Special-shaped rail slip-form for toe plate of rock-fill dam and construction method

Abstract

The application discloses a special-shaped rail slipform for a rock-fill dam toe plate, which comprises a surface slipform and a lifting guide mechanism, the rear end of the side slipform of the surface slipform is connected with a side finishing platform, the front end surface of the main slipform is respectively provided with safety mechanism two and safety mechanism one on both sides, the front part of the main slipform is fixedly provided with an operation platform and a protective guardrail thereon, and the rear end of the main slipform is fixedly provided with a main finishing platform and a main protective guardrail; the lifting guide mechanism comprises a sliding rail one, a sliding rail two and two winches arranged side by side. The application further discloses a construction method of the special-shaped toe plate, and the construction stage steps comprise the following steps: 1) concrete production and transportation; 2) concrete storage pouring; 3) concrete vibrating; 4) slipform lifting; 5) concrete finishing; and 6) concrete curing, thereby completing the concrete pouring construction of one stroke. The slipform and the construction method are convenient to operate and can accelerate the progress and efficiency.

Description

Technical Field

[0001] This invention belongs to the field of toe slab construction technology for concrete-faced rockfill dams, and relates to an irregularly shaped tracked slipform for rockfill dam toe slabs, as well as a construction method for irregularly shaped toe slabs. Background Technology

[0002] The concrete face, peripheral toe slabs, and grouting system are the main seepage control structures of a concrete-faced rockfill dam, requiring sufficient strength, durability, and the ability to adapt to deformation. The toe slab, located at the contact point between the concrete face and the bedrock, primarily ensures an impermeable connection between the concrete face and the dam foundation, extending the seepage path while also serving as a cover for the grouting in the dam foundation. It is a crucial component of the seepage control system for concrete-faced rockfill dams. The toe slab and the concrete face are connected by peripheral joints with water-stopping features, together forming the seepage control body above the dam foundation. Simultaneously, the toe slab integrates with the stabilized bedrock after consolidation grouting and curtain grouting treatment, sealing the seepage channels below ground level and forming a complete seepage control system.

[0003] For the concrete-faced gravel dam in this project, the left and right bank toe slabs are connected from the top of the high toe piers (elevation 1510m) to the bottom of the wave wall (elevation 1703.2m), with the middle section connected by high toe piers. The left bank concrete toe slab adopts a flat toe slab design, with varying width and thickness along the elevation. Due to the influence of topographical and geological conditions, the right bank toe plate consists of a lower sloping toe plate, a middle horizontal toe plate, and an upper sloping toe plate. The bottom of the lower sloping toe plate is the top of the high toe pier, with a width of 13.0m and a thickness of 1.2m. The bottom of the middle horizontal toe plate has an elevation of 1564m, a width of 13.0m, and a thickness of 1.0m. The width of the upper sloping toe plate is 9.0m below the elevation of 1650m, and gradually changes from the elevation of 1650m to the elevation of 1703.2m, reaching 5.0m at the elevation of 1703.2m. The thickness gradually changes from 1.00m at the elevation of 1564m to 0.5m at the elevation of 1703.2m.

[0004] As can be seen, the width and thickness of the right bank toe slab vary at different elevations, and the cross-section of the right bank toe slab is an irregular structure, characterized by its connection to the panel via a nose-shaped sill structure on the side closest to the perimeter seam. To accelerate the toe slab construction progress and improve its construction quality, slipform construction technology was used for both the lower and upper inclined toe slab sections of the right bank toe slab during concrete pouring. Therefore, considering the aforementioned actual working conditions and construction requirements, the irregularly shaped tracked slipform in this patent was designed and manufactured. Actual construction testing revealed that this irregularly shaped tracked slipform effectively addresses the complex and variable structure of the toe slab, enabling continuous concrete forming, improving pouring quality, saving significant amounts of formwork and manpower, and reducing construction costs. Summary of the Invention

[0005] The purpose of this invention is to provide an irregularly shaped tracked slipform for the toe slab of a rockfill dam, which solves the problem that the existing toe slab slipform structure is difficult to adapt to the construction requirements of complex and ever-changing sites and is difficult to accurately realize concrete pouring construction.

[0006] Another objective of this invention is to provide a construction method for irregular toe plates, which solves the problems of insufficient adaptability of conventional toe plate slipform structures and low construction efficiency of irregular toe plate concrete pouring in the prior art.

[0007] The technical solution adopted in this invention is an irregularly shaped tracked slipform for the toe slab of a rockfill dam, which consists of a surface slipform and a lifting and guiding mechanism. The surface slipform includes a side slipform and a main slipform, with a side finishing platform connected to the rear end of the side slipform. The front end of the main slipform is provided with a second safety mechanism and a first safety mechanism, respectively. An operating platform is fixedly installed at the front of the main slipform, and the operating platform is equipped with an upper guardrail. The rear end of the main slipform is fixedly installed with a main finishing platform, and the main finishing platform is equipped with a main guardrail. The lifting and guiding mechanism includes a first slide rail, a second slide rail, and two winches arranged in parallel.

[0008] Another technical solution adopted in this invention is a construction method for irregularly shaped toe plates, which utilizes the aforementioned irregularly shaped tracked slipform and is implemented according to the following steps: Preparation stage: including installing a winch, erecting two slide rails, installing two fixed pulleys, lowering the slipform, erecting side formwork, erecting a chute, and cleaning the surface; then proceeding to the construction stage:

[0009] Step 1: Concrete production and transportation;

[0010] Step 2: Concrete pouring into the formwork;

[0011] Step 3: Vibrate the concrete;

[0012] Step 4: Slipform lifting;

[0013] Step 5: Concrete finishing;

[0014] Step 6: Concrete curing. This completes one round of concrete pouring. Then, through multiple consecutive slipforming operations, the construction of all irregular toe slabs on site is completed.

[0015] The beneficial effects of this invention are: the irregularly shaped tracked slipform can adapt to the complex features of the irregularly shaped toe plate structure on the inclined surface, and can also realize rapid, continuous, and high-precision concrete pouring; the two finishing platforms and safety guardrails are all made of hollow steel pipes, making the slipform relatively lightweight; through the stress analysis design of the slipform structure, and with the addition of protective guardrails and safety insurance mechanisms, construction is safe and reliable; the two finishing platforms make the surface smoother after forming, and the slipform process also improves the pouring quality of the internal concrete; it saves a lot of formwork and manpower, reducing construction costs; the irregularly shaped tracked slipform is easy to operate, simplifies the construction process, and accelerates the construction progress and efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of the irregular toe plate targeted by the irregular track sliding formwork of the present invention;

[0017] Figure 2 This is a three-dimensional structural schematic diagram of the irregular-shaped track sliding mode of the present invention;

[0018] Figure 3 This is a top view of the irregular-shaped tracked sliding mold of the present invention;

[0019] Figure 4 This is a simplified installation diagram of the side sliding mold and the main sliding mold in the irregular-shaped track sliding mold of the present invention;

[0020] Figure 5 This is a partial simplified diagram of the side sliding mold and the main sliding mold in the irregular-shaped track sliding mold of the present invention;

[0021] Figure 6 This is a simplified structural diagram of the side troweling platform in the irregular-shaped tracked sliding mold of the present invention;

[0022] Figure 7 This is a partial installation diagram of the limiting wheel and the slide rail in the irregular-shaped track sliding mold of the present invention;

[0023] Figure 8 This is a schematic diagram of the working state of the irregular-shaped track sliding formwork of the present invention;

[0024] Figure 9 This is a three-dimensional structural diagram of the conventional side mold of the irregular toe plate DE, EF and FG surfaces.

[0025] In the diagram, 1. Wire rope, 2. Traction lug, 3. Safety mechanism one, 4. Operating platform, 5. Upper guardrail, 6. Slide rail one, 7. Safety mechanism two, 8. Irregular toe plate, 9. Side sliding formwork, 10. Side finishing platform, 11. Main guardrail, 12. Main finishing platform, 13. Lifting lug, 14. Main sliding formwork, 15. Limiting wheel, 16. Slide rail two, 17. Fixed pulley, 18. Winch, 19. Concrete block, 20. Feed hopper, 21. Chute, 22. Welded stiffening plate, 23. Conventional side formwork. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] Reference Figure 1 This is a cross-sectional view of the irregular toe plate targeted by the irregular-shaped guide slipform of this invention. Conventional side molds need to be erected on the AB, EF, and FG surfaces upstream of the irregular toe plate. In particular, irregular-shaped guide slipforms (hereinafter referred to as slipforms) need to be used on the straight section BC and the nose sill section CD. This solves the problems of varying toe plate thickness, changing perimeter waterstop positions, and different over- and under-excavation backfill templates. The straight section of the slipform is machined according to several length dimensions of the straight section BC of the toe plate to accommodate various changes in BC length. The nose sill section of the slipform has its DE edge machined into a slider with two degrees of freedom to accommodate different changes in CD length and the angles of points D and E.

[0028] Reference Figure 2 , Figure 3 The irregular-shaped tracked sliding formwork of the present invention is mainly composed of a surface sliding formwork and a lifting and guiding mechanism. The surface sliding formwork mainly includes a side sliding formwork 9 and a main sliding formwork 14. The rear end of the side sliding formwork 9 is connected to a side troweling platform 10. The front end face of the main sliding formwork 14 is provided with a second safety mechanism 7 and a first safety mechanism 3 respectively. The front part of the main sliding formwork 14 is fixedly provided with an operating platform 4, which is equipped with an upper guardrail 5. The rear end of the main sliding formwork 14 is fixedly provided with a main troweling platform 12, which is equipped with a main guardrail 11.

[0029] The operating platform 4 consists of a frame welded from hollow square steel and a work platform panel fixed on the upper surface of the frame. Seven vertical hollow square steels of equal length and spacing are welded to the middle of the main sliding mold 14. The tops of the seven vertical hollow square steels are correspondingly overlapped and welded to seven horizontal hollow square steels of equal length. The front ends of the seven horizontal hollow square steels of equal length are fixed to the front of the main sliding mold 14. The upper surface of the seven horizontal hollow square steels of equal length is welded to an 8mm thick work platform panel.

[0030] The main guardrail 11 is welded to the rear edge of the main plastering platform 12. The main guardrail 11 is welded from a circular steel pipe with a diameter of 50mm. An upper guardrail 5 is welded to the rear edge of the operating platform 4. It is also welded from a circular steel pipe with a diameter of 50mm. Both the main guardrail 11 and the upper guardrail 5 are used to ensure the safety of construction personnel.

[0031] To prevent loss of control due to the sudden breakage of the wire rope 1, safety mechanisms 1 (3) and 2 (7) are symmetrically welded on both sides of the front end of the operating platform 4. Safety mechanisms 1 (3) and 2 (7) have identical structures, both consisting of a channel steel frame chassis, a safety rope drum, a locking assembly, and a turntable. The safety rope extending from the safety rope drum is connected to the toe plate reinforcing mesh. A locking pin secures one end of the safety rope drum, and the turntable rotates the coaxial safety rope drum to extend and retract the safety rope.

[0032] Reference Figure 4 , Figure 5 The side sliding mold 9 has a parallelogram frame structure, while the main sliding mold 14 has a rectangular frame structure. Both the side sliding mold 9 and the main sliding mold 14 are constructed by welding No. 22 channel steel together. Steel panels are fixedly connected to the lower surfaces of both frames. The top surface of the toe plate nose sill is formed by the dragging of the side sliding mold 9, and the top surface of the toe plate horizontal section is formed by the dragging of the main sliding mold 14. The mating surfaces of the side sliding mold 9 and the main sliding mold 14 are each welded with a steel plate with bolt holes. The two load-bearing steel plates are connected by two rows of 16 M bolts each. 16 The connection is fixed with bolts, and two anti-slip bolts are installed at the bottom connection apex to prevent misalignment at the connection when the side sliding mold 9 and the main sliding mold 14 are pulled up. The angle between the side sliding mold 9 and the main sliding mold 14 in the top view plane (parallel to the horizontal top surface of the toe plate) is 40°, and the upward angle of the side sliding mold 9 relative to the main sliding mold 14 in the front view plane is 20°. Due to this 20° upward angle, there is an angle between the frame of the side sliding mold 9 and the steel plate with screw holes on the connecting side, which may cause the welding between the two to be weak. Therefore, three welded stiffeners 22 are provided between the three main steel frames of the side sliding mold 9 and the steel plate with screw holes. Each welded stiffener 22 is formed by butt welding of three small steel plates.

[0033] Reference Figure 6 The side troweling platform 10 is composed of a pair of bent hollow square steel bars. Each bent hollow square steel bar has a bend with an included angle of 148° near its lower end. The upper end of each bent hollow square steel bar is connected to two lifting lugs 1 by bolts whose positions can be finely adjusted. Both lifting lugs 1 are welded to the lower end face of the side sliding mold 9. The angle can be adjusted as needed to achieve precise troweling.

[0034] The main plastering platform 12 consists of seven bent hollow square steel bars and a plastering panel. Each bent hollow square steel bar has the same structure as the side plastering platform 10. Similarly, it is connected to two lifting lugs 2 by bolts whose positions can be finely adjusted. Both lifting lugs 2 are welded to the lower end face of the main sliding mold 14 to realize the connection between the main plastering platform 12 and the main sliding mold 14. The plastering panel is made of 8mm thick steel plate and is welded to the bent sections of the seven bent hollow square steel bars.

[0035] Reference Figure 2 , Figure 7 and Figure 8The lifting and guiding mechanism consists of slide rail 16, slide rail 2 16, and two winches 18 arranged in parallel.

[0036] Among them, slide rail 16 and slide rail 26 are both hollow square steel, arranged along the longitudinal sides of the irregular toe plate 8, serving as the moving track of the surface sliding mold; correspondingly, three wheel seats made of hollow square steel are welded longitudinally on the main frame at both ends of the main sliding mold 14, and each wheel seat is equipped with a limiting wheel 15 downwards, see Figure 7 The three limiting wheels 15 installed on the left end face of the main sliding mold 14 are precisely engaged with the slide rail 1 6, and the three limiting wheels 15 installed on the right end face of the main sliding mold 14 are precisely engaged with the slide rail 2 16. Figure 2 The six limit wheels 15 together support the main sliding mold 14, and the main sliding mold 14 then drives the side sliding mold 9 to move up and down along the slide rail 1 6 and the slide rail 2 16.

[0037] Reference Figure 2 and Figure 5 Two traction lugs 2 are symmetrically welded on both sides of the front end face of the main sliding mold 14. The lower end of each wire rope 1 is hooked into the circular hole of a traction lug 2, and the upper end of each wire rope 1 is wound around the wire rope drum of a winch 18. A fixed pulley 17 is also provided in the middle section of each wire rope 1. In addition, in order to facilitate the overall hoisting and transportation of the sliding mold, two lifting lugs 13 are welded on the front end face and the rear end face of the main sliding mold 14. The positions of the four lifting lugs 13 are symmetrical about the center of gravity of the main sliding mold 14.

[0038] Reference Figure 9 The conventional side formwork 23 is existing technology and mainly consists of triangular templates, struts, tie rods, steel templates, wooden templates, and wooden blocks located in section DE. It is used for concrete forming on the upstream AB, DE, EF, and FG surfaces of the irregular toe slab. The structure of the conventional side formwork 23 will not be described in detail here.

[0039] The construction method of the irregular toe plate of the present invention is carried out by utilizing the irregular tracked slipform of the present invention according to the following steps:

[0040] Preparation phase:

[0041] 1.1) Install the winch: See Figure 8 Two winches 18 and two fixed pulleys 17 are arranged side by side on a horizontal platform and weighed down with large concrete blocks 19. At the same time, the chassis of the two winches 18 are fixed to the horizontal platform with steel piles, requiring that they will not slide or overturn during the slipform construction process.

[0042] 1.2) Install two slide rails: install steel bars and waterstops inside the irregular toe plate 8, and install slide rail 1 6 and slide rail 2 16 on the top steel bars;

[0043] 1.3) Install two fixed pulleys 17: Based on the height characteristics of slide rail 1 6, slide rail 2 16, and limit wheel 15, determine the top height of the groove of the fixed pulley 17 so that the wire rope 1 can be parallel to the inclined surface of the irregular toe plate 8.

[0044] 1.4) Lowering the sliding mold: See Figure 2 The lifting wire rope is equipped with four hooks and one lifting ring. The lifting ring is hung in the crane hook, and the four hooks are respectively hung on the four lifting lugs 13 of the main sliding form 14. The lifting wire rope is required to have sufficient tensile strength. The crane lifts the irregular rail sliding form of the present invention as a whole and places it at the initial position close to the construction section, so that the six limit wheels 15 are just locked onto the sliding rail 1 6 and the sliding rail 2 16.

[0045] Hooks at the lower ends of the two wire ropes 1 are respectively hooked into the round holes of the two traction lugs 2, and the connection between the crane wire rope and the lifting lug 13 is disconnected; at the same time, the two winches 18 are started, and the speed of the winches 18 is adjusted synchronously and reasonably to ensure that the wire rope drums of the two winches 18 rotate synchronously and slowly, so that the two wire ropes 1 are gradually released synchronously. Under the action of their own weight, the entire irregular-shaped rail sliding formwork of the present invention will slowly slide down within a certain range on the irregular-shaped toe plate 8. When it is transported to the initial position of the predetermined construction, the reducer or brake is opened to achieve accurate and stable stopping; then the safety ropes on the safety mechanism 1 3 and the safety mechanism 2 7 on the sliding formwork are fixed to the toe plate reinforcement.

[0046] 1.5) Erecting the side formwork: Erect the conventional side formwork 23 on the upstream AB, DE, EF and FG surfaces of the irregular toe plate to ensure that the conventional side formwork 23 has an accurate shape, accurate support position and firm support;

[0047] 1.6) Constructing chutes: See Figure 8 Multiple chutes 21 are set up, and feed hoppers 20 are installed at the upper end of the chutes 21. The chutes 21 are used to transport concrete from the horizontal platform to the designated pouring position. The feed hoppers 20 are equipped with windproof and sunshade canvas to reduce the moisture loss of concrete in strong winds and high temperatures, and to ensure the workability of concrete when it is put into the formwork.

[0048] 1.7) Cleaning the pouring surface: Use high-pressure air to remove debris from the pouring location to ensure it is clean, free of debris, water, and scum; after the construction management personnel and supervisors have inspected and approved all preparations, concrete pouring can begin.

[0049] Construction phase:

[0050] Step 1, Concrete Production and Transportation: See Figure 8 The concrete is transported to the feed hopper 20 and then slid down through the chute 21 to the designated pouring position.

[0051] Step 2, Concrete pouring: When pouring concrete into the formwork, spread it evenly and flat within a range of about 30cm in front of the slipform, supplemented by manual spreading.

[0052] Step 3, Concrete Vibration: After the concrete is poured into the formwork, it should be vibrated in a timely manner. The vibrator operator should stand on the operating platform 4 at the front of the slipform. The vibrator should be inserted evenly with a spacing of no more than 40cm. The insertion depth should reach 5cm below the bottom of the newly poured concrete layer. The vibration time should be controlled between 20 and 30 seconds. The concrete should be visually inspected until it no longer sinks significantly, no air bubbles appear, and the surface begins to show cement paste.

[0053] Step 4, Slipforming Lifting: Before slipforming, remove any excess concrete at the front edges of the side slipforms 9 and main slipforms 14 to reduce slipforming resistance. During slipforming, simultaneously start two winches 18 to ensure smooth, uniform, and synchronized lifting of the two steel wire ropes 1, preventing damage to the already poured slab. Slipform once after each layer of concrete is poured, and the slipforming distance must not exceed the pouring width of the concrete. The side slipforms 9 and main slipforms 14 must be pulled once within 30 minutes to prevent the lower steel slab from sticking to the concrete surface. Strictly control the slipforming speed; too fast a speed can easily cause slipform lifting, poor compaction, and a wavy concrete surface, making finishing difficult. Too slow a speed can easily cause the formwork to stick, leading to concrete cracking.

[0054] Step 5, Concrete Smoothing: During each slipforming process, the concrete surface is smoothed using the side smoothing platform 10 and the main smoothing platform 12, which is called smoothing. After the initial setting of the concrete, a second smoothing and polishing process is performed to ensure that the concrete surface is flat, without cracks, micro-channels, etc.

[0055] Step 6, Concrete Curing: After each layer of plastering is completed, cover the concrete surface with a composite geomembrane and sprinkle water to keep the concrete surface moist.

[0056] This completes one round of concrete pouring; then, through multiple consecutive slipforming operations, the construction of all the irregular toe slabs on site is completed.

[0057] The working principle of this invention, the irregular-shaped guide sliding form, is as follows:

[0058] The stress characteristics of the irregular track-mounted slipform of this invention under the most unfavorable load condition are analyzed. Since the speed change during the slipform's ascent is very small, it can be considered to be a uniform ascent. Therefore, the most unfavorable condition for the slipform is considered to be from the time the slipform is in place until the concrete is poured. When performing the stress calculation analysis, the following loads are mainly considered: the component of the total weight of the irregular track-mounted slipform structure itself, the counterweight, and the construction personnel along the inclined plane under the maximum slope condition; the length of each type of steel is calculated using the design drawings of the irregular track-mounted slipform structure of this invention; the mass is calculated based on the cross-section of each type of steel; the total weight of the slipform structure is obtained as G0 = 80KN; and the construction load of the construction personnel is calculated as 1KN / m. 2 Calculate the sliding friction on the slipform guide rail; the main slipform 14 on the straight end is subject to rolling friction, and the side slipform 9 on the nose section is subject to sliding friction. For ease of calculation, all are simplified to sliding friction calculation; the concrete adhesion force is calculated according to conventional slipform calculation; the safety factor is taken as 1.5 to 2.0. If other unexpected situations are considered, the load-bearing capacity of the wire rope 1 can be appropriately increased. The specific calculation process is as follows:

[0059] a) Calculation of slipform counterweight: According to the "Technical Specification for Slipform Construction of Hydraulic Structures"

[0060] (SL32-2014) 6.4.2, Clause 2: The self-weight and counterweight of the slipform shall not be less than the maximum value of the supporting force exerted on the formwork by the freshly poured concrete, i.e., satisfying the following expression:

[0061]

[0062] In formula (1), G1 is the self-weight of the slipform and the construction load. The size of the operating platform 4 is 12m×1.2m. G1=80+12×1.2×1=94.4KN; G2 is the minimum counterweight of the slipform, in KN. Let be the angle between the slipform slope and the horizontal plane. Based on the upstream slope of the dam being 1:1.6, then we have... Therefore, cos32° = 0.848; P is the upward force exerted by the newly poured concrete on the formwork, in kN, calculated by the following formula:

[0063] P = P n ×L×B, (2)

[0064] In formula (2), L is the transverse length of the contact surface between the slipform and the concrete, which is taken as 12m; B is the longitudinal width of the slipform, and the height of each slip is about 30cm. After the concrete has initially set, it no longer has an upward force. The calculation takes the width of 3 slips, that is, the contact width between the slipform and the flowing concrete is 0.9m; P nThe standard value of the normal force of freshly poured concrete on the formwork is given by Article 77.2.3 of the "Technical Standard for Sliding Formwork Engineering" (GB50113-2019). When the inclination angle of the formwork is less than 45°, the upward force of the freshly poured concrete on the formwork is taken as 3-5 kN / m. 2 The value is taken as 4 kN / m in the calculation. 2 Therefore, P = 4 × 12 × 0.9 = 43.2 kN.

[0065] Therefore, the template's self-weight meets the requirements, and no additional counterweight is needed.

[0066] b) Calculation of total traction force of the sliding mode:

[0067] According to section 7.2.5 of the "Technical Standard for Slipform Engineering GBT50113—2019", the formula for calculating the slipform traction force is as follows:

[0068]

[0069] In formula (3), R is the slipform traction force, in kN; F is the bond force between the slipform and the concrete, which is preferably taken as 0.5 kN / m² according to 7.2.3.4 of the "Technical Standard for Slipform Traction Force in Engineering GBT50113—2019"; A is the contact area between the slipform and the concrete, A = 12 × 1.5 = 18 m². 2 G3 is the self-weight of the slipform system, including counterweight and construction load, G3 = 94.4 kN; P c Let f1 be the design value of the normal force of concrete on the formwork, calculated from the above formula as 43.2 kN; f2 be the friction coefficient between the sliding formwork and the concrete, with a value of 0.4-0.5, preferably 0.5; f3 be the friction coefficient between the roller or slider and the track, according to 7.2.3.4 of the "Technical Standard for Traction Force of Sliding Formwork GBT50113—2019", the coefficient for the slider is 0.15-0.5, preferably 0.3; K be the safety factor of traction force, with a value of 1.5-2.0, preferably 1.5; then:

[0070] R = [0.5×18 + 94.4×0.529 + 0.5×(94.4×0.848-43.2) + 0.3×94.4×0.848]×1.5 = 152.07KN. The traction force of the secondary finishing trolley is calculated as follows:

[0071]

[0072] In equation (4), T is the traction force of the secondary finishing trolley, in kN; G4 is the self-weight of the secondary finishing trolley system (including counterweight and construction load), calculated according to the design drawings as G4 = 40 kN; μ is the friction coefficient between the steel wheel and the concrete surface, with a preferred value of 0.15, then:

[0073] T=(40×0.529+0.15×40×0.848)=26.25KN.

[0074] According to Article 2.1.1 of the "Technical Specification for Combined Steel Formwork" GBJ214-89, the allowable stress for the design of combined steel formwork should be calculated by multiplying the allowable stress of the current national standard by an improvement factor of 1.25. Therefore:

[0075] R 总 = (152.07 + 26.25) × 1.25 = 222.9 KN. Therefore, the total traction force required for the slipform is 222.9 KN. Two 15-ton slow-speed winches 18 can meet the requirements.

[0076] c) Safety calculations for wire rope 1:

[0077] Two winches 18 are configured, requiring a total traction force of 222.9 KN, with each winch requiring a traction force of R1 = 111.45 KN. According to section 7.2.6 of the "Technical Standard for Sliding Formwork Engineering" (GB50113-2019), considering a safety factor of 5, the minimum breaking strength of wire rope 1 must be greater than 5 × 111.45 = 557.25 KN.

[0078] The wire ropes 1 of both winches 18 are made of The wire rope has a nominal tensile strength of 1870 N / mm². 2 In the standard GB8918-2006 "Steel Wire Ropes for Important Purposes", the formula for calculating the minimum breaking force of steel wire ropes is as follows:

[0079] F = K' × D 2 ×R / 1000, (5)

[0080] In formula (5), F is the minimum breaking force of the wire rope, in KN; K' is the minimum breaking force coefficient of the wire rope, with a value of 0.33; D is the nominal diameter of the wire rope, in mm; and R is the nominal tensile strength of the wire rope, with a value of 1870 MPa.

[0081] Calculations show that F = 0.33 × 36 × 36 × 1870 / 1000 = 800 KN > 557.25 KN, therefore wire rope 1 meets the technical requirements.

[0082] d) Calculation of winch stability:

[0083] Stability calculations include overturning resistance calculations and skid resistance stability calculations. According to section 15.1.5 of the "Road and Bridge Construction Calculation Handbook," the overturning resistance calculation for the winch is as follows:

[0084]

[0085] The horizontal anti-slip calculation of the winch is as follows:

[0086]

[0087] In equations (6) and (7), K1 is the overturning safety factor, not less than 1.5; G5 is the weight of the winch, taken as 30KN according to specifications; a is the vertical distance from the winch's center of gravity to the overturning point, taken as 0.75m according to the winch's dimensions; Q1 is the weight of the counterweight, in KN; b is the distance from the counterweight's center of gravity to the overturning point, taken as 3m according to the concrete block and winch dimensions; R1 is the traction force of a single steel wire rope, R1 = 111.45KN; h is the distance from the traction force to the overturning point, taken as 1.1m according to the height of the pulley and the winch drum; e is the horizontal distance from the winch's center of gravity to the overturning point, taken as 0.47m; μ1 is the friction coefficient between the concrete block and the ground, and μ2 is the friction coefficient between the steel plate and the ground, both taken as 0.4; then the calculation yields:

[0088]

[0089] Q1≥[111.45*0.848-(30+111.45*0.529)*0.4] / 0.4=147.32KN, so Q1≥147.32KN.

[0090] The winch counterweight uses 2m×1m×1m precast concrete blocks, i.e., concrete block 19, with a concrete unit weight of 23 kN / m³. 3 Therefore, the weight of a single concrete block 19 is 46KN, so a total of 4 counterweights are needed.

[0091] Example 1

[0092] The irregular-shaped tracked sliding formwork of this invention consists of a side sliding formwork 9 and a main sliding formwork 14. The rear end of the side sliding formwork 9 is connected to a side finishing platform 10. Safety mechanisms 7 and 3 are respectively installed on both sides of the front end face of the main sliding formwork 14. An operating platform 4 is fixedly installed at the front of the main sliding formwork 14, and the operating platform 4 is equipped with an upper protective railing 5. A main finishing platform 12 is fixedly installed at the rear end of the main sliding formwork 14, and the main finishing platform 12 is equipped with a main protective railing 11. The side sliding formwork 9 has a parallelogram frame structure, and the main sliding formwork 14 has a rectangular frame structure. Both the frame structures of the side sliding formwork 9 and the main sliding formwork 14 are welded together using No. 22 channel steel. Steel panels are fixedly connected to the lower surface of both frames. The mating surfaces of the side sliding formwork 9 and the main sliding formwork 14 are each welded with a steel plate with screw holes. The two load-bearing steel plates are connected by two rows of 16 M-type screws each. 16The connection is fixed with bolts, and two anti-slip bolts are installed at the bottom connection apex; the angle between the side sliding mold 9 and the main sliding mold 14 in the top view plane (parallel to the horizontal top surface of the toe plate) is 40°, and the angle of the side sliding mold 9 relative to the main sliding mold 14 in the front view plane is 20°; three welded stiffeners 22 are provided between the three main steel frames of the side sliding mold 9 and the steel plate with bolt holes, and each welded stiffener 22 is formed by butt welding of three small steel plates. The side troweling platform 10 consists of a pair of bent hollow square steel bars. Each bent hollow square steel bar has a bend with an included angle of 148° near its lower end. The upper end of each bent hollow square steel bar is connected to two lifting lugs 1 by bolts whose positions can be finely adjusted. Both lifting lugs 1 are welded to the lower end face of the side sliding mold 9. The main troweling platform 12 consists of seven bent hollow square steel bars and a troweling panel. Each bent hollow square steel bar has the same structure as the side troweling platform 10. Similarly, it is connected to two lifting lugs 2 by bolts whose positions can be finely adjusted. Both lifting lugs 2 are welded to the lower end face of the main sliding mold 14. The troweling panel is made of 8mm thick steel plate and is welded to the bent sections of the seven bent hollow square steel bars.

[0093] The lifting guide mechanism consists of slide rail 16, slide rail 26, and two winches 18 arranged in parallel. Slide rail 16 and slide rail 26 are both hollow square steel, arranged along the longitudinal sides of the irregular toe plate 8, serving as the moving track for the surface sliding mold. Correspondingly, three hollow square steel wheel seats are welded longitudinally to the main frame at both ends of the main sliding mold 14. Each wheel seat has a limiting wheel 15 installed downwards. The three limiting wheels 15 installed on the left end face of the main sliding mold 14 are precisely engaged with slide rail 16, and the right end face of the main sliding mold 14... The three limit wheels 15 installed are just locked onto the slide rail 16; two traction lugs 2 are symmetrically welded on both sides of the front end face of the main sliding mold 14. The lower end of each wire rope 1 is hooked into the circular hole of a traction lug 2, and the upper end of each wire rope 1 is wound around the wire rope drum of a winch 18. A fixed pulley 17 is also provided in the middle section of each wire rope 1; two lifting lugs 13 are welded on the front end face and the rear end face of the main sliding mold 14. The positions of the four lifting lugs 13 are symmetrical about the center of gravity of the main sliding mold 14.

[0094] The total width of the right-side foundation plates 24-29 is 13m, with a slope ratio of 1:1.6 and a horizontal angle of 32 degrees. The outer side of the right-side foundation plates has a reverse slope structure with a slope ratio of 1:2.228 and an inclined length of approximately 2.374m. To ensure that the shape and dimensions of the reverse slope structure are within the design range, the slipform design should select a structural form that can control the position and dimensions of the slipform.

[0095] The main slip form 14 has a transverse length of 10m and a width of 1.5m. The main slip form 14 has a large dimension in the width direction, which can extend the concrete demolding time and better adapt to the characteristics of large temperature difference between day and night and large evaporation, effectively avoiding surface evaporation and shrinkage that can cause cracks.

[0096] Example 2

[0097] The irregular-shaped track sliding formwork of this invention consists of a side sliding formwork 9 and a main sliding formwork 14. The rear end of the side sliding formwork 9 is connected to a side finishing platform 10. The front end face of the main sliding formwork 14 is provided with a second safety mechanism 7 and a first safety mechanism 3, respectively. An operating platform 4 is fixedly installed at the front of the main sliding formwork 14, and the operating platform 4 is equipped with an upper guardrail 5. The rear end of the main sliding formwork 14 is fixedly installed with a main finishing platform 12, and the main finishing platform 12 is equipped with a main guardrail 11. The operating platform 4 consists of a frame welded from hollow square steel and a working platform panel fixed to the upper surface of the frame. The working platform panel is 8mm thick. The main guardrail 11 is welded from a circular steel pipe with a diameter of 50mm. The upper guardrail 5 is also welded from a circular steel pipe with a diameter of 50mm. The first safety mechanism 3 and the second safety mechanism 7 have the same structure, both consisting of a channel steel frame base, a safety rope roller, a locking assembly, and a turntable.

[0098] The lifting guide mechanism consists of slide rail 16, slide rail 26, and two winches 18 arranged in parallel. Slide rail 16 and slide rail 26 are both hollow square steel, arranged along the longitudinal sides of the irregular toe plate 8, serving as the moving track for the surface sliding mold. Correspondingly, three hollow square steel wheel seats are welded longitudinally to the main frame at both ends of the main sliding mold 14. Each wheel seat has a limiting wheel 15 installed downwards. The three limiting wheels 15 installed on the left end face of the main sliding mold 14 are precisely engaged with slide rail 16, and the right end face of the main sliding mold 14... The three limit wheels 15 installed are just locked onto the slide rail 16; two traction lugs 2 are symmetrically welded on both sides of the front end face of the main sliding mold 14. The lower end of each wire rope 1 is hooked into the circular hole of a traction lug 2, and the upper end of each wire rope 1 is wound around the wire rope drum of a winch 18. A fixed pulley 17 is also provided in the middle section of each wire rope 1; two lifting lugs 13 are welded on the front end face and the rear end face of the main sliding mold 14. The positions of the four lifting lugs 13 are symmetrical about the center of gravity of the main sliding mold 14.

[0099] The total width of the right-side foundation plates 24-29 is 13m, with a slope ratio of 1:1.6 and a horizontal angle of 32 degrees. The outer side of the right-side foundation plates has a reverse slope structure with a slope ratio of 1:2.228 and an inclined length of approximately 2.374m. To ensure that the shape and dimensions of the reverse slope structure are within the design range, the slipform design should select a structural form that can control the position and dimensions of the slipform.

[0100] The main slip form 14 has a transverse length of 10m and a width of 1.5m. The main slip form 14 has a large dimension in the width direction, which can extend the concrete demolding time and better adapt to the characteristics of large temperature difference between day and night and large evaporation, effectively avoiding surface evaporation and shrinkage that can cause cracks.

[0101] Example 3

[0102] The irregular-shaped track sliding formwork of this invention consists of a side sliding formwork 9 and a main sliding formwork 14. The rear end of the side sliding formwork 9 is connected to a side finishing platform 10. The front end face of the main sliding formwork 14 is provided with a second safety mechanism 7 and a first safety mechanism 3, respectively. An operating platform 4 is fixedly installed at the front of the main sliding formwork 14, and the operating platform 4 is equipped with an upper guardrail 5. The rear end of the main sliding formwork 14 is fixedly installed with a main finishing platform 12, and the main finishing platform 12 is equipped with a main guardrail 11. The operating platform 4 consists of a frame welded from hollow square steel and a working platform panel fixed to the upper surface of the frame. The working platform panel is 8mm thick. The main guardrail 11 is welded from a circular steel pipe with a diameter of 50mm. The upper guardrail 5 is also welded from a circular steel pipe with a diameter of 50mm. The first safety mechanism 3 and the second safety mechanism 7 have the same structure, both consisting of a channel steel frame base, a safety rope roller, a locking assembly, and a turntable. The side sliding mold 9 has a parallelogram frame structure, while the main sliding mold 14 has a rectangular frame structure. Both the side sliding mold 9 and the main sliding mold 14 are constructed by welding No. 22 channel steel together. Steel panels are fixedly connected to the lower surfaces of both frames. The mating surfaces of the side sliding mold 9 and the main sliding mold 14 are each welded with a steel plate with bolt holes. The two load-bearing steel plates are connected by two rows of 16 M bolts each. 16 The connection is fixed with bolts, and two anti-slip bolts are installed at the bottom connection apex. The angle between the side sliding mold 9 and the main sliding mold 14 in the top view (parallel to the horizontal top surface of the toe plate) is 40°, and the angle of inclination of the side sliding mold 9 relative to the main sliding mold 14 in the front view is 20°. Three welded stiffeners 22 are provided between the three main steel frames of the side sliding mold 9 and the steel plate with bolt holes. Each welded stiffener 22 is formed by butt welding three small steel plates. The side finishing platform 10 is composed of a pair of bent hollow square steels. Each bent hollow square steel has a bend with an angle of 148° near the lower end. The main finishing platform 12 is composed of seven bent hollow square steels and a finishing panel. Each bent hollow square steel has the same structure as the side finishing platform 10. The finishing panel is made of 8mm thick steel plate and welded to the bent sections of the seven bent hollow square steels.

[0103] The total width of the right-side foundation plates 24-29 is 13m, with a slope ratio of 1:1.6 and a horizontal angle of 32 degrees. The outer side of the right-side foundation plates has a reverse slope structure with a slope ratio of 1:2.228 and an inclined length of approximately 2.374m. To ensure that the shape and dimensions of the reverse slope structure are within the design range, the slipform design should select a structural form that can control the position and dimensions of the slipform.

[0104] The main slip form 14 has a transverse length of 10m and a width of 1.5m. The main slip form 14 has a large dimension in the width direction, which can extend the concrete demolding time and better adapt to the characteristics of large temperature difference between day and night and large evaporation, effectively avoiding surface evaporation and shrinkage that can cause cracks.

[0105] Practice has proven that the slipform construction process allows for parallel construction of concrete pouring, rebar tying, and side formwork erection, accelerating the concrete pouring speed on slopes. It enables continuous concrete forming with a smooth surface, improving pouring quality and curing effectiveness. Furthermore, it saves a significant amount of formwork, achieving a high degree of mechanization while conserving manpower and reducing construction costs. In addition, the slipform for irregularly shaped toe slabs on the right bank is lightweight, flexible in hoisting and adjustment, easy to operate, and features reliable safety protection facilities, making it suitable for use in narrow spaces on bank slopes.

Claims

1. A non-circular tracked slipform for the toe slab of a rockfill dam, characterized in that: Including surface slip molding and lifting guide mechanism, The surface sliding mold has the following structure: it includes a side sliding mold (9) and a main sliding mold (14). The rear end of the side sliding mold (9) is connected to a side troweling platform (10). The front end of the main sliding mold (14) is provided with a second safety mechanism (7) and a first safety mechanism (3) respectively. The front part of the main sliding mold (14) is fixedly provided with an operating platform (4). The operating platform (4) is equipped with an upper guardrail (5). The rear end of the main sliding mold (14) is fixedly provided with a main troweling platform (12). The main troweling platform (12) is equipped with a main guardrail (11). The side sliding mold (9) has a parallelogram frame structure, and the main sliding mold (14) has a rectangular frame structure. The lower surfaces of the frame structures of the side sliding mold (9) and the main sliding mold (14) are fixedly connected with steel panels. The angle between the side sliding mold (9) and the main sliding mold (14) in the top view is 40°, and the angle of the side sliding mold (9) relative to the main sliding mold (14) in the front view is 20°. The side troweling platform (10) is composed of a pair of bent hollow square steels. Each bent hollow square steel has a bend with an included angle of 148° near its lower end. The upper end of each bent hollow square steel is connected to two lifting lugs by bolts. Both lifting lugs are welded to the lower end face of the side sliding mold (9). The main troweling platform (12) consists of seven bent hollow square steel bars and a troweling panel. Each bent hollow square steel bar has the same structure as the side troweling platform (10) and is connected to two lifting lugs by bolts. The two lifting lugs are welded to the lower end face of the main sliding mold (14). The lifting guide mechanism consists of slide rail one (6), slide rail two (16), and two winches (18) arranged in parallel.

2. The irregularly shaped tracked slipform for the toe slab of a rockfill dam according to claim 1, characterized in that: The operating platform (4) includes a frame, in which seven vertical hollow square steel bars are welded to the middle of the main sliding mold (14). The top ends of the seven vertical hollow square steel bars are correspondingly overlapped and welded to seven horizontal hollow square steel bars. The front ends of the seven horizontal hollow square steel bars are fixed to the front of the main sliding mold (14). The upper surfaces of the seven horizontal hollow square steel bars are welded together with a work platform panel.

3. The irregularly shaped tracked slipform for the toe slab of a rockfill dam according to claim 1, characterized in that: The side sliding mold (9) and the main sliding mold (14) are each welded with a steel plate with screw holes. The two steel plates with screw holes are fixedly connected by bolts, and two anti-slip bolts are installed at the bottom connection apex.

4. The irregularly shaped tracked slipform for the toe slab of a rockfill dam according to claim 1, characterized in that: The side sliding mold (9) has three main steel frames and three welded stiffeners (22) between the steel plate with screw holes. Each welded stiffener (22) is formed by welding three small steel plates together.

5. The irregularly shaped tracked slipform for the toe slab of a rockfill dam according to claim 1, characterized in that: The slide rail 1 (6) and slide rail 2 (16) are both hollow square steel, arranged along the longitudinal sides of the irregular toe plate (8); the three limiting wheels (15) installed on the left end face of the main slide mold (14) are engaged on the slide rail 1 (6), and the three limiting wheels (15) installed on the right end face of the main slide mold (14) are engaged on the slide rail 2 (16). The six limiting wheels (15) together support the main slide mold (14).

6. The irregularly shaped tracked slipform for the toe slab of a rockfill dam according to claim 5, characterized in that: Two traction lugs (2) are symmetrically welded on the front side of the main sliding mold (14). The lower end of each wire rope (1) is hooked into the circular hole of a traction lug (2). The upper end of each wire rope (1) is wound around the wire rope drum of a winch (18). A fixed pulley (17) is also provided in the middle section of each wire rope (1). Two lifting lugs (13) are welded on the front and rear sides of the main sliding mold (14). The positions of the four lifting lugs (13) are symmetrical about the center of gravity of the main sliding mold (14).

7. A construction method for an irregularly shaped toe plate, characterized in that, Using the irregularly shaped tracked slipform for the toe slab of a rockfill dam as described in any one of claims 1-6, the following steps are performed: Preparation stage: including setting up the winch, erecting two slide rails, installing two fixed pulleys, lowering the slipform, erecting the side formwork, erecting the chute, and cleaning the storage surface; Then the construction phase begins: Step 1: Concrete production and transportation; Step 2: Concrete pouring into the formwork; Step 3: Vibrate the concrete; Step 4: Slipform lifting; Step 5: Concrete finishing; Step 6: Concrete curing. This completes one round of concrete pouring. Then, through multiple consecutive slipforming operations, the construction of all irregular toe slabs on site is completed.

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