Anti-seismic asphalt concrete core wall rock-fill dam and construction method thereof

Abstract

The invention discloses an anti-seismic asphalt concrete core wall rock-fill dam and a construction method thereof, and relates to the technical field of water conservancy and hydropower engineering. The invention discloses an anti-seismic asphalt concrete core wall rock-fill dam. Comprising an upstream cofferdam, an upstream rockfill I area, an upstream dry stone revetment, an upstream anti-seismic area, a dam crest structure, a downstream anti-seismic area, an upstream transition area, a downstream transition area, an asphalt concrete core wall, a foundation grouting gallery, foundation consolidation grouting, curtain grouting, a downstream rockfill II area, a downstream rockfill III area, a downstream dry stone revetment, a downstream rockfill I area, a downstream pressure slope body and the like. The construction method of the anti-seismic asphalt concrete core wall rock-fill dam comprises the steps that diversion tunnel and flood discharge tunnel construction is conducted; construction of the closure embankment; upstream and downstream cofferdams are constructed; excavating and constructing a dam foundation; constructing a dam foundation concrete diaphragm wall; consolidation grouting is conducted on the foundation; a foundation grouting gallery is constructed, and an upstream transition area, an asphalt concrete core wall, a downstream transition area, an upstream rockfill I area, a downstream rockfill II area, a downstream rockfill III area and a downstream rockfill I area are constructed.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and in particular to an earthquake-resistant asphalt concrete core wall rockfill dam and a construction method thereof. Background Art

[0002] In the prior art, a variety of asphalt concrete core rockfill dam construction schemes have been proposed. Among them, the commonly used construction method is to build the core wall base on the dam foundation, and then pour asphalt concrete on the core wall base layer by layer, and at the same time carry out synchronous filling and rising of the rockfill area to form a stable structure of the dam body.

[0003] Although the existing technology provides a feasible asphalt concrete core wall rockfill dam construction plan, there are still some problems and shortcomings in practical application. First, the existing technology neither considers the impact of curtain grouting on the dam filling period nor the later maintenance cost during the core wall construction process, resulting in a long construction period, high cost and difficult maintenance. Secondly, due to the complex and diverse terrain of my country, the terrain is high in the west and low in the east, distributed in a stepped manner, frequent geological tectonic activities, earthquakes, volcanoes and other natural disasters occur from time to time, and the seismic performance of the dam body is not considered; finally, although the rolled asphalt concrete dam has developed rapidly in engineering practice, it lags far behind engineering practice in terms of material research and design theory, resulting in the design and construction of the asphalt concrete core wall dam is still empirical, far from meeting the actual needs of the project, which has restricted the development of this type of dam.

[0004] In summary, the asphalt concrete core wall rockfill dam construction method in the prior art has the problems of long construction period, great construction difficulty, high maintenance cost, and difficulty in effectively solving the earthquake resistance. Therefore, it is necessary to provide an improved construction method to solve the problems and shortcomings in the prior art. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide an earthquake-resistant asphalt concrete core wall rockfill dam and a construction method thereof, which can solve the problems raised by the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an earthquake-resistant asphalt concrete core wall rockfill dam, comprising an upstream cofferdam, an upstream rockfill zone I, an upstream dry stone slope protection, an upstream earthquake-resistant zone, a dam crest structure, a downstream earthquake-resistant zone, an upstream transition zone, a downstream transition zone, an asphalt concrete core wall, a foundation grouting gallery, foundation consolidation grouting, curtain grouting, a downstream rockfill zone II, a downstream rockfill zone III, a downstream dry stone slope protection, a downstream rockfill zone I, a downstream slope pressure body, and the like.

[0007] The invention discloses an earthquake-resistant asphalt concrete core wall rockfill dam, wherein:

[0008] Upstream cofferdam: It is arranged in conjunction with the dam and is part of the dam body. It serves as a cofferdam during the construction period and as a dam body during the operation period.

[0009] Upstream rockfill area I: Located in the upstream area of ​​the dam body, it is the main support body for bearing water loads. The quality, density and settlement of the rock directly affect the safety of the dam.

[0010] Upstream dry stone slope protection: to protect the dam slope from being washed away by wind and waves, thus affecting the safe operation of the dam;

[0011] Upstream and downstream earthquake-resistant zones: can effectively reduce casualties and mitigate earthquake damage to the dam;

[0012] Dam top structure: It has the functions of transportation, wave protection, passing, drainage, anti-seepage, aesthetics, cable arrangement, lighting, etc., ensuring the integrity and coordination of the entire dam project;

[0013] Upstream and downstream transition zones: important measures to ensure the safety and stability of the entire dam structure. They can not only improve the anti-seepage performance and deformation adaptability of the core wall, but also protect the core wall from erosion and damage from the external environment, while ensuring effective control of seepage inside the dam body and drainage and decompression;

[0014] Asphalt concrete core wall: its main functions are to prevent water seepage, improve the stiffness of the transition layer, reduce the displacement of the core wall, and improve the stress-strain properties of the asphalt concrete core wall;

[0015] Foundation grouting gallery: It has the functions and significance of facilitating grouting construction, improving anti-seepage performance, monitoring seepage conditions, improving project quality, facilitating later maintenance, and ensuring project safety;

[0016] Foundation consolidation grouting: The main function is to improve the integrity and homogeneity of the rock mass, the compressive strength and elastic modulus of the rock mass, and reduce the deformation and uneven settlement of the rock mass;

[0017] Curtain grouting: connect the foundation grouting gallery, foundation consolidation grouting and dam body, and the grouting bottom goes into a certain depth of relatively impermeable rock layer to prevent or reduce the infiltration of groundwater in the foundation, and work together with the downstream drainage system to reduce the uplift pressure of the infiltration water flow on the dam;

[0018] Downstream rockfill areas I, II and III: located in the downstream area of ​​the dam body, their main function is to protect the stability of the main rockfill body and the downstream slope;

[0019] Downstream dry stone slope protection: It can effectively prevent the scouring of the dam body by the downstream water flow and reduce the erosion of the dam body materials by the water flow, thereby protecting the stability of the dam body. It can also prevent the frost heave and cracking of the dam body due to freezing, maintain the integrity and durability of the dam body. In addition, it can also play a certain role in beautifying the environment and making the dam body look more tidy and beautiful.

[0020] Downstream slope pressure body: It improves the stability of the dam and enhances the drainage function. By increasing the weight and friction of the dam slope, it effectively reduces the possibility of sliding of the downstream dam slope, thereby enhancing the overall stability of the dam. For the landslide problem caused by the escape of the infiltration line from the dam slope, the slope pressure body can help lower the infiltration line by building a seepage ditch on the dam slope and connecting it to the drainage body, ensuring that the seepage can be discharged smoothly and avoiding accumulation in the dam body to cause landslide or seepage damage.

[0021] A construction method for an earthquake-resistant asphalt concrete core wall rockfill dam, used for constructing the earthquake-resistant asphalt concrete core wall rockfill dam, comprises the following steps:

[0022] S1. Construction of diversion tunnel and spillway: According to the design data, four working faces are set up at the entrance and exit of diversion tunnel and spillway respectively, and the construction is carried out in opposite directions along the center line of diversion tunnel and spillway;

[0023] S2. Construction of dikes: The dikes are constructed after the flood season. The dikes are constructed by blocking the river from the right bank to the left bank with single dikes. The dikes are made of reinforced gabions, concrete tetrahedrons and other earth and stone filling materials. The dike top width is 20m.

[0024] S3. Construction of upstream and downstream cofferdams: Determine the flood recurrence period and the crest elevation according to the flood control design standards. The upstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio is 1:2, and the downstream slope ratio is 1:1.75. It will be used as the upstream dam body in the later stage; the downstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio of the downstream cofferdam is 1:1.5, and the downstream slope ratio is 1:1.75. It will be used as the downstream pressure slope body in the later stage; the downstream pressure slope body is a mixture of strongly weathered and weakly weathered materials, with a porosity of ≤23%, a content of less than 0.075mm ≤5%, a content of less than 5mm ≤40%, a maximum particle size of 1000mm, a permeability coefficient of >10-3cm / s, a compaction layer thickness of 800mm, and 8 to 12 compaction times.

[0025] S4. Excavation and construction of dam foundation: Asphalt concrete core wall foundation: placed at the bottom of weakly weathered or strongly weathered rock mass, and strengthened with foundation consolidation grouting; Dam foundation excavation: remove the loose part of the riverbed cover from below the upstream cofferdam to the downstream dam foot to ensure that the dam foundation has the corresponding bearing capacity.

[0026] S5. Construction of concrete anti-seepage wall at dam foundation: The foundation anti-seepage adopts concrete anti-seepage wall + anti-seepage curtain measures. The anti-seepage curtain is arranged along the core wall foundation under the concrete base and concrete anti-seepage wall, and curtain grouting holes are set at the shoulders of both sides to extend to the shore. The dam foundation and the anti-seepage curtains on both sides are controlled to be 5m below the 5Lu line. The anti-seepage wall is 1m thick and the bottom is embedded in the bedrock 1m.

[0027] S6. Foundation consolidation grouting: In order to improve the integrity of the rock mass, reduce the permeability of the surface rock mass, and improve the contact conditions between the concrete base and the bedrock, consolidation grouting is carried out on the core wall foundations on both sides of the slope. The foundation consolidation grouting is located at the bottom of the core wall foundation and the grouting gallery. The consolidation grouting holes are spaced 2m apart and 5m deep.

[0028] S7. Construction of foundation grouting corridor: To facilitate the construction of foundation and curtain grouting on both sides, curtain grouting corridors and adit are set up on the riverbed and dam shoulders on both sides. The net size meets the requirements of curtain grouting construction. The foundation grouting corridor is a city gate type with a width x height of 2.5x3.5m, a top arch radius of 1.25m, and 0.2x0.2m drainage ditches at the left and right corners. The asphalt concrete core wall of the riverbed is horizontally connected to the foundation grouting corridor, and asphalt mastic is laid at the connection.

[0029] S8. Construction of upstream transition zone, asphalt concrete core wall, downstream transition zone, upstream rockfill zone I, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I: To ensure balanced stress between the upstream and downstream sides of the dam and prevent stress deformation, the upstream rockfill zone I, upstream transition zone, asphalt concrete core wall, downstream transition zone, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I shall be filled and raised simultaneously; the downstream rockfill zone II shall be weakly weathered material with a porosity of ≤20% and a content of less than 0.075 mm ≤5 %, less than 5mm content ≤30%, maximum particle size 800mm, permeability coefficient>10-2cm / s, compaction layer thickness 800mm, rolling times 8 to 12 times; downstream rockfill III area is a mixture of strong weathering and weak weathering, with strong weathering parameters ≤50%, porosity ≤20%, less than 0.075mm content ≤5%, less than 5mm content ≤30%, maximum particle size 800mm, permeability coefficient>10-2cm / s, compaction layer thickness 800mm, rolling times 8 to 12 times.

[0030] S9. Construction of upstream dry stone slope protection and downstream dry stone slope protection: In order to protect the safe and stable operation of the dam and prevent the upstream wave erosion and the downstream dam slope from being eroded by rainwater, dry stone slope protection is set up on the upstream and downstream dam slopes, and the facilities are synchronized with the dam body filling.

[0031] S10. Construction of upstream and downstream earthquake-resistant zones: Since the dam is located in a strong earthquake zone and on a large river, the dam body is relatively high. In order to reduce the impact of earthquakes on the dam, earthquake-resistant zones are set up upstream and downstream in the area 1 / 3 of the height from the dam top, and synchronous facilities are installed for dam body filling.

[0032] S11. Dam crest structure construction: The dam crest structure includes wave-breaking walls, pavement, cable trenches, drainage ditches, railings and other parts, which will be implemented after the dam is filled and settled for one flood season.

[0033] Preferably, the upstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage, with an upstream slope ratio of 1:2 and a downstream slope ratio of 1:1.75. A 1m thick block stone slope protection is adopted on the water-facing side, the concrete anti-seepage wall is 0.8m thick and penetrates 1m into the bedrock, and the permeability coefficient of the weir foundation is 10-6 to 10-7cm / s, which will serve as a component of the upstream dam body in the later stage.

[0034] Preferably, the upstream rockfill zone I and the downstream rockfill zone I are a mixture of strongly weathered and weakly weathered materials, with a strongly weathered parameter ≤20%, a porosity ≤20%, a content less than 0.075 mm ≤5%, a content less than 5 mm ≤30%, a maximum particle size of 800 mm, a permeability coefficient >10-2 cm / s, a rolling layer thickness of 800 mm, and 8 to 12 rolling times.

[0035] Preferably, the upstream dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.8m, a maximum particle size of 800mm, and a porosity of ≤23%.

[0036] Preferably, the upstream seismic resistant zone and the downstream seismic resistant zone are located on the upstream and downstream sides of the top of the dam body, with a height of about 3 / 10 of the dam height. A layer of geogrid is laid every 2m, extending to the dry stone slope protection on the outside and to the upstream and downstream transition zones on the inside.

[0037] Preferably, the dam top structure consists of a wave-breaking wall, a pavement, a cable trench, a drainage ditch, a railing, etc. The dam top width is 10m, an L-shaped concrete wave-breaking wall is arranged on the upstream side, the wall height is 2.2m, the bottom is at the same height as the top of the asphalt concrete core wall, copper waterstop is used for connection, the structure is C25W6F100 concrete, a cable trench is arranged on the upstream side of the dam top pavement, a drainage ditch and a railing are arranged on the downstream side, and the dam surface is inclined toward the downstream drainage ditch at 0.5%.

[0038] Preferably, the upstream transition zone and the downstream transition zone are artificial aggregates with a horizontal thickness of 4m, a porosity of ≤18%, a content of less than 0.075mm ≤5%, a content of less than 5mm ≤35%, a maximum particle size of 80mm, a permeability coefficient of >5x10-3cm / s, a rolling layer thickness of 300mm, and 8 to 12 rolling passes.

[0039] Preferably, the downstream dry stone slope protection is a concrete frame beam + dry stone slope protection structure, the concrete frame beam has a longitudinal and transverse spacing of 3m and a thickness of 0.5m; the dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.5m.

[0040] Preferably, the bottom thickness of the asphalt concrete core wall is 1 / 70 of the dam height, and the top thickness is 0.5m. The bottom of the core wall is expanded, the height of the expanded area is 3m, the expansion angle is 10°, and the end is arranged in an arc shape to connect with the core wall base. The porosity is ≤3%, the permeability coefficient is ≤10-8cm / s, the bending strength is ≥400Kpa, the bending strain is ≥1%, the internal friction angle is ≥20°, the bonding strength is ≥300Kpa, and the compressive strength is ≥3Mpa.

[0041] The present invention is applicable to terrain and geological conditions such as large river flow, complex geological conditions, and no natural anti-seepage materials near the dam site. The method can make full use of the terrain and geological characteristics, not only has good stability and earthquake resistance, but also improves the anti-seepage performance and deformation adaptability of the dam, with simple construction, simple equipment, flexible progress, good durability, and convenient maintenance, and has significant economic and social benefits.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The asphalt concrete core rockfill dam has high anti-seepage performance, which can effectively prevent water leakage and improve the stability and safety of the dam body.

[0044] 2. Using asphalt concrete as the core wall material can improve the scour resistance of the dam body and reduce the damage to the dam body caused by water impact.

[0045] 3. The setting of the core wall foundation grouting corridor can effectively reduce construction interference, save construction time, reduce maintenance costs and improve investment efficiency.

[0046] 4. After the successful interception, the upstream dike serves as a part of the upstream cofferdam, and the upstream cofferdam later serves as a part of the dam body, which not only greatly saves construction time and investment, but also increases the overall stability of the dam body, providing guarantee for the safe and stable operation of the dam.

[0047] 5. After the dam construction is completed, the downstream cofferdam is transformed into a pressure slope behind the dam. It can not only serve as a drainage prism at the dam foot to effectively remove the water accumulated inside the dam body, reduce the seepage pressure of the dam body, but also improve the stability of the dam body.

[0048] In summary, compared with the prior art, the asphalt concrete core rockfill dam of the present invention has better anti-seepage performance, anti-scouring performance and overall stability, can improve the safety and reliability of the dam body, and has obvious advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0050] Figure 1 It is a schematic diagram of a cross section of a typical dam section of the patent of the present invention;

[0051] Figure 2 It is a cross-sectional schematic diagram of the upstream seismic resistance zone of the present invention;

[0052] Figure 3 This is a schematic diagram of the connection between the asphalt concrete core wall and the foundation grouting gallery of the patented invention.

[0053] In the figure: 1-upstream cofferdam, 2-upstream rockfill area I, 3-upstream dry stone slope protection, 4-upstream seismic zone, 5-dam crest structure, 6-downstream seismic zone, 7-upstream transition zone, 8-downstream transition zone, 9-asphalt concrete core wall, 10-foundation grouting gallery, 11-foundation consolidation grouting, 12-curtain grouting, 13-downstream rockfill area II, 14-downstream rockfill area III, 15-downstream dry stone slope protection, 16-downstream rockfill area I, 17-downstream slope pressure body, 4-1-geogrid, 9-1-asphalt mastic. DETAILED DESCRIPTION

[0054] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0055] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0056] In the description of the present invention, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0057] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0058] See also Figure 1-3The present invention provides a technical solution: an earthquake-resistant asphalt concrete core wall rockfill dam, comprising an upstream cofferdam 1, an upstream rockfill zone I 2, an upstream dry stone slope protection 3, an upstream earthquake-resistant zone 4, a dam top structure 5, a downstream earthquake-resistant zone 6, an upstream transition zone 7, a downstream transition zone 8, an asphalt concrete core wall 9, a foundation grouting gallery 10, foundation consolidation grouting 11, curtain grouting 12, a downstream rockfill zone II 13, a downstream rockfill zone III 14, a downstream dry stone slope protection 15, a downstream rockfill zone I 16 and a downstream slope pressure body 17.

[0059] Among them, the upstream cofferdam 1 and the downstream pressure slope body 17 are implemented on the upstream and downstream sides of the dam body respectively; the upstream cofferdam 1 is used as a diversion project in the early stage and as a part of the dam body in the later stage; the upstream dry stone slope protection 3 is laid on the water-facing surface of the upstream side of the dam body and is located above the upstream rockfill area I 2; the foundation consolidation grouting 11 is carried out after the core wall foundation is excavated, and its width is 5-10 times that of the core wall foundation; the foundation grouting gallery 10 is located above the foundation consolidation grouting 11 and below the asphalt concrete core wall 9, and is filled and raised synchronously with the upstream transition area 7 and the downstream transition area 8, and is a city gate type;

[0060] Secondly, the upstream transition zone 7 and the downstream transition zone 8 are located on the upstream and downstream sides of the asphalt concrete core wall 9, and are filled and raised synchronously with the asphalt concrete core wall 9; the upstream seismic resistant zone 4 is located above the upstream rockfill zone I 2 and is evenly distributed; the downstream rockfill zone II 13 is adjacent to the downstream transition zone 8 on the left, and adjacent to the downstream rockfill zone III 14 and the downstream rockfill zone I 16 on the right; the downstream slope pressure body 17 serves as the downstream cofferdam before the dam construction, and serves as the rear slope pressure body after the dam is put into operation.

[0061] A construction method for an earthquake-resistant asphalt concrete core wall rockfill dam, used for constructing the earthquake-resistant asphalt concrete core wall rockfill dam, comprises the following steps:

[0062] S1. Construction of diversion tunnel and spillway: According to the design data, four working faces are set up at the entrance and exit of diversion tunnel and spillway respectively, and the construction is carried out in opposite directions along the center line of diversion tunnel and spillway;

[0063] S2. Construction of dikes: The dikes are constructed after the flood season. The dikes are constructed by blocking the river from the right bank to the left bank with single dikes. The dikes are made of reinforced gabions, concrete tetrahedrons and other earth and stone filling materials. The dike top width is 20m.

[0064] S3. Construction of upstream and downstream cofferdams: Determine the flood recurrence period and the crest elevation according to the flood control design standards. The upstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio is 1:2 and the downstream slope ratio is 1:1.75. It will be used as the upstream dam body in the later stage. The downstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio of the downstream cofferdam is 1:1.5 and the downstream slope ratio is 1:1.75. It will be used as the downstream pressure slope in the later stage. The upstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio is 1:2 and the downstream slope ratio is 1:1.75. The water-facing side adopts a 1m thick block stone slope protection, the concrete anti-seepage wall is 0.8m thick, and penetrates 1m into the bedrock. The permeability coefficient of the weir foundation is 10-6~10-7cm / s, which will be used as the upstream dam body in the later stage.

[0065] The upstream rockfill area I and the downstream rockfill area I are a mixture of strongly weathered and weakly weathered materials, with strongly weathered parameters ≤20%, porosity ≤20%, content less than 0.075mm ≤5%, content less than 5mm ≤30%, maximum particle size 800mm, permeability coefficient >10-2cm / s, compaction layer thickness 800mm, and 8 to 12 rolling times; the downstream slope pressure body is a mixture of strongly weathered and weakly weathered materials, with porosity ≤23%, content less than 0.075mm ≤5%, content less than 5mm ≤40%, maximum particle size 1000mm, permeability coefficient >10-3cm / s, compaction layer thickness 800mm, and 8 to 12 rolling times.

[0066] S4. Excavation and construction of dam foundation: Asphalt concrete core wall foundation: placed at the bottom of weakly weathered or strongly weathered rock mass, and strengthened with foundation consolidation grouting; Dam foundation excavation: remove the loose part of the riverbed cover from below the upstream cofferdam to the downstream dam foot to ensure that the dam foundation has the corresponding bearing capacity.

[0067] S5. Construction of concrete anti-seepage wall at dam foundation: The foundation anti-seepage adopts concrete anti-seepage wall + anti-seepage curtain measures. The anti-seepage curtain is arranged along the core wall foundation under the concrete base and concrete anti-seepage wall, and curtain grouting holes are set at the shoulders of both sides to extend to the shore. The dam foundation and the anti-seepage curtains on both sides are controlled to be 5m below the 5Lu line. The anti-seepage wall is 1m thick and the bottom is embedded in the bedrock 1m.

[0068] S6. Foundation consolidation grouting: In order to improve the integrity of the rock mass, reduce the permeability of the surface rock mass, and improve the contact conditions between the concrete base and the bedrock, consolidation grouting is carried out on the core wall foundations on both sides of the slope. The foundation consolidation grouting is located at the bottom of the core wall foundation and the grouting gallery. The consolidation grouting holes are spaced 2m apart and 5m deep.

[0069] S7. Construction of foundation grouting gallery: To facilitate the construction of foundation and curtain grouting on both sides, curtain grouting gallery and adit are set up on the riverbed and dam shoulders on both sides. The net size meets the requirements of curtain grouting construction. The foundation grouting gallery is a city gate tunnel type with a width x height of 2.5x3.5m, a top arch radius of 1.25m, and 0.2x0.2m drainage ditches are set at the left and right corners; the asphalt concrete core wall at the riverbed is horizontally connected to the foundation grouting gallery, and asphalt mastic is laid at the connection;

[0070] The bottom thickness of the asphalt concrete core wall is 1 / 70 of the dam height, and the top thickness is 0.5m. The bottom of the core wall is expanded. The height of the expanded area is 3m, the expansion angle is 10°, and the end is set in an arc shape to connect with the core wall base. The porosity is ≤3%, the permeability is ≤10-8cm / s, the bending strength is ≥400Kpa, the bending strain is ≥1%, the internal friction angle is ≥20°, the bonding force is ≥300Kpa, and the compressive strength is ≥3Mpa.

[0071] S8. Construction of upstream transition zone, asphalt concrete core wall, downstream transition zone, upstream rockfill zone I, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I: To ensure balanced stress on the upstream and downstream sides of the dam and prevent stress deformation, the entire sections of upstream rockfill zone I, upstream transition zone, asphalt concrete core wall, downstream transition zone, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I shall be filled and raised simultaneously;

[0072] The upstream transition zone and the downstream transition zone are artificial aggregates with a horizontal thickness of 4m, a porosity of ≤18%, a content of less than 0.075mm ≤5%, a content of less than 5mm ≤35%, a maximum particle size of 80mm, a permeability coefficient of >5x10-3cm / s, a rolling layer thickness of 300mm, and 8 to 12 rolling passes;

[0073] The downstream rockfill zone II is weakly weathered material, with porosity ≤20%, content less than 0.075mm ≤5%, content less than 5mm ≤30%, maximum particle size 800mm, permeability coefficient >10-2cm / s, compaction layer thickness 800mm, and 8 to 12 rolling times; the downstream rockfill zone III is a mixture of strongly weathered and weakly weathered materials, with strongly weathered parameters ≤50%, porosity ≤20%, content less than 0.075mm ≤5%, content less than 5mm ≤30%, maximum particle size 800mm, permeability coefficient >10-2cm / s, compaction layer thickness 800mm, and 8 to 12 rolling times.

[0074] S9. Construction of upstream dry stone slope protection and downstream dry stone slope protection: In order to protect the safe and stable operation of the dam and prevent it from being eroded by upstream waves and the downstream dam slope from being eroded by rainwater, dry stone slope protection is set up on the upstream and downstream dam slopes, and the facilities are synchronized with the dam body filling; the upstream dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.8m, a maximum particle size of 800mm, and a porosity of ≤23%; the downstream dry stone slope protection is a concrete frame beam + dry stone slope protection structure, with a longitudinal and transverse spacing of 3m for the concrete frame beam and a thickness of 0.5m; the dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.5m.

[0075] S10. Construction of upstream and downstream earthquake-resistant zones: Since the dam is located in a strong earthquake zone and on a large river, the dam body is relatively high. In order to reduce the impact of earthquakes on the dam, earthquake-resistant zones are set up upstream and downstream in the area 1 / 3 of the height from the dam top, and the dam body is filled with synchronous facilities; the upstream and downstream earthquake-resistant zones are located on the upstream and downstream sides of the top of the dam body, with a height of about 3 / 10 of the dam height. A layer of geogrid is laid every 2m, extending from the outside to the dry stone slope protection, and from the inside to the upstream and downstream transition zones.

[0076] S11. Construction of dam crest structure: The dam crest structure includes wave-breaking walls, pavement, cable trenches, drainage ditches, railings, etc., and is implemented after the dam is filled and settled for a flood season. The dam crest structure consists of wave-breaking walls, pavement, cable trenches, drainage ditches, railings, etc. The dam crest width is 10m, and an L-shaped concrete wave-breaking wall is set on the upstream side. The wall is 2.2m high and the bottom is at the same height as the top of the asphalt concrete core wall. Copper waterstop connections are used. The structure is C25W6F100 concrete. A cable trench is set on the upstream side of the dam crest pavement, and a drainage ditch and railing are set on the downstream side. The dam surface is inclined toward the downstream drainage ditch at 0.5%.

[0077] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. An earthquake-resistant asphalt concrete core rockfill dam, characterized in that: include: Upstream cofferdam (1), upstream rockfill zone I (2), upstream dry stone slope protection (3), upstream seismic zone (4), dam crest structure (5), downstream seismic zone (6), upstream transition zone (7), downstream transition zone (8), asphalt concrete core wall (9), foundation grouting gallery (10), foundation consolidation grouting (11), curtain grouting (12), downstream rockfill zone II (13), downstream rockfill zone III (14), downstream dry stone slope protection (15), downstream rockfill zone I (16) and downstream slope pressure body (17). The upstream cofferdam (1) and the downstream pressure slope body (17) are respectively implemented on the upstream and downstream sides of the dam body; The upstream cofferdam (1) is used as a closure project in the early stage and as a part of the dam body in the later stage; The upstream dry stone slope protection (3) is laid on the water-facing surface of the upstream side of the dam body and is located above the upstream rockfill area I (2); The foundation consolidation grouting (11) is carried out after the core wall foundation is excavated, and its width is 5-10 times of the core wall foundation; The foundation grouting gallery (10) is located above the foundation consolidation grouting (11) and below the asphalt concrete core wall (9), and is filled and raised synchronously with the upstream transition zone (7) and the downstream transition zone (8), and is of a city gate type; The upstream transition zone (7) and the downstream transition zone (8) are located at the upstream and downstream sides of the asphalt concrete core wall (9), and are filled and raised synchronously with the asphalt concrete core wall (9); The upstream earthquake-resistant zone (4) is located above the upstream rockfill zone I (2) and is evenly distributed; The downstream rockfill zone II (13) is adjacent to the downstream transition zone (8) on the left side, and adjacent to the downstream rockfill zone III (14) and the downstream rockfill zone I (16) on the right side; The downstream slope pressure body (17) serves as a downstream cofferdam before the dam is constructed, and serves as a rear slope pressure body after the dam is put into operation.

2. A construction method for an earthquake-resistant asphalt concrete core wall rockfill dam, used to construct the earthquake-resistant asphalt concrete core wall rockfill dam described in claim 1, characterized in that: The following steps are involved: S1. Construction of diversion tunnel and spillway: According to the design data, four working faces are set up at the entrance and exit of diversion tunnel and spillway respectively, and the construction is carried out in opposite directions along the center line of diversion tunnel and spillway; S2. Construction of dikes: The dikes are constructed after the flood season. The dikes are constructed by blocking the river from the right bank to the left bank with single dikes. The dikes are made of reinforced gabions, concrete tetrahedrons and other earth and stone filling materials. The dike top width is 20m. S3. Construction of upstream and downstream cofferdams: Determine the flood recurrence period and the crest elevation according to the flood control design standards. The upstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio is 1:2, and the downstream slope ratio is 1:1.

75. It will be used as the upstream dam body in the later stage; the downstream cofferdam is an earth-rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio of the downstream cofferdam is 1:1.5, and the downstream slope ratio is 1:1.

75. It will be used as the downstream pressure slope body in the later stage; the downstream pressure slope body is a mixture of strongly weathered and weakly weathered materials, with a porosity of ≤23%, a content of less than 0.075mm ≤5%, a content of less than 5mm ≤40%, a maximum particle size of 1000mm, a permeability coefficient of >10-3cm / s, a compaction layer thickness of 800mm, and 8 to 12 compaction times. S4. Excavation and construction of dam foundation: Asphalt concrete core wall foundation: placed at the bottom of weakly weathered or strongly weathered rock mass, and strengthened with foundation consolidation grouting; Dam foundation excavation: remove the loose part of the riverbed cover from below the upstream cofferdam to the downstream dam foot to ensure that the dam foundation has the corresponding bearing capacity. S5. Construction of concrete anti-seepage wall at dam foundation: The foundation anti-seepage adopts concrete anti-seepage wall + anti-seepage curtain measures. The anti-seepage curtain is arranged along the core wall foundation under the concrete base and concrete anti-seepage wall, and curtain grouting holes are set at the shoulders of both sides to extend to the shore. The dam foundation and the anti-seepage curtains on both sides are controlled to be 5m below the 5Lu line. The anti-seepage wall is 1m thick and the bottom is embedded in the bedrock 1m. S6. Foundation consolidation grouting: In order to improve the integrity of the rock mass, reduce the permeability of the surface rock mass, and improve the contact conditions between the concrete base and the bedrock, consolidation grouting is carried out on the core wall foundations on both sides of the slope. The foundation consolidation grouting is located at the bottom of the core wall foundation and the grouting gallery. The consolidation grouting holes are spaced 2m apart and 5m deep. S7. Construction of foundation grouting corridor: To facilitate the construction of foundation and curtain grouting on both sides, curtain grouting corridors and adit are set up on the riverbed and dam shoulders on both sides. The net size meets the requirements of curtain grouting construction. The foundation grouting corridor is a city gate type with a width x height of 2.5x3.5m, a top arch radius of 1.25m, and 0.2x0.2m drainage ditches at the left and right corners. The asphalt concrete core wall of the riverbed is horizontally connected to the foundation grouting corridor, and asphalt mastic is laid at the connection. S8. Construction of upstream transition zone, asphalt concrete core wall, downstream transition zone, upstream rockfill zone I, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I: To ensure balanced stress between the upstream and downstream sides of the dam and prevent stress deformation, the upstream rockfill zone I, upstream transition zone, asphalt concrete core wall, downstream transition zone, downstream rockfill zone II, downstream rockfill zone III, and downstream rockfill zone I shall be filled and raised simultaneously; the downstream rockfill zone II shall be weakly weathered material with a porosity of ≤20% and a content of less than 0.075 mm ≤5 %, less than 5mm content ≤30%, maximum particle size 800mm, permeability coefficient>10-2cm / s, compaction layer thickness 800mm, rolling times 8 to 12 times; downstream rockfill III area is a mixture of strong weathering and weak weathering, with strong weathering parameters ≤50%, porosity ≤20%, less than 0.075mm content ≤5%, less than 5mm content ≤30%, maximum particle size 800mm, permeability coefficient>10-2cm / s, compaction layer thickness 800mm, rolling times 8 to 12 times. S9. Construction of upstream dry stone slope protection and downstream dry stone slope protection: In order to protect the safe and stable operation of the dam and prevent the upstream wave erosion and the downstream dam slope from being eroded by rainwater, dry stone slope protection is set up on the upstream and downstream dam slopes, and the facilities are synchronized with the dam body filling. S10. Construction of upstream and downstream earthquake-resistant zones: Since the dam is located in a strong earthquake zone and on a large river, the dam body is relatively high. In order to reduce the impact of earthquakes on the dam, earthquake-resistant zones are set up upstream and downstream in the area 1 / 3 of the height from the dam top, and synchronous facilities are installed for dam body filling. S11. Dam crest structure construction: The dam crest structure includes wave-breaking walls, pavement, cable trenches, drainage ditches, railings and other parts, which will be implemented after the dam is filled and settled for one flood season.

3. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 2, characterized in that: The upstream cofferdam is an earth and rock cofferdam, which adopts concrete anti-seepage wall + composite geomembrane for anti-seepage. The upstream slope ratio is 1:2, and the downstream slope ratio is 1:1.

75. The water-facing side adopts 1m thick block stone slope protection. The concrete anti-seepage wall is 0.8m thick and penetrates 1m into the bedrock. The permeability coefficient of the weir foundation is 10-6~10-7cm / s, which will serve as a component of the upstream dam body in the later stage.

4. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 3, characterized in that: The upstream rockfill zone I and the downstream rockfill zone I are a mixture of strongly weathered and weakly weathered materials, with strongly weathered parameters ≤20%, porosity ≤20%, content less than 0.075mm ≤5%, content less than 5mm ≤30%, maximum particle size 800mm, permeability coefficient >10-2cm / s, compaction layer thickness 800mm, and compaction times 8 to 12 times.

5. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 4, characterized in that: The upstream dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.8m, a maximum particle size of 800mm, and a porosity of ≤23%.

6. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 5, characterized in that: The upstream seismic resistant zone and downstream seismic resistant zone are located on the upstream and downstream sides of the top of the dam body, with a height of about 3 / 10 of the dam height. A layer of geogrid is laid every 2m, extending to the dry stone slope protection on the outside and to the upstream and downstream transition zones on the inside.

7. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 6, characterized in that: The dam top structure consists of a wave-breaking wall, pavement, cable trench, drainage ditch, railings, etc. The dam top width is 10m, and an L-shaped concrete wave-breaking wall is set on the upstream side. The wall height is 2.2m, and the bottom is at the same height as the top of the asphalt concrete core wall. Copper waterstop connections are used. The structure is C25W6F100 concrete. A cable trench is set on the upstream side of the dam top pavement, and drainage ditches and railings are set on the downstream side. The dam surface is inclined toward the downstream drainage ditch at 0.5%.

8. The construction method of a seismic resistant asphalt concrete core rockfill dam according to claim 7, characterized in that: The upstream transition zone and the downstream transition zone are artificial aggregates with a horizontal thickness of 4m, a porosity of ≤18%, a content of less than 0.075mm ≤5%, a content of less than 5mm ≤35%, a maximum particle size of 80mm, a permeability coefficient of >5x10-3cm / s, a rolling layer thickness of 300mm, and 8 to 12 rolling times.

9. The construction method of a seismic resistant asphalt concrete core wall rockfill dam according to claim 8, characterized in that: The downstream dry stone slope protection is a concrete frame beam + dry stone slope protection structure, the concrete frame beam has a longitudinal and transverse spacing of 3m and a thickness of 0.5m; the dry stone slope protection is a mixture of strongly weathered and weakly weathered materials, with a thickness of 0.5m.

10. The construction method of a seismic resistant asphalt concrete core rockfill dam according to claim 9, characterized in that: The bottom thickness of the asphalt concrete core wall is 1 / 70 of the dam height, and the top thickness is 0.5m. The bottom of the core wall is expanded, the height of the expansion area is 3m, the expansion angle is 10°, and the end is arranged in an arc shape to connect with the core wall base. The porosity is ≤3%, the permeability coefficient is ≤10-8cm / s, the bending strength is ≥400Kpa, the bending strain is ≥1%, the internal friction angle is ≥20°, the bonding strength is ≥300Kpa, and the compressive strength is ≥3Mpa.

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