A dam silt delta underwater sand selection device and sand selection process

Abstract

The present application relates to the field of reservoir sediment deposition cleaning, and discloses a dam deposition delta underwater sand selection device and sand selection process, which comprises three steps: step one, sampling and analyzing the particle composition of the reservoir, and determining the characteristic particles; step two, determining the range of the reservoir tail deposition delta and the key position of the slope by exploration equipment; and step three, screening and removing the characteristic particles at the key position by the sand selection device. The present application can solve the problem of reservoir tail deposition at a low cost and with small engineering quantity, greatly improve the treatment ability and efficiency of the reservoir tail deposition problem, and has important significance for the long-term safe operation of the reservoir.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of reservoir sediment deposition cleaning, in particular to a dam deposition delta underwater sand selection device and sand selection process. BACKGROUND

[0002] Reservoir sediment deposition is a long-term accumulation process, and the reservoir capacity loss rate caused by sediment deposition is close to 1% per year. The number and quality of dams in China have reached the world leading level, and there are 29 dams built on the main stream of the Yellow River and the Yangtze River. The reservoir deposition problem caused by the operation of the dam reduces the benefits of all parties of the reservoir and also brings a series of ecological problems.

[0003] The deposition rate is determined by the water and sediment conditions and the operation mode of the reservoir. After the operation mode is determined, the river type reservoir will eventually establish a balance state similar to an alluvial river. The backwater extension caused by reservoir deposition will not only increase the inundation area and affect the navigation at the reservoir tail, but also have a serious impact on the flood control capacity. In order to ensure the health of the river and the sustainable use of the dam, it is necessary to solve the deposition problem. The top slope or the scouring and deposition slope of the deposition delta is the most important parameter to determine the shape of the reservoir deposition delta, and the important factor that determines this slope is the underwater repose angle of the deposited sediment. The repose angle of the sediment is the intersection angle between the slope and the horizontal plane when the sediment particles on the slope no longer slide, which is related to the size, shape, density and particle composition of the sediment particles, among which the size of the sediment particles in the natural state is the main influencing factor.

[0004] China is at the forefront of the world in using natural forces to control deposition, and the use of natural forces to regulate sediment and dredge has good effect on the position in front of the dam. However, for large reservoirs such as the Three Gorges, which is hundreds of kilometers long, it is impossible to solve the problem of the deposition delta at the reservoir tail. SUMMARY

[0005] The present application aims to provide a dam deposition delta underwater sand selection device to solve the technical problems of large amount of dredging work and limited dredging effect at the reservoir tail of the existing reservoir dredging device.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a dam deposition delta underwater sand selection device, comprising a working ship body, a suspended sand selection mechanism, a sand mining mechanism and a sand and soil container, the sand and soil container being fixedly arranged on the ship body;

[0007] The suspended sand selection mechanism comprises a first traction member and a jet device, one end of the first traction member being fixedly arranged on the ship body, and the other end of the first traction member being fixedly connected with the jet device;

[0008] The jet flow device comprises multiple groups of jet flow assemblies, each group of jet flow assemblies comprises a jet flow device body, a high-pressure water pump, a vibrator and a plurality of valves, the jet flow device body is a double-cone body, a plurality of through openings and jet flow channels are formed in the jet flow device body, the through openings on one side are water inlets, the high-pressure water pump is arranged at the water inlets, the remaining through openings are water outlets, the valves are arranged in the jet flow channels connected with the water outlets, and the vibrator is fixedly arranged in the jet flow device body.

[0009] The sand mining mechanism comprises a second traction member and a grab bucket, one end of the second traction member is fixedly arranged on the ship body, and the grab bucket is fixedly connected with the other end of the second traction member.

[0010] The beneficial effects of the scheme are:

[0011] 1. The sand is screened by the jet flow device, the jet flow device enters the sand layer through vibration, small sand particles with small particle sizes and large proportions in the sand layer are suspended and moved to downstream areas along with natural water flow through jet flow, and then large sand particles with small proportions and large particle sizes are concentrated and removed, the overall dredging work has a small amount of engineering and a short operation time.

[0012] 2. The large sand particles removed and salvaged on the shore by the scheme have overall particle sizes meeting the demand of the building industry, and can be directly used, thereby saving the cost of sand screening.

[0013] Further, the sand suspension and selection mechanism further comprises a main water inlet steel pipe, two auxiliary water inlet steel pipes and two connecting steel pipes, the jet flow assemblies are four groups, the water inlets of two groups of jet flow assemblies are connected through the auxiliary water inlet steel pipes, the water inlets of the other two groups of jet flow assemblies are connected through the other auxiliary water inlet steel pipe, the two auxiliary water inlet steel pipes are communicated through the main water inlet steel pipe, and the water outlets of the two groups of jet flow assemblies not communicated through the auxiliary water inlet steel pipes are communicated through the connecting steel pipes.

[0014] Beneficial effects: the working efficiency of sand suspension and selection can be improved, the sand suspension and selection work of the sand layer in the target area can be completed faster in the same time, and the expected effect can be achieved.

[0015] Further, the sand mining mechanism further comprises a first positioning member, and the first positioning member is fixedly arranged on the grab bucket.

[0016] Beneficial effects: the first positioning member can help the grab bucket to be accurately positioned and reduce repeated work, thereby improving the sand mining efficiency, because the first traction member can deviate from the predetermined vertical target in the descending process due to the action of water flow in water.

[0017] Further, the sand suspension and selection mechanism further comprises a second positioning member, and the second positioning member is fixedly arranged in the jet flow device body.

[0018] Beneficial effects: The jet flow device can be precisely controlled to land on the specific position of the sand layer surface, and the sand suspension and selection operation is carried out according to the expected planned sand selection path, thereby further improving the working efficiency of the sand selection device.

[0019] Further, the sand suspension and selection mechanism further comprises a high-voltage power supply fixedly arranged on the working ship body and connected with the high-pressure water pump of the jet flow assembly.

[0020] Beneficial effects: The high-pressure water pump of the jet flow assembly can be provided with continuous and stable high-voltage stable current, so that the working efficiency of the jet flow assembly is greatly improved.

[0021] Another object of the present application is to provide a dam silt delta underwater sand selection process, characterized by comprising the following three steps:

[0022] Step one, determine the characteristic particle: in the reservoir area, the composition of the particles in the reservoir basin is analyzed by sampling investigation, and based on the principle that the rest angle of different particle sizes is different, the characteristic particle size determining the slope of the dam silt delta is determined;

[0023] Step two, determine the key position: through field investigation, the range of the silt in the reservoir tail silt delta distributed according to the characteristic particle size and the key position determining the slope are determined;

[0024] Step three, screen and remove the characteristic particle: the characteristic particle of the key position determined in the foregoing step is screened and mechanically removed by the dam silt delta underwater sand selection device according to claim 5.

[0025] The beneficial effects of the present application are:

[0026] By accurately determining the characteristic particle determining the slope of the dam silt delta tail through extensive sampling, the range of the silt delta and the key position determining the slope are determined by artificial and mechanical detection, and finally the sand particles with particle size greater than or equal to the characteristic particle size are removed, the overall workload is small, it can be widely and long-term implemented, and the dredging effect can reach the expectation, the safety of the reservoir area is protected, and the normal development requirements of the reservoir capacity and ecological environment are ensured.

[0027] Further, the step three mechanical screening and removal comprises the following steps:

[0028] S1: select the steepest part of the silt delta slope, put the jet flow device into the sand layer surface through the first traction piece, start the vibrator, open the valve of the jet flow channel at the bottom of the jet flow device body, adjust the high-pressure water pump to jet downward at pressure P1, make the jet flow device vertically enter the sand layer inside a distance L1, and then stop the vibration and jet flow;

[0029] S2: open the valve of the jet flow channel at the top of the jet flow device body, adjust the high-pressure water pump to jet upward at pressure P2, so that fine particles smaller than the characteristic particle size are discharged from the sand layer to above the upper surface of the sand layer, forming a fine particle turbidity layer under water, and coarse sand particles equal to or larger than the characteristic particle size remain in the sand layer;

[0030] S3: when most of the fine particles in the sand layer are discharged, close the valve of the jet flow channel at the top of the jet flow device body, open the vibrator, open the valve of the jet flow channel at the side of the jet flow device body, adjust the high-pressure water pump to jet at pressure P1, so that the jet flow device moves horizontally in the sand layer for a distance L2, then close the vibrator, close the valve of the jet flow channel at the side of the jet flow device body, and repeat the operation of S2, so that the jet flow device moves in an "arch" shape until the selected sand range completely covers the key position;

[0031] S4: when most of the fine particle turbidity layer is dissipated, drive the second traction member to release the grab bucket, accurately grab the sand particles with a particle size greater than or equal to the characteristic particle size after treatment, and store them in the sand container, with a grabbing depth of L1 each time.

[0032] Beneficial effects: using the sand selection device provided by the present application, and performing the suspended sand selection and sand removal operation according to the above operation steps, the predetermined area can be efficiently and effectively removed, and good results can be achieved, so that the accumulation delta at the tail of the reservoir is prevented from developing and advancing to the front of the dam, and the safety of the reservoir area and the normal development of the ecological environment upstream are protected.

[0033] Further, the particle size range of the characteristic particle is 0.06-2 mm.

[0034] Beneficial effects: according to past experience, the particle size of the sand that determines the underwater rest angle of the key position of the delta slope in most of the main sand and gravel composition of the reservoir area is within the range of 0.06-2 mm, which can effectively reduce the workload of determining the characteristic particle in the early stage, and avoid the interference of abnormally large particle size sand particles on the work.

[0035] Further, in the S1 step, the vibration frequency of the vibrator is 80-100 Hz, and the pressure P1 in the S1 and S3 steps is 10-30 kPa.

[0036] Beneficial effects: the vibration frequency is maintained at 80-100 Hz, and the downward jet pressure is controlled at 10-30 kPa, which can effectively push the sand layer below the jet flow device to the surrounding, so that the jet flow device enters the sand layer for subsequent suspended sand selection and sand removal operation, and at the same time, excessive disturbance to the sand layer at the "key position" is avoided, so that the original "key position" form is not destroyed, the subsequent sand selection and sand removal operation is not affected, and the 10-30 kPa pressure is sufficient to cause the sand particles below the "characteristic particle" size to be discharged to the sand layer above under the action of water flow or to be washed to the downstream area with natural water flow.

[0037] Further, the L1 is 1-1.5m, the water depth of the current sand layer is H, and the pressure range of P2 is [10*(H+L1)+40]kPa-[10*(H+L1)+60]kPa.

[0038] Beneficial effects: the above data cooperate, which can complete the rapid movement of the jet flow device in the sand layer, and can avoid the great damage to the sand layer shape of the key part, ensure the screening and removal of the characteristic particle engineering according to the expected plan. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a working schematic diagram of the sand selecting device in the embodiment of the application;

[0040] Figure 2 It is a sectional view of the jet flow assembly in the sand selecting device in the embodiment of the application;

[0041] Figure 3 It is a combined structure schematic diagram of the four groups of jet flow assemblies in the sand selecting mechanism in the embodiment of the application. DETAILED DESCRIPTION

[0042] The following is further described in detail through specific embodiments:

[0043] The reference signs in the drawings of the specification include: dam body 1, riverbed 2, sand layer 3, workboat body 4, jet flow device 5, water inlet 51, top jet flow channel 52, upper side wall jet flow channel 53, side jet flow channel 54, lower side wall jet flow port 55, bottom jet flow channel 56, valve 57, vibrator 58, second positioning piece 59, grab bucket 6, high-voltage power supply 7, sand container 8, total water inlet 91, main water inlet steel pipe 92, additional water inlet steel pipe 93, and connecting steel pipe 94.

[0044] EMBODIMENT

[0045] The scheme is used for dredging the silt delta at the tail of the reservoir. Due to the obstruction of the dam body 1 to the original river channel, the water flow speed is relatively slow in the reservoir, especially at the tail of the reservoir, and the silt is easy to accumulate on the riverbed 2 to form an underwater delta, that is, the sand layer 3 is formed on the riverbed, and the front part of the sand layer 3, that is, the front position of the silt delta, will gradually push towards the dam body 1, and further affect the reservoir capacity and endanger the safety of the reservoir.

[0046] The scouring and silting balance slope of the silting delta is the most important parameter for determining the shape of the reservoir silting delta, and the important factor for determining the slope is the underwater repose angle of the silting sediment. The size of the sediment particles is the most important factor for determining the size of the underwater repose angle. The characteristic particle refers to the sediment particle with the highest proportion in the reservoir area corresponding to a certain particle size range. The sand particles with the particle size greater than or equal to the characteristic particle are removed to solve the problem of the accumulation of the sediment on the riverbed to form the delta and continuously push forward to the dam body.

[0047] A sand selection process for a dam silting delta underwater, comprising the following steps:

[0048] Step one: Investigate the sand particle composition in the target reservoir area through on-site sampling to determine which sand particle with the particle size in the range of 0.06-2 mm has the highest proportion, i.e., to determine the characteristic particle;

[0049] Step two: Determine the specific location of the tail reservoir silting delta and the key position for determining the slope by means of a sonar and the like;

[0050] Step three: Screen and remove the characteristic particle at the key position by using a sand selection device.

[0051] The sand selection device used in the embodiment is substantially as shown in the accompanying drawings Figures 1-3 , such as Figure 1The underwater sand selecting device for dam siltation delta shown in the application comprises a working ship body 4, a suspended sand selecting mechanism, a sand collecting mechanism and a sand container 8, the sand container 8 is fixedly arranged on the working ship body 4, the suspended sand selecting mechanism comprises a high-voltage power supply 7, a first traction member and a plurality of groups of suspended sand selecting assemblies, the fixed end of the first traction member is welded on the working ship body 4, each group of the suspended sand selecting assemblies comprises a jet device 5, the jet device 5 comprises a jet device body, a high-pressure water pump, a vibrator 58, a second positioning member 59 and a plurality of valves 57, the jet device body is provided with a jet channel, a top jet channel 52 is formed on the top of the jet device body, a water inlet 51 and three side jet channels 54 are formed on the circumferential direction of the jet device body, a bottom jet channel 56 is formed on the bottom of the jet device body, four upper sidewall jet channels 53 are formed on the sidewall of the upper cone, four lower sidewall jet channels 55 are formed on the sidewall of the lower cone, the valves 57 are arranged in the jet channels, the jet channels are communicated with each other, the vibrator 58 and the second positioning member 59 are fixedly arranged in the jet device body, in the embodiment, the jet assemblies are 4 groups, further comprising a main water inlet steel pipe 92, two auxiliary water inlet steel pipes 93 and two connecting steel pipes 94, the two ends of the main water inlet steel pipe 92 are connected with the middle portions of the two auxiliary water inlet steel pipes 93 and form a passage, a main water inlet 91 is formed on the middle portion of the main water inlet steel pipe 92, the high-pressure water pump is arranged at the main water inlet 91 and is driven by the high-voltage power supply 7, the two ends of the two auxiliary water inlet steel pipes 93 are respectively communicated with the water inlets 51 of the four jet devices, the two jet devices 5 not connected through the auxiliary water inlet steel pipes 93 are connected with the side jet channels 54 of the jet devices through the connecting steel pipes 94, the movable end of the first traction member is bolted with the main water inlet steel pipe.

[0052] The sand collecting mechanism comprises a second traction member and a grab bucket 6, the fixed end of the second traction member is welded on the working ship body 4, the movable end of the second traction member is fixedly connected with the grab bucket 6, and the first positioning member is fixedly arranged on the grab bucket 6.

[0053] The first traction member and the second traction member are both electric traction ropes, and the first positioning member and the second positioning member 59 are both GPS positioners.

[0054] The specific implementation process is as follows:

[0055] S1: the critical position of the siltation delta slope is selected, that is, the steepest position, the first traction member is driven to place the jet device 5 into the sand layer 3 with a water depth of 5 m under the guidance of the second positioning member 56, the vibrator 58 is started to vibrate at a frequency of 90 Hz, the valve 57 of the bottom jet channel 56 is opened, the high-pressure water pump is started and jets downward at a pressure of 20 kPa, so that the jet device 5 vertically enters 1 m deep below the sand layer 3, the vibration is stopped and the valve 57 of the bottom jet channel 56 is closed;

[0056] S2: open the valve 57 of the top jet channel 52 of the jetting device 5, set the pressure of the high-pressure water pump to 110 kPa, jet upward to make the fine particles smaller than the characteristic particle size in the sand layer 3 to be discharged to the upper surface of the sand layer 3, in the embodiment, the characteristic particle size is 0.15 mm, i.e. the fine particles with a particle size smaller than 0.15 mm are discharged to the upper surface of the sand layer 3, a fine particle turbidity layer is formed under the water, and the coarse particles remain in the sand layer 3;

[0057] S3: when the fine particles in the sand layer are almost discharged, close the valve 57 of the top jet channel 52, open the vibrator 58, the valve 57 of the side jet channel 54 and the high-pressure water pump, and after the jetting device 5 moves horizontally in the sand layer by 0.6 m, close the valve 57 of the vibrator and the side jet channel 54, repeat step S2 to perform the suspended sand and sand selection operation, until the "arch" type movement in the same plane is completed with a moving distance of 0.6 m per section and the key parts are completely covered;

[0058] S4: when the fine particle turbidity layer is almost completely moved to the lower stream with the water flow, i.e. at this time the sand layer 3 is in a clear state, the residual sand after treatment is accurately grabbed by the grab bucket 6 through the second traction member, the depth of the grab bucket 6 is controlled by the first positioning member, and the grabbing depth is 1 m each time, and the large particle sand grains collected on the shore can be directly reused as building materials.

[0059] The above is only an embodiment of the present application, and the specific technical solutions and / or common knowledge of characteristics in the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific embodiments in the specification can be used to explain the content of the claims.

Claims

1. An underwater select sand process for a dam silt delta, characterized by: The method comprises the following three steps: Step 1: determining characteristic particles: in the reservoir area, the composition of the particles entering the reservoir is analyzed by sampling investigation, and based on the principle that the different particle sizes have different angles of repose, the characteristic particle size determining the slope of the reservoir delta is determined; Step 2: determining the key position: through field investigation, the range of the sediment in the reservoir tail delta that meets the characteristic particle size and the key position determining the slope are determined; Step 3: screening and removing the characteristic particles: the characteristic particles in the key position are screened and removed mechanically; The step 3 of screening and removing the characteristic particles comprises the following steps: S1: selecting the steepest part of the delta slope, placing the jetting device into the sand layer surface through the first traction member, starting the vibrator, opening the valve of the jetting channel at the bottom of the jetting device body, adjusting the high-pressure pump to jet downward at a pressure P1, and stopping the vibration and jetting after the jetting device vertically enters the sand layer by a distance L1; S2: opening the valve of the jetting channel at the top of the jetting device body, adjusting the high-pressure pump to jet upward at a pressure P2, discharging the fine particles smaller than the characteristic particle size in the sand layer to the upper surface of the sand layer, forming a fine particle turbidity layer under the water, and leaving the coarse sand particles equal to or greater than the characteristic particle size in the sand layer; S3: when most of the fine particles in the sand layer are discharged, closing the valve of the jetting channel at the top of the jetting device body, opening the vibrator, opening the valve of the jetting channel at the side of the jetting device body, adjusting the high-pressure pump to jet at a pressure P1, moving the jetting device horizontally in the sand layer by a distance L2, then closing the vibrator and the valve of the jetting channel at the side of the jetting device body, and repeating the operation of S2 to make the jetting device move in an "arch" shape until the selected sand range completely covers the key position; S4: when the fine particle turbidity layer almost disappears, driving the second traction member to release the grab bucket, accurately grabbing the sand particles with a particle size equal to or greater than the characteristic particle size and storing them in the sand container, and the grabbing depth is L1 each time.

2. A process for underwater sand selection of a dam silt delta according to claim 1, characterized in that: The particle size of the characteristic particles ranges from 0.06 mm to 2 mm.

3. A dam silt delta underwater sand selection process according to claim 2, characterized in that: In the step S1, the vibration frequency of the vibrator is 80-100 Hz, and the pressure P1 in the steps S1 and S3 is 10-30 kPa.

4. A process for underwater sand selection of a dam silt delta according to claim 3, characterized in that: L1 is 1-1.5 m, the current water depth of the sand layer is H, and the pressure range of P2 is [10*(H+L1)+40]kPa-[10*(H+L1)+60]kPa.

5. A dam silt delta underwater sand selection process as claimed in claim 1, wherein: The underwater sand selecting device for the dam delta comprises a working ship body, a suspended sand selecting mechanism, a sand collecting mechanism and a sand container. The suspended sand selecting mechanism comprises a first traction member and a jetting device, one end of the first traction member is fixedly arranged on the ship body, and the other end of the first traction member is fixedly connected with the jetting device. The jet flow device comprises multiple groups of jet flow assemblies, each group of jet flow assemblies comprising a jet flow device body, a high-pressure water pump, a vibrator and a plurality of valves, the jet flow device body being a double-cone body, a plurality of through openings and jet flow channels being formed in the jet flow device body, one side of the through openings being water inlets, the high-pressure water pump being arranged at the water inlets, the remaining through openings being water outlets, the valves being arranged in the jet flow channels connected with the water outlets, and the vibrator being fixedly arranged inside the jet flow device body. The sand mining mechanism comprises a second traction member and a grab bucket, one end of the second traction member being fixedly arranged on the ship body, and the grab bucket being fixedly connected with the other end of the second traction member.

6. A dam silt delta underwater sand selection process as claimed in claim 5, wherein: The sand suspension and selection mechanism further comprises a main water inlet steel pipe, two auxiliary water inlet steel pipes and two connecting steel pipes, the jet flow assemblies are four groups, two groups of the jet flow assemblies are connected through the auxiliary water inlet steel pipes between the water inlets, the other two groups of the jet flow assemblies are connected through another auxiliary water inlet steel pipe between the water inlets, the two auxiliary water inlet steel pipes are communicated through the main water inlet steel pipe, and the water outlets of the two groups of jet flow assemblies which are not communicated through the auxiliary water inlet steel pipes are communicated through the connecting steel pipes.

7. A dam silt delta underwater sand selection process as claimed in claim 6, characterized in that: The sand mining mechanism further comprises a first positioning member, the first positioning member being fixedly arranged on the grab bucket, and the sand suspension and selection mechanism further comprises a second positioning member, the second positioning member being fixedly arranged inside the jet flow device body.

8. A dam silt delta underwater sand selection process as claimed in claim 7, characterized in that: The sand suspension and selection mechanism further comprises a high-voltage power supply, the high-voltage power supply being fixedly arranged on the working ship body and being connected with the high-pressure water pump of the jet flow assemblies.

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