Reverse monitoring structure and method for leakage of composite concrete face rockfill dam

Abstract

The present invention discloses a reverse monitoring structure for the leakage of a compound concrete panel rockfill dam. On the basis of an existing compound concrete panel rockfill dam, the structure includes a maintenance drainage gallery, a water measuring weir is arranged in the maintenance drainage gallery, and 2 to 4 layers of drainage pipes are arranged in the space between the filter area and the drainage strip of the horizontal section and facing the maintenance drainage gallery. The present invention also discloses a reverse monitoring method for the leakage of a compound concrete panel rockfill dam, the steps are: step 1, setting a water measuring weir in the maintenance drainage gallery; step 2, laying drainage pipes in the stone dam; step 3, calculating the leakage of the compound concrete panel rockfill dam; step 4, completing the evaluation of the leakage of the compound concrete panel rockfill dam. The present invention belongs to the technical field of hydropower engineering, and solves the problems of unreasonable structure and great limitations in the existing technology for monitoring the leakage of compound concrete panel rockfill dams.

Description

Technical Field

[0001] The invention belongs to the technical field of hydropower engineering, and relates to a reverse monitoring structure for leakage of a compound concrete panel rockfill dam. The invention also relates to a reverse monitoring method for leakage of a compound concrete panel rockfill dam. Background Art

[0002] There is no unified agreement in the dam construction industry at home and abroad on the classification of the height of concrete panel rockfill dams. The compound concrete panel rockfill dam referred to in the present invention refers to a concrete panel rockfill dam with a dam height greater than 250 meters. The existing method of monitoring the leakage of concrete panel rockfill dams is mainly to lay out a closed water interception system such as a cutoff wall and a curtain behind the dam, collect the leakage water from the dam and foundation, and discharge it uniformly through drainage ditches or drainage corridors, and use a water measuring weir for monitoring. When the covering layer is relatively thick and the infiltration water surface line is lower than the foundation of the dam, it is usually adopted to lay three or more water level monitoring holes at the maximum leakage section to monitor the hydraulic gradient and qualitatively and indirectly understand the changes in the leakage. The above methods are collectively referred to as conventional methods. Conventional methods basically rely on cut-off walls and anti-seepage curtains, which require the sealing and elevation of the foundation and the leakage surface line inside the dam body. The disadvantages are: first, the structure is complex and increases the investment in the project; second, the long-term operation of the high leakage water level inside the foundation and the dam body will accelerate the degradation of the performance of engineering materials and reduce the safety of the dam to a certain extent; third, the leakage monitoring is also affected by the downstream water level, and it cannot be monitored when the downstream water level is too high.

[0003] Therefore, it is urgent to develop a new leakage monitoring method for concrete face rockfill dams to overcome the shortcomings of the above conventional methods. Summary of the invention

[0004] The purpose of the present invention is to provide a reverse monitoring structure for seepage of a compound concrete panel rockfill dam, which solves the problem of the internal seepage line of the dam body being too high due to downstream drainage restrictions in the leakage monitoring process of the prior art.

[0005] Another object of the present invention is to provide a reverse monitoring method for the leakage of a compound concrete panel rockfill dam, which solves the problems of unreasonable structure and great limitations in the prior art for monitoring the leakage of a compound concrete panel rockfill dam.

[0006] The technical solution adopted by the present invention is a reverse monitoring structure for seepage of a compound concrete panel rockfill dam, which includes a maintenance drainage gallery on the basis of the compound concrete panel rockfill dam, a water measuring weir is arranged in the maintenance drainage gallery, and 2 to 4 layers of drainage pipes are arranged in the space between the reverse filtration area and the drainage strip of the horizontal section toward the maintenance drainage gallery.

[0007] Another technical solution adopted by the present invention is a reverse monitoring method for seepage of a composite concrete face rockfill dam, which is implemented according to the following steps:

[0008] Step 1, setting a water measuring weir in the maintenance drainage gallery of the compound concrete face rockfill dam;

[0009] Step 2: laying a drainage pipe in the compound concrete face rockfill dam;

[0010] Step 3, calculating the leakage of the composite concrete face rockfill dam;

[0011] Step 4: Complete the evaluation of the leakage of the composite concrete face rockfill dam.

[0012] The beneficial effect of the present invention is that the drainage corridor at the bottom of the gravity-type high-toe pier arranged on the upstream side is used to intercept the leakage water in the drainage strip and foundation of the dam body through the buried drainage pipe, and the leakage water is reversely diverted to the bottom maintenance drainage corridor. The leakage amount is monitored by arranging a water measuring weir in the bottom maintenance drainage corridor. It does not rely on the cut-off wall and curtain closure of the existing compound concrete panel rockfill dam, which can reduce the project investment, and at the same time will not increase the leakage water surface line, which is also beneficial to the safety of the dam, and is not affected by the downstream water level. The method of the present invention changes the traditional method of diverting the leakage water of the compound concrete panel rockfill dam to the downstream, can avoid the interception and drainage measures such as the cut-off wall and the closed curtain, and the drainage ditch, and reduce the leakage water surface line of the dam body. At the same time, it can accurately monitor the leakage of the dam body foundation, effectively solve or improve the problem that the monitoring of the leakage amount of the rockfill dam must rely on the cut-off wall and the closed curtain, and has a great application value in the monitoring of the leakage amount of the panel rockfill dam. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of a prior art composite concrete face rockfill dam;

[0014] Figure 2 It is a schematic diagram of the conventional monitoring method for leakage of rockfill dams in the prior art;

[0015] Figure 3 Schematic diagram of leakage monitoring principle of the method of the present invention;

[0016] Figure 4 is a cross-sectional view of a four-layer arrangement of a drainage pipe used in the method of the present invention;

[0017] Figure 5 is a plan view of the drainage pipe layout used in the method of the present invention;

[0018] Figure 6 It is an enlarged structural diagram of the drainage pipe used in the method of the present invention.

[0019] In the figure, 1. reinforced concrete panel, 2. cushion area, 3. transition area, 4. upstream rockfill area, 5. gravity high toe pier, 5-1. downstream surface of gravity high toe pier, 6. maintenance drainage corridor, 7. consolidation grouting, 8. anti-seepage curtain, 9. anti-filtration area, 10. drainage area, 11. drainage strip, 12. downstream dam stone area I, 13. downstream dam stone area II, 14. downstream block stone slope protection, 15. foundation surface, 16. drainage pipe, 16-1. buried pipe section, 16-2. flower pipe section, 16-3. permeable hole, 16-4. non-woven geotextile, 17. seepage water collection path, 18. downstream cutoff wall, 19. water measuring weir observation well, 20. water measuring weir. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The directions of “up, down, left, and right” mentioned in the following text are all intuitive descriptions of the corresponding drawings and are not intended to limit the installation positions of the components of the device structure. The actual installation positions shall be deduced accordingly.

[0022] The reverse monitoring structure and method for rockfill dam leakage of the present invention is aimed at a compound concrete panel rockfill dam with a gravity-type high-toe pier structure, and utilizes the inspection and drainage gallery at the bottom layer of the concrete gravity pier structure arranged on the upstream side to monitor the leakage of the dam body and foundation.

[0023] Reference Figure 1 The prior art composite concrete face rockfill dam has the following structure: in the dam body at the upper part of the upstream dam surface, a reinforced concrete face plate 1, a cushion layer area 2, a transition area 3, and an upstream rockfill area 4 are arranged in sequence from the outside to the inside, and an anti-filtration area 9 is arranged inside the upstream rockfill area 4. The anti-filtration area 9 is divided into two sections. The inner side of a section of the anti-filtration area 9 along the inclined upstream dam surface is set as a drainage area 10, and the upper surface of a section of the anti-filtration area 9 along the horizontal section of the dam bottom is set as a drainage strip 11;

[0024] At the dam foundation position below the upstream dam surface, a gravity high toe pier 5, consolidation grouting 7, and an anti-seepage curtain 8 are arranged in sequence from top to bottom, and a maintenance drainage gallery 6 is arranged inside the gravity high toe pier 5; it also includes a foundation surface 15, which is led out from the lower end of the cushion area 2 and the lower end of the transition area 3, and after reaching the bottom along the reverse slope of the gravity high toe pier 5, it horizontally meanders through the downstream dam surface of the dam body;

[0025] A downstream block stone slope protection 14 is arranged on the surface of the downstream dam surface, and the interior of the downstream block stone slope protection 14 is respectively provided with an upper downstream dam stone area I 12, a middle downstream dam stone area II 13, and a lower downstream dam stone area I 12 from top to bottom. The drainage strip 11, the filter area 9 and the foundation surface 15 all pass from below the lower downstream dam stone area I 12 toward the downstream.

[0026] The downstream dam rock area I 12 and the downstream dam rock area II 13 at both locations are rockfill materials, but the requirements for rockfill materials are different, such as particle size, grading, and mechanical properties of rockfill materials. Both are conventional settings.

[0027] Reference Figure 2 For a composite concrete face rockfill dam, the conventional method for monitoring leakage is that the water in the dam reservoir seeps through the face plate 1, consolidation grouting 7, and anti-seepage curtain 8 and is collected in the upstream rockfill area 4. Since a cutoff wall 18 is arranged at the rear slope of the dam, the water surface line in the dam body gradually rises, and then is diverted to the water measuring weir observation well 19 through the drainage strip 11, and the leakage is obtained by measuring the water measuring weir.

[0028] Figure 1 It is a composite concrete face rockfill dam structure. Under this structure, conventional leakage monitoring methods can be used, and the method of the present invention can also be used. The present invention focuses on the use of reverse leakage monitoring structure and method. The setting of the monitoring structure is different from that of the conventional leakage monitoring method. Figure 1 The structure is related and has good engineering application advantages.

[0029] Reference Figure 3 The improved structure adopted by the monitoring method of the present invention is based on Figure 1 The composite concrete face rockfill dam shown has been eliminated. Figure 2 In addition to the cut-off wall 18 and the water measuring weir observation well 19 used in the conventional leakage monitoring method, a drainage pipe 16 is newly set, that is, 2 to 4 layers of drainage pipes 16 are set in the space between the horizontal section's filter area 9 and the drainage strip 11 toward the maintenance drainage gallery 6. Due to the existence of the drainage pipe 16, the seepage water collection path 17 of the seepage water in the upstream rockfill area 4 is changed, and the seepage water will be diverted along the drainage strip 11 to the maintenance drainage gallery 6 at the bottom of the gravity high toe pier, and finally the leakage amount is measured through the water measuring weir 20.

[0030] In general, the elevation of the inspection drainage gallery 6 at the bottom of the gravity high-toe pier is much lower than the water-measuring weir observation well 19, and is also slightly lower than the downstream side foundation surface 15. Due to the existence of the drainage pipe 16, the dam body seepage water can be concentrated and diverted to the inspection drainage gallery 6 without the cutoff wall 18. Therefore, the elimination of the cutoff wall 18 and the water-measuring weir observation well 19 can significantly reduce the construction difficulty; compared with the conventional leakage monitoring method, the water surface line in the upstream rockfill area 4 will also be greatly reduced, which is conducive to the stability of the rockfill body and the long-term operation of the dam.

[0031] Reference Figure 4The specific arrangement of the drainage pipes 16 is to arrange the drainage pipes 16 in layers and side by side on both sides based on the center line of the drainage strip 11. The drainage pipes 16 are arranged in 2 to 4 layers at different elevations, with 5 to 10 pipes arranged side by side in each layer, and the distance between adjacent drainage pipes 16 is 1 to 2 m; when 2 layers are arranged, they are arranged at angles of 15° and 20° respectively; when 3 layers are arranged, they are arranged at angles of 15°, 20°, and 25° respectively; when 4 layers are arranged, they are tilted up by 15°, 20°, 25°, and 30° respectively.

[0032] Reference Figure 5 , Figure 6 The structure of the drainage pipe 16 is that it includes a buried pipe section 16-1 and a flower pipe section 16-2. The buried pipe section 16-1 is arranged inside the gravity high toe pier 5 (i.e., the buried pipe section in the concrete), and is connected to the maintenance drainage gallery 6. The flower pipe section 16-2 is arranged inside the upstream rockfill area 4 (i.e., the flower pipe section in the rockfill body), and the front end of the flower pipe section 16-2 extends forward to the drainage strip 11, and the water permeable holes 16-3 on the circumference of the flower pipe section 16-2 are within the range of the transition area 3 and the anti-filtration area 9;

[0033] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0034] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with 1 to 3 layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0035] The working principle of the present invention is that the dam body anti-seepage structure of the existing compound concrete panel rockfill dam is mainly composed of reinforced concrete panel 1, gravity high toe pier 5, and anti-seepage curtain 8. The dam body leakage is mainly caused by the reduction of the anti-seepage performance of the panel, and the dam foundation leakage is caused by the reduction of the anti-seepage performance of the foundation anti-seepage curtain and the gravity high toe pier and the foundation surface joint. Whether it is panel or foundation leakage, it will cause the rise of the leakage water surface line inside the dam body, and finally enter the drainage area 10 and drainage strip 11 through the upstream rockfill area 4 and the anti-filtration area 9 inside the dam body. The traditional method is to set a closed curtain and a cut-off wall 18 behind the dam, and lay a water measuring weir observation well 19 and a water measuring weir 20 to monitor the leakage. The method of the present invention is to lay a drainage pipe 16 on the upstream side, reversely guide the leakage water in the upstream rockfill area 4, the drainage area 10, and the drainage strip 11 into the maintenance drainage gallery 6 set inside the gravity high toe pier 5, and monitor it by laying a water measuring weir in the maintenance drainage gallery 6. Through the leakage monitoring structure and method proposed in the present invention, the investment in leakage monitoring facilities can be reduced by more than 90%, the construction period can be shortened by more than 70%, and at the same time, the stability and durability of the rockfill material at the bottom of the dam body can be significantly improved, which has significant social and economic benefits.

[0036] The reverse monitoring method for leakage of a composite concrete face rockfill dam of the present invention is implemented according to the following steps:

[0037] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0038] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0039] Step 2: Lay out the drainage pipe 16 according to Figure 3 , Figure 4 , Figure 5 In the structure shown, the cut-off wall 18 and the water measuring weir observation well 19 are eliminated, and a drainage pipe 16 is arranged.

[0040] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0041] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0042] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with 1 to 3 layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0043] Step 3: Calculate the leakage amount.

[0044] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0045] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0046] Step 4: Complete the leakage assessment.

[0047] There is no clear safety standard for the leakage of composite concrete face rockfill dams. The criterion is usually that there is no deformation damage, seepage damage, and no impact on the overall stability of the dam and power generation efficiency. According to domestic and foreign statistics, the leakage of most concrete face rockfill dams is below 300L / s; if the leakage value does not exceed 300L / s, and the monthly increase in leakage is not more than 3% and the annual cumulative increase is not more than 5%, that is, there is no obvious increase in the trend, and no deformation damage or seepage damage has occurred after evaluation, the leakage can be considered stable. If the leakage value exceeds 300L / s, it is necessary to focus on monitoring, investigate the cause in time, and make emergency measures.

[0048] Example 1

[0049] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0050] According to the above structure, a water measuring weir is set up, and 4 layers of drainage pipes 16 are laid out at different elevations, with 10 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 1m; when laying out four layers, the angles are 15°, 20°, 25°, and 30° respectively.

[0051] Then, follow the steps below to implement reverse monitoring of leakage:

[0052] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0053] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0054] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0055] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0056] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0057] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with a layer of non-woven geotextile 16-4 to achieve the permeable and sand-isolating function.

[0058] Step 3: Calculate the leakage amount.

[0059] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0060] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0061] Step 4: Complete the leakage assessment.

[0062] There is no clear safety standard for the leakage of composite concrete face rockfill dams. The usual criteria are that no deformation or seepage damage occurs and that the overall stability of the dam body and the power generation efficiency are not affected.

[0063] After one month of monitoring, the calculated leakage rate was 39L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

[0064] Example 2

[0065] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0066] According to the above structure, a water measuring weir is set up, and 4 layers of drainage pipes 16 are laid out at different elevations, with 5 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 2m; when four layers are laid out, they are tilted up by 15°, 20°, 25°, and 30° respectively.

[0067] Then, follow the steps below to implement reverse monitoring of leakage:

[0068] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0069] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0070] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0071] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0072] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0073] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%. The surface of the pipe section where the permeable holes 16-3 are located is wrapped with two layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0074] Step 3: Calculate the leakage amount.

[0075] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0076] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement;H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0077] Step 4: Complete the leakage assessment.

[0078] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0079] After one month of monitoring, the calculated leakage rate was 63L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

[0080] Example 3

[0081] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0082] According to the above structure, a water measuring weir is set up, and two layers of drainage pipes 16 are laid out at different elevations, with 6 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 1.5m; when four layers are laid out, they are tilted up 15° and 20° respectively.

[0083] Then, follow the steps below to implement reverse monitoring of leakage:

[0084] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0085] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0086] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0087] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0088] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0089] The permeable holes 16-3 are plum blossom-shaped holes with a diameter of 5 mm, evenly distributed, and an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with 3 layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0090] Step 3: Calculate the leakage amount.

[0091] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0092] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0093] Step 4: Complete the leakage assessment.

[0094] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0095] After one month of monitoring, the calculated leakage rate was 58L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

[0096] Example 4

[0097] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0098] According to the above structure, a water measuring weir is set up, and 3 layers of drainage pipes 16 are laid out at different elevations, with 8 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 1.2m; when four layers are laid out, they are tilted up by 15°, 20°, and 25° respectively.

[0099] Then, follow the steps below to implement reverse monitoring of leakage:

[0100] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0101] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0102] Step 2: Follow Figure 3 , Figure 4 , Figure 5In the structure shown, a drainage pipe 16 is arranged.

[0103] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0104] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0105] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with a layer of non-woven geotextile 16-4 to achieve the permeable and sand-isolating function.

[0106] Step 3: Calculate the leakage amount.

[0107] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0108] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0109] Step 4: Complete the leakage assessment.

[0110] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0111] After one month of monitoring, the leakage was calculated to be 331L / s. The monthly increase in leakage was greater than 3% and the annual cumulative increase was no more than 5%, indicating that the leakage of the concrete panel rockfill dam slightly exceeded the allowable range and that monitoring needed to be strengthened and the cause should be found in a timely manner.

[0112] Example 5

[0113] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0114] According to the above structure, a water measuring weir is set up, and 3 layers of drainage pipes 16 are laid out at different elevations, with 6 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 1.0m; when four layers are laid out, they are tilted up 15°, 20°, and 25° respectively.

[0115] Then, follow the steps below to implement reverse monitoring of leakage:

[0116] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0117] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0118] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0119] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0120] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0121] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%. The surface of the pipe section where the permeable holes 16-3 are located is wrapped with two layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0122] Step 3: Calculate the leakage amount.

[0123] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0124] in,Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0125] Step 4: Complete the leakage assessment.

[0126] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0127] After one month of monitoring, the calculated leakage rate was 41L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

[0128] Example 6

[0129] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0130] According to the above structure, a water measuring weir is set up, and two layers of drainage pipes 16 are laid out at different elevations, with 8 pipes laid side by side in each layer, and the spacing between adjacent drainage pipes 16 is 1.0m; when four layers are laid out, they are tilted up 15° and 20° respectively.

[0131] Then, follow the steps below to implement reverse monitoring of leakage:

[0132] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0133] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0134] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0135] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0136] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0137] The permeable holes 16-3 are plum blossom-shaped holes with a diameter of 5 mm, evenly distributed, and an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with 3 layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0138] Step 3: Calculate the leakage amount.

[0139] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0140] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0141] Step 4: Complete the leakage assessment.

[0142] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0143] After one month of monitoring, the calculated leakage rate was 281L / s, and the monthly increase in leakage was no more than 3%, indicating that the leakage of the concrete panel rockfill dam was close to the allowable range, and it was necessary to strengthen monitoring and find the cause in time.

[0144] Example 7

[0145] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0146] According to the aforementioned structure, a water measuring weir is set up, and 4 layers of drainage pipes 16 are laid out at different elevations, with 8 pipes laid side by side in each layer, and the spacing between adjacent drainage pipes 16 is 1.1m; when laying out four layers, the angles are respectively 15°, 20°, 25°, and 30° upward.

[0147] Then, follow the steps below to implement reverse monitoring of leakage:

[0148] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0149] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0150] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0151] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0152] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0153] The permeable holes 16-3 are plum blossom-shaped small holes with a diameter of 5 mm, which are evenly distributed and have an opening rate of 15%. The surface of the pipe section where the permeable holes 16-3 are located is wrapped with two layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0154] Step 3: Calculate the leakage amount.

[0155] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0156] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement;H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0157] Step 4: Complete the leakage assessment.

[0158] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0159] After one month of monitoring, the calculated leakage rate was 66L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

[0160] Example 8

[0161] Leakage monitoring was carried out on a compound concrete face rockfill dam at a certain location.

[0162] According to the above structure, a water measuring weir is set up, and 4 layers of drainage pipes 16 are laid out at different elevations, with 6 pipes laid side by side in each layer, and the distance between adjacent drainage pipes 16 is 1.2m; when laying out four layers, the angles are 15°, 20°, 25°, and 30° respectively.

[0163] Then, follow the steps below to implement reverse monitoring of leakage:

[0164] Step 1: Set a water measuring weir 20 in the maintenance drainage gallery 6.

[0165] The water measuring weir 20 adopts a trapezoidal thin-wall weir, and the specific structural setting of the water measuring weir 20 is determined in accordance with the "Technical Specifications for Safety Monitoring of Concrete Dams" (DL / T 2016).

[0166] Step 2: Follow Figure 3 , Figure 4 , Figure 5 In the structure shown, a drainage pipe 16 is arranged.

[0167] When burying the flower pipe section 16-2, a 20 cm thick transition material (the maximum particle size of the gravel material used in the transition material is not more than 80 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid in the flower pipe section 16-2 area to form a local transition zone 21; then, a 10 cm thick anti-filter material (the maximum particle size of the gravel material used in the anti-filter material is not more than 50 mm, wherein the mass percentage of the gravel material with a particle size less than 5 mm is 15% to 25%, and the mass percentage of the gravel material with a particle size less than 0.075 mm is not more than 10%) is laid on the transition material to form a local anti-filter area 22; finally, the drainage pipe 16 is laid for burial, and the local transition area 21 and the local anti-filter area 22 are constructed synchronously with the flower pipe section 16-2.

[0168] The drainage pipe 16 is made of hot-dip galvanized steel pipe, preferably with an outer diameter of 114 mm and a wall thickness of 7 mm;

[0169] The permeable holes 16-3 are plum blossom-shaped holes with a diameter of 5 mm, evenly distributed, and an opening rate of 15%; the surface of the pipe section where the permeable holes 16-3 are located is wrapped with 3 layers of non-woven geotextiles 16-4 to achieve the permeable and sand-isolating function.

[0170] Step 3: Calculate the leakage amount.

[0171] Calculate the leakage according to the following formula: Q =1.86 B H 1.5 ,

[0172] in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir 20, in m; b It is the crest length of the water measuring weir 20, in m.

[0173] Step 4: Complete the leakage assessment.

[0174] There is no clear safety standard for the leakage of composite concrete face rockfill dams, and the criterion is usually to avoid deformation and penetration damage.

[0175] After one month of monitoring, the calculated leakage rate was 109L / s, indicating that the leakage rate of the concrete face rockfill dam was within the allowable range.

Claims

1. The leakage reverse monitoring structure of the compound concrete face rockfill dam is based on the compound concrete face rockfill dam and is characterized by: It comprises a maintenance drainage gallery (6), a water measuring weir (20) is arranged in the maintenance drainage gallery (6), and 2 to 4 layers of drainage pipes (16) are arranged in the space between the anti-filtration area (9) and the drainage strip (11) of the horizontal section and facing the maintenance drainage gallery (6); The structure of the composite concrete face rockfill dam is: In the dam body at the upper part of the upstream dam surface, a reinforced concrete face plate (1), a cushion layer area (2), a transition area (3), and an upstream rockfill area (4) are arranged in sequence from the outside to the inside. A filter area (9) is arranged inside the upstream rockfill area (4). The filter area (9) is divided into two sections. The inner side of a section of the filter area (9) along the inclined upstream dam surface is arranged as a drainage area (10), and the upper surface of a section of the filter area (9) along the horizontal dam bottom is arranged as a drainage strip (11); At the dam foundation position below the upstream dam surface, a gravity high toe pier (5), consolidation grouting (7), and an anti-seepage curtain (8) are arranged in order from top to bottom, and a maintenance drainage gallery (6) is arranged inside the gravity high toe pier (5); and also includes a foundation surface (15), which is led out from the lower end of the cushion layer area (2) and the lower end of the transition area (3), and after reaching the bottom along the reverse slope of the gravity high toe pier (5), it horizontally meanders through the downstream dam surface of the dam body; A downstream block stone slope protection (14) is arranged on the surface of the downstream dam surface. The interior of the downstream block stone slope protection (14) is provided with an upper downstream dam stone area I (12), a middle downstream dam stone area II (13), and a lower downstream dam stone area I (12) from top to bottom. The drainage strip (11), the filter area (9) and the foundation surface (15) all pass through the lower downstream dam stone area I (12) toward the downstream.

2. The leakage reverse monitoring structure of a composite concrete face rockfill dam according to claim 1 is characterized by: The specific arrangement of the drainage pipes (16) is to arrange the drainage pipes (16) in layers and side by side on both sides based on the center line of the drainage strip (11), with 5 to 10 pipes arranged side by side in each layer, and the distance between adjacent drainage pipes (16) is 1 to 2 m; The drainage pipe (16) is arranged at an angle of 15° and 20° when two layers are arranged; at an angle of 15°, 20° and 25° when three layers are arranged; and at an angle of 15°, 20°, 25° and 30° when four layers are arranged. The structure of the drainage pipe (16) is that it comprises a buried pipe section (16-1) and a flower pipe section (16-2), wherein the buried pipe section (16-1) is arranged inside a gravity-type high-toe pier (5), the buried pipe section (16-1) is connected to a maintenance drainage gallery (6), the flower pipe section (16-2) is arranged inside an upstream rockfill area (4), the front end of the flower pipe section (16-2) extends forward to the drainage strip (11), and the water-permeable holes (16-3) on the circumference of the flower pipe section (16-2) are within the range of the transition area (3) and the reverse filter area (9), and the surface of the pipe section where the water-permeable holes (16-3) are located is wrapped with a non-woven geotextile (16-4).

3. A method for reverse monitoring leakage of a composite concrete panel rockfill dam, using the reverse monitoring structure for leakage of a composite concrete panel rockfill dam according to claim 1 or 2, characterized in that: Follow these steps to implement: Step 1, reversely arranging the drainage pipe (16) in the compound concrete face rockfill dam; in step 1, the specific structure of the water measuring weir (20) is determined according to the Technical Specification for Safety Monitoring of Concrete Dams DL / T 2016; Step 2: a water measuring weir (20) is arranged in the maintenance drainage gallery (6) of the composite concrete face rockfill dam. The specific process is: During the laying process of the drainage pipe (16), when the flower pipe section (16-2) is buried, a 20 cm thick transition material is laid in the flower pipe section (16-2) area to form a local transition area (21); then, a 10 cm thick filter material is laid on the transition material to form a local filter area (22); finally, the drainage pipe (16) is laid and buried; Step 3: Calculate the leakage of the composite concrete face rockfill dam. The specific process is: Calculate the leakage according to the following formula: Q =1.86 B H 1.5 , in, Q is the seepage rate, in m 3 / s, that is, the flow rate at the time of measurement; H is the water head above the weir (20), in m; b is the crest length of the water measuring weir (20), in m; Step 4: Complete the evaluation of the leakage of the composite concrete face rockfill dam. The specific process is: If the leakage value does not exceed 300L / s and there is no trend of increasing development, and it is evaluated that there is no deformation damage, seepage damage, and it does not affect the overall stability of the dam and the power generation efficiency, then the leakage is considered to be stable; If the leakage value exceeds 300L / s, focus on monitoring and find out the cause in time.

Images