in the debris flow channel into the downstream of the debris flow channel or the river. The bottom drain pipe for the slag is divided into section A and section B. Section A is the water collection section, and section B is the water discharge section; the bottom blind ditch for the slag is arranged at the bottom of the waste slag body every 10 - 20 m. There are holes on the pipe wall of the bottom drain pipe for the slag so that the water in the waste slag body can flow into the bottom drain pipe for the slag through the bottom blind ditch and the holes in the bottom drain pipe for the slag; several water diversion pipes are connected to the riverside side of section B of the bottom drain pipe for the slag. The water diversion pipes are arranged in a comb shape and are used to introduce the water in the bottom drain pipe for the slag into the river for discharge.

3. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 2, characterized in that, an anti-filter layer is arranged around the bottom drain pipe for the slag.

4. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 3, characterized in that, the anti-filter layer is composed of pebbles.

5. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 2, characterized in that, the grid framework adopts a reinforced concrete structure.

6. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 2, characterized in that, a retaining wall is arranged on one side of the waste slag body close to the river.

7. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 6, characterized in that, drainage holes are arranged on the retaining wall part corresponding to section B of the bottom drain pipe for the slag.

8. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 4, characterized in that, the end of the water diversion pipe connected to the bottom drain pipe for the slag is higher than the end of the water diversion pipe far from the bottom drain pipe for the slag.

9. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 4, characterized in that, the retaining structure further includes a buffer structure. The buffer structure includes a baffle plate on the side of the retaining dam facing away from the waste slag body and a buffer layer connecting the baffle plate and the retaining dam. The baffle plate is located above the grid framework.

10. The comb-shaped debris flow prevention and control system for a slag yard stacked along a river according to claim 9, characterized in that, the buffer layer is composed of buffer springs.

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