Head structure of high asphalt concrete core wall dam on deep overburden in wide river valley under strong earthquake

Abstract

The present invention provides a high asphalt concrete core wall dam head pivot structure on a strong earthquake wide valley deep cover layer, including a high asphalt concrete core wall dam, an upstream cofferdam, a downstream cofferdam, a diversion tunnel and a flood discharge and emptying tunnel; the high asphalt concrete core wall dam includes an upstream geomembrane, a support layer under the geomembrane, an upstream soil and rock area, an upstream soil and rock mold-increasing area, an upstream transition layer area II, an upstream transition layer area I, a high asphalt concrete core wall, a downstream transition layer area I, a downstream transition layer area II, a downstream soil and rock area and a downstream soil and rock mold-increasing area, and the diversion tunnel and the flood discharge and emptying tunnel have the function of quickly emptying the reservoir. The present invention uses the upstream cofferdam to form two independent anti-seepage systems, namely: the high asphalt concrete core wall is used as the main anti-seepage system, and the upstream geomembrane and the upstream cofferdam jointly constitute auxiliary anti-seepage, thereby greatly improving the anti-seepage reliability of the dam body; the high asphalt concrete core wall is flexibly connected to the foundation anti-seepage wall through a block-softened reinforced concrete pad, which can adapt to the larger deformation of the dam foundation.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt concrete core wall dams of water conservancy and hydropower engineering, and in particular to a head hub structure of a high asphalt concrete core wall dam on a deep overburden layer in a wide river valley due to strong earthquakes. Background Art

[0002] At present, the asphalt concrete core wall dam has only one anti-seepage system of asphalt concrete core wall. The core wall is connected to the foundation anti-seepage wall through a reinforced concrete base cast throughout the length, and rigid connections are adopted between the reinforced concrete base and the core wall, as well as between the reinforced concrete base and the foundation anti-seepage wall. Except for the enlarged head of the core wall connected to the two banks, the core walls at the same elevation are of equal thickness and all adopt asphalt concrete configured with ordinary asphalt content. Therefore, the existing asphalt concrete core wall dam has the problem of weak deformation coordination ability. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a head pivot structure of a high asphalt concrete core wall dam on a deep overburden layer in a wide river valley in strong earthquakes, which can effectively solve the above problems.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The present invention provides a high asphalt concrete core wall dam head hub structure on a strong earthquake wide river valley deep cover layer, comprising a high asphalt concrete core wall dam (1), an upstream cofferdam (2), a downstream cofferdam (3), a diversion tunnel (4) and a flood discharge and emptying tunnel (5);

[0006] The high asphalt concrete core wall dam (1) is located between the upstream cofferdam (2) and the downstream cofferdam (3); the high asphalt concrete core wall dam (1) comprises an upstream geomembrane (6), a support layer below the geomembrane (7), an upstream soil and rock area (8), an upstream soil and rock mold-increasing area (9), an upstream transition layer area II (10), an upstream transition layer area I (11), a high asphalt concrete core wall (12), a downstream transition layer area I (13), a downstream transition layer area II (14), a downstream soil and rock area (15) and a downstream soil and rock mold-increasing area (16);

[0007] The high asphalt concrete core wall (12) is arranged along the transverse direction, and comprises a core wall main area (12.1), a core wall enlarged area (12.2) and a core wall enlarged foot (12.3); wherein the core wall main area (12.1) and the core wall enlarged area (12.2) are arranged at intervals along the transverse direction;

[0008] The dam body corresponding to the core wall main body area (12.1) is arranged along the water flow direction, and the upstream geomembrane (6), the lower support layer of the geomembrane (7), the upstream soil and rock area (8), the upstream transition layer area II (10), the upstream transition layer area I (11), the core wall main body area (12.1), the downstream transition layer area I (13), the downstream transition layer area II (14) and the downstream soil and rock area (15) are arranged in sequence from the upstream cofferdam (2) to the downstream cofferdam (3);

[0009] The dam body corresponding to the core wall enlargement area (12.2) is arranged along the water flow direction, and the upstream geomembrane (6), the lower support layer of the geomembrane (7), the upstream soil and rock mold enhancement area (9), the upstream transition layer area II (10), the upstream transition layer area I (11), the core wall enlargement area (12.2), the downstream transition layer area I (13), the downstream transition layer area II (14) and the downstream soil and rock mold enhancement area (16) are arranged in sequence from the upstream cofferdam (2) to the downstream cofferdam (3);

[0010] There are multiple diversion tunnels (4) distributed on both banks. After the diversion construction is completed, they are not blocked. Gates are used to block water during operation. The tunnel structure meets the requirements for emptying the reservoir in an emergency.

[0011] There are multiple flood discharge and emptying holes (5) distributed on both banks, and the scale of their arrangement meets the requirement of quickly emptying the reservoir to below the dead water level.

[0012] Preferably, the upstream cofferdam (2) serves as a part of the upstream dam foot of the high asphalt concrete core wall dam (1), and the top of the cofferdam is exposed; the downstream cofferdam (3) serves as a part of the downstream dam foot of the high asphalt concrete core wall dam (1).

[0013] Preferably, the upstream geomembrane (6) and the upstream cofferdam (2) jointly constitute an auxiliary anti-seepage system of the high asphalt concrete core wall dam (1);

[0014] The upstream geomembrane (6) is laid from the upstream side of the weir crest of the upstream cofferdam (2) to a range of at least 2 m above the normal water storage level, and is layered and covered every 10 m to 30 m of height difference, with the length of the covering section being not less than 1 m;

[0015] The support layer (7) below the geomembrane is made of a water-permeable material with a flat surface and good gradation, and has a thickness of 20 cm to 40 cm;

[0016] The upstream soil and rock area (8) and the downstream soil and rock area (15) are made of rockfill, sand and gravel, soil or soil and rock materials;

[0017] The upstream soil and rock mold increasing area (9) and the downstream soil and rock mold increasing area (16) are molded by adding cementitious materials to the damming materials to reduce regional deformation; wherein the cementitious materials include cement and other materials; the cement dosage is not less than 30kg / m 3 The total amount of the cementitious material is not less than 60 kg / m 3 ;

[0018] The width of the upstream soil and rock mold increasing area (9) and the downstream soil and rock mold increasing area (16) corresponds to the outer edge width of the core wall enlargement area (12.2) and extends to both banks for not less than 1m;

[0019] The upstream transition layer II zone (10) and the downstream transition layer II zone (14) have a top width of not less than 2 m and a bottom width of not less than 4 m;

[0020] The width of the upstream transition layer zone I (11) and the downstream transition layer zone I (13) is not less than 1.5 m.

[0021] Preferably, the core wall main area (12.1) has a thickness B, a top thickness of not less than 0.6 m, and a bottom thickness of not less than 1 / 100 of the dam height and not less than 1.5 m;

[0022] The core wall enlarged area (12.2) is arranged at intervals of 200m to 400m in the transverse direction, and includes a middle equal thickness area (12.2.1) and an end enlarged area (12.2.2); both ends of the middle equal thickness area (12.2.1) are connected to the core wall main area (12.1) through the end enlarged area (12.2.2); the length L of the middle equal thickness area (12.2.1) is 1 Not less than 1m, thickness B 1 =2B~3B; the length L of the end expansion area (12.2.2) 2 2m~4m, thickness B 2 From B 1 Gradient to B.

[0023] Preferably, the high-asphalt concrete core wall (12) is connected at both banks and the dam foundation by reinforced concrete pads (25), and the reinforced concrete pads (25) are arranged in blocks along the transverse direction of the river, and flexible connections are adopted at the block joints between the reinforced concrete pads (25); the connection between the reinforced concrete pads (25) and the high-asphalt concrete core wall (12), as well as the connection between the reinforced concrete pads (25) and the foundation anti-seepage wall (26) are all flexibly connected.

[0024] Preferably, the width of the foundation anti-seepage wall (26) is not less than 1 m, and the depth is not less than 1 times the maximum dam height;

[0025] The core wall enlarged foot (12.3) of the high asphalt concrete core wall (12) is arranged at a position close to the reinforced concrete pad (25), and the length L of the core wall enlarged foot (12.3) is 0 2m~4m, thickness B 0 Gradually changes from B to 2B~3B; wherein B is the thickness of the core wall main area (12.1);

[0026] The oil-rock ratio of the core wall enlarged foot (12.3) and the core wall enlarged area (12.2), that is, the asphalt accounts for the weight of the mineral material, is increased by 0.2% to 0.5% based on the oil-rock ratio of 6.5% to 7.0% in other areas.

[0027] Preferably, the reinforced concrete pad (25) has a thickness of 2m to 3m and a width greater than the bottom thickness of the core wall enlarged foot (12.3);

[0028] The block length of the reinforced concrete cushion (25) is 6m to 12m, the width of the gap between the blocks is 5cm to 10cm, the gap is filled with asphalt (27), and a horizontal copper water stop (28) is set in the middle of the gap;

[0029] The junction of the reinforced concrete base (25) and the core wall enlarged foot (12.3), and the junction of the reinforced concrete base (25) and the foundation anti-seepage wall (26) are all paved with 3cm to 5cm thick asphalt mastic (30), and a vertical copper water stop (29) is provided along the center line of the core wall.

[0030] Preferably, the transverse copper water stop (28) is W-shaped, with the nose and legs on the upstream side; the nose width is not less than 4 cm, the nose height and the legs height are not less than 20 cm, and the flat section length is not less than 50 cm;

[0031] The vertical copper water stop (29) is T-shaped, with a nose on the upstream side, a nose width of not less than 4 cm, a nose height of not less than 20 cm, and a flat section length of not less than 50 cm.

[0032] Preferably, the high asphalt concrete core wall dam (1) further comprises a dam body foundation surface (17), a filter drainage layer (18), a dam foundation transition layer (19), a maintenance platform (20), a geogrid (21), anti-rust steel bars (22), an observation and grouting gallery (23) and a turnaround yard (24);

[0033] The anti-filtration drainage layer (18) and the dam foundation transition layer (19) are arranged from bottom to top between the dam body foundation surface (17) of the high asphalt concrete core wall dam (1) and the downstream soil and rock area (15);

[0034] The maintenance platform (20) is arranged at a position above the dead water level of the upstream dam slope of the high asphalt concrete core wall dam (1);

[0035] The geogrid (21) and the anti-rust steel bars (22) are laid in layers in the upstream soil and rock area (8), the upstream soil and rock mold-increasing area (9), the downstream soil and rock area (15) and the downstream soil and rock mold-increasing area (16);

[0036] At least two layers of observation and grouting corridors (23) penetrating the river valley are arranged on the downstream side of the high-asphalt concrete core wall (12), and each layer of the observation and grouting corridors (23) is connected up and down;

[0037] The turning yard (24) is arranged on the downstream side of the dam top corresponding to the downstream soil and rock mold increasing area (16).

[0038] Preferably, the thickness of the reverse filtration and drainage layer (18) is not less than 3 m;

[0039] The thickness of the dam foundation transition layer (19) is not less than 2 m;

[0040] The top width of the maintenance platform (20) is not less than 8m;

[0041] The geogrid (21) and the antirust steel bar (22) have a length of not less than 20 m in the upstream and downstream dam bodies that are more than 1 / 2 of the dam height in the direction of water flow, and a height difference of 2 m to 5 m between adjacent layers. During construction, the geogrid (21) is laid first, and then the antirust steel bar (22) is laid;

[0042] The cross-sectional dimensions of the observation and grouting gallery (23) are not less than 3.0 m in width and 3.5 m in height; wherein the observation and grouting gallery (23) of the lower layer is arranged at the bottom of the high asphalt concrete core wall (12) and has outlets on both sides; the observation and grouting gallery (23) of the upper layer is arranged in layers according to a height difference of 40 m to 70 m and is located above the downstream water level. In addition to the outlets on both sides, an outlet leading to the downstream of the dam and a vertical passage connecting the upper and lower layers are arranged every 400 m to 800 m;

[0043] The plane dimensions of the vehicle turning yard (24) meet the requirements for vehicle turning and stacking emergency supplies.

[0044] The head hub structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley provided by the present invention has the following advantages:

[0045] 1) Use the upstream cofferdam to form two independent anti-seepage systems, namely: the high asphalt concrete core wall is used as the main anti-seepage system, and the upstream geomembrane and the upstream cofferdam are combined to form auxiliary anti-seepage systems, thereby greatly improving the anti-seepage reliability of the dam body;

[0046] 2) The high asphalt concrete core wall is flexibly connected to the foundation anti-seepage wall through a block-softened reinforced concrete pad, which can adapt to the larger deformation of the dam foundation;

[0047] 3) The thickness of the high asphalt concrete core wall at the same elevation is designed with unequal thickness in different zones. The asphalt concrete used in the core wall enlargement area and the core wall enlargement foot is slightly softer than that in other parts. The upstream and downstream soil and rock areas are set with mold-increasing areas to reduce the overall displacement of the core wall while improving its ability to adapt to deformation;

[0048] 4) Geogrids and rust-proof steel bars are laid in layers in the upstream and downstream soil and rock areas and the upstream and downstream soil and rock mold-increasing areas, thereby improving the seismic resistance of the core wall dam; in addition, rust-proof steel bars are used to avoid the corrosion of ordinary steel bars;

[0049] 5) A maintenance platform is set up on the upstream dam slope, a turnaround yard is set up downstream of the dam crest, and observation and grouting corridors are set up in layers and connected up and down; diversion tunnels and flood discharge and emptying tunnels are set up to have the function of quickly emptying the reservoir, providing maintenance conditions for high asphalt concrete core wall dams on deep overburden layers in wide river valleys during strong earthquakes, which has broad guiding and promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic plan view of the first pivot structure of the high asphalt concrete core wall dam on a strong earthquake wide valley deep cover layer of the present invention;

[0051] Figure 2 It is the A-A section of the plan schematic diagram of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley of the present invention;

[0052] Figure 3 It is the B-B section of the plan schematic diagram of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley of the present invention;

[0053] Figure 4 It is the C-C section of the plan schematic diagram of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley of the present invention;

[0054] Figure 5 A is a detailed diagram of the plan view of the head hub structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley of the present invention;

[0055] Figure 6 It is a detailed diagram B of the plan view of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley of the present invention, section A-A;

[0056] Figure 7 It is a detailed view of the transverse copper water stop of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden of the strong earthquake wide river valley of the present invention;

[0057] Figure 8 It is a detailed drawing of the vertical copper water stop of the head pivot structure of the high asphalt concrete core wall dam on the deep overburden of the strong earthquake wide river valley of the present invention;

[0058] in:

[0059] 1- high asphalt concrete core wall dam; 2- upstream cofferdam; 3- downstream cofferdam; 4- diversion tunnel; 5- flood discharge and emptying tunnel; 6- upstream geomembrane; 7- support layer under geomembrane; 8- upstream soil and rock area; 9- upstream soil and rock mold increase area; 10- upstream transition layer area II; 11- upstream transition layer area I; 12- high asphalt concrete core wall; 13- downstream transition layer area I; 14- downstream transition layer area II; 15- downstream soil and rock area; 16- downstream soil and rock mold increase area; 17- dam body foundation surface; 18- anti-filtration and drainage layer; 19- dam foundation transition layer; 20- maintenance platform; 21- geogrid; 22- anti-rust steel bars; 23- observation and grouting corridor; 24- turnaround yard; 25- reinforced concrete pad; 26- foundation anti-seepage wall; 27- asphalt; 28- horizontal copper water stop; 29- vertical copper water stop; 30- asphalt mastic;

[0060] 12.1-core wall main area; 12.2-core wall enlarged area; 12.3-core wall enlarged foot; 12.2.1-middle equal thickness area; 12.2.2-end enlarged area;

[0061] The direction indicated by the arrow is the direction of water flow. DETAILED DESCRIPTION

[0062] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0063] The purpose of the present invention is to provide a head pivot structure of a high asphalt concrete core wall dam on a deep covering layer in a wide river valley resistant to strong earthquakes. It is a head pivot structure of an ultra-long high asphalt concrete core wall dam that can adapt to strong earthquakes and large deformations. It can solve the technical problems faced by traditional center wall dams, such as excessive deformation of the dam foundation covering layer, dam body and core wall, large-scale damage to the asphalt concrete core wall, and no conditions for repair after damage.

[0064] like Figure 1-8 As shown, the present invention provides a head pivot structure of a high asphalt concrete core wall dam on a deep overburden layer in a wide river valley with strong earthquakes, comprising a high asphalt concrete core wall dam 1, an upstream cofferdam 2, a downstream cofferdam 3, a diversion tunnel 4 and a flood discharge and emptying tunnel 5;

[0065] The high asphalt concrete core wall dam 1 is located between the upstream cofferdam 2 and the downstream cofferdam 3; the high asphalt concrete core wall dam 1 comprises an upstream geomembrane 6, a support layer under the geomembrane 7, an upstream soil and rock area 8, an upstream soil and rock mold-increasing area 9, an upstream transition layer area II 10, an upstream transition layer area I 11, a high asphalt concrete core wall 12, a downstream transition layer area I 13, a downstream transition layer area II 14, a downstream soil and rock area 15 and a downstream soil and rock mold-increasing area 16;

[0066] The high asphalt concrete core wall 12 is arranged along the transverse direction, and includes a core wall main area 12.1, a core wall enlarged area 12.2 and a core wall enlarged foot 12.3; wherein the core wall main area 12.1 and the core wall enlarged area 12.2 are arranged at intervals along the transverse direction;

[0067] The dam body corresponding to the core wall main area 12.1 is arranged along the water flow direction, from the upstream cofferdam 2 to the downstream cofferdam 3, the upstream geomembrane 6, the lower support layer of the geomembrane 7, the upstream soil and rock area 8, the upstream transition layer area II 10, the upstream transition layer area I 11, the core wall main area 12.1, the downstream transition layer area I 13, the downstream transition layer area II 14 and the downstream soil and rock area 15 are arranged in sequence;

[0068] The dam body corresponding to the core wall enlargement area 12.2 is arranged along the water flow direction, from the upstream cofferdam 2 to the downstream cofferdam 3, the upstream geomembrane 6, the lower support layer of the geomembrane 7, the upstream soil and rock mold enhancement area 9, the upstream transition layer area II 10, the upstream transition layer area I 11, the core wall enlargement area 12.2, the downstream transition layer area I 13, the downstream transition layer area II 14 and the downstream soil and rock mold enhancement area 16 are arranged in sequence;

[0069] In the traditional scheme, the diversion tunnel and the flood discharge tunnel generally do not have the function of emptying the reservoir. The diversion tunnel is blocked after the construction diversion is completed and cannot be used during the operation period; the flood discharge tunnel is set at a high elevation and cannot empty the reservoir water below the dead water level. In the present invention, the diversion tunnel 4 is multiple and distributed on both sides. It is not blocked after the construction diversion is completed. The gate is used to block water during the operation period. The tunnel structure meets the requirements of emptying the reservoir in an emergency; the flood discharge and emptying tunnel 5 is multiple and distributed on both sides. Its setting scale meets the requirements of quickly emptying the reservoir below the dead water level.

[0070] The following is a detailed introduction to the above structural design methods:

[0071] (1) Upstream cofferdam 2, downstream cofferdam 3, upstream geomembrane 6

[0072] The upstream cofferdam 2 is part of the upstream dam foot of the high asphalt concrete core wall dam 1, and the top of the cofferdam is exposed; the downstream cofferdam 3 is part of the downstream dam foot of the high asphalt concrete core wall dam 1. The weir structure and foundation treatment measures of the upstream cofferdam 2 and the downstream cofferdam 3 meet the operation requirements of the permanent dam body.

[0073] The upstream geomembrane 6 and the upstream cofferdam 2 jointly constitute the auxiliary anti-seepage system of the high asphalt concrete core wall dam 1; wherein, the upstream geomembrane 6 is laid from the upstream side of the top of the upstream cofferdam 2 to at least 2m above the normal water storage level, and is layered and covered every 10m to 30m of height difference, and the covering section length is not less than 1m.

[0074] (2) Geomembrane support layer 7

[0075] The supporting layer 7 below the geomembrane is made of a water-permeable material with a flat surface (such as natural sand and gravel) and good gradation, and has a thickness of 20 cm to 40 cm.

[0076] (3) Upstream soil and rock area 8 and downstream soil and rock area 15

[0077] The upstream soil and rock area 8 and the downstream soil and rock area 15 are made of materials such as rockfill, sand and gravel, soil or soil and rock. The zoning can be refined based on the quality and quantity of the material source, but the outer area must be of good material.

[0078] (4) Upstream soil and rock mold enhancement area 9 and downstream soil and rock mold enhancement area 16

[0079] By optimizing the material source, grading and strengthening the rolling process control of the upstream soil-rock mold-enhancing area 9 and the downstream soil-rock mold-enhancing area 16, the mold is increased by adding cementitious materials to the dam-building materials to reduce regional deformation; the cementitious materials include cement, fly ash and other cementitious materials; the cement dosage is not less than 30kg / m 3 , the total amount of cementitious materials is not less than 60kg / m 3 By increasing the upstream soil-rock mold-enhancing zone 9 and the downstream soil-rock mold-enhancing zone 16, regional deformation can be reduced.

[0080] The width of the upstream soil and rock mold increasing area 9 and the downstream soil and rock mold increasing area 16 corresponds to the outer edge width of the core wall enlargement area 12.2 and extends to both banks by no less than 1m.

[0081] (5) upstream transition layer II zone 10, upstream transition layer I zone 11, downstream transition layer I zone 13 and downstream transition layer II zone 14

[0082] The top width of the upstream transition layer II zone 10 and the downstream transition layer II zone 14 is not less than 2 m, and the bottom width is not less than 4 m;

[0083] The width of the upstream transition layer zone I 11 and the downstream transition layer zone I 13 is not less than 1.5 m.

[0084] (6) High asphalt concrete core wall 12

[0085] The high asphalt concrete core wall 12 is arranged along the transverse direction of the river, and includes a core wall main area 12.1, a core wall enlarged area 12.2 and a core wall enlarged foot 12.3.

[0086] The core wall main area 12.1 has a thickness of B, the top thickness is not less than 0.6m, and the bottom thickness is not less than 1 / 100 of the dam height and not less than 1.5m.

[0087] The core wall enlarged area 12.2 is arranged at intervals of 200m to 400m in the transverse direction, and includes a middle equal thickness area 12.2.1 and an end enlarged area 12.2.2; both ends of the middle equal thickness area 12.2.1 are connected to the core wall main area 12.1 through the end enlarged area 12.2.2; the length L of the middle equal thickness area 12.2.1 1 Not less than 1m, thickness B 1 =2B~3B; the length L of the end expansion area 12.2.2 2 2m~4m, thickness B 2 From B 1 Gradient to B.

[0088] The structural features of the core wall enlarged foot 12.3 are introduced in the flexible connection section below.

[0089] (7) High asphalt concrete core wall dam 1

[0090] As a specific design method, the dam top of the high asphalt concrete core wall dam 1 is not provided with a wave-breaking wall, the guardrail is fixed in sections to avoid full-length cracking, and movable guardrails are reserved to facilitate the maintenance of the dam body;

[0091] The crest width of the high asphalt concrete core wall dam 1 is increased and shall not be less than 12m. The dam crest elevation is determined by the reservoir static water level under the most unfavorable working condition + the wave climbing height on the dam slope + the wind-induced water surface height + the safety superelevation corresponding to the dam grade and operating water level + the settlement superelevation after the dam body is filled, and is superimposed with sufficient earthquake safety superelevation (including earthquake settlement and earthquake surge height) and the surge height caused by large-volume bank collapse or landslide that may occur in the reservoir area.

[0092] The upstream and downstream dam slopes of the high asphalt concrete core wall dam 1 are slowed down on the basis of the calculated stable dam slope and are not steeper than 1:1.8. The upper dam slope should be even slower.

[0093] During the construction of the high asphalt concrete core wall dam 1, the surface covering layer of the dam foundation is first removed, and then strong tamping, crushed stone vibratory piles and other treatments are carried out to meet the requirements of foundation bearing capacity and reduce deformation.

[0094] On the basis of the above structure, the present invention further carries out the following innovative designs:

[0095] (1) Flexible connection structure

[0096] The high asphalt concrete core wall 12 is connected on both banks and at the dam foundation by reinforced concrete pads 25, and the reinforced concrete pads 25 are arranged in blocks along the cross-river direction, and flexible connections are used at the block joints between each reinforced concrete pad 25; the joints between the reinforced concrete pads 25 and the high asphalt concrete core wall 12, as well as the joints between the reinforced concrete pads 25 and the foundation anti-seepage wall 26 are all flexibly connected.

[0097] The width of the foundation anti-seepage wall 26 shall not be less than 1m, and the depth shall not be less than 1 times the maximum dam height;

[0098] The core wall enlarged foot 12.3 of the high asphalt concrete core wall 12 is arranged near the reinforced concrete pad 25, and the length L of the core wall enlarged foot 12.3 is 0 2m~4m, thickness B 0 Gradually changes from B to 2B-3B; wherein B is the thickness of the core wall main area 12.1;

[0099] The asphalt concrete in the core wall enlarged foot 12.3 and the core wall enlarged area 12.2 is slightly soft, and its asphalt-to-stone ratio, that is, the asphalt to mineral weight, is increased by 0.2% to 0.5% on the basis of the asphalt-to-stone ratio of 6.5% to 7.0% in other areas;

[0100] The reinforced concrete pad 25 has a thickness of 2m to 3m and a width greater than the bottom thickness of the core wall enlarged foot 12.3;

[0101] The block length of the reinforced concrete pad 25 is selected from 6m to 12m depending on the foundation conditions, the width of the joint between the blocks is 5cm to 10cm, the joint is filled with asphalt 27, and a horizontal copper water stop 28 is set in the middle of the joint;

[0102] The junction of the reinforced concrete pad 25 and the core wall enlarged foot 12.3, as well as the junction of the reinforced concrete pad 25 and the foundation anti-seepage wall 26, are all paved with 3cm-5cm thick asphalt mastic 30, and a vertical copper water stop 29 is set along the center line of the core wall.

[0103] (2) Arrangement of horizontal copper water stop 28 and vertical copper water stop 29

[0104] The horizontal copper water stop 28 is W-shaped, with the nose and legs on the upstream side; the nose width is not less than 4cm, the nose height and leg height are not less than 20cm, and the flat section length is not less than 50cm;

[0105] The vertical copper water stop 29 is T-shaped, with the nose on the upstream side, the nose width is not less than 4cm, the nose height is not less than 20cm, and the flat section length is not less than 50cm.

[0106] (3) The high asphalt concrete core wall dam 1 also includes a dam body foundation surface 17, a filter drainage layer 18, a dam foundation transition layer 19, a maintenance platform 20, a geogrid 21, anti-rust steel bars 22, an observation and grouting gallery 23 and a turnaround yard 24;

[0107] (3.1) Filter drainage layer 18 and dam foundation transition layer 19

[0108] Between the dam body foundation surface 17 of the high asphalt concrete core wall dam 1 and the downstream soil and rock area 15, a filter drainage layer 18 and a dam foundation transition layer 19 are arranged from bottom to top;

[0109] The thickness of the filter and drainage layer 18 is not less than 3m; the thickness of the dam foundation transition layer 19 is not less than 2m;

[0110] (3.2) Inspection platform 20 Inspection platform 20 is set above the dead water level on the upstream dam slope of high asphalt concrete core wall dam 1; the top width of the inspection platform 20 is not less than 8m; the top elevation is determined by the dead water level + the height of the wave climbing on the dam slope under common working conditions and the height of the wind-dammed water surface + the safety superelevation corresponding to the dam grade and the operating water level;

[0111] (3.3) Geogrids 21 and antirust steel bars 22 are laid in layers in the upstream soil and rock area 8, the upstream soil and rock mold enhancement area 9, the downstream soil and rock area 15 and the downstream soil and rock mold enhancement area 16; wherein, the length of geogrids 21 and antirust steel bars 22 in the upstream and downstream dam bodies above 1 / 2 of the dam height in the direction of water flow is not less than 20m, and the height difference between adjacent layers is 2m to 5m, wherein the smaller value is taken in the upper part of the dam body and the larger value is taken in the lower part; during construction, geogrids 21 are laid first, followed by antirust steel bars 22, with a spacing of no more than 1m;

[0112] (3.4) Observation and grouting gallery 23

[0113] At least two layers of observation and grouting corridors 23 that penetrate the river valley are arranged on the downstream side of the high asphalt concrete core wall 12, and each layer of the observation and grouting corridors 23 is connected up and down; wherein the cross-sectional dimensions of the observation and grouting corridors 23 are not less than 3.0m wide by 3.5m high; wherein the lower layer of the observation and grouting corridors 23 is arranged at the bottom of the high asphalt concrete core wall 12, and has outlets on both sides; the upper layer of the observation and grouting corridors 23 is arranged in layers according to the height difference of 40m to 70m, and is located above the downstream water level. In addition to the outlets on both sides, outlets leading to the downstream of the dam and vertical passages connecting the upper and lower layers are arranged every 400m to 800m;

[0114] An observation and grouting gallery 23 is set up to treat the dam body and foundation that may be damaged;

[0115] (3.5) Car return lot 24

[0116] A turnaround yard 24 is provided on the downstream side of the dam crest corresponding to the downstream soil and rock mold increasing area 16. The plane size of the turnaround yard 24 meets the requirements of vehicle turning and stacking emergency supplies.

[0117] The turning yard 24 is provided to handle the dam body and dam foundation that may be damaged.

[0118] The following is a further description of a large hydropower station project using the technical solution of the present invention as an example with reference to the accompanying drawings:

[0119] A high asphalt concrete core wall dam of a large hydropower station on a strong earthquake wide river valley deep overburden has a dam crest length of 1000m, a maximum dam height of 130m, and an overburden thickness of about 300m. The head pivot structure of the high asphalt concrete core wall dam on a strong earthquake wide river valley deep overburden of the present invention is adopted.

[0120] like Figure 1-8 As shown in the figure, the head hub structure of the high asphalt concrete core wall dam on the strong earthquake wide valley deep cover layer is mainly composed of the high asphalt concrete core wall dam 1, the upstream cofferdam 2, the downstream cofferdam 3, the diversion tunnel 4 and the flood discharge and emptying tunnel 5. The high asphalt concrete core wall dam 1 uses the upstream cofferdam 2 and the downstream cofferdam 3 as part of the upstream and downstream dam foots, and the weir top structure is outside the dam body.

[0121] The high asphalt concrete core wall dam 1 comprises an upstream geomembrane 6, a supporting layer below the geomembrane 7, an upstream soil and rock area 8, an upstream soil and rock mold-increasing area 9, an upstream transition layer area II 10, an upstream transition layer area I 11, a high asphalt concrete core wall 12, a downstream transition layer area I 13, a downstream transition layer area II 14, a downstream soil and rock area 15 and a downstream soil and rock mold-increasing area 16;

[0122] The high asphalt concrete core wall 12 is arranged along the transverse direction, and includes a core wall main area 12.1, a core wall enlarged area 12.2 and a core wall enlarged foot 12.3; wherein the core wall main area 12.1 and the core wall enlarged area 12.2 are arranged at intervals along the transverse direction;

[0123] The dam body corresponding to the core wall main area 12.1 is arranged along the water flow direction, from the upstream cofferdam 2 to the downstream cofferdam 3, the upstream geomembrane 6, the lower support layer of the geomembrane 7, the upstream soil and rock area 8, the upstream transition layer area II 10, the upstream transition layer area I 11, the core wall main area 12.1, the downstream transition layer area I 13, the downstream transition layer area II 14 and the downstream soil and rock area 15 are arranged in sequence;

[0124] The dam body corresponding to the core wall enlargement area 12.2 is arranged along the water flow direction, from the upstream cofferdam 2 to the downstream cofferdam 3, the upstream geomembrane 6, the lower support layer of the geomembrane 7, the upstream soil and rock mold enhancement area 9, the upstream transition layer area II 10, the upstream transition layer area I 11, the core wall enlargement area 12.2, the downstream transition layer area I 13, the downstream transition layer area II 14 and the downstream soil and rock mold enhancement area 16 are arranged in sequence;

[0125] The high asphalt concrete core wall 12 is connected on both banks and at the dam foundation by reinforced concrete pads 25, and the reinforced concrete pads 25 are arranged in blocks along the cross-river direction, and flexible connections are used at the block joints between each reinforced concrete pad 25; the joints between the reinforced concrete pads 25 and the high asphalt concrete core wall 12, as well as the joints between the reinforced concrete pads 25 and the foundation anti-seepage wall 26 are all flexibly connected.

[0126] The high asphalt concrete core wall dam 1 also includes a dam body foundation surface 17, a filter drainage layer 18, a dam foundation transition layer 19, a maintenance platform 20, a geogrid 21, anti-rust steel bars 22, an observation and grouting gallery 23 and a turnaround yard 24;

[0127] Between the dam body foundation surface 17 of the high asphalt concrete core wall dam 1 and the downstream soil and rock area 15, a filter drainage layer 18 and a dam foundation transition layer 19 are arranged from bottom to top;

[0128] A maintenance platform 20 is provided above the dead water level on the upstream dam slope of the high asphalt concrete core wall dam 1;

[0129] Geogrids 21 and anti-rust steel bars 22 are laid in layers in the upstream soil-rock area 8, the upstream soil-rock mold-enhancing area 9, the downstream soil-rock area 15 and the downstream soil-rock mold-enhancing area 16;

[0130] At least two layers of observation and grouting corridors 23 penetrating the river valley are arranged on the downstream side of the high asphalt concrete core wall 12, and each layer of the observation and grouting corridors 23 is connected up and down;

[0131] A turning yard 24 is provided on the downstream side of the dam crest corresponding to the downstream soil and rock mold increasing area 16 .

[0132] There are two diversion tunnels 4, one on each bank. They are not blocked after the diversion is completed. Gates are used to block water during the operation period. The tunnel structure meets the requirements of emptying the reservoir in an emergency. There are two flood discharge and emptying tunnels 5, one on each bank. The scale of their setting meets the requirements of quickly emptying the reservoir to below the dead water level. The elevation of the inlet bottom plate on the left bank is 2m lower than the dead water level. There is no wave wall on the top of the high asphalt concrete core wall dam 1. The railings are fixed every 20m, and a movable railing is reserved every 200m. The width of the dam top is 15m, and the elevation of the dam top is 6m higher than the normal water storage level; the upstream and downstream dam slopes are 1:1.9. First, remove 10m of the surface covering layer of the dam foundation, and then carry out strong tamping and 60m deep gravel vibrating pile treatment. The upstream geomembrane 6 and the upstream cofferdam 2 jointly form an auxiliary anti-seepage system. The two-cloth-one-film composite geomembrane is laid from the upstream side of the weir top to 2m above the normal water storage level, and is layered and covered every 10m height difference. The covering section is 1m long. The support layer 7 under the geomembrane is a well-graded natural sand and gravel with a thickness of 30 cm. The upstream soil and rock area 8 and the downstream soil and rock area 15 are made of rockfill. The rockfill in the upstream soil and rock mold area 9 and the downstream soil and rock mold area 16 is mixed with cement and fly ash at 30 kg / m 3 The rolling is strengthened, and its width corresponds to the outer edge width of the core wall enlargement area 12.2 and extends 1m to both banks. The top width of the upstream transition layer area II 10 and the downstream transition layer area II 14 are 2m wide and 4m wide at the bottom. The upstream transition layer area I 11 and the downstream transition layer area I 13 are 2m wide. The high asphalt concrete core wall 12 is beaded in the transverse direction of the river. The thickness of the core wall main area 12.1 is B, the top thickness is 0.6m, and the bottom thickness is 1.5m; the core walls on both banks and the riverbed are provided with core wall enlargement feet 12.3 near the reinforced concrete pad 25, and its length is L0 3m, thickness B 0 Gradually change from B to 2B~3B. The core wall enlarged area 12.2 is set at intervals of 200m in the transverse direction, including the middle equal thickness area 12.2.1 and the end enlarged area 12.2.2. The length of the middle equal thickness area 12.2.1 is L 1 2m, thickness B 1 =2B~3B; the length L of the end expansion area 12.2.2 2 4m, thickness B 2 From B 1 Gradually change to B. The asphalt concrete of the core wall enlargement foot 12.3 and the core wall enlargement area 12.2 is slightly softer, and its asphalt concrete ratio is increased by 0.3% based on 6.5% of the core wall in other parts.

[0133] The joints between the reinforced concrete pad 25 and the core wall enlarged foot 12.3, and between the reinforced concrete pad 25 and the foundation anti-seepage wall 26 are all flexibly connected. The reinforced concrete pad 25 is 3m thick; the width is greater than the bottom thickness of the core wall enlarged foot 12.3; the block length is selected as 10m according to the foundation conditions, the width of the joint between the blocks is 5cm, the joint is filled with asphalt 27, and a horizontal copper water stop 28 is set in the middle. The joints between the reinforced concrete pad 25 and the core wall enlarged foot 12.3, and between the reinforced concrete pad 25 and the foundation anti-seepage wall 26 are paved with 4cm thick asphalt mastic 30, and a vertical copper water stop 29 is set along the center line of the core wall.

[0134] The horizontal copper water stop 28 is W-shaped, with the nose and legs on the upstream side, the nose width is 4 cm, the nose height and legs height are 20 cm, and the flat section length is 50 cm. The vertical copper water stop 29 is T-shaped, with the nose on the upstream side, the nose width is 5 cm, the nose height is 30 cm, and the flat section length is 70 cm.

[0135] The thickness of the anti-filtration drainage layer 18 is 3m. The thickness of the dam foundation transition layer 19 is 2m. The top width of the maintenance platform 20 is 8m; the top elevation is 4m higher than the dead water level. The geogrid 21 and antirust steel bars 22 are laid in layers, and the length of the upstream and downstream dam bodies along the water flow direction is 30m. The height difference between adjacent layers above 3 / 4 of the dam height is 2m, and the height difference between adjacent layers above 1 / 2 to 3 / 4 of the dam height is 5m. The geogrid 21 is laid first, and then the antirust steel bars 22 are laid, with a spacing of 1m.

[0136] Two layers of observation and grouting corridors 23 running through the river valley are set on the downstream side of the high asphalt concrete core wall 12, with a gate-shaped section size of 3.0m wide and 3.5m high. The lower layer of the observation and grouting corridor is set at the bottom of the core wall, with exits on both sides; the upper layer of the observation and grouting corridor is set up in layers with a height difference of 60m. In addition to the exits on both sides, there are exits leading to the downstream of the dam and elevators connecting the upper and lower layers every 400m.

[0137] The turnaround area 24 is set in the downstream area of ​​the dam top corresponding to the downstream soil and rock mold area 16, and the plane size meets the requirements of vehicle turning and stacking emergency supplies. The foundation anti-seepage wall 26 is 1.2m wide and 130m deep.

[0138] The head pivot structure of the high asphalt concrete core wall dam on the deep overburden of the wide river valley in strong earthquakes quickly drains the reservoir through the diversion tunnel 4 and the flood discharge and emptying tunnel 5. Curtain grouting and other treatment measures are taken for the damaged dam body and dam foundation at the dam top, maintenance platform 20 and observation and grouting gallery 23, and the upstream geomembrane 6 is repaired.

[0139] By adopting the above technical solution disclosed in the present invention, the following beneficial effects are obtained:

[0140] 1) Use the upstream cofferdam to form two independent anti-seepage systems, namely: the high asphalt concrete core wall is used as the main anti-seepage system, and the upstream geomembrane and the upstream cofferdam are combined to form auxiliary anti-seepage systems, thereby greatly improving the anti-seepage reliability of the dam body;

[0141] 2) The high asphalt concrete core wall is flexibly connected to the foundation anti-seepage wall through a block-softened reinforced concrete pad, which can adapt to the larger deformation of the dam foundation;

[0142] 3) The thickness of the high asphalt concrete core wall at the same elevation is designed with unequal thickness in different zones. The asphalt concrete used in the core wall enlargement area and the core wall enlargement foot is slightly softer than that in other parts. The upstream and downstream soil and rock areas are set with mold-increasing areas to reduce the overall displacement of the core wall while improving its deformation adaptability. In the traditional scheme, there is no mold-increasing area in the upstream and downstream soil and rock areas.

[0143] 4) Geogrids and rust-proof steel bars are laid in layers in the upstream and downstream soil and rock areas and the upstream and downstream soil and rock mold-increasing areas, thereby improving the seismic resistance of the core wall dam; in addition, rust-proof steel bars are used to avoid the corrosion of ordinary steel bars;

[0144] 5) In the traditional scheme, there is no maintenance platform on the dam slope, and there is no turnaround yard on the dam crest; the observation and grouting gallery is only set up in the lower part of the dam body. In the present invention, a maintenance platform is set up on the upstream dam slope, a turnaround yard is set up downstream of the dam crest, and the observation and grouting gallery is set up in layers and connected up and down; diversion tunnels and flood discharge and emptying tunnels are set up, which have the function of quickly emptying the reservoir, providing maintenance conditions for high asphalt concrete core wall dams on deep overburden layers in wide river valleys during strong earthquakes, and has broad guidance and promotion significance.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A high asphalt concrete core wall dam head hub structure on a strong earthquake wide valley deep overburden, characterized in that: It includes a high asphalt concrete core wall dam (1), an upstream cofferdam (2), a downstream cofferdam (3), a diversion tunnel (4) and a flood discharge and emptying tunnel (5); The high asphalt concrete core wall dam (1) is located between the upstream cofferdam (2) and the downstream cofferdam (3); the high asphalt concrete core wall dam (1) comprises an upstream geomembrane (6), a support layer below the geomembrane (7), an upstream soil and rock area (8), an upstream soil and rock mold-increasing area (9), an upstream transition layer area II (10), an upstream transition layer area I (11), a high asphalt concrete core wall (12), a downstream transition layer area I (13), a downstream transition layer area II (14), a downstream soil and rock area (15) and a downstream soil and rock mold-increasing area (16); The high asphalt concrete core wall (12) is arranged along the transverse direction, and comprises a core wall main area (12.1), a core wall enlarged area (12.2) and a core wall enlarged foot (12.3); wherein the core wall main area (12.1) and the core wall enlarged area (12.2) are arranged at intervals along the transverse direction; The dam body corresponding to the core wall main body area (12.1) is arranged along the water flow direction, and the upstream geomembrane (6), the lower support layer of the geomembrane (7), the upstream soil and rock area (8), the upstream transition layer area II (10), the upstream transition layer area I (11), the core wall main body area (12.1), the downstream transition layer area I (13), the downstream transition layer area II (14) and the downstream soil and rock area (15) are arranged in sequence from the upstream cofferdam (2) to the downstream cofferdam (3); The dam body corresponding to the core wall enlargement area (12.2) is arranged along the water flow direction, and the upstream geomembrane (6), the lower support layer of the geomembrane (7), the upstream soil and rock mold enhancement area (9), the upstream transition layer area II (10), the upstream transition layer area I (11), the core wall enlargement area (12.2), the downstream transition layer area I (13), the downstream transition layer area II (14) and the downstream soil and rock mold enhancement area (16) are arranged in sequence from the upstream cofferdam (2) to the downstream cofferdam (3); There are multiple diversion tunnels (4) distributed on both banks. After the diversion construction is completed, they are not blocked. Gates are used to block water during operation. The tunnel structure meets the requirements for emptying the reservoir in an emergency. There are multiple flood discharge and emptying holes (5) distributed on both banks, and the scale of their arrangement meets the requirement of quickly emptying the reservoir to below the dead water level.

2. The head hub structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide valley according to claim 1 is characterized in that: The upstream cofferdam (2) serves as a part of the upstream dam foot of the high asphalt concrete core wall dam (1), and the top of the cofferdam is exposed; the downstream cofferdam (3) serves as a part of the downstream dam foot of the high asphalt concrete core wall dam (1).

3. The head hub structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley according to claim 1 is characterized in that: The upstream geomembrane (6) and the upstream cofferdam (2) jointly constitute an auxiliary anti-seepage system of the high asphalt concrete core wall dam (1); The upstream geomembrane (6) is laid from the upstream side of the weir crest of the upstream cofferdam (2) to a range of at least 2 m above the normal water storage level, and is layered and covered every 10 m to 30 m of height difference, with the length of the covering section being not less than 1 m; The support layer (7) below the geomembrane is made of a water-permeable material with a flat surface and good gradation, and has a thickness of 20 cm to 40 cm; The upstream soil and rock area (8) and the downstream soil and rock area (15) are made of rockfill, sand and gravel, soil or soil and rock materials; The upstream soil and rock mold increasing area (9) and the downstream soil and rock mold increasing area (16) are molded by adding cementitious materials to the damming materials to reduce regional deformation; wherein the cementitious materials include cement and other materials; the cement dosage is not less than 30kg / m 3 The total amount of the cementitious material is not less than 60 kg / m 3 ; The width of the upstream soil and rock mold increasing area (9) and the downstream soil and rock mold increasing area (16) corresponds to the outer edge width of the core wall enlargement area (12.2) and extends to both banks for not less than 1m; The upstream transition layer II zone (10) and the downstream transition layer II zone (14) have a top width of not less than 2 m and a bottom width of not less than 4 m; The width of the upstream transition layer zone I (11) and the downstream transition layer zone I (13) is not less than 1.5 m.

4. The head hub structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide valley according to claim 1 is characterized in that: The core wall main area (12.1) has a thickness B, a top thickness of not less than 0.6 m, and a bottom thickness of not less than 1 / 100 of the dam height and not less than 1.5 m; The core wall enlarged area (12.2) is arranged at intervals of 200m to 400m in the transverse direction, and includes an intermediate equal thickness area (12.2.1) and an end enlarged area (12.2.2); the two ends of the intermediate equal thickness area (12.2.1) are connected to the core wall main area (12.1) through the end enlarged area (12.2.2); the length L1 of the intermediate equal thickness area (12.2.1) is not less than 1m, and the thickness B1=2B~3B; the length L2 of the end enlarged area (12.2.2) is 2m~4m, and the thickness B2 gradually changes from B1 to B.

5. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide valley according to claim 1 is characterized in that: The high-asphalt concrete core wall (12) is connected at both banks and the dam foundation by reinforced concrete pads (25), and the reinforced concrete pads (25) are arranged in blocks along the transverse direction of the river, and flexible connections are used at the block joints between the reinforced concrete pads (25); the connection between the reinforced concrete pads (25) and the high-asphalt concrete core wall (12), as well as the connection between the reinforced concrete pads (25) and the foundation anti-seepage wall (26) are all flexibly connected.

6. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide valley according to claim 5 is characterized in that: The width of the foundation anti-seepage wall (26) is not less than 1m, and the depth is not less than 1 times the maximum dam height; The core wall enlarged foot (12.3) of the high asphalt concrete core wall (12) is arranged at a position close to the reinforced concrete pad (25), the length L0 of the core wall enlarged foot (12.3) is 2m to 4m, and the thickness B0 gradually changes from B to 2B to 3B; wherein B is the thickness of the core wall main area (12.1); The oil-rock ratio of the core wall enlarged foot (12.3) and the core wall enlarged area (12.2), that is, the asphalt accounts for the weight of the mineral material, is increased by 0.2% to 0.5% based on the oil-rock ratio of 6.5% to 7.0% in other areas.

7. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley according to claim 5 is characterized in that: The reinforced concrete pad (25) has a thickness of 2m to 3m and a width greater than the bottom thickness of the core wall enlarged foot (12.3); The block length of the reinforced concrete cushion (25) is 6m to 12m, the width of the gap between the blocks is 5cm to 10cm, the gap is filled with asphalt (27), and a horizontal copper water stop (28) is set in the middle of the gap; The junction of the reinforced concrete base (25) and the core wall enlarged foot (12.3), and the junction of the reinforced concrete base (25) and the foundation anti-seepage wall (26) are all paved with 3cm to 5cm thick asphalt mastic (30), and a vertical copper water stop (29) is provided along the center line of the core wall.

8. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley according to claim 7 is characterized in that: The transverse copper water stop (28) is W-shaped, with the nose and legs on the upstream side; the nose width is not less than 4 cm, the nose height and the leg height are not less than 20 cm, and the flat section length is not less than 50 cm; The vertical copper water stop (29) is T-shaped, with a nose on the upstream side, a nose width of not less than 4 cm, a nose height of not less than 20 cm, and a flat section length of not less than 50 cm.

9. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide river valley according to claim 1 is characterized in that: The high asphalt concrete core wall dam (1) also includes a dam body foundation surface (17), a filter drainage layer (18), a dam foundation transition layer (19), a maintenance platform (20), a geogrid (21), anti-rust steel bars (22), an observation and grouting gallery (23) and a turnaround yard (24); The anti-filtration drainage layer (18) and the dam foundation transition layer (19) are arranged from bottom to top between the dam body foundation surface (17) of the high asphalt concrete core wall dam (1) and the downstream soil and rock area (15); The maintenance platform (20) is arranged at a position above the dead water level of the upstream dam slope of the high asphalt concrete core wall dam (1); The geogrid (21) and the anti-rust steel bars (22) are laid in layers in the upstream soil and rock area (8), the upstream soil and rock mold-increasing area (9), the downstream soil and rock area (15) and the downstream soil and rock mold-increasing area (16); At least two layers of observation and grouting corridors (23) penetrating the river valley are arranged on the downstream side of the high-asphalt concrete core wall (12), and each layer of the observation and grouting corridors (23) is connected up and down; The turning yard (24) is arranged on the downstream side of the dam top corresponding to the downstream soil and rock mold increasing area (16).

10. The head pivot structure of the high asphalt concrete core wall dam on the deep overburden layer of the strong earthquake wide valley according to claim 9, characterized in that: The thickness of the reverse filtration and drainage layer (18) is not less than 3 m; The thickness of the dam foundation transition layer (19) is not less than 2 m; The top width of the maintenance platform (20) is not less than 8m; The geogrid (21) and the antirust steel bar (22) have a length of not less than 20 m in the upstream and downstream dam bodies that are more than 1 / 2 of the dam height in the direction of water flow, and a height difference of 2 m to 5 m between adjacent layers. During construction, the geogrid (21) is laid first, and then the antirust steel bar (22) is laid; The cross-sectional dimensions of the observation and grouting gallery (23) are not less than 3.0 m in width and 3.5 m in height; wherein the observation and grouting gallery (23) of the lower layer is arranged at the bottom of the high asphalt concrete core wall (12) and has outlets on both sides; the observation and grouting gallery (23) of the upper layer is arranged in layers according to a height difference of 40 m to 70 m and is located above the downstream water level. In addition to the outlets on both sides, an outlet leading to the downstream of the dam and a vertical passage connecting the upper and lower layers are arranged every 400 m to 800 m; The plane dimensions of the vehicle turning yard (24) meet the requirements for vehicle turning and stacking emergency supplies.

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