I. Overview
The newly opened spillway tunnel of Meishan Reservoir is located in the southwest of the water plant on the left bank of the dam, and a plane gate and an arc working door are set at the entrance section of the dam. Technical parameters of radial gate: orifice size (width× height) 12.0mm×8.0mm, sill elevation10.00mm, radial gate 16.0mm, hub center elevation 122.00mm, and gate. The gate size (width× height)11.917mm×100mm is a super-large steel gate, which requires high quality of gate manufacture and installation.
Installation preparation
1, organize relevant construction technicians to be familiar with the construction drawings, conduct on-the-spot investigation, and formulate feasible installation schemes according to the on-site construction environment.
2. Embedding the rings of lifting arm and hinge seat. When pouring floor concrete, four φ25mm round steel rings (made of q235) are embedded in the appropriate position of the hole floor, with the length of round steel being 2.5m, the length of anchor hooks at both ends of the round steel being 6.25d, and the bifurcation in the hooks being 2.5d, and two 5t cranes are welded and fixed with the main reinforcement of the floor. Two φ25mm round steel rings are embedded in the bottom plates of holes below the two hinged seats, the length of the round steel is 2.5m, the length of the anchor hooks at both ends of the round steel is 6.25d, and the hook crotch is 2.5d. The rings are welded with the main reinforcement on the bottom plate to fix the single-door steering pulley. When pouring corbel concrete, each corbel is embedded with four φ25mm round steel rings for lifting the hinge seat in place; When pouring concrete for the ceiling, two φ60mm round steel rings with the length of 10m are embedded in the ceiling above the joint of two arms and hinges, with the length of anchor hooks at both ends of the round steel being 6.25d and the bifurcation in the hooks being 2.5d. In addition, steel bars are embedded on the top plate of the embedded lifting ring, and the encryption area on both sides of the lifting point is 2×30cm. The main stress bar is changed from φ28 spacing of 200 in the original design to φ200 embedded φ 16mm round steel ring, which is located next to φ60mm round steel ring and used for hoisting the pulley block. Two Φ φ25mm round steel rings are pre-embedded in proper positions on the floor side of the holes below the two hinges, which are used for towing the arm and supporting the hinges; Then, in the direction of the door leaf at the center of the two hinges 1 1m, a φ50mm circular steel ring is embedded in the ceiling above the arm to lift the end of the arm to facilitate the connection between the gate and the arm.
Installation of embedded parts of radial gate
1, the installation conditions of built-in parts have been met in civil engineering, the door slot steel dowel meets the design requirements, the concrete surface of the door slot has been chiseled, and the impurities in the door slot have been cleaned up.
2. The control lines of window sill elevation, door slot centerline and orifice centerline have been provided to the installation unit.
3. Threshold installation: After the door slot is delivered and installed, check whether the steel dowel meets the design and specification requirements. When the requirements are met item by item, the center line of the gate slot and the center line of the gate orifice shall be set out according to the control line provided by the civil engineering, the threshold shall be installed according to the center line of the gate slot and the center line of the orifice, the sill shall be hoisted in place, and the adjusting bolts shall be welded, and the elevation and level shall be roughly calibrated first, and then fine calibrated. After the window sill is installed and adjusted, it shall be welded firmly with φ20mm round steel or steel bar.
4. Hinge seat plate installation: The hinge seat plate installation process is the most important process in the installation of radial gate, and its installation accuracy directly affects the installation quality of hinge seat and hinge arm. During installation, it must be adjusted repeatedly to meet the design and specification requirements. Set up an installation platform under two supports, determine the horizontal position of the seat plate according to the center of sill hole and the mileage of the seat plate, and determine the installation position of the seat plate according to the elevation and horizontal position of the seat plate. After the seat plate is hoisted in place, adjust it, and then reinforce it with ∠60×60×6 angle steel and φ20mm round steel to prevent deformation and movement. Because the seat plate has a certain inclination angle, make a special wedge with an included angle of 3 1.329 1, check whether the installation angle of the seat plate meets the design and specification requirements, and pour the second phase concrete after it is accepted.
5. Installation of water seal seat plate and side rail of radial gate: Find out the hinge center, determine the center of side rail according to the arc radius of 16m, and control the verticality of side rail and side water seal seat plate with hanging ball or instrument to make it meet the specification requirements. Because there are few lap welded round steel in the design, the side rail is easy to deform and move when pouring the second stage concrete. Due to the addition of post-pouring belt, the second-stage concrete is increased from the original design of 40~50cm to 150~ 160cm. In order to prevent the deformation and movement of the side rail, the side rail needs special reinforcement, and 30 m ∠ 60× 60 angle steel is added for reinforcement. After the acceptance, the second phase of concrete pouring will be carried out.
Fourth, the radial gate hoisting
1. Lifting of radial gate: radial gate is manufactured in sections in the factory and assembled into a whole at the construction site. The whole gate is hoisted into the gate slot. The hoisting of the gate is carried out in two steps. Step 1: The crane (in actual hoisting, a 300-ton crane is hired) backs to the hoisting site, turns the radial gate face upwards into a beam, and uses the crane to translate the gate to the vicinity of the lock chamber. In the second part, the crane reverses near the gate chamber and slowly lifts the gate.
Verb (abbreviation of verb) Installation of radial gate
1. Installation of boom: connect the boom and hinge together in the factory, transport it to the construction site, and slowly put the boom on the floor of the hole with a crane. Because the crane can't lift the arm in place, the door arm and hinge seat must be lifted twice in the hole. Before the boom, two 5-ton cranes are hoisted into the hole, and the pulley block is transported to the hole for installation. Pull the hinge seat and the hinge into a straight line, and use two 16# channel steel to support them from the lower parts of the two flanges of the hinge seat and the hinge to ensure that the bottom surface of the hinge seat is vertical to the ground. Drag the boom into the hole with two 5t winches, then slowly lift it, and stop when it approaches the elevation 122m. At this time, the parallelism between the hinge bottom plate and the embedded seat plate can be adjusted by using the starting pulley block and chain at the end of the boom. Build a hinged installation platform, people stand on both sides of the platform, use chain block to pull the bracket to the seat plate, and lift the arm bit by bit so that the screw holes of the bracket are aligned with the bolts on the seat plate. When the bolts on the seat plate pass through the screw holes of the bracket, tighten the four bolts on the four corners with nuts to adjust the bracket. The crosshair on the bracket coincides with the crosshair on the seat plate. Tighten the four bolts until the bracket bottom plate is closely combined with the seat plate. Then tighten all nuts and remove the hanging bolts. Install the other arm in the same way. After the boom is installed, check whether the installation quality of the hinge seat meets the design and specification requirements. After the acceptance, the two arms will be hung at the designated position with pulley block and 10 ton chain.
2. Assemble the radial gate and the support arm: hoist the radial gate with a crane to align the bottom edge of the radial gate with the baseline of the sill, tilt the gate toward the support arm, make the connecting plate on the gate cling to the connecting plate of the support arm, fine-tune the two arms up and down or left and right, align the screw holes of the connecting plate on the main beam with the screw holes of the connecting plate of the support arm, and connect them tightly with bolts. Check whether the installation size of radial gate meets the design and specification requirements.
3. Arc gate welding: formulate gate welding technology to control gate deformation. Weld the weld first, and then weld the weld. After the welding is completed, check whether the geometric dimensions have changed, and carry out visual inspection and internal flaw detection on the weld.
4. Anti-corrosion of the middle weld of the gate panel and its two sides: After the gate weld passes the visual inspection and internal flaw detection, the rust, scale, oil stain, welding slag and other attachments on the weld and its two sides shall be removed, and the weld and its two sides shall be derusted manually. The surface derusting grade is sa2.5. After the manual derusting inspection is qualified, spray zinc. The metal coating should have a uniform appearance, and there should be no inclusions, peeling, holes, unevenness, coarse particles and caking. After the zinc spraying thickness meets the design requirements, apply sealing paint and topcoat, and clean the dust on the coating surface before painting. Painting should be carried out when the coating is still warm.
5. Installation of water seal rubber: jack the gate with two 50t jacks 10cm. Check whether the bottom water seal rubber and pressure plate meet the design requirements. Ensure the rubber preloading of the gate 10mm when drilling rubber holes, and ensure the straightness of the bottom water seal when installing the bottom water seal. After installing the bottom water seal, start to install the side water seal. First, check whether the pressure plate screw hole is consistent with the water seal screw hole on the arc door side. If it is not, correct it. After preloading the side water seal for 3.5 mm, punch a rubber hole. At the top of the door, lift the water seal rubber with an inverted chain and connect the bolts from bottom to top. When tightening the rubber, the force should be even to ensure that the rubber is evenly compressed.
6. Installation of lintel and top water seal: according to the actual position of the gate, put the lintel in place, adjust the installation position of the lintel, and make the installation of the lintel meet the design and specification requirements. After the acceptance, pour the second-stage concrete. After reaching 70% strength, install the top water seal, pre-tighten the top water seal by 4mm, and then install the corner water seal.
7. After the rubber water seal is installed, when the gate is in working condition, the compression of the rubber water seal should conform to the design pattern, and the light transmission should be checked, and there should be no brightness or gap. If the construction conditions permit, do a flushing test to check its water sealing effect.
8. Gate test: After the gate is installed, a full-stroke waterless opening and closing test shall be conducted. Whether the water stop is tight at the lowest position, at the same time, all sundries on the door leaf and in the door slot must be removed, and the connection of the suspender must be checked. When opening and closing, the rubber water seal should be watered and lubricated. When conditions permit, the working gate should be opened and closed by running water. During the opening and closing of the gate, the operation of the rotating part of the hinge should be checked, and there is no jam during the gate rotation. The left and right sides of the opening and closing equipment shall be synchronized, and the rubber water seal shall not be damaged.
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