A clay core dam heightening structure

Abstract

The utility model discloses a clay core wall dam heightening type structure contains the original clay core wall anti -seepage reinforcement structure, the slope heightening panel rockfill dam, the new old anti -seepage link structure, the old dam body reinforcement structure, the original core wall earth -rock dam and dam top structure, the original clay core wall anti -seepage reinforcement structure sets up the concrete anti -seepage wall in the original clay core wall, and the bedrock part adopts curtain grouting anti -seepage closure, and the slope heightening panel rockfill dam contains the anti -seepage panel and downstream rockfill slope heightening, and the heightening part anti -seepage panel is the heightening part dam body upstream side anti -seepage structure, and the downstream rockfill slope satisfies the engineering side slope stability safety requirement, and the new old anti -seepage link structure adopts the concrete connecting plate, and the old dam body reinforcement structure adopts high -pressure rotary jetting pile reinforcement treatment to the original dam body deputy core wall and concrete connecting plate lower dam body, improves the original dam body bearing capacity, reduces uneven settlement, and the dam top structure is the traffic channel of the dam after heightening, and is equipped with relevant drainage, power supply, inspection and other functions.

Description

Technical Field

[0001] This utility model relates to the field of clay core wall dam heightening technology in water conservancy and hydropower engineering, specifically a clay core wall dam heightening structure. By rationally setting up a slope-adhesive rockfill dam with raised panels, a new and old seepage prevention connection structure, an old dam body reinforcement structure, and a dam top structure, the original clay core wall dam can be heightened and expanded, thereby improving the function and benefits of water conservancy facilities. Background Technology

[0002] In the 1850s, constrained by the relatively underdeveloped economic base and limited engineering technology, the construction of dams in the field of water conservancy mostly adopted the earth-rock dam scheme using locally sourced materials, employing clay core walls for seepage prevention, with secondary core walls located upstream and downstream of the clay core walls. This scheme, by directly utilizing surrounding natural resources, to a certain extent met the needs of water resource allocation and simple flood control at the time, achieving the basic functions of water conservancy projects at a relatively low construction cost.

[0003] However, with the advancement of the times and the rapid development of the social economy, the demands of modern society for water infrastructure have undergone a fundamental transformation. The public's requirements for drinking water quality are constantly increasing, necessitating a higher quality and more stable water supply; frequent extreme weather events have made flood control a crucial issue concerning people's lives and property, and traditional flood control standards are no longer sufficient to meet current needs; simultaneously, the advancement of ecological civilization construction has placed higher demands on ecological water use, requiring the guarantee of river ecological base flow and wetland water use. Furthermore, after long-term development, high-quality geological conditions suitable for constructing new large-scale reservoirs are becoming increasingly scarce, and building new dams in suitable areas faces challenges such as high geological risks and dramatically increased construction costs.

[0004] Against this backdrop, raising the height of existing clay core dams to meet expansion needs, thereby tapping the potential of existing water conservancy facilities and improving the comprehensive utilization efficiency of water resources, has become an important way to alleviate the contradiction between water supply and demand, strengthen flood control capabilities, and maintain ecological balance. Research and innovation on clay core dam raising technology has also become an urgent need in the field of water conservancy engineering.

[0005] In the process of raising clay core dams, the primary challenge is the reconstruction of the seepage prevention system caused by rising reservoir water levels. Due to historical construction limitations, the original dam body suffers from structural defects such as uneven gradation of the dam fill material. Furthermore, the presence of the secondary core wall results in a composite structure in the seepage prevention system. Under the influence of increased water level load, this heterogeneous dam structure is prone to stress concentration, which can lead to seepage channels. Utility Model Content

[0006] To address the challenges of reconstructing the anti-seepage system and controlling uneven settlement of old dams in existing technologies for raising clay core dams, this invention provides a clay core dam raising structure with features such as a fully enclosed anti-seepage system, dual control of uneven settlement, efficient utilization of old dam resources, and integrated dam crest functions. Through composite structural design, innovative anti-seepage connection, targeted reinforcement, and multi-functional dam crest planning, this invention achieves efficient raising and performance improvement of existing clay core dams, adapting to the needs of modern water conservancy projects.

[0007] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0008] This utility model discloses a clay core dam heightening structure, comprising an existing clay core earth-rock dam, with secondary core walls of the original dam body located upstream and downstream of the existing clay core wall. The structure further includes a slope-adjusted heightened face-panel rockfill dam, a new and old seepage prevention connection structure, an old dam body reinforcement structure, and a dam crest structure. The slope-adjusted heightened face-panel rockfill dam is located downstream of and connected to the existing clay core earth-rock dam. The existing clay core wall is reinforced with a seepage prevention reinforcement structure. The concrete cutoff wall is arranged longitudinally. The bedrock portion below the concrete cutoff wall is provided with a curtain grouting layer for seepage prevention and sealing. The top of the concrete cutoff wall is provided with a cast-in-place head wall and supported by corbels. The new and old cutoff wall connection structure is used to connect the concrete cutoff wall with the cutoff structure of the slope-adjusted and heightened rockfill dam. The old dam body reinforcement structure acts on the soil of the original core wall earth-rock dam (the old dam body reinforcement structure is the original dam body secondary core wall and the downstream dam slope gravel reinforcement structure). The dam top structure is set on the top of the slope-adjusted and heightened rockfill dam.

[0009] Preferably, the slope-adjusted raised rockfill dam includes a concrete anti-seepage panel and a downstream rockfill slope-adjusted raised section. The concrete anti-seepage panel constitutes the anti-seepage structure on the upstream side of the slope-adjusted raised rockfill dam, and it constitutes the upstream dam face structure between the top of the original core wall earth-rock dam and the raised dam crest structure. The upper part of the concrete anti-seepage panel is connected to the dam crest structure.

[0010] Preferably, the downstream riprap slope elevation includes a cushion layer zone, a transition zone, a main riprap zone, and a secondary riprap zone with soil and rock mixture. The upper part of the soil and rock mixture is provided with a downstream upper grass slope protection, the lower part of the soil and rock mixture is provided with a downstream lower dry-laid stone slope protection, and a drainage prism is provided below the downstream riprap slope elevation.

[0011] Preferably, the new and old seepage prevention connection structure includes a concrete connecting plate located at the top of the original clay core dam. The concrete connecting plate is located between the concrete seepage prevention wall and the concrete seepage prevention panel to form a dam seepage prevention and sealing structure.

[0012] Preferably, the new and old seepage prevention connection structure also includes a concrete toe slab located at the top of the original clay core dam, the concrete connecting plate is located between the concrete toe slab and the concrete seepage prevention wall, the lower part of the concrete seepage prevention panel is connected to the concrete toe slab, one end of the concrete connecting plate rests on the corbel of the concrete seepage prevention wall, and the other end is permanently joined with the concrete toe slab (22), with copper sheet waterstop installed in the gap; the lower part of the concrete connecting plate and the concrete toe slab is respectively provided with cushion material and transition material.

[0013] Preferably, high-pressure jet grouting piles are installed in the secondary core wall of the original dam body downstream of the original clay core wall for reinforcement, and high-pressure jet grouting piles are installed in the dam body below the concrete connecting plate for reinforcement. The bearing capacity of the original dam body is improved by the high-pressure jet grouting piles in the secondary core wall and the high-pressure jet grouting piles, and uneven settlement is reduced.

[0014] Preferably, the dam crest structure forms a traffic channel for the heightened dam, the upstream gravity retaining wall of the dam crest structure forms a wave wall, a patrol passage is provided at the front toe of the upstream gravity retaining wall, a railing is provided on the water-facing side of the patrol passage, the dam crest road has an asphalt concrete pavement, a cable drainage ditch is provided on the downstream edge of the dam crest road for drainage of the dam crest road surface and for the routing of dam crest streetlights, and a drainage pipe is installed in the cable drainage ditch to drain water to the downstream slope to meet the natural water requirements of the vegetation; the upstream gravity retaining wall forms a wave wall, and the wave wall is connected to the upper part of the concrete anti-seepage panel.

[0015] Preferably, the railing is one or both of stainless steel railing and bluestone railing.

[0016] Beneficial effects:

[0017] 1. Maximize the potential of existing dams and save investment costs. Fully utilize the existing clay core dam structure, and on this basis, carry out slope widening and heightening construction to increase the dam's height. Slope widening and heightening requires relatively less investment in the construction of the new slope section and corresponding reinforcement work, thus avoiding the high costs associated with large-scale reconstruction. This allows limited funds to achieve greater efficiency and significantly saves investment costs.

[0018] 2. Reduce land occupation and promote efficient resource utilization. In today's context of increasingly precious land resources, the renovation of existing dam structures eliminates the need for large-scale redevelopment of the dam site, minimizing the occupation and impact on surrounding land resources. This contributes to the efficient utilization of land resources and the stability of the surrounding ecological environment and land use patterns.

[0019] 3. Overcoming the challenge of uneven settlement in old dam bodies, facilitating the implementation of a new approach to slope-fitting and heightening. The internal structure of the dam body consists of a clay core, a secondary core, and the dam shell. The soil uniformity within the dam body is poor, and variations in geological conditions and bearing pressure make uneven settlement prone to occur during subsequent slope-fitting and heightening processes. This invention addresses this problem by reinforcing the original secondary core with high-pressure jet grouting piles and installing a concrete connecting plate between the concrete cutoff wall and the concrete panel, rationally arranging the construction sequence, and controlling deformation during construction. Attached Figure Description

[0020] Figure 1 This is a typical cross-sectional view of the dam heightening according to an embodiment of this utility model.

[0021] Figure 2 This is a detailed drawing of the dam crest structure according to an embodiment of this utility model.

[0022] Figure 3 This is a detailed structural drawing of the toe plate and connecting plate according to an embodiment of this utility model.

[0023] In the diagram: 1-Existing clay core wall seepage prevention and reinforcement structure; 11-Concrete seepage prevention wall; 12-Cast-in-place head wall; 13-Corner; 14-Curtain grouting layer; 2-Slope-adjusted raised face rockfill dam; 21-Concrete seepage prevention face; 22-Concrete toe slab; 23-Subbase zone; 24-Transition zone; 25-Main rockfill zone; 26-Secondary rockfill zone; 27-Soil-rock mixture; 28a-Downstream upper grass slope protection; 28b-Dry-laid stone slope protection; 29-Drainage 3-Pyramid; 4-New and old seepage prevention connection structure; 5-Concrete; 6-Subbase material; 7-Transition material; 8-Old dam reinforcement structure; 9-Secondary core wall high-pressure jet grouting pile; 10-Dam body high-pressure jet grouting pile; 11-Existing core wall earth-rock dam; 12-Clay core wall; 23-Secondary core wall; 44-Dam crest structure; 55-Guardrail; 66-Patrol passage; 77-Wave wall; 88-Dam crest road; 98-Cable drainage ditch; 109-Dam crest street light; 100-Drainage pipe. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of the utility model, it should be noted that the terms "upper", "lower", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device 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 the utility model.

[0026] The technical principle / solution of this utility model: This utility model proposes a complete technical solution for the heightening requirements of clay core wall dams, innovating from structural design to construction methods, and solving the traditional heightening problems. The specific summary is as follows:

[0027] Structural System: A composite structure is constructed, consisting of "existing core wall reinforcement + slope-mounted rockfill heightening + new and old seepage prevention connection + old dam body reinforcement + dam crest functional integration". Based on the existing core wall earth-rock dam, the core wall's seepage prevention is strengthened through concrete cut-off walls and curtain grouting. Downstream, the slope-mounted rockfill dam is heightened, utilizing concrete cut-off panels, multi-layered rockfill zones (cushion layer, transition layer, main rockfill, etc.), slope protection, and drainage prisms to ensure the stability and seepage prevention of the heightened dam body. The new and old seepage prevention connection structure (concrete connecting slab, toe slab combined with cushion layer material and transition material) achieves a closed connection between different seepage prevention structures. The old dam body reinforcement structure (secondary core wall and high-pressure jet grouting piles under the connecting slab) addresses uneven settlement. The dam crest structure integrates traffic, patrol, wave protection, drainage, power supply, and ecological functions, forming a fully functional heightened system.

[0028] Innovative seepage prevention system: A fully enclosed seepage prevention system consisting of a concrete cutoff wall, connecting plate, cutoff panel, toe slab, and curtain grouting. The longitudinal concrete cutoff wall extends deep into the original core wall, and the bedrock curtain grouting reinforces the bottom seepage prevention. At the junction of the old and new structures, the concrete connecting plate, supported by corbels and with joint sealing, works in conjunction with the toe slab to connect the original cutoff wall and the new cutoff panel. The bedding material and transition material deform gradually to ensure continuous seepage prevention and effectively address the risk of seepage after the reservoir water level rises.

[0029] Settlement control: A dual strategy of "soil reinforcement + structural transition" is adopted. High-pressure jet grouting piles are applied to the soil under the original dam's secondary core wall and connecting plate to improve the soil's mechanical properties and increase its bearing capacity. In the transition structure between the old and new anti-seepage structures, the joint design of the connecting plate and toe plate, as well as the deformation coordination of the cushion material and transition material, combined with a reasonable construction sequence (reinforcing the old dam first, then constructing the new structure), effectively control the uneven settlement during the slope-adjusting and heightening process and subsequent operation, ensuring the safety of the dam structure.

[0030] Resource utilization and functional expansion: Fully explore the value of the old dam, rely on the original core wall earth-rock dam renovation, reduce the land occupation and building material consumption of the new dam body, and save investment; the dam crest structure integrates inspection channels, wave walls, asphalt pavement, cable drainage ditches (which take into account drainage and power supply), ecological drainage pipes, etc., to meet the needs of transportation, safety, operation and maintenance and ecology in one stop, and adapt to the multi-functional and eco-friendly development direction of modern water conservancy projects.

[0031] Construction Method: Following the principles of "layered construction, orderly connection, and reinforcement before heightening," the dam surface is cleaned and backfilled with rockfill in layers to form a construction platform, after which the old dam body is reinforced. The original core wall seepage prevention structure (seepage prevention wall, curtain grouting) and the new seepage prevention structure (toe slab, seepage prevention panel) are constructed sequentially, with precise connection plates at the joints. Finally, the functional structure at the dam crest is integrated. Each process is controlled through deformation monitoring, seepage monitoring, and quality inspection to ensure construction quality and dam performance.

[0032] In summary, the technical solution of this utility model achieves reliable seepage prevention, controllable settlement, resource conservation, and functional improvement in the heightening of clay core wall dams, providing an effective technical path for upgrading and transforming existing water conservancy facilities, and helping water conservancy projects adapt to the needs of modern water resource utilization and ecological protection.

[0033] The overall structure of this utility model consists of:

[0034] This utility model discloses a clay core wall dam heightening structure, based on an existing core wall earth-rock dam 5 with an original clay core wall 51. The original dam body has auxiliary core walls 52 located upstream and downstream of the original clay core wall 51. The newly added structure includes a slope-adhesive raised face rockfill dam 2, a new and old seepage prevention connection structure 3, an old dam body reinforcement structure 4, and a dam crest structure 6. These components work together to achieve dam heightening and performance improvement. The specific construction is as follows:

[0035] The raised rockfill dam 2 with a concrete cut-off panel is located downstream of and connected to the existing core rockfill dam 5. It is one of the main structures for raising the dam body and includes a concrete cut-off panel 21 and a downstream raised rockfill slope. The concrete cut-off panel 21 constitutes the upstream cut-off structure and also serves as the upstream dam face structure between the top of the original core rockfill dam 5 and the raised dam crest structure 6, with its upper part connected to the dam crest structure 6. The downstream raised rockfill slope consists of a cushion layer 23, a transition zone 24, a main rockfill zone 25, a secondary rockfill zone 26, and a soil-rock mixture 27, from the inside out. The upper part of the soil-rock mixture 27 is provided with a downstream upper grass slope revetment 28a, and the lower part with a downstream lower dry-laid stone revetment 28b. A drainage prism 29 is provided below to ensure structural stability and drainage requirements.

[0036] The original clay core wall seepage prevention and reinforcement structure 1 is a concrete seepage prevention wall 11 set longitudinally inside the clay core wall 51. The bedrock part below is provided with a curtain grouting layer 14 for seepage prevention and sealing. The top is provided with a cast-in-place head wall 12 and a corbel 13 to support it, thereby strengthening the seepage prevention performance of the original clay core wall.

[0037] New and old seepage prevention connection structure 3: a seepage prevention structure used to connect the concrete seepage prevention wall 11 and the slope-adjusted and heightened rockfill dam 2, including a concrete connecting plate 31 and a concrete toe plate 22. The concrete toe plate 22 is located at the top of the original clay core dam 5, and the concrete connecting plate 31 is located between the concrete toe plate 22 and the concrete seepage prevention wall 11. The lower part of the concrete seepage prevention panel 21 is connected to the concrete toe plate 22. One end of the concrete connecting plate 31 rests on the corbel 13 of the concrete seepage prevention wall 11, and the other end is connected to the joint copper sheet waterstop of the concrete toe plate 22. The lower parts of the concrete connecting plate 31 and the concrete toe plate 22 are respectively provided with a cushion material 32 and a transition material 33 to form a seepage prevention and sealing structure for the dam.

[0038] The old dam reinforcement structure 4 acts on the soil of the original core wall earth-rock dam 5. High-pressure jet grouting piles 41 are installed in the original dam secondary core wall 52 downstream of the original clay core wall 51, and high-pressure jet grouting piles 42 are installed in the dam body below the concrete connecting plate 31. Through these two methods, the bearing capacity of the original dam body is improved and uneven settlement is reduced.

[0039] The dam crest structure 6 forms the traffic passage for the heightened dam. The upstream gravity retaining wall also serves as a wave wall 63, with a patrol passage 62 at its front toe. The patrol passage 62 has a railing 61 on the water-facing side (which can be one or both of stainless steel and bluestone railings). The dam crest road 64 uses asphalt concrete pavement. A cable drainage ditch 65 is set on the downstream side line for drainage of the dam crest road 64 and for the wiring of the dam crest streetlights 66. Drainage pipes 67 are installed inside to drain water to the downstream slope to meet the water needs of the vegetation. The wave wall 63 is connected to the upper part of the concrete anti-seepage panel 21.

[0040] Construction steps for the heightening structure of this utility model:

[0041] When raising a clay core dam, follow these steps to ensure orderly construction of each structure and overall performance:

[0042] S1. Dam surface cleaning and slope backfilling: The downstream dam surface of the original clay core dam 5 was cleaned, and riprap was used for slope backfilling to lay the foundation for subsequent construction.

[0043] S2. Preparation for reinforcement of old dam body: When the slope-adjusted and heightened rockfill dam 2 is filled to the required elevation and a construction platform is available, the original dam body secondary core wall 52 will be reinforced with secondary core wall high-pressure jet grouting piles 41 and the lower part of the dam body of concrete connecting plate 31 with high-pressure jet grouting piles 42 to enhance the bearing capacity of the old dam body and pre-control uneven settlement.

[0044] S3. Construction of concrete anti-seepage wall: Concrete anti-seepage wall 11 is constructed inside the original clay core wall 51. The foundation adopts curtain grouting layer 14, and the top is cast-in-place head wall 12 with corbels 13, thus constructing the main body of the original core wall anti-seepage reinforcement.

[0045] S4. Toe slab pouring, rockfill dam heightening and panel pouring: Concrete toe slab 22 is poured on the top of the existing clay core wall dam 5. The rockfill dam 2 with the panel is heightened and sloped. First, the main rockfill area 25, the secondary rockfill area 26, and the soil-rock mixture 27 are backfilled in layers. Then, the concrete anti-seepage panel 21 on the water-facing side is poured to improve the rockfill dam structure and anti-seepage system.

[0046] S5. Construction of concrete connection plate: Concrete connection plate 31 is poured between concrete toe plate 22 and concrete anti-seepage wall 11. Before pouring, the lower cushion material 32 and transition material 33 are laid to realize the connection between the new and old anti-seepage structures.

[0047] S6. Construction of the dam crest structure: Construction of the dam crest structure 6 will be carried out first, including the wave wall 63 on the water-facing side and the cable drainage ditch 65 on the back water side. Finally, the dam crest road surface 64 will be poured to improve the traffic, protection and drainage functions of the dam crest.

[0048] A specific embodiment of this utility model is described in detail below, in conjunction with the accompanying drawings and actual engineering scenarios, to ensure that the construction and functional realization of each structure are clear and operable:

[0049] I. Pre-construction preparation

[0050] Before construction, a comprehensive inspection and evaluation of the original clay core dam was conducted, including the physical and mechanical properties of the dam soil, the integrity of the original seepage prevention structure, and historical data on dam deformation and seepage. This clarified the original dam condition and provided a basis for setting construction parameters and optimizing reinforcement schemes. At the same time, debris and loose soil were cleared from the downstream face of the original clay core dam, and the quarrying and transportation routes for riprap were planned to ensure the supply of construction materials and the cleanliness of the site.

[0051] II. Key Points for Construction of Each Structure

[0052] Construction of the slope-supported and heightened rockfill dam 2, specifically:

[0053] Downstream rockfill slope raising: carried out in layers according to the design, starting from drainage prism 29, and then rolling the main rockfill area 25, secondary rockfill area 26, and soil-rock mixture 27 in sequence. The thickness of each layer and the rolling parameters (such as the number of rolling passes and the tonnage of the rolling machinery) are strictly controlled to ensure that the density and internal friction angle of the rockfill meet the design requirements. During construction, the settlement and displacement of the rockfill are monitored in real time, and the construction parameters are adjusted in a timely manner.

[0054] Construction of concrete anti-seepage panels 21: This process begins after the rockfill dam body has been filled to the corresponding elevation and the conditions for panel construction are met. First, the panel foundation surface is treated to ensure it is flat and clean. Formwork casting or slipform construction techniques can be used (this application does not impose specific restrictions; the choice can be made based on actual conditions). The concrete mix ratio, pouring temperature, and vibration quality are controlled to ensure the anti-seepage performance and structural strength of the panels. At the connection points between the panels and the wave wall 63 and the concrete toe slab 22, proper construction joint treatment and water-stopping structures are implemented to ensure continuous anti-seepage.

[0055] Construction of the existing clay core wall seepage prevention and reinforcement structure 1, specifically:

[0056] Construction of concrete anti-seepage wall 11: Trenching equipment is used to form trenches within the original clay core wall 51, and the division of trench sections, verticality of trenching, and stability of trench walls are strictly controlled; a suitable concrete mix ratio is selected, and concrete is poured using the tremie method to ensure the integrity and anti-seepage performance of the anti-seepage wall; wall quality testing (such as ultrasonic testing) is carried out during construction to ensure the continuity and density of the wall.

[0057] Construction of curtain grouting layer 14: In the bedrock area below the concrete anti-seepage wall 11, curtain grouting is carried out according to the designed hole positions and depths. Appropriate grouting materials (such as cement-based grouting materials) and grouting processes (such as circulating grouting, segmented grouting, etc.) are used to control the grouting pressure and grout diffusion range, forming a continuous and effective bedrock anti-seepage sealing layer. The grouting effect is tested through water pressure tests, etc.

[0058] Construction of cast-in-place head wall 12 and corbel 13: On the top of the concrete anti-seepage wall 11, formwork is erected to cast in-place head wall 12 and corbel 13, ensuring that the formwork is firm and the dimensions are accurate; during the concrete pouring process, the concrete is vibrated to make it dense, and attention is paid to the construction quality of the joint with the top of the anti-seepage wall to ensure the stability of the subsequent concrete connecting plate 31.

[0059] Construction of the new and old seepage prevention connection structure 3, specifically:

[0060] Construction of concrete toe slab 22: On the top of the original clay core wall dam 5, concrete toe slab 22 is poured according to the design dimensions and elevation. The joint surface between the toe slab and the original dam body is treated (such as roughening, cleaning, and laying interface agent) to ensure that the toe slab is firmly connected to the original dam body. During the construction of the toe slab, water-stopping components that are connected to the concrete anti-seepage panel 21 and the concrete connecting plate (31) are pre-embedded to ensure reliable anti-seepage connection.

[0061] Construction of concrete connecting plate 31: Between concrete toe slab 22 and concrete anti-seepage wall 11, first lay cushion material 32 and transition material 33, spread in layers and compacted, and control its particle size distribution and density to meet the design requirements; then set up formwork and pour concrete connecting plate 31. One end of the connecting plate is accurately placed on the corbel 13 of concrete anti-seepage wall 11, and the other end is connected to concrete toe slab 22 with joint copper sheet water stop according to the design. During the pouring process, strictly control the concrete quality and construction joint treatment to ensure the anti-seepage effect.

[0062] Construction of the old dam reinforcement structure 4, specifically:

[0063] Construction of high-pressure jet grouting piles 41 in the secondary core wall: Within the existing secondary core wall 52 of the dam body, high-pressure jet grouting piles are constructed according to the designed pile positions, pile lengths, and pile diameters. Appropriate jet grouting parameters (such as jetting pressure, lifting speed, rotation speed, etc.) are selected to ensure the strength and seepage prevention performance of the piles. During construction, the piles are subjected to quality testing (such as core sampling and load testing) to ensure the reinforcement effect.

[0064] High-pressure jet grouting pile 42 construction (lower dam body of concrete connecting plate 31): In the dam body area below the concrete connecting plate 31, high-pressure jet grouting pile construction is carried out in accordance with the design requirements. The pile layout and construction parameters are controlled to make the pile body and the surrounding soil form an integral whole, thereby improving the bearing capacity and deformation resistance of the dam body. After construction, the quality of the pile body and the reinforcement effect of the dam body are tested.

[0065] Construction of the wave wall 63 and upstream gravity retaining wall of the dam crest structure 6: The construction adopts the cast-in-place concrete process. The formwork is set up according to the design dimensions and elevation. During the pouring process, attention is paid to the construction quality of the connection part with the upper part of the concrete anti-seepage panel 21 to ensure the wave-proof and anti-seepage functions. A patrol passage 62 space is reserved at the front toe of the retaining wall. After the construction is completed, the patrol passage is hardened or a protective surface layer is laid.

[0066] Installation of railing 61: On the water-facing side of the patrol passage 62, install railing 61 according to the designed spacing and height. If it is a stainless steel railing, ensure anti-corrosion treatment; if it is a bluestone railing, ensure the quality of the stone and the firmness of the installation to ensure the safety of personnel during patrols.

[0067] Construction of the dam crest road 64: After the base course of the dam crest is properly treated, asphalt concrete pavement is laid. The mix ratio, paving temperature and compaction process of the asphalt concrete are strictly controlled to ensure the smoothness and strength of the pavement. At the same time, cable drainage ditches 65 are precisely set up on the downstream edge of the road and drainage pipes 67 are pre-buried to ensure smooth drainage and meet the wiring requirements of the dam crest streetlights 66. During the construction of the cable drainage ditches, the connection with the dam crest road and the downstream slope is properly handled.

[0068] III. Construction Process Monitoring and Quality Control

[0069] Multi-dimensional monitoring and quality control are required throughout the entire construction process:

[0070] Deformation monitoring: Settlement and displacement monitoring points are set up at key parts of the original core wall earth-rock dam and slope-adjusted raised face rockfill dam (such as dam crest, dam slope, seepage prevention structure connection, etc.). Leveling instruments, total stations and other equipment are used for regular monitoring to keep track of the dam deformation in real time. If abnormal deformation occurs (such as excessive settlement rate, displacement exceeding the limit, etc.), the cause is analyzed in time and construction parameters are adjusted or reinforcement measures are taken.

[0071] Seepage Monitoring: Seepage pressure and flow rate monitoring devices (such as piezometers and flow rate observation weirs) are installed on the dam's seepage prevention structures (such as concrete cutoff walls, concrete cutoff panels, and concrete connecting plates) and the dam foundation curtain grouting layer to monitor changes in seepage parameters, ensuring the effectiveness of the seepage prevention system. If abnormal seepage is detected (such as increased flow rate or excessive seepage pressure), leaks are promptly investigated and addressed. Construction Quality Inspection: Incoming inspections are conducted on all construction materials (such as concrete raw materials, riprap, and grouting materials) to ensure material quality. Process and finished product inspections are carried out on the construction quality of each procedure (such as concrete pouring and vibration quality, riprap compaction density, and jet grouting pile integrity). Strict quality acceptance standards are enforced; the next procedure cannot proceed if the previous procedure fails to meet quality standards, ensuring the overall project quality is reliable.

[0072] Through the above specific implementation methods, the orderly and high-quality construction of the clay core wall dam heightened structure can be achieved, ensuring that the heightened dam body meets the needs of modern water conservancy projects in terms of seepage prevention, stability, and functionality, giving full play to the potential of existing water conservancy facilities, and improving the comprehensive utilization benefits of water resources and the engineering flood control and ecological protection capabilities.

[0073] Through the above technical solutions, the present invention can ultimately achieve the following technical features:

[0074] Reliable seepage prevention performance: Through the original clay core wall seepage prevention reinforcement structure (concrete seepage prevention wall + curtain grouting layer), the concrete seepage prevention panel of the slope-adjusted and heightened rockfill dam, and the new and old seepage prevention connection structure (concrete connecting plate, concrete toe plate, etc. working together), a continuous and closed seepage prevention system is constructed, which effectively solves the seepage problem after the reservoir water level rises and ensures the stability of seepage in the dam body.

[0075] Make full use of existing dam resources and save costs: upgrade and heighten the existing core-walled earth-rock dam without the need for large-scale new dam construction, reduce land occupation and building material input, and lower project costs; at the same time, tap the potential of the existing dam, improve the utilization efficiency of existing facilities, and make limited funds play a greater role.

[0076] Effective control of uneven settlement: In the reinforcement structure of the old dam, the high-pressure jet grouting piles of the secondary core wall and the high-pressure jet grouting piles under the concrete connecting plate reinforce the original dam soil. With the reasonable construction and construction sequence control of the new and old seepage prevention connection structure, the uniformity of the dam soil is effectively improved, the uneven settlement during the slope raising process and the later operation is reduced, and the safety and stability of the dam structure is ensured.

[0077] With comprehensive functions to meet diverse needs: The dam crest structure integrates functions such as traffic, patrol, wave protection, drainage, power supply and ecological water supply guarantee. The upstream gravity retaining wall also serves as a wave wall. Patrol passages and railings ensure personnel safety. Cable drainage ditches and drainage pipes work together to meet drainage and ecological needs. Asphalt concrete pavement ensures smooth traffic. It meets the needs of modern water conservancy projects for multi-functionality and eco-friendliness.

[0078] Finally, it should be noted that this utility model is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A clay-core dam heightened structure, comprising an existing core earth-rock dam (5) with an existing clay core wall (51), wherein an existing dam body auxiliary core wall (52) is provided upstream and downstream of the existing clay core wall (51), characterized in that: It also includes a slope-adjusted and heightened rockfill dam (2), a new and old seepage prevention connection structure (3), an old dam body reinforcement structure (4), and a dam crest structure (6). The slope-adjusted and heightened rockfill dam (2) is located downstream of the original core wall earth-rock dam (5) and is connected to the original core wall earth-rock dam (5). The original clay core wall (51) is reinforced with an original clay core wall seepage prevention reinforcement structure (1). The original clay core wall seepage prevention reinforcement structure (1) is a longitudinally arranged concrete seepage prevention wall (11). The bedrock section below is provided with a curtain grouting layer (14) for seepage prevention and sealing. The concrete cutoff wall (11) is provided with a cast-in-place head wall (12) and a corbel (13) is placed on top. The new and old cutoff connection structure (3) is used to connect the concrete cutoff wall (11) with the cutoff structure of the slope-adjusted raised rockfill dam (2). The old dam body reinforcement structure (4) is the original dam body secondary core wall (52) and the downstream dam slope gravel reinforcement structure. The dam top structure (6) is set on the top of the slope-adjusted raised rockfill dam (2).

2. The clay core dam heightened structure according to claim 1, characterized in that: The slope-adjusted raised rockfill dam (2) includes a concrete anti-seepage panel (21) and downstream rockfill slope-adjusted raised rockfill. The concrete anti-seepage panel (21) constitutes the anti-seepage structure on the upstream side of the slope-adjusted raised rockfill dam (2), and it constitutes the upstream dam face structure between the top of the original core wall earth-rock dam (5) and the raised dam crest structure (6). The upper part of the concrete anti-seepage panel (21) is connected to the dam crest structure (6).

3. The clay core dam heightened structure according to claim 2, characterized in that: The downstream rockfill slope elevation includes a cushion layer area (23), a transition area (24), a main rockfill area (25), a secondary rockfill area (26), and a soil-rock mixture (27). The upper part of the soil-rock mixture (27) is provided with a downstream upper grass slope protection (28a), and the lower part of the soil-rock mixture (27) is provided with a downstream lower dry-laid stone slope protection (28b). A drainage prism (29) is provided below the downstream rockfill slope elevation.

4. A clay core dam heightened structure according to claim 1, 2, or 3, characterized in that: The new and old seepage prevention connection structure (3) includes a concrete connecting plate (31) located on top of the original core wall earth-rock dam (5). The concrete connecting plate (31) is located between the concrete seepage prevention wall (11) and the concrete seepage prevention panel (21) to form a dam seepage prevention and sealing structure.

5. The clay core dam heightened structure according to claim 4, characterized in that: The new and old seepage prevention connection structure (3) also includes a concrete toe slab (22) located on top of the original core wall earth-rock dam (5). The concrete connecting plate (31) is located between the concrete toe slab (22) and the concrete seepage prevention wall (11). The lower part of the concrete seepage prevention panel (21) is connected to the concrete toe slab (22). One end of the concrete connecting plate (31) rests on the corbel (13) of the concrete seepage prevention wall (11), and the other end is permanently joined with the concrete toe slab (22). Copper sheet waterstop is installed in the gap. The lower part of the concrete connecting plate (31) and the concrete toe slab (22) are respectively provided with cushion material (32) and transition material (33).

6. A clay core dam heightened structure according to claim 1, 2, 3, or 5, characterized in that: The original dam body is reinforced by high-pressure jet grouting piles (41) in the secondary core wall (52) downstream of the original clay core wall (51), and high-pressure jet grouting piles (42) are installed in the dam body below the concrete connecting plate (31). The bearing capacity of the original dam body is improved and uneven settlement is reduced by the high-pressure jet grouting piles (41) and high-pressure jet grouting piles (42) in the secondary core wall.

7. The clay core dam heightened structure according to claim 1, characterized in that: The dam crest structure (6) forms a traffic channel for the heightened dam. The upstream gravity retaining wall of the dam crest structure (6) forms a wave wall (63). A patrol channel (62) is provided at the front toe of the upstream gravity retaining wall. A railing (61) is provided on the water-facing side of the patrol channel (62). The dam crest road (64) is provided with an asphalt concrete pavement. A cable drainage ditch (65) is provided on the downstream edge of the dam crest road (64) for drainage of the dam crest road (64) and for the routing of the dam crest streetlights (66). A drainage pipe (67) is provided in the cable drainage ditch (65) to drain water to the downstream slope to meet the natural water requirements of the green plants. The upstream gravity retaining wall forms a wave wall (63). The wave wall (63) is connected to the upper part of the concrete anti-seepage panel (21).

8. A clay core dam heightened structure according to claim 7, characterized in that: The railing (61) is one or both of stainless steel railing and bluestone railing.

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