A vibration anti-floating structure and application method for the steel reinforcement cage of large-volume shaft segment

Abstract

The present invention provides a vibration anti-floating structure for the steel bar cage of large-volume shaft segment linings. The control end of the anti-floating mechanism abuts against the steel bar cage, and the anchoring steel bars are fixed at the longitudinal main steel bars of the steel bar cage. The present invention also provides an application method for the vibration anti-floating structure of the steel bar cage of large-volume shaft segment linings. The present invention forms a locking of the steel bar cage through the anti-floating mechanism on the outer formwork of the segment mold in cooperation with the anchoring steel bars at the longitudinal main steel bars of the steel bar cage, playing a role of collaborative anti-floating; it can real-time regulate the pressure of the control end of the anti-floating mechanism on the steel bar cage during the concrete pouring process. Through the anchoring force between the anchoring steel bars and the concrete and the pressure exerted by the anti-floating mechanism on the steel bar cage, the buoyancy generated by the concrete pouring of the steel bar cage and the vibration is completely offset, greatly reducing the risk of uneven concrete cover thickness caused by the floating of the steel bar cage and the rework situation caused by the floating problem, and avoiding the waste of steel bars and concrete materials.

Description

Technical Field

[0001] The present invention relates to the technical field of the casting of the steel bar cage for shaft segments, and particularly relates to a vibration anti-floating structure for the steel bar cage of a large-volume shaft segment and an application method thereof. Background Art

[0002] During the construction process of shaft tunneling, the quality of large-volume shaft segments is of crucial importance. During the casting process of large-volume shaft segments, the upward floating of the steel bar cage inside the mold has always been a key issue affecting the quality of the segments. Due to a series of uncertain factors such as the buoyancy, backwash force, vibration force generated during concrete casting, the self-weight of the steel bar cage, and unstable fixation, the steel bar cage will float upward, resulting in the distribution of the steel bar cage inside the segment not meeting the design requirements in the concrete, seriously affecting the mechanical properties such as the strength, crack resistance, and impermeability of the segment, and affecting the construction safety of the shaft and the service life of the segment.

[0003] Currently, the technologies applied to the anti-floating of the steel bar cage mainly include: the method of increasing the counterweight, placing heavy objects on the steel bar cage of the segment to increase the self-weight of the steel bar cage to resist the buoyancy generated during concrete casting. This method is relatively simple to operate, but it is necessary to accurately calculate the weight of the counterweight. Insufficient or excessive counterweight will affect the construction efficiency. Improving the concrete casting process, on the one hand, controlling the concrete casting speed, adopting the method of layered casting, slowly pouring the concrete into the mold to reduce the impact force and buoyancy of the concrete on the steel bar cage. At the same time, according to the fluidity and slump of the concrete, reasonably control the casting speed. On the other hand, optimizing the concrete vibration process, selecting appropriate vibration methods and vibration frequencies to reduce the vibration force on the steel bar cage. Additionally, improving the design of the segment mold, strengthening the steel bar cage fixing device, setting a more firm fixing device for the steel bar cage on the segment mold to effectively limit the displacement of the steel bar cage. Improving the sealing performance of the mold to ensure good sealing of the segment mold and prevent the phenomenon of concrete leakage during the casting process. Currently, in the actual application of these existing measures, there are still problems such as unsatisfactory anti-floating effect or complex construction.

[0004] Therefore, in order to effectively control the upward floating problem of the steel bar cage during casting, a vibration anti-floating structure for the steel bar cage of a large-volume shaft segment and an application method thereof are needed. Summary of the Invention

[0005] To solve the above problems, the present invention aims to propose a vibration anti-floating structure for the steel bar cage of a large-volume shaft segment and an application method thereof, which forms a locking on the steel bar cage through the floating stop mechanism on the outer formwork of the segment mold in cooperation with the anchoring bars at the longitudinal main bars of the steel bar cage, playing a role of collaborative anti-floating.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A vibration anti - floating structure for the steel reinforcement cage of large - volume shaft segment linings, including a floating stop mechanism, anchor reinforcement, and a computer installed on the outer formwork of the segment mold. The control end of the floating stop mechanism abuts against the steel reinforcement cage, and the anchor reinforcement is fixed at the longitudinal main bars of the steel reinforcement cage.

[0008] Further, the floating stop mechanism includes a floating stop box. A driving mechanism is fixedly arranged inside the floating stop box. The driving mechanism is connected with a vertical threaded column. The vertical threaded column is in threaded connection with a lifting control plate. Both sides of the lifting control plate are connected with telescopic pressure rods. A circular channel corresponding to and matching the telescopic pressure rods is arranged below the floating stop box. The telescopic pressure rods are in contact with the steel reinforcement cage through the circular channel.

[0009] Further, a bearing is arranged at the lower part of the vertical threaded column, and a receiving opening corresponding to the bearing is arranged below the floating stop box.

[0010] Further, a linkage mechanism is also connected to the vertical threaded column. A circular cover plate is arranged on the circular channel. When the telescopic pressure rod passes through the circular channel, the linkage mechanism drives the circular cover plate to open. When the telescopic pressure rod withdraws from the circular channel, the linkage mechanism drives the circular cover plate to close.

[0011] Further, the linkage mechanism includes a first gear fixed to the lower part of the vertical threaded column. A second gear and a third gear are respectively meshed on both sides of the first gear. Step shafts are connected above the second gear and the third gear. Steel wire ropes are wound on the surfaces of the step shafts. The steel wire ropes are connected to the circular cover plate on the corresponding side through hooks. The circular cover plate is hinged on the circular channel. Annular hanging rings are also arranged on both sides of the circular cover plate. Hooks are correspondingly installed at the bottom of the floating stop box. A return spring is connected between the annular hanging rings and the hooks.

[0012] Further, the telescopic pressure rod internally is provided with a telescopic arm, a pressure sensor, and a pressure rod. The pressure sensor is connected to the telescopic arm through a bolt. The pressure sensor is connected to the lower pressure rod through welding. The pressure sensor is connected to the computer. A triangular pressure claw corresponding to and mating with the steel reinforcement cage is installed at the bottom of the telescopic pressure rod. Toothed pulleys are arranged at both ends of the lifting control plate. Vertical toothed tracks corresponding to and mating with the toothed pulleys are arranged on both sides of the floating stop box.

[0013] Further, the driving mechanism includes a reversible motor, a universal coupling, and a flange plate. The reversible motor is connected to the computer. There are heat sinks on the outer shell of the reversible motor. Both ends of the universal coupling are respectively hinged to the vertical threaded column and the output shaft of the reversible motor through flange plates.

[0014] Further, the anchoring steel bars are connected to the steel reinforcement cage by welding, and the welding position is on the longitudinal main bars of the steel reinforcement cage near the edge of the segment. Two installation holes are distributed on the outer formwork of the segment mold, and the sizes of the two installation holes match the size below the circular cover plate. The telescopic pressure rod abuts against the steel reinforcement cage through the circular channel and the installation holes.

[0015] To achieve the above object, the present invention also provides an application method for the vibration and anti-floating structure of the large-volume shaft segment steel reinforcement cage, including the following steps:

[0016] Step 1: Fabricate the steel reinforcement cage. After the steel reinforcement cage is fabricated, weld a certain number of anchoring steel bars, and place the steel reinforcement cage into the segment mold.

[0017] Step 2: Install the anti-floating mechanism. Install the anti-floating box on both sides of the outer formwork of the segment mold, align it with the installation holes previously opened on the outer formwork of the segment mold, so that the circular cover plate can cover the installation holes, and connect the reversible motor and the pressure sensor to the computer.

[0018] Step 3: Turn on the reversible motor. The driving mechanism drives to open the circular channel, and the telescopic pressure rod descends to make the triangular pressure claw abut against the steel reinforcement cage, providing pressure for the first pouring of concrete.

[0019] Step 4: Pour concrete for the first time. Slowly pour the concrete onto the segment mold, stop pouring after the concrete reaches below the anchoring steel bars, and then insert a vibrating rod to vibrate the already poured part to make the concrete more dense and uniform.

[0020] Step 5: Pour concrete again. Pour concrete again 2 - 3 hours after the first pouring and vibration are completed. At the same time, observe the reading of the pressure sensor. When the pressure reduction is almost zero, retract the telescopic pressure rod upward, control the computer to turn on the reversible motor, the reversible motor drives the lifting control plate upward, the return spring pulls the circular cover plate downward to cover the installation hole, insert the vibrating rod into the concrete in the mold again for vibration. After vibration, wait for the concrete to start to set. Before the concrete starts to set, open the segment mold and plaster the surface of the concrete to eliminate cracks and unevenness on the surface of the concrete.

[0021] Step 6: Cure and demold the segment. After the segment reaches the demolding strength, use demolding equipment to remove the segment from the mold.

[0022] Further, in Step 1, the anchoring steel bars are welded to the steel reinforcement cage. After pouring concrete, the force exerted by the anchoring steel bars for anti-floating is F 锚 , and the calculation formula for the anti-floating force is as follows:

[0023] Formula (1)

[0024] In formula (1), n is the number of the anchoring steel bars welded to the steel reinforcement cage; l is the anchoring length of the anchoring steel bar, m; A is the cross-sectional area of the anchoring steel bar, m 2 ; f c is the compressive strength of the concrete cylinder, MPa;

[0025] In the said step 4, when pouring the concrete, the steel reinforcement cage will be subject to the vertically upward buoyancy force exerted by the immersed concrete F 1

[0026] Formula (2)

[0027] In formula (2), ρ 液 is the density of the concrete liquid poured into the mold, kg / m 3 ; g is the acceleration due to gravity, which can be taken as 9.8 m / s at this moment 2 ; v 排 is the volume of the steel reinforcement cage immersed in the concrete liquid, m 3 ;

[0028] The steel reinforcement cage will be subject to the upward impact force during the concrete pouring. During the concrete pouring process, the concrete is poured from the bottom upwards. Under the action of stamping, the concrete is continuously backwashed from the bottom to the upper part. During the upward movement of the concrete, an upward extrusion force is exerted on the steel reinforcement cage F 2 , for the mixed fluid, combining the law of conservation of momentum, the maximum impact force on the steel reinforcement cage is:

[0029] Formula (3)

[0030] In formula (3), ρ 砼 is the density of the poured concrete, kg / m 3 ; q v is the pouring speed of the concrete, m 3 / s; D is the outlet pipe diameter of the concrete conduit, m;

[0031] The steel reinforcement cage will be subject to the upward frictional force F 3, the upward frictional force is related to the concrete pouring speed and the pouring height of the concrete. When the pouring speed is slow, the steel reinforcement cage will not be affected by obvious frictional force. When the pouring speed is fast, the flow rate of the concrete will also be relatively fast, generating an upward frictional force on the steel reinforcement cage. When the concrete is poured from a relatively high position and impacts the steel reinforcement cage, an upward frictional force component may be generated instantaneously; the steel reinforcement cage is subjected to an upward frictional force F 3 is:

[0032] Formula (4)

[0033] In Formula (4), f is the lateral pressure of the poured concrete on the steel reinforcement cage, kN; h is the embedment depth of the steel reinforcement cage in the concrete, m; μ is the dynamic friction coefficient; F n is the lateral pressure of the poured concrete on any cross-section of the steel reinforcement cage, kN;

[0034] The above-mentioned Formulas (2), (3), and (4) are the upward buoyant forces received by the steel reinforcement cage during pouring, and the force provided by the floating stop mechanism is F 压 , satisfying: .

[0035] Beneficial effects: The present invention forms a lock on the steel reinforcement cage through the floating stop mechanism on the outer formwork of the segment mold and the anchoring steel bars at the longitudinal main bars of the steel reinforcement cage, playing a collaborative anti-floating role; it can real-time regulate the pressure of the control end of the floating stop mechanism on the steel reinforcement cage during the concrete pouring process. Through the anchoring force between the anchoring steel bars and the concrete and the pressure exerted by the floating stop mechanism on the steel reinforcement cage, the buoyant force generated by the concrete pouring and vibrating of the steel reinforcement cage is completely offset, greatly reducing the risk of uneven concrete cover thickness caused by the upward floating of the steel reinforcement cage and the rework situation caused by the upward floating problem, avoiding the waste of steel bars and concrete materials, and having an important significance in ensuring construction quality, improving construction efficiency, and saving costs in the field of vibration anti-floating of large-volume shaft segment steel reinforcement cages. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 is a schematic structural diagram of the floating stop mechanism on the outer formwork of the segment mold of the vibration anti-floating structure of the large-volume shaft segment steel reinforcement cage described in the embodiment of the present invention;

[0038] Figure 2 Schematic diagram of the anchoring steel bar structure on the steel bar cage of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0039] Figure 3 Schematic diagram of the floating stop mechanism of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the driving mechanism of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0041] Figure 5 Schematic diagram of the structure of the lifting control plate and the vertical threaded column of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0042] Figure 6 Schematic diagram of the linkage mechanism of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0043] Figure 7 Schematic diagram of the cooperation between the toothed pulley and the vertical toothed track of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention;

[0044] Figure 8 Schematic diagram of the structure of the telescopic pressure rod of the large-volume shaft segment steel bar cage vibration anti-floating structure according to the embodiment of the present invention. Detailed implementation manner

[0045] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0046] The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0047] Embodiment 1

[0048] See Figure 1-8 : A large-volume shaft segment steel bar cage vibration anti-floating structure, including a floating stop mechanism 2 and an anchoring steel bar 3 installed on the outer formwork 1 of the segment mold. The control end of the floating stop mechanism 2 abuts against the steel bar cage 4, and the anchoring steel bar 3 is fixed at the longitudinal main bars of the steel bar cage 4.

[0049] In this embodiment, the floating stop mechanism on the outer formwork of the segment mold cooperates with the anchoring steel bars at the longitudinal main bars of the steel reinforcement cage to lock the steel reinforcement cage, playing a role in collaborative anti-floating; it can real-time control the pressure of the control end of the floating stop mechanism on the steel reinforcement cage during the concrete pouring process. Through the anchoring force between the anchoring steel bars and the concrete and the pressure exerted by the floating stop mechanism on the steel reinforcement cage, the buoyancy generated by the pouring and vibration of the steel reinforcement cage in the concrete is completely offset, greatly reducing the risk of uneven concrete cover thickness caused by the upward floating of the steel reinforcement cage, the rework situation caused by the upward floating problem, avoiding the waste of steel bars and concrete materials, and having an important significance in aspects such as ensuring construction quality, improving construction efficiency, and saving costs in the field of vibration anti-floating of large-volume shaft segment steel reinforcement cages.

[0050] In a specific example, the floating stop mechanism 2 includes a floating stop box 201. A driving mechanism 202 is fixedly arranged inside the floating stop box 201. The driving mechanism 202 is connected with a vertical threaded column 203. The vertical threaded column 203 is threadedly connected with a lifting control plate 204. Both sides of the lifting control plate 204 are connected with telescopic pressure rods 205. A circular channel 206 corresponding and matching with the telescopic pressure rods 205 is arranged below the floating stop box 201. The telescopic pressure rods 205 are in contact with the steel reinforcement cage 4 through the circular channel 206.

[0051] In this embodiment, the driving mechanism can drive the vertical threaded column to rotate, thereby driving the lifting control plate to move up and down, and then controlling the telescopic pressure rods on both sides to move up and down. The telescopic pressure rods can be in contact with the steel reinforcement cage through the circular channel to complete the locking of the steel reinforcement cage and prevent the steel reinforcement cage from floating upward.

[0052] In a specific example, a bearing 2031 is arranged at the lower part of the vertical threaded column 203, and a receiving opening corresponding to the bearing 2031 is arranged below the floating stop box 201.

[0053] In this embodiment, the vertical threaded column is balanced and limited in its up and down position through the cooperation of the bearing and the receiving opening below the floating stop box, enabling the vertical threaded column to maintain its original position and rotate freely, thereby realizing the stable lifting of the lifting control plate.

[0054] In a specific example, a linkage mechanism 207 is further connected to the vertical threaded column 203. A circular cover plate 208 is arranged on the circular channel 206. When the telescopic pressure rod 205 passes through the circular channel 206, the linkage mechanism 207 drives the circular cover plate 208 to open. When the telescopic pressure rod 205 withdraws from the circular channel 206, the linkage mechanism 207 drives the circular cover plate 208 to close.

[0055] It should be noted that in this embodiment, the linkage mechanism can drive the circular cover plate to open or close, realizing the automatic linkage with the telescopic pressure rod entering and exiting the circular channel. When the telescopic pressure rod passes through or exits the circular channel, the circular cover plate will form an avoidance and will not collide with the telescopic pressure rod to affect the movement track of the telescopic pressure rod.

[0056] In a specific example, the linkage mechanism 207 includes a first gear 2071 fixed to the lower part of the vertical threaded column 203. A second gear 2072 and a third gear 2073 are respectively meshed on both sides of the first gear 2071. Step shafts 2074 are connected above the second gear 2072 and the third gear 2073. A steel wire rope 2075 is wound around the surface of the step shaft 2074. The steel wire rope 2075 is connected to the circular cover plate 208 on the corresponding side through a hook 2076. The circular cover plate 208 is hinged on the circular channel 206. Annular hanging rings are further provided on both sides of the circular cover plate 208. Hooks are correspondingly installed at the bottom of the floating stop box 201, and a return spring 2077 is connected between the annular hanging ring and the hook.

[0057] In this embodiment, when the vertical threaded column rotates, it can drive the first gear to rotate. The rotation of the first gear drives the second and third gears to rotate, and with the cooperation of the return spring, the steel wire rope on the step shaft is wound and released, controlling the opening and reset closing of the circular cover plate at the end of the steel wire rope, realizing the linkage with the telescopic pressure rod.

[0058] It should be noted that the second and third gears in this embodiment are both rotatably connected to the lower part inside the floating stop box.

[0059] In a specific example, the floating stop mechanism 2 further includes a computer 209. Inside the telescopic pressure rod 205, there are a telescopic arm 2051, a pressure sensor 2052, and a pressure rod 2053. The pressure sensor 2052 is connected to the telescopic arm 2051 by bolts, the pressure sensor 2052 is connected to the lower pressure rod 2053 by welding, the pressure sensor 2052 is connected to the computer 209. A triangular pressure claw 20531 corresponding to and abutting against the steel reinforcement cage 4 is installed at the bottom of the pressure rod 2053. Toothed pulleys 2041 are provided at both ends of the lifting control plate 204. Vertical toothed tracks 2011 corresponding to and cooperating with the toothed pulleys 2041 are provided on both sides of the floating stop box 201.

[0060] The telescopic arm in this embodiment has a certain independent stroke. The computer cooperates with the pressure sensor to control a constant F of the triangular pressure claw 压 , thereby improving the stability of the abutment through the triangular pressure claw. The lifting control plate is driven by the rotation of the vertical threaded column to move the toothed pulley up and down along the toothed slide rail, thereby realizing the stable up and down movement of the lifting control plate.

[0061] In a specific example, the driving mechanism 202 includes a reversible motor 2021, a universal coupling 2022, and a flange 2023; the reversible motor 2021 is connected to the computer 209, and there is a heat sink 20211 on the outer shell of the reversible motor 2021. The two ends of the universal coupling 2022 are respectively hinged to the vertical threaded column 203 and the output shaft of the reversible motor 2021 through the flange 2023.

[0062] The reversible motor of this embodiment is controlled by a computer. The driving mechanism adopts a reversible motor and is hinged to a universal coupling through a flange, making the power output of the driving mechanism more adaptable, providing buffering, shock absorption, and improving the dynamic performance of shaft power transmission.

[0063] In a specific example, the anchoring steel bars 3 are connected to the steel reinforcement cage 4 by welding. The welding position is on the longitudinal main bars of the steel reinforcement cage 4 close to the edge of the segment. There are two mounting holes distributed on the outer formwork 1 of the segment mold. The sizes of the two mounting holes match the size below the circular cover plate 208. The telescopic pressure rod 205 abuts against the steel reinforcement cage 4 through the circular channel 206 and the mounting holes.

[0064] The working principle of the large-volume shaft segment steel reinforcement cage vibration-proof and anti-floating structure of this embodiment is as follows: Install a reversible motor, connect the motor, universal coupling, and vertical threaded column together to form a power device for the floating prevention mechanism; turn on the reversible motor, and the motor provides clockwise power. Drive the vertical threaded column to rotate through the universal coupling. The vertical threaded column drives the first gear to rotate. The first gear drives the second and third gears to rotate, driving the stepped shaft above the two gears to rotate counterclockwise. The steel wire rope is tightened and wound around the stepped shaft, pulling the circular cover plate upward to open the circular channel. Before the cover plate is completely pulled open, the triangular claw cannot contact the upward movement track of the cover plate; at the same time, the rotation of the vertical threaded column drives the lifting control plate to slide downward along the vertical slide rail, driving the triangular claw to pass through the circular channel and the outer arc side formwork mounting hole to abut against the steel reinforcement cage until the rotational speed of the reversible motor decreases, then turn off the reversible motor; when the work of pressing the steel reinforcement cage is completed, turn on the reversible motor again. The motor provides counterclockwise power. First, the triangular claw is subjected to an upward pulling force, releasing the pressing effect on the steel reinforcement cage and rising along the vertical track. During the upward movement, the triangular claw cannot contact the downward movement track of the cover plate. When the circular cover plate moves downward and completely covers the circular channel, the floating prevention device work is completed, and the motor stops running.

[0065] Embodiment 2

[0066] To achieve the above object, this embodiment also provides an application method of a large-volume shaft segment steel reinforcement cage vibration-proof and anti-floating structure, including the following steps:

[0067] Step 1: Fabricate the steel reinforcement cage 4. After the fabrication of the steel reinforcement cage 4 is completed, weld a certain number of anchoring steel bars 3, and place the steel reinforcement cage 4 into the segment mold.

[0068] Step 2: Install the floating stop mechanism 2. Install the floating stop box 201 on both sides of the outer formwork 1 of the segment mold, align it with the installation holes previously opened on the outer formwork 1 of the segment mold, so that the circular cover plate 208 can cover the installation holes, and connect the reversible motor 2021 and the pressure sensor 2052 to the computer 209.

[0069] Step 3: Turn on the reversible motor 2021. The driving mechanism 202 drives to open the circular channel 206, and the telescopic pressure rod 205 descends to make the triangular pressure claw 20531 press against the steel reinforcement cage 4, providing pressure for the first pouring of concrete.

[0070] Step 4: Pour concrete for the first time. Slowly pour the concrete onto the segment mold. Stop pouring after the concrete reaches below the anchoring steel bars 3, and then insert a vibrating rod to vibrate the already poured part to make the concrete more dense and uniform.

[0071] Step 5: Pour concrete again. Pour concrete again 2 - 3 hours after the first pouring and vibration are completed. At the same time, observe the reading of the pressure sensor 2052. When the pressure decreases rapidly to nearly 0, retract the telescopic pressure rod 205 upward, control the computer 209 to turn on the reversible motor 2021. The reversible motor 2021 drives the lifting control plate 204 upward, and the return spring 2077 pulls the circular cover plate 208 downward to cover the installation holes. Insert the vibrating rod into the concrete in the mold again for vibration. After vibration, wait for the concrete to initially set. Before the concrete initially sets, open the segment mold and plaster the surface of the concrete to eliminate cracks and unevenness on the surface of the concrete.

[0072] Step 6: Cure and demold the segment. After the segment reaches the demolding strength, use the demolding equipment to remove the segment from the mold.

[0073] It should be noted that during the demolding process, attention should be paid to avoiding damage to the segment, checking the appearance quality of the segment, and ensuring that there are no defects such as cracks and deformations in the segment due to problems such as the floating of the steel reinforcement cage.

[0074] In a specific example, in the said Step 1, the anchoring steel bars are welded to the steel reinforcement cage. After pouring concrete, the force exerted by the anchoring steel bars to resist floating is F 锚 , and the calculation formula for the anti - floating force is as follows:

[0075] Formula (1)

[0076] In formula (1), n is the number of the anchoring steel bars welded to the steel reinforcement cage; l is the anchoring length of the anchoring steel bars, in m; A is the cross-sectional area of the anchoring steel bars, in m 2 ; f c is the compressive strength of the concrete cylinder, in MPa;

[0077] In step 4, when pouring concrete, the steel reinforcement cage will be subject to a vertically upward buoyancy force F exerted by the immersed concrete 1

[0078] Formula (2)

[0079] In formula (2), ρ 液 is the density of the concrete liquid poured into the mold, in kg / m 3 ; g is the acceleration due to gravity, which can be taken as 9.8 m / s 2 ; v 排 is the volume of the steel reinforcement cage immersed in the concrete liquid, in m 3 ;

[0080] The steel reinforcement cage will be subject to an upward impact force during concrete pouring. During the process of concrete pouring, the concrete is poured from the bottom upwards. Under the action of ramming, the concrete is continuously backwashed from the bottom to the upper part

[0081] During the upward movement of the concrete, an upward extrusion force F is exerted on the steel reinforcement cage 2 . For the mixed fluid, combining with the law of conservation of momentum, the maximum impact force on the steel reinforcement cage is:

[0082] Formula (3)

[0083] In formula (3), ρ 砼 is the density of the poured concrete, in kg / m 3 ; q v is the pouring speed of the concrete, in m 3 / s; D is the diameter of the outlet of the concrete conduit, in m;

[0084] The steel reinforcement cage will be subject to an upward frictional force F 3 . The upward frictional force is related to the pouring speed of the concrete and the pouring height of the concrete. When the pouring speed is slow, the steel reinforcement cage will not be subject to an obvious frictional force. When the pouring speed is fast, the flow speed of the concrete will also be relatively fast, which will generate an upward frictional force on the steel reinforcement cage; when the concrete is poured from a relatively high position and impacts the steel reinforcement cage, there may be an upward frictional force component generated instantaneously; the upward frictional force F 3 received by the steel reinforcement cage is:

[0085] Formula (4)

[0086] In formula (4), f is the lateral pressure of the concrete pouring on the steel reinforcement cage, in kN; h is the buried depth of the steel reinforcement cage in the concrete, in m; μ is the dynamic friction coefficient; F n is the lateral pressure of the concrete pouring on any cross-section of the steel reinforcement cage, in kN;

[0087] The above formulas (2), (3), and (4) are the buoyancy forces acting on the steel reinforcement cage during pouring, and the force provided by the floating stop mechanism is F 压 , satisfying: .

[0088] The anti-buoyancy formula of this embodiment plays a key theoretical support and quantitative design role in this embodiment, specifically reflected in the following aspects:

[0089] 1. Quantify the dynamic balance of anti-buoyancy and buoyancy

[0090] Anchoring force calculation (formula 1): Through the number, length of the anchoring steel bars and the concrete strength, accurately calculate the anti-buoyancy force F provided by the anchoring system 锚 , ensuring that the anchoring design meets the minimum resistance requirements and avoiding the deficiencies of empirical design.

[0091] Buoyancy decomposition (formulas 2 - 4): Decompose the buoyancy force of the steel reinforcement cage into buoyancy F 1 , impact force F 2 and frictional force F 3 , comprehensively covering the influence of the concrete fluid behavior, impact momentum and frictional effect during the pouring process, providing a theoretical basis for dynamic control.

[0092] 2. Guide the precise regulation of the floating stop device

[0093] Determine the pressure threshold: Through the formula , clarify the real-time F that the floating stop device needs to provide 压 , ensuring the stability of the steel reinforcement cage during vibration; The monitoring data of the pressure sensor is linked with the calculation result of the formula to trigger the lifting of the telescopic pressure rod to achieve automatic anti-buoyancy.

[0094] 3. Optimize construction parameters and material usage

[0095] Dynamically adjust the pouring strategy: The parameters in the formula (such as pouring speed q v , catheter diameter D) are directly related to the construction operation, guiding the engineer to adjust the pouring speed or catheter size to avoid a sharp increase in the impact force caused by too fast pouring.

[0096] Economical design of materials: By calculating the number n and cross-sectional area A of the anchoring steel bars, avoid over-design, save material costs, and ensure structural safety at the same time.

[0097] 4. Improve the quality and process reliability of segment

[0098] Prevent quality defects: By precisely controlling the upward buoyancy, reduce the risk of steel cage displacement, prevent cracks or deformation after segment demolding, and ensure the appearance and structural integrity.

[0099] Optimize the vibration process: Combining the calculation results of the formula, carry out staged pouring and vibration (such as pouring again 2 - 3 hours after the initial vibration), avoid sudden changes in buoyancy caused by changes in concrete fluidity, and improve the density.

[0100] 5. Innovate in theoretical support technology

[0101] Momentum - friction coupling model: Formulas 3 and 4 combine fluid mechanics and friction theory, innovatively incorporate concrete impact and flow friction into the anti - floating analysis, and provide a new method for similar projects.

[0102] Computer - linked control: Formula parameters (such as q v , D) and sensor data are input into the computer to achieve real - time feedback control, reflecting the innovation of intelligent construction.

[0103] 6. Risk avoidance and standardized construction

[0104] Risk early warning: By presetting the formula threshold, if the pressure is monitored to be close to the critical value (F 压 →0) during construction, the system automatically adjusts to avoid human judgment errors.

[0105] Standardization basis: The formula provides a unified calculation standard for similar projects, reduces dependence on experience, and promotes process standardization.

[0106] In the specific implementation, in the large - volume shaft segment steel cage vibration anti - floating structure of this application: F 压 is the key force provided by the floating prevention device to resist the upward floating of the steel cage. The F 压 result calculated by the formula directly determines the design parameters and operating status of the floating prevention mechanism. For example, based on the calculated F 压 size, the power of the reversible motor in the driving mechanism can be reasonably selected to ensure that it has sufficient power to drive the telescopic pressure rod, so that the triangular pressure claw provides stable and required pressure. At the same time, the F 压 result also provides a reference for adjusting the relevant parameters of the anchor reinforcement (such as quantity, length, cross - sectional area) to achieve the coordination of the anchoring force of the anchor reinforcement and the F 压 of the floating prevention mechanism, precisely offset the buoyancy, upward impact force, and upward friction force received by the steel cage during concrete pouring and vibration, ensure the stability of the steel cage during pouring, and prevent upward floating.

[0107] Taking a cast-in-place project of segmental lining for a caisson-type shaft as an example, the segmental lining includes a multi-ring structure. Each ring of the segmental lining is composed of 6 identical segmental lining blocks. The central angle of each segmental lining block is α = 60°. The ring width H of the segmental lining block is 1000 - 1500 mm, and no taper is set on the ring surface. The lining ring is assembled with staggered joints, and the staggered joint angle is 20°. The segmental linings are sequentially connected by bolt splicing from bottom to top. In the cast-in-place project of segmental lining for a caisson-type shaft, the following relevant parameters are known:

[0108] Density ρ of the cast-in-place concrete 液 =ρ 砼 = 2400 kg / m 3 ; Pouring speed q of the concrete v = 0.03 m 3 / s; Outlet diameter D of the concrete conduit = 0.25 m; Volume v of the steel reinforcement cage immersed in the concrete liquid 排 = 0.1933 m 3 ; Lateral pressure F of the poured concrete on the steel reinforcement cage n = 25 kN / m 2 ; Embedding depth h of the steel reinforcement cage in the concrete = 0.45 m; Dynamic friction coefficient μ = 0.25; Acceleration due to gravity g = 9.8 m / s 2 .

[0109] Due to the requirements of the steel bar reinforcement ratio of the segment and the layout of the internal test system, no anchoring steel bars are installed. The following formula 2-4 is used to calculate the various forces acting on the steel reinforcement cage:

[0110] Calculating the buoyancy force

[0111] Calculating the upward impact force

[0112] Calculating the upward frictional force F 3

[0113]

[0114] 4) Calculating the force F that the floating stop device needs to provide 压 , because F 压 should satisfy offsetting the upward buoyancy force acting on the steel reinforcement cage, that is , so calculating F 压 = 5223.253 N.

[0115] Therefore, in this embodiment, the force F provided by the floating stop device 压It should be at least 5223.253 N to ensure that the steel reinforcement cage does not float during the concrete pouring process. In actual engineering applications, according to the specific situation of the project (such as the size of the steel reinforcement cage, concrete pouring technology, etc.), calculate F accurately 压 and reasonably design the anti-floating mechanism, such as selecting a reversible motor with an appropriate power, to ensure that the anti-floating mechanism can provide sufficient pressure F 压 to balance the upward buoyancy force on the steel reinforcement cage, thus ensuring the construction quality. Or when carrying out the vibration anti-floating construction of the large-volume shaft segment steel reinforcement cage, based on this application, adopt the displacement control method (i.e., the constant steel reinforcement cage displacement = 0), and measure the actual F through the pressure sensor of the pressure rod 压 for verification and calibration.

[0116] Conclusion:

[0117] The anti-buoyancy formula is not only a theoretical tool but also a bridge connecting design, construction, and control. It ensures the stability of the steel reinforcement cage through quantitative analysis, drives the intelligent response of the anti-floating device, and ultimately realizes the high-quality production of the segment, reflecting the scientificity and practicality of this method in engineering practice. The introduction of such formulas in patent applications significantly improves the rigor and innovation value of the technical solutions.

[0118] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A large-volume vertical shaft segment steel cage vibration anti-floating structure, characterized in that: The invention comprises a floating stop mechanism (2) and anchoring steel bars (3) installed on the outer template (1) of the segment mold, wherein the control end of the floating stop mechanism (2) abuts against the steel cage (4), and the anchoring steel bars (3) are fixed to the longitudinal main bars of the steel cage (4). The floating stop mechanism (2) comprises a floating stop box (201), and a driving mechanism (202) is fixedly arranged inside the floating stop box (201), and the driving mechanism (202) is connected to a vertical threaded column (203), and the vertical threaded column (203) is threadedly connected to a lifting control plate. (204), telescopic pressure rods (205) are connected to both sides of the lifting control plate (204), a circular channel (206) corresponding to the telescopic pressure rod (205) is provided below the floating stop box (201), the telescopic pressure rod (205) is in contact with the steel cage (4) through the circular channel (206), the vertical threaded column (203) is also connected to a linkage mechanism (207), and a circular cover plate (208) is provided on the circular channel (206). When the telescopic pressure rod (205) passes through the circular channel (20 6), the linkage mechanism (207) drives the circular cover plate (208) to open; when the telescopic pressure rod (205) exits the circular channel (206), the linkage mechanism (207) drives the circular cover plate (208) to close; the floating stop mechanism (2) further comprises a computer (209); a telescopic arm (2051), a pressure sensor (2052) and a pressure rod (2053) are provided inside the telescopic pressure rod (205); the pressure sensor (2052) and the telescopic arm (2051) are connected to each other by bolts. The pressure sensor (2052) is connected to the pressure rod (2053) below by welding, the pressure sensor (2052) is connected to the computer (209), the bottom of the pressure rod (2053) is installed with a triangular pressure claw (20531) corresponding to the steel cage (4), the lifting control plate (204) is provided with toothed pulleys (2041) at both ends, and the floating stop box (201) is provided with vertical toothed tracks (2011) corresponding to the toothed pulleys (2041) on both sides.

2. The large-volume vertical shaft segment steel cage vibrating anti-floating structure according to claim 1 is characterized in that: A bearing (2031) is provided at the lower portion of the vertical threaded column (203), and a receiving opening corresponding to the bearing (2031) is provided at the lower portion of the floating stop box (201).

3. The large-volume vertical shaft segment steel cage vibrating anti-floating structure according to claim 2 is characterized in that: The linkage mechanism (207) comprises a first gear (2071) fixed to the lower part of the vertical threaded column (203), the first gear (2071) is meshed with a second gear (2072) and a third gear (2073) on both sides, the second gear (2072) and the third gear (2073) are connected to a stepped shaft (2074) above, a steel wire rope (2075) is wound around the surface of the stepped shaft (2074), the steel wire rope (2075) is connected to the circular cover plate (208) on the corresponding side through a hook (2076), the circular cover plate (208) is hinged on the circular channel (206), and annular hanging rings are also provided on both sides of the circular cover plate (208), a hook is correspondingly installed at the bottom of the floating stop box (201), and a reset spring (2077) is connected between the annular hanging ring and the hook.

4. The large-volume vertical shaft segment steel cage vibrating anti-floating structure according to claim 3 is characterized in that: The driving mechanism (202) comprises a reversible motor (2021), a universal coupling (2022) and a flange (2023); the reversible motor (2021) is connected to the computer (209), a heat sink (20211) is provided on the outer shell of the reversible motor (2021), and two ends of the universal coupling (2022) are respectively hinged to the vertical threaded column (203) and the output shaft of the reversible motor (2021) through the flange (223).

5. The large-volume vertical shaft segment steel cage vibrating anti-floating structure according to claim 4 is characterized in that: The anchoring steel bar (3) is connected to the steel cage (4) by welding, and the welding position is located on the longitudinal main reinforcement of the steel cage (4) close to the edge of the pipe segment. The outer template (1) of the pipe segment mold is provided with two mounting holes, and the sizes of the two mounting holes match the sizes of the bottom of the circular cover plate (208). The telescopic pressure rod (205) is pressed against the steel cage (4) through the circular channel (206) and the mounting hole.

6. An application method of the large-volume vertical shaft segment steel cage vibrating anti-floating structure as claimed in claim 5, characterized in that: The following steps are involved: Step 1, manufacturing a steel cage (4), welding a certain number of anchoring steel bars (3) after the steel cage (4) is manufactured, and placing the steel cage (4) into a segment mold; Step 2, installing the floating stop mechanism (2), installing the floating stop box (201) on both sides of the outer template (1) of the segment mold, aligning with the mounting holes previously opened on the outer template (1) of the segment mold, so that the circular cover plate (208) can cover the mounting holes, and connecting the reversible motor (2021) and the pressure sensor (2052) to the computer (209); Step 3, turning on the reversible motor (221), the driving mechanism (202) drives the circular channel (206) to open, and the telescopic pressure rod (205) lowers the triangular pressure claw (20531) to press against the steel cage (4), thereby providing pressure for the first step of pouring concrete; Step 4: pouring concrete for the first time. Slowly pour concrete on the segment mold. Stop pouring after the concrete is poured under the anchor steel bar (3). Insert a vibrating rod to vibrate the poured part to make the concrete more dense and uniform. Step 5, pouring concrete again. Pour concrete again 2-3 hours after the initial pouring and vibration. Observe the reading of the pressure sensor (2052) at the same time. When the pressure is reduced to almost 0, retract the telescopic pressure rod (205) upward, control the computer (209) to turn on the reversible motor (2021), and the reversible motor (2021) drives the lifting control board (204) upward. The return spring (2077) pulls the circular cover plate (208) downward to cover the installation hole. Insert the vibrating rod into the concrete in the mold again to vibrate. After the vibration is completed, wait for the concrete to initially set. Open the segment mold before the concrete initially sets, and plaster the concrete surface to eliminate cracks and unevenness on the concrete surface. Step 6: Curing and demoulding the segments. When the segments reach demoulding strength, demoulding equipment is used to remove the segments from the mold.

7. The application method of the large-volume vertical shaft segment steel cage vibrating anti-floating structure according to claim 6 is characterized in that: In step 1, the anchor steel bar is welded to the steel cage. After pouring concrete, the anti-floating force of the anchor steel bar is F 锚 , F 锚 The calculation formula is as follows: Formula (1) In formula (1), n The number of anchor steel bars welded to the steel cage; l is the anchorage length of the anchor steel bar, m; A is the cross-sectional area of ​​the anchor steel bar, m 2 ; f c is the compressive strength of the concrete cylinder, MPa; In step 4, when pouring concrete, the steel cage will be subjected to the vertical upward buoyancy of the concrete. F 1 Formula (2) In formula (2), ρ 液 is the density of the concrete liquid poured into the mold, kg / m 3 ; g is the acceleration due to gravity, which can be taken as 9.8m / s at this moment 2 ; v 排 is the volume of the steel cage immersed in the concrete liquid, m 3 ; The steel cage will be subjected to the upward impact force during concrete pouring. During the concrete pouring process, the concrete is poured from the bottom to the top. Under the action of the stamping, the concrete is continuously rebounded from the bottom to the top. During the upward movement of the concrete, the steel cage is subjected to the upward squeezing force. F 2. For the mixed fluid, combined with the law of conservation of momentum, the maximum impact force on the steel cage is: Formula (3) In formula (3), ρ 砼 is the density of poured concrete, kg / m 3 ; q v is the pouring speed of concrete, m 3 / s; D is the concrete conduit outlet diameter, m; The steel cage will be subjected to an upward friction force F 3. The upward friction force is related to the pouring speed and height of concrete. When the pouring speed is slow, the steel cage will not be subject to obvious friction. When the pouring speed is fast, the flow speed of concrete will also be faster, which will produce an upward friction force on the steel cage. When concrete is poured from a higher position and impacts the steel cage, it is possible to generate an upward friction force component in an instant. The steel cage is subject to upward friction force. F 3 is: Formula (4) In formula (4), f is the lateral pressure of the poured concrete on the steel cage, kN; h is the buried depth of the steel cage in the concrete, m; μ is the dynamic friction factor; F n is the lateral pressure of poured concrete on any section of the steel cage, kN; Formulas (2), (3) and (4) are the buoyancy forces on the steel cage during pouring. The force provided by the floating stop mechanism is: F 压 ,satisfy: .

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