Construction method of hybrid dam with T-shaped double-cantilever dam top structure

Abstract

The application discloses a construction method of a mixed dam with a T-shaped double-cantilever dam top structure, which comprises the following steps: ① completing concrete pouring of a dam body below upstream and downstream cantilever arms and corresponding earth-rock dam structure filling, and reserving dam top structure inserting bars; ② filling a core wall to a dam top elevation; ③ excavating and removing part of the core wall; ④ brushing mud on the top of the core wall as a lower earth formwork, combining with the dam top structure inserting bars, pouring a T-shaped double-cantilever dam top structure, and pre-burying grouting holes; ⑤ removing a formwork of the dam top structure and maintaining, and completing remaining part of an outer wrapped earth-rock dam structure filling; ⑥ grouting a contact part of the concrete dam and the earth-rock dam; ⑦ completing wave-eliminating reverse-arc block pouring and ecological flower pond pouring; and ⑧ completing ecological flower pond humus paving, street lamp installation and road surface structure construction. The application can avoid stress deformation problems caused by the joint of two different materials of a dam top road foundation, eliminate longitudinal settlement joints of the top road foundation, and ensure dam body safety.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering construction technology, and in particular to a construction method for a hybrid dam with a T-shaped double cantilever dam crest structure. Background Technology

[0002] Due to limitations imposed by topographical and geological conditions, an increasing number of reservoir projects are adopting a hybrid dam layout. Conventional hybrid dams typically consist of a concrete dam encased in an earth-rock dam structure. These concrete dams usually employ a gravity dam cross-section, with a crest width typically ranging from 6 to 8 meters to meet flood control and traffic requirements. Because of the large cross-sectional area of ​​concrete gravity dams, the overall investment is high. To address this, some projects have attempted to balance flood control, traffic flow, and investment by "reducing the crest width of the gravity dam while simultaneously increasing it using an external earth-rock dam." However, due to differences in materials, permeability coefficients, and elastic moduli at the dam body joints, different parts of the dam crest experience varying consolidation settlement after construction, resulting in longitudinal settlement joints at the crest and posing safety hazards. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a low-cost, high-quality construction method for a hybrid dam with a T-shaped double cantilever dam crest structure, specifically employing the following technical solution: The present invention discloses a construction method for a hybrid dam with a T-shaped double cantilever dam crest structure. The hybrid dam consists of a concrete dam and an earth-rock dam located upstream and downstream of it. The top surface of the concrete dam is higher than that of the earth-rock dam, and the top of the concrete dam has an upstream cantilever arm extending upstream and a downstream cantilever arm extending downstream. A wave-breaking wall is provided at the end of the upstream cantilever arm. Wave-dissipating anti-arc blocks are provided on the outer side of the wave-breaking wall. An upstream ecological flower bed and a dam crest street light are provided on the top of the wave-breaking wall. A cable trench is provided on the inner side of the wave-breaking wall. A curb stone and a downstream ecological flower bed are provided at the end of the downstream cantilever arm. The dam crest road surface is located between the cable trench and the curb stone. A pre-buried drainage pipe connected to the cable trench and the downstream ecological flower bed is provided below the dam crest road surface. The construction method includes the following steps: S1, following the conventional construction sequence, complete the concrete pouring of the dam body below the upstream cantilever arm and the downstream cantilever arm, as well as the corresponding earth-rock dam structure filling, and reserve reinforcement bars for the dam top structure at the top of the dam body; S2, according to the material specifications and filling standards required by the design, the core wall will be filled to the dam crest elevation; S3, according to the lower edge contour lines of the upstream and downstream cantilever arms, partially excavate the core wall filled in step 2; S4, apply mud to the top of the core wall excavated in step 3 as the lower soil formwork, and combine it with the reinforcing bars of the dam top structure to pour the T-shaped double cantilever dam top structure including the upstream cantilever arm and the downstream cantilever arm. During pouring, grouting holes are pre-embedded in the upstream cantilever arm and the downstream cantilever arm on both sides. The upstream wave wall reinforcing bars, cable trench structure and pre-embedded drainage pipe are reserved on the top side of the upstream cantilever arm, and the downstream ecological flower bed is reserved on the top of the downstream cantilever arm. S5. After the dam crest structure has reached the design age after demolding and curing, the remaining part of the outer wrapping earth-rock dam structure is filled. S6. Grouting is carried out at the contact points between concrete dams and earth-rock dams using pre-embedded grouting pipes. After grouting is completed, the pre-embedded grouting pipes are sealed. S7, complete the pouring of the upper wave-dissipating anti-arc block and ecological flower bed of the upstream wave wall; S8, completed the ecological flower bed humus filling, street light installation, and road structure construction.

[0004] The upstream and downstream cantilever arms are symmetrically arranged, and the sum of the widths of the upstream and downstream cantilever arms is half the width of the concrete dam crest. The heights of the upstream and downstream cantilever arms are both twice the cantilever height.

[0005] The wave-breaking wall is set 1.2m above the top surface of the upstream cantilever arm, and the wave-dissipating anti-arc block is set on the top of the outer side of the wave-breaking wall, and the bottom surface of the wave-dissipating anti-arc block is a quarter-elliptical curve arc segment.

[0006] The upstream ecological flower beds are set in sections, and the dam top streetlights are set between adjacent upstream ecological flower beds. One dam top streetlight is set every 30m. A conduit is set inside the mixed dam body, and the cable of the dam top streetlight is extended through the conduit to the cable trench.

[0007] The top surface of the curbstone and the downstream ecological flower bed is set 0.1m higher than the road surface of the dam top.

[0008] The dam crest road surface is sloped downwards from the upstream side to the downstream side at a 2% gradient.

[0009] The construction method of the hybrid dam with a T-shaped double cantilever dam crest structure provided by this invention focuses on constructing a concrete dam with upstream and downstream cantilever arms. Since the dam crest is made of a single material, it avoids the stress deformation problem caused by the connection of two different materials in the dam crest road foundation, eliminates longitudinal settlement joints in the dam crest road foundation, and ensures the safety of the dam body. At the same time, the T-shaped cross-section structure of the concrete dam can meet the traffic demand of a wider dam crest. Its combination with earth-rock dam can effectively reduce investment costs, thereby saving costs and maintaining good economic benefits.

[0010] Compared with the prior art, the advantages of the present invention are as follows: 1. Prevent settlement cracks from appearing on the dam crest The T-shaped double cantilever dam crest structure is adopted to ensure that the dam crest structure uses the same material, thus avoiding settlement cracks in the dam crest of the mixed dam joint due to the different materials and different consolidation settlement.

[0011] 2. Reduce the dam cross-section to save investment. The T-shaped double cantilever dam crest structure is adopted, which ensures the width of the dam crest while effectively reducing the structural cross-section of the concrete gravity dam, optimizing the structural shape of the insertion section, and saving investment.

[0012] 3. Optimize the upstream breakwater and downstream curb stones for a safe, ecological, and aesthetically pleasing design. The upstream of the wave-breaking wall is equipped with a wave-damping anti-arc to reduce wave rise; the top of the wave-breaking wall is equipped with ecological flower beds and street light foundations, which are both practical and aesthetically pleasing; the lower part of the wave-breaking wall has a built-in cable trench for easy inspection and maintenance; and the downstream curb is equipped with ecological flower beds for safety and ecology.

[0013] 4. Phased backfilling improves construction quality. Combining the T-shaped double cantilever dam crest structure, a phased backfilling and shaped soil formwork construction scheme is proposed for the construction of the outer earth-rock dam structure. The construction method at the joint between the two dam materials is optimized to improve the construction quality. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the hybrid dam described in this invention.

[0015] Figure 2 yes Figure 1 Enlarged view of part A in the image.

[0016] Figure 3 yes Figure 1 Enlarged view of part B in the image.

[0017] Figures 4a-4h This is a schematic diagram of the construction steps of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific working processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0019] like Figure 1-3As shown, the hybrid dam with a T-shaped double cantilevered crest structure of the present invention consists of a concrete dam 1 located at the center and earth-rock dams 2 surrounding it on its upstream and downstream sides. The concrete dam 1 has a symmetrical T-shaped cross-section, with its top surface higher than the earth-rock dam 2. Therefore, the width of the top surface of the concrete dam 1 is the width of the entire dam crest. Since the entire dam crest is made of only concrete, settlement cracks in the dam body can be avoided. The crest width of the concrete dam 1 is 8m, with the central main body being 4 meters wide. The two sides of the main body cantilever outwards, extending 2 meters upstream to form an upstream cantilever arm and 2 meters downstream to form a downstream cantilever arm. The height of both the upstream and downstream cantilever arms is 0.8 meters, and the cantilever height is 0.4 meters, meaning the height of the cantilever arm is twice the cantilever height.

[0020] To prevent waves from overrunning the dam crest, a wave wall 3 is installed at the end of the upstream cantilever arm, serving to prevent waves, floods, and water flow. This wave wall 3, a stable, robust, impermeable, and integrally formed reinforced concrete structure installed on the dam crest, is typically 1.2m high, designed not to obstruct the view, thus reducing the dam crest elevation and saving on dam construction work. Furthermore, wave-damping anti-arc blocks 4 are installed on the outer top of the wave wall 3. These blocks utilize the structural curvature to reduce wave rise, preventing waves from surging and overrunning the dam crest under high water and wind speed conditions, and effectively reducing water mist and vapor generated by direct wave impact on the wave wall. The bottom surface of the wave-damping anti-arc blocks 4 is a quarter-elliptical curve segment, the curve conforming to… .

[0021] The aforementioned wave-damping anti-arc block 4 is located on the top outer side of the wave-dam 3, which can further increase the top width of the wave-dam 3 and increase the safety of protection. In this embodiment, an upstream ecological flower bed 5 and a dam-top street light can be installed on the top of the wave-dam 3 and the wave-damping anti-arc block 4. The upstream ecological flower bed 5 is filled with humus soil and pre-buried drainage pipes. Some landscape plants are planted to beautify the wave-dam and enhance the landscape effect of the dam top. Under normal circumstances, the upstream ecological flower bed 5 is cut off every 30m, and the street light foundation is pre-buried on the dam top. The conduit is pre-buried in the lower wave-dam 3 to connect the street light power supply from the cable trench 6. The street light foundation no longer occupies the dam top road surface, increasing the effective width of the dam top road surface. At the same time, the power supply is directly connected from the lower cable trench 6, avoiding the wires crossing the dam top and facilitating later operation and maintenance.

[0022] The cable trench 6 is located inside the wave wall 3 and has a built-in cable tray for easy inspection and maintenance. The top cover can be used as a pedestrian passage on the top of the dam without occupying the effective width of the top of the dam. A drainage ditch is set at the bottom of the cable trench 6, which is connected to the pre-buried drainage pipe 7 set in the dam body to guide the water collected in the ditch to the downstream dam slope for discharge.

[0023] The downstream cantilever arm is equipped with a curb and a downstream ecological flower bed 8. Between the cable trench 6 and the curb, there is a dam top road surface 9 with a 2% slope from the upstream side to the downstream side. The pre-buried drainage pipe 7 is located below the dam top road surface 9 and is connected to both the cable trench 6 and the downstream ecological flower bed 8.

[0024] The main function of the dam crest downstream curb is to isolate the dam crest road surface 9 structure from the downstream dam body, keep the edges of the dam crest road surface 9 neat and beautiful, and at the same time serve a certain warning function to prevent pedestrians from trampling on the downstream dam slope. Currently, most projects use precast concrete curbs, which are 0.2 to 0.3 meters higher than the dam crest road surface structure after being laid. Although they serve an isolation function, they are not aesthetically pleasing and also affect the drainage of the dam crest road surface, posing certain safety hazards.

[0025] In this embodiment, the curbstone is widened to 0.74m, and a downstream ecological flower bed 8 is set up, filled with humus and pre-buried drainage pipes. By planting some landscape plants, the top of the dam is beautified, which not only isolates the structure of the road surface 9 on the top of the dam, but also reduces the possibility of pedestrians accidentally slipping on the downstream dam slope. Combined with the structure of the road surface 9 on the top of the dam, its height is reduced to less than 0.1m above the road surface structure, basically level with it. Drainage outlets are reserved every 30m and connected to the drainage ditch on the downstream dam slope. This does not affect the drainage of the top of the dam, but increases the safety and landscape effect of the top of the dam.

[0026] The construction method for the hybrid dam with a T-shaped double cantilever dam crest structure described in this invention is carried out according to the following steps: 1) Following the conventional construction sequence, complete the concrete pouring of the dam body below the dam crest and the corresponding earth-rock dam structure filling. Reserve reinforcing bars for the dam crest structure at the top of the dam body, such as... Figure 4a ; 2) Fill the core wall to the dam crest elevation according to the material specifications and filling standards required by the design, such as... Figure 4b ; 3) Partially excavate the core wall filled in step 2) according to the dam crest structure, that is, the outline surface after the excavation work is completed matches the lower surface of the upstream and downstream cantilever arms of the concrete dam 1, such as... Figure 4c ; 4) Apply mud slurry to the top of the excavated core wall in step 3) to serve as the lower soil formwork. Combined with the pre-reserved reinforcing bars on the dam crest, pour the T-shaped double cantilever dam crest structure. Pre-embed grouting holes in the upstream and downstream cantilever arms on both sides. Reserve wave-breaking wall reinforcing bars, cable trench structure, and pre-embedded drainage pipes on the top side of the upstream cantilever arm. Reserve an ecological flower bed on the top of the downstream cantilever arm. Figure 4d ; 5) After the dam crest structure has reached its design age after demolding and curing, complete the remaining external earth-rock dam structure filling, such as... Figure 4e ; 6) Grout the contact area between the concrete dam 1 and the earth-rock dam 2 using pre-embedded grouting pipes. After grouting, seal the pre-embedded grouting pipes. Figure 4f ; 7) Complete the pouring of the upper wave-dissipating anti-arc blocks of the wave-breaking wall and the ecological flower beds (foundations for roads, etc.), such as... Figure 4g ; 8) Complete the construction of ecological flower bed humus filling, street light installation, road surface structure, etc., such as Figure 4h .

[0027] It should be noted that in the description of this invention, terms such as "front," "rear," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

Claims

1. A construction method for a hybrid dam with a T-shaped double cantilever dam crest structure, characterized in that: The hybrid dam consists of a concrete dam and an earth-rock dam located upstream and downstream of it. The top surface of the concrete dam is higher than that of the earth-rock dam, and the top of the concrete dam has an upstream cantilever arm extending upstream and a downstream cantilever arm extending downstream. A wave wall is provided at the end of the upstream cantilever arm, and wave-dissipating anti-arc blocks are provided on the outside of the wave wall. An upstream ecological flower bed and a dam top street light are provided on the top of the wave wall, and a cable trench is provided on the inside of the wave wall. A curb stone and a downstream ecological flower bed are provided at the end of the downstream cantilever arm. The dam top road surface is located between the cable trench and the curb stone. A pre-buried drainage pipe connected to the cable trench and the downstream ecological flower bed is provided below the dam top road surface. The construction method includes the following steps: S1, following the conventional construction sequence, complete the concrete pouring of the dam body below the upstream cantilever arm and the downstream cantilever arm, as well as the corresponding earth-rock dam structure filling, and reserve reinforcement bars for the dam top structure at the top of the dam body; S2, according to the material specifications and filling standards required by the design, the core wall will be filled to the dam crest elevation; S3, according to the lower edge contour lines of the upstream and downstream cantilever arms, partially excavate the core wall filled in step 2; S4, apply mud to the top of the core wall excavated in step 3 as the lower soil formwork, and combine it with the reinforcing bars of the dam top structure to pour the T-shaped double cantilever dam top structure including the upstream cantilever arm and the downstream cantilever arm. During pouring, grouting holes are pre-embedded in the upstream cantilever arm and the downstream cantilever arm on both sides. The upstream wave wall reinforcing bars, cable trench structure and pre-embedded drainage pipe are reserved on the top side of the upstream cantilever arm, and the downstream ecological flower bed is reserved on the top of the downstream cantilever arm. S5. After the dam crest structure has reached the design age after demolding and curing, the remaining part of the outer wrapping earth-rock dam structure is filled. S6. Grouting is carried out at the contact points between concrete dams and earth-rock dams using pre-embedded grouting pipes. After grouting is completed, the pre-embedded grouting pipes are sealed. S7, complete the pouring of the upper wave-dissipating anti-arc block and ecological flower bed of the upstream wave wall; S8, completed the ecological flower bed humus filling, street light installation, and road structure construction.

2. The construction method of the hybrid dam with T-shaped double cantilever dam crest structure according to claim 1, characterized in that: The upstream and downstream cantilever arms are symmetrically arranged, and the sum of the widths of the upstream and downstream cantilever arms is half the width of the concrete dam crest. The heights of the upstream and downstream cantilever arms are both twice the cantilever height.

3. The construction method of the hybrid dam with T-shaped double cantilever dam crest structure according to claim 1, characterized in that: The wave-breaking wall is set 1.2m above the top surface of the upstream cantilever arm, and the wave-dissipating anti-arc block is set on the top of the outer side of the wave-breaking wall, and the bottom surface of the wave-dissipating anti-arc block is a quarter-elliptical curve arc segment.

4. The construction method of the hybrid dam with T-shaped double cantilever dam crest structure according to claim 1, characterized in that: The upstream ecological flower beds are set in sections, and the dam top streetlights are set between adjacent upstream ecological flower beds. One dam top streetlight is set every 30m. A conduit is set inside the mixed dam body, and the cable of the dam top streetlight is extended through the conduit to the cable trench.

5. The construction method of the hybrid dam with T-shaped double cantilever dam crest structure according to claim 1, characterized in that: The top surface of the curbstone and the downstream ecological flower bed is set 0.1m higher than the road surface of the dam top.

6. The construction method of the hybrid dam with T-shaped double cantilever dam crest structure according to claim 1, characterized in that: The dam crest road surface is sloped downwards from the upstream side to the downstream side at a 2% gradient.

Images