Fabricated plain concrete thin-wall dam and construction method thereof

Abstract

The invention discloses a fabricated plain concrete thin-wall dam and a construction method thereof, and belongs to the technical field of municipal water conservancy projects. The dam comprises a water retaining dam body, an inhaul cable, an anchor bed and a hydraulic membrane. The construction method of the dam comprises the steps that the prefabricated stand columns are fixed to the stand column foundations, the supporting rods are installed between the tops and the lower portions of the adjacent stand columns, and a diagonal bridging structure is formed; a plain concrete arch ring is built on the ring beam foundation, suspension clasps are arranged on the inner ring face of the plain concrete arch ring and connected through steel wires, and the two ends of the steel wires are fixed to the rear ends of stand columns to form a pull net. Anchor seats are fixed on the upstream of the dam, one ends of inhaul cables are fixed to the top ends of the stand columns, and the other ends are connected to the anchor seats; a hydraulic membrane is laid, the part, above the water surface, of the hydraulic membrane is hung on the top of the dam body, the part, below the water surface, of the hydraulic membrane is connected with an underground anti-seepage structure, sealing performance is ensured, and fine sand is laid below the hydraulic membrane. The dam can adapt to different terrains and geological conditions, and the overall stability of the dam body is ensured by establishing a force transmission system between the plain concrete arch ring and the anchor bearing.

Description

Technical Field

[0001] The present invention belongs to the technical field of municipal water conservancy projects, and particularly relates to a prefabricated plain concrete thin-wall dam and a construction method thereof. Background Art

[0002] A buttress dam is a light dam with a delicate structure, which can save 20% - 60% of concrete compared with a gravity dam, and is especially suitable for areas with a relatively wide river valley, good geological conditions and poor transportation conditions. For traditional buttress dams, since the water weight on the inclined panel is utilized to help the dam body stabilize, and the uplift pressure on the buttress foundation is small, the volume of the dam is greatly reduced. However, the buttresses bear the weight, and thus need to have extremely strong compressive and anti-sliding capabilities, which requires very high requirements for the foundation and must be built on rock foundations. The buttress dam is light in volume and less in material consumption, but has a large amount of steel bars, and the structure and construction are complex. The buttress dam is provided with a support structure at the dam foundation and dam shoulder positions, and these support structures are used to bear the water pressure and other external forces of the dam body, and are applicable to the case of good foundation conditions.

[0003] The existing buttress dams have the following problems: (1) The traditional buttress arch dam adopts the method of in-situ casting, with complex construction technology, extremely high requirements for geological conditions, long construction period, low efficiency and poor adaptability, and it is difficult to meet the requirements of projects with complex geological conditions.

[0004] (2) When the traditional buttress arch dam is applied under complex conditions, stress concentration is likely to occur in local areas of the dam body. Stress concentration may cause the dam body to crack or deform, and the local structural damage affects the overall stability and durability, and may lead to the instability of the overall structure, with relatively high safety risks.

[0005] (3) After local damage to the traditional buttress arch dam, the maintenance construction is difficult and time-consuming, and the construction and use costs are high.

[0006] With the progress of technology, the cost of concrete materials has decreased, and it is easy to prepare on-site. It has become a common practice to directly use concrete with regular shapes to replace natural stones to build concrete block dams; with the popularization of water-retaining membrane products, the practice of laying flexible water-retaining membranes in dam construction to form an independent waterproof layer has achieved good application effects; in modern architecture, the use of anchor seats and cables can efficiently provide strong tensile force for building components, and has been widely used in bridges and large-span buildings. In dam construction, if these technologies can be fully integrated, a new type of dam with a more concise structure and lighter shape can be built. Summary of the Invention

[0007] In view of the above problems, the present invention proposes a new type of prefabricated plain concrete thin-wall dam and a construction method thereof, and a force transmission system is established between the plain concrete arch ring and the anchor seat to conduct the pressure borne by the plain concrete arch ring to the anchor seat to maintain the anti-sliding stability of the dam body.

[0008] The dam is constructed by stacking and assembling plain concrete blocks, the plain concrete blocks being laid out in a manner similar to that of a conventional dam, and the dam being fixed to the foundations of the columns. The anchors are located on the riverbanks on both sides upstream of the dam, above the verified flood level. Cables connect the tops of the columns to the anchors. The direction of the resultant tension of the cables on each column is opposite to the direction of the resultant water pressure on the column. The direction of the resultant tension is perpendicular to the dam axis and points upstream. The anti-seepage system consists of a hydraulic membrane and an underground anti-seepage body. The underground anti-seepage body is arranged on the upstream side of the dam body. An anti-seepage wall is set on the top of the underground anti-seepage body. The hydraulic membrane is sealed and connected to the anti-seepage wall with a water-stop joint plate; the hydraulic membrane covers the water-facing side of the dam body and the reservoir bottom between the dam body and the underground anti-seepage body. The top of the hydraulic membrane is suspended on the top of the dam body to form a continuous and closed anti-seepage base surface; a protective layer is set under the hydraulic membrane, hydraulic cloth is laid on steep areas, and fine-grained river sand is laid on flat areas.

[0009] A method for constructing an assembled plain concrete thin-wall dam, characterized by comprising the following steps: S1. Design the reservoir dam based on the reservoir size, topography, and geological conditions. Anchors shall be installed on the riverbanks on both sides upstream of the dam at a location above the reservoir high water level, perpendicular to the dam axis where the columns are located. If no suitable location is available in front of the dam, anchors shall be installed on both sides of the dam and tensioned with the columns via cables, with the two cables tensioning the same column symmetrically. If no suitable location is available on both sides of the dam, anchors shall be installed on the reservoir bottom in front of the dam using pull-out piles. Water intake, water transfer, and flood discharge facilities shall be installed on the riverbanks or other dam sections outside the concrete thin-walled dam section, and dam components shall be prefabricated according to the design specifications. S2: Arrange an anti-seepage system upstream of the dam axis of the plain concrete thin-wall dam section, set a reinforced concrete anti-seepage wall on top of the anti-seepage system, and embed a waterstop plate on top of the anti-seepage wall; S3. Excavate the dam foundation to solid bedrock or a foundation that meets the dam construction requirements after strengthening treatment. Trim the cross-section foundation into a vertical bank slope step type, and pour concrete column foundations on the foundation. The column foundations are evenly arranged along the dam axis; pour arch ring beams between adjacent columns; S4. Set up scaffolds and scaffolding. Fix the columns on the column foundations by means of post-cast strips to connect the columns and column foundations into one body; for the columns at the ends, pour and connect them directly to the column foundations on the side close to the shore or the vertical surface of the stepped rock foundation. For the plain concrete arch rings adjacent to other dam sections, the arch feet at the end close to other dam sections are directly set on other dam sections; S5. Install struts and cross braces; install cables. After all are connected, gradually tighten the cables in a cycle; use concrete blocks to build the arch rings on the arch ring beams. Only plain concrete blocks of the same specification are used for one layer of the arch ring, and plain concrete blocks of different specifications must be used for the adjacent upper and lower layers; the blocks are connected by load transfer bars between the blocks and between the blocks and the columns to limit relative displacement; all arch rings are built step by step symmetrically and cyclically, rising synchronously. During the building process, connect the backwater surface hanging buckles synchronously and install wire meshes to prevent the blocks or baffles from slipping towards the water-facing surface; then disassemble and remove the scaffolds and scaffolding; S6. On the reservoir bottom between the front side of the thin-walled dam and the water stop connection plate, lay a fine-grained river sand cushion layer, and thicken the laying at the corners; on the steep water-facing surface of the thin-walled dam and the top surface of the fine-grained river sand, lay geotextiles, and lay geomembranes on the geotextiles. The geomembranes are connected to the surrounding water stop connection plates and are suspended and fixed; for the protruding parts of the sub-structures in contact with the geomembrane under the geomembrane, round corners are made.

[0010] Further, the distance between the arch feet of the arch rings on both sides of the water-facing surface of the column is greater than 0.4 m, which is convenient for construction and makes the arc segments of the concrete arch rings in contact with the water body on the water-facing surface be complete and strict semi-circles, so as to ensure that there is only a normal pressure perpendicular to the contact surface between the column and the arch ring and between the arch ring blocks. All the main load-bearing members are connected without hinges, and local stress concentration is eliminated through controllable mutual displacement to avoid damage to the members, thereby improving the overall safety and durability of the dam.

[0011] Further, the joints of the plain concrete blocks adjacent to each other up and down in the same plain concrete arch ring are staggered. Load transfer bar sockets are opened on the four connecting surfaces of the upper, lower, left, and right of each plain concrete block, and load transfer bars are inserted between the plain concrete blocks adjacent to each other up and down and left and right and between the columns and the plain concrete blocks for connection.

[0012] The beneficial effects of the present invention are as follows: Compared with existing dam types, the prefabricated plain concrete thin-wall dam described in the present invention has the advantages of light weight and material saving in the structure of buttress arch dams, small uplift pressure on the dam foundation, etc., and also has the following advantages: (1) This dam type reduces the requirements for the geological conditions of the dam foundation and has strong adaptability. The water-retaining surface of the buttress arch dam is an inclined plane, which bears the heavy pressure of the upper water body, and the pressure on the buttress foundation is large; the connection surface between the thin-shell dam surface and the dam foundation is thin, and the anti-seepage pressure difference of the foundation is large; traditional arch dams have high requirements for the compressive and anti-seepage properties of the dam foundation; the water-retaining surface of the dam type described in the present invention is vertical, and the dam foundation only bears the weight of the thin-wall dam body itself. The distance between the underground anti-seepage body located upstream and the dam axis is large, and the pressure difference corresponding to the unit length of the anti-seepage body is small, reducing the requirements for the compressive and anti-seepage properties of the dam foundation. (2) The construction difficulty is small and the speed is fast. The water-retaining surface of the buttress arch dam is a thin-shell curved surface, which requires high construction technology and great difficulty for formwork engineering, and the maintenance period of cast-in-place reinforced concrete is long. The underground anti-seepage body and the water-retaining dam are located in the same section, and the construction is carried out from bottom to top and gradually unfolds, with a long construction period; the dam body and dam foundation of this dam type do not bear the gravity of the water body, the load on the components and the dam foundation is small, the material and process requirements are low, the dam body components are connected in series with each other by dowel bars and assembled without binder, the support and fixation difficulty is small, the installation accuracy is high, and the construction speed is fast. On the main river course, the underground anti-seepage body and the water-retaining dam are staggered up and down, which is convenient for organizing parallel construction and accelerating the overall construction speed; (3) The construction and use costs are low. The load characteristics of the columns and thin-wall arches with equal diameter and equal depth are completely the same, and their shapes and specifications are the same, which is conducive to standardization and sizing, fine design and mass production. The dam body is thin and the components are light and small, which is convenient for the rapid assembly of the dam body and reduces the use of large construction machinery and equipment; the price of plain concrete is low, and the independent anti-seepage structure makes the load-bearing structure members of the water-retaining dam not immersed in water, with excellent working conditions, significantly improved weather resistance, and enhanced anti-freezing and anti-corrosion capabilities, which can reduce the requirements for dam-building materials and processes and extend the service life; all components of this dam type are movably connected, and the flexible splicing can flexibly adapt to local deformations, avoid stress concentration, reduce component damage, and each assembled component is independent. When damage occurs, it can be quickly replaced and repaired at low cost, which can further reduce the life-cycle cost of this type of dam.

[0013] Compared with traditional dams that rely on high-strength materials or complex reinforcement measures, the force transmission system composed of cables, columns and wire meshes in the present invention is designed more simply and efficiently, with significant technical advantages. Using plain concrete blocks and geomembranes as the main materials, the material cost is low, and it is easy to mass-produce and transport. In addition, the prefabricated structure reduces the complexity of on-site construction and labor costs, further reducing the overall construction cost. Description of the Drawings

[0014] Figure 1 It is a schematic plan layout diagram of a prefabricated plain concrete thin-wall dam.

[0015] Figure 2 It is a schematic longitudinal section diagram of the dam in Example 1 along the river.

[0016] Figure 3 Schematic diagram of the cross-section of the dam in the river direction for Example 2

[0017] Figure 4 Schematic diagram of the cross-section of the axis of an assembled plain concrete thin-wall dam

[0018] Figure 5 Partial top view of the plain concrete of an assembled plain concrete thin-wall dam

[0019] Figure 6 Schematic diagram of the plain concrete block structure

[0020] Wherein: 1 - anchor seat, 2 - cable, 3 - column, 31 - column foundation, 4 - strut, 5 - plain concrete arch ring, 51 - arch ring beam, 52 - first block, 53 - second block, 6 - hydraulic membrane, 61 - water stop connection plate, 62 - hydraulic cloth, 7 - fine-grained river sand, 8 - load transfer bar, 81 - load transfer bar socket, 9 - bedrock, 10 - hanging buckle, 11 - wire mesh, 12 - underwater anchor seat, 13 - uplift resistance pile, 14 - cut-off wall, 15 - underground anti-seepage body, 16 - dam axis, 17 - gravity dam, 18 - spillway Specific implementation method

[0021] Example 1: A certain river is a wide and shallow river. The right bank is steep, the left bank is relatively gentle, the alluvial layer of the riverbed is thin, and the bedrock is exposed on both sides of the riverbank. A composite dam is designed and constructed. The main river channel part adopts a plain concrete thin-wall dam, and a total of 7 equal-diameter plain concrete arch rings are set. The two banks are concrete gravity dams. The assembled plain concrete thin-wall dam includes a water retaining dam body, a cable 2, an anchor seat 1 and an anti-seepage system. The water retaining dam body is composed of columns 3 and a plain concrete arch ring 5. The plain concrete arch ring 5 is a semi-circular straight column surface convex upstream formed by stacking plain concrete blocks. The column 3 is a reinforced concrete truss. The columns 3 are evenly arranged along the dam axis and fixed on the column foundation 31. The column foundation 31 is a cast-in-place concrete anti-sliding pile; a scissors brace is erected between adjacent columns 3 using a strut 4, and a strut 4 is horizontally arranged and connected at the top between them; a ring beam foundation 51 is provided at the bottom of the plain concrete arch ring 5; the columns 3 and the plain concrete arch ring 5 are spaced apart from each other and are horizontally connected to form a water retaining dam body; one or more hanging buckles 10 are provided on one side of the inner ring surface of each plain concrete block on the plain concrete arch ring 5. The hanging buckles on the same layer of concrete blocks are connected using steel wires and the two ends are fixed on both sides of the rear end of the column 3. The steel wires of each layer are vertically connected to form a wire mesh 11 on the back water surface of adjacent columns 3

[0022] The anchor seat 1 is arranged on the riverbanks on both sides of the upstream of the dam at a position higher than the reservoir high water level. The top of the column 3 is connected to the anchor seat 1 through the cable 2. The resultant force direction of the cable 2 tension on each column 3 is opposite to the resultant force direction of the water pressure received by the column 3. The resultant force direction of the tension is perpendicular to the dam axis and points upstream

[0023] The anti-seepage system consists of a hydraulic membrane 6 and an underground anti-seepage body 15. The underground anti-seepage body 15 is arranged on the upstream face of the dam body. An anti-seepage wall 14 is set on the top of the underground anti-seepage body 15. The hydraulic membrane 6 is sealed with the anti-seepage wall 14 by a water-stop joint plate 61; the hydraulic membrane 6 covers the water-facing surface of the dam body and the reservoir bottom between the dam body and the underground anti-seepage body 15. The top of the hydraulic membrane 6 is suspended on the top of the dam body, and the remaining peripheral edges are sealed with the water-stop joint plate 61 on the top of the anti-seepage wall 14, thereby forming a continuous and closed anti-seepage base surface; a protective layer is provided under the hydraulic membrane 6, with hydraulic cloth 62 laid on steep areas and fine-grained river sand 7 laid on flat areas; the parts where the structures under the membrane contact the hydraulic membrane 6 are rounded at the protruding corners and wrapped with flexible materials to ensure a smooth contact surface.

[0024] The prefabricated plain concrete thin-wall dam is constructed according to the following steps: S1, anchorage 1 is set at the bank slopes on both sides of the upstream where they are higher than the verified flood level. The anchorages on the left bank are combined into a single anchorage, and 5 anchorages are set on the right bank. Both banks are connected to the river bank with concrete gravity dams 17. A spillway 18 is set on the concrete dam section 17 on the left bank with open terrain. The bank slope is flat and stable, and the conditions for water flow to return to the channel are good.

[0025] S2, prefabricated assembled plain concrete thin-walled dam components according to the design specifications and quantity, column 3 is a variable-section T-shaped column with a web that is wider at the bottom and narrower at the top, and is prefabricated with reinforced concrete, and the plain concrete blocks include two specifications, the first block 52 and the second block 53, which are prefabricated with lightweight aggregate concrete.

[0026] S2, an underground anti-seepage body 15 is arranged upstream of the axis of the plain concrete thin-wall dam. A reinforced concrete anti-seepage wall 14 is set on top of the underground anti-seepage body 15, and a water-stop plate 61 is buried on top of the anti-seepage wall 14.

[0027] S3: Excavate the dam foundation to solid bedrock or a foundation that meets dam construction requirements after strengthening treatment. Cast gravity dams 17 on both sides. Divide the plain concrete thin-walled dam sections into sections of different depths. The cross-section foundation is trimmed into a vertical bank step. Concrete column foundations 31 are cast on the foundation. The column foundations 31 are anti-slip piles that meet the requirements for anti-slip and bearing capacity and are arranged equidistantly along the dam axis. Cast arch ring beams 51 between the columns 3.

[0028] S4, set up the bracket and scaffolding, install the column 3 on the column foundation 31, fix the column 3 on the column foundation 31 by using the post-cast strip method, and connect the column 3 and the column foundation 31 into one; the end column 3 is directly cast and connected to the foundation with the column foundation 31 against the shore or the vertical side of the stepped rock foundation, and the plain concrete arch ring 5 adjacent to the gravity dam 17 is directly built on the gravity dam 17 by the arch foot at one end of the gravity dam 17.

[0029] S5. Use struts 4 to install cross braces between the top ends of adjacent columns 3. After all the cables 2 are connected, gradually tighten them in a cyclic manner. On the arch ring beam 51, use blocks to build the arch ring 5. Only use plain concrete blocks of the same specification for one layer of the arch ring. Different specifications of the first block 52 and the second block 53 shall be used for the adjacent upper and lower layers of the arch ring, and the first block 52 and the second block 53 shall be used alternately from bottom to top. The blocks are connected to each other and to the columns by inserting force transfer bars 8 into the reserved force transfer bar insertion holes 81 to limit relative displacement. All the arch rings are built step by step symmetrically and cyclically, rising synchronously. During the building process, hanging buckles 10 are installed synchronously and steel wire ropes are pulled to form a wire mesh 11 to prevent the blocks from slipping on the water-facing side. Remove the supports and scaffolds.

[0030] S6. On the reservoir bottom between the water stop connection plate 61 at the top of the water retaining dam body and the underground anti-seepage body 15, lay a fine-grained river sand 7 cushion layer, and thicken the laying at the corners such as the dam toe and the foundation steps. Lay a geotextile 62 on the water-facing side of the thin-walled dam and on the top of the fine-grained river sand 7 cushion layer. Lay a geomembrane 6 on the geotextile 62. The geomembrane is hermetically connected to the water stop connection plate 61, and the geomembrane 6 is suspended and fixed. For the protruding parts of the sub-membrane structures in contact with the geomembrane 6, rounded corners shall be made or padding protection shall be provided to protect the geomembrane.

[0031] Embodiment 2: For a wide and shallow river course, the river surface upstream of the dam site becomes wider, the terrain is flat, the distance between the river banks is far and the height is low, making it difficult to find suitable anchor seat setting points. Therefore, in the bedrock 9 under the riverbed in the upstream river course, anti-pull piles 13 are driven, underwater anchor seats 12 are set, and the cables 2 are anchored, corresponding one by one to the columns 3. Underwater anchor seats 12 are respectively set directly above the columns. The remaining construction methods are the same as those in Embodiment 1.

Claims

1. A prefabricated plain concrete thin-walled dam, characterized in that: It includes a water retaining dam body, stay cables, anchor seats and an anti-seepage system. The water retaining dam body is composed of columns and plain concrete arch rings. The plain concrete arch ring is a positive semi-circular vertical column surface convex upstream, which is formed by stacking plain concrete blocks. The columns are made of reinforced concrete, concrete-filled steel tubes or steel truss. The columns are evenly arranged along the dam axis and fixed on the column foundation. The column foundation is a cast-in-place concrete anti-slide pile. A scissors brace is erected between adjacent columns using a strut, and a strut is horizontally arranged and connected end to end at the top between them. A ring beam foundation is arranged at the bottom of the plain concrete arch ring. The columns and the plain concrete arch rings are spaced apart from each other and are transversely connected to form a water retaining dam body. One or more hanging buckles are arranged on one side of the inner ring surface of each plain concrete block on the plain concrete arch ring. The hanging buckles on the same layer of concrete blocks are connected by steel wires and the two ends are fixed on both sides of the rear end of the column. The steel wires of each layer are vertically connected to form a wire mesh on the back water surface of adjacent columns. The anchor seats are arranged on the river banks on both sides of the upstream of the dam at a place higher than the check flood level. The top of the column is connected to the anchor seat by a stay cable. The resultant direction of the stay cable tension on each column is opposite to the resultant direction of the water pressure received by the column. The resultant direction of the tension is perpendicular to the dam axis and points upstream. The anti-seepage system is composed of a hydraulic membrane and a subsurface anti-seepage body. The subsurface anti-seepage body is arranged on the upstream surface of the water retaining dam body. An anti-seepage wall is arranged at the top of the subsurface anti-seepage body. The hydraulic membrane is hermetically connected to the anti-seepage wall using a water stop joint plate. The hydraulic membrane covers the upstream surface of the water retaining dam body and the reservoir bottom between the water retaining dam body and the subsurface anti-seepage body. The top of the hydraulic membrane is suspended at the top of the water retaining dam body to form a continuous and closed anti-seepage base surface. A protective layer is arranged under the hydraulic membrane. Geotextile is laid on the steep places and fine-grained river sand is laid on the gentle places.

2. The precast plain concrete thin-walled dam according to claim 1, characterized in that The distance between the arch feet of the arch rings on both sides of the column's upstream surface is greater than 0.4 m.

3. The prefabricated plain concrete thin-wall dam according to claim 1, wherein The joints of the plain concrete blocks adjacent to each other vertically and horizontally on the same plain concrete arch ring are staggered. Transmission rod insertion holes are opened on the four connecting surfaces of each plain concrete block, namely, the upper, lower, left and right surfaces. Transmission rods are inserted between the plain concrete blocks adjacent to each other vertically and horizontally and between the column and the plain concrete block for connection.

4. A construction method of an assembled plain concrete thin-walled dam, characterized in that It includes the following steps: S1. According to the reservoir scale, terrain and geological conditions, design the reservoir dam. Anchor seats are arranged at positions on the river banks on both sides of the upstream of the reservoir higher than the reservoir high water level. When there is no suitable position in front of the dam, anchor seats are arranged on both banks in front of the dam and the columns are tensioned through stay cables. The two stay cables for tensioning the same column are symmetrical with the perpendicular line of the dam axis of the column. When there is no suitable position for arranging anchor seats on both banks, anti-pulling piles are used to arrange anchor seats on the reservoir bottom in front of the dam, and the protective measures for the stay cables are strengthened. Water intake, water conveyance and flood discharge facilities are arranged on the river bank outside the dam section of the concrete thin-wall dam or other dam sections. The dam construction components are prefabricated according to the design specifications. S2. Arrange the anti-seepage system on the upstream of the dam axis of the plain concrete thin-wall dam section. A reinforced concrete anti-seepage wall is arranged at the top of the anti-seepage system. A water stop joint plate is buried at the top of the anti-seepage wall. S3. Excavate the dam foundation to solid bedrock or a foundation that meets the dam construction requirements after strengthening treatment. Pour concrete gravity dams on both banks. The plain concrete thin-wall dam sections are segmented according to different depths, and the cross-section foundation is trimmed into a stepped shape with vertical slopes on both sides. Pour concrete column foundations on the foundation. The column foundations are anti-sliding piles that can meet the requirements of both anti-sliding and bearing capacity, and are evenly arranged along the dam axis. Pour arch ring beams between adjacent columns. S4. Set up scaffolds and scaffolding. Fix the columns on the column foundations by means of post-cast strips, and connect the columns and column foundations into one body. The columns at the ends are directly poured and connected to the column foundations on the side close to the shore or the vertical surface of the stepped rock foundation. The arch feet of the plain concrete arch rings adjacent to other dam sections on the side close to other dam sections are directly set on other dam sections. S5. Install struts between adjacent columns and set up cross braces. Install cables, and gradually tighten the cables in a cyclic manner after all are connected. Use concrete blocks to build the arch rings on the arch ring beams. Only plain concrete blocks of the same specification are used for one layer of the arch ring, and blocks of different specifications must be used for the upper and lower adjacent layers of the arch ring. The blocks are connected to each other and to the columns through load transfer bars to limit relative displacement. All the arch rings are built step by step symmetrically and cyclically, rising synchronously. During the building process, the hanging buckles on the back water surface are connected synchronously, and a wire mesh is installed to prevent the blocks or baffles from slipping towards the water-facing side. Then, remove the scaffolds and scaffolding. S6. On the reservoir bottom between the front side of the thin-wall dam and the water stop connection plate, lay a fine-grained river sand cushion, with thicker laying at the corners. On the steep water-facing side of the thin-wall dam and the top surface of the fine-grained river sand, lay a geotextile, and lay a geomembrane on the geotextile. The geomembrane is connected to the water stop connection plate and is suspended and fixed. The protruding parts of the sub-structures in contact with the geomembrane under the geomembrane are rounded.

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