T-beam pre-tensioning, grouting and end sealing integrated construction method

Abstract

The invention discloses a T-beam pre-tensioning, mud jacking and end sealing integrated construction method which comprises the following steps that a corrugated pipe is pre-arranged in a T-beam, anchorage device bases are fixedly connected to the two ends of the corrugated pipe, the anchorage device bases are embedded into the T-beam to be fixed, a set amount of steel strands penetrate into each hole channel, and the two ends of each steel strand penetrate through the anchorage device bases; pre-stressed anchorage devices are installed at the two ends of the multiple steel strands in each corrugated pipe, two tensioning machines are adopted for conducting symmetrical pre-tensioning on the two ends of the multiple steel strands in each hole channel, the multiple steel strands are stopped after reaching the set prestress and the set tensioning length, and the anchorage devices at the two ends abut against anchorage device bases and are fixed to the anchorage device bases; the anchorage device seat supports the prestressed steel strands, redundant steel strands outside the anchorage device are removed, and steel strand pre-tensioning anchoring of other hole channels is completed; after the steel strand is tensioned and anchored through prestress, the steel strand is placed in the hole channel to complete grouting within 48 hours, and it can be at least guaranteed that the grouting amount in one hole channel is 1.5 times of the volume of the corrugated pipe; and after grouting is completed, anchor sealing is conducted on the two ends of the T-shaped beam through high-strength quick-hardening grouting materials.

Description

Technical Field

[0001] The invention belongs to the technical field of T-beam construction, and relates to a T-beam pre-tensioning, grouting and end-sealing integrated construction method. Background Art

[0002] T-beam prefabrication is primarily divided into reinforcement, formwork, concrete, and prestressed concrete. The traditional method for grouting bridge pipes with anchors is to use a "mushroom-shaped" method to seal and maintain pressure. However, this sealing and pressure-maintaining effect is less than ideal during actual construction, affecting the density of the slurry in the pipes. During the pressure-maintaining phase of the grouting process, the anchor cement seal is damaged, resulting in a loss of pressure. This can lead to incomplete grouting of the prestressed pipes, which can cause bridge defects during subsequent operation. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an integrated construction method for pre-tensioning, grouting and end sealing of T-beams, which can achieve stable pressure maintenance, ensure the density of the slurry in the corrugated pipe, make the prestressed pipe grouting full, and improve the performance of the T-beam.

[0004] The technical solution adopted by the present invention is: a T-beam pre-tensioning, grouting and end-sealing integrated construction method, the method comprising the following steps:

[0005] Step 1: Pre-install an upper corrugated pipe, a middle corrugated pipe, and two lower corrugated pipes in the T-beam to form a channel. Both ends of the upper corrugated pipe, the middle corrugated pipe, and the lower corrugated pipe are fixedly connected with anchor seats. The anchor seats are embedded in the T-beam and remain fixed. A set amount of steel strands are inserted into each channel and both ends pass through the anchor seats;

[0006] Step 2: Prestressed anchors are installed at both ends of the multiple steel strands in each corrugated pipe. Two tensioning machines are used to symmetrically pre-tension the multiple steel strands in each channel. The multiple steel strands are stopped after reaching the set prestress and set tensioning length. The anchors at both ends are pressed against and fixed to the anchor seats. The anchor seats support the prestressed steel strands. The excess steel strands outside the anchors are removed, and the pre-tensioned anchoring of the steel strands in the remaining channels is completed.

[0007] Step 3, grouting of the channel: After the prestressed anchorage of the steel strand, the grouting of the channel where the steel strand is placed should be completed within 48 hours. During the grouting process, the grouting ports set at the anchor seats at the ends of the four channels at one end of the T-beam are connected to the grouting machine, and the grouting ports at both ends of the other channels are connected in series, and finally return to the grouting machine to form a circulating grouting. A grouting cover is fixedly and sealed at the end of the anchor to ensure that the grouting volume in one channel is at least 1.5 times the volume of the corrugated pipe;

[0008] Step 4: After grouting is completed, high-strength fast-hardening grouting material is used to seal the two ends of the T-beam.

[0009] Furthermore, in the above step five, multiple anchor sealing templates are used to seal the anchor at each end. The anchor sealing template includes a steel plate and a screw. The steel plate covers the groove at the entire anchor. Two screws are used. The inner ends are symmetrically fixed in the threaded holes of the anchor seat, and the outer ends are locked with nuts after passing through the steel plate. A slurry inlet is provided on the top of the steel plate. The slurry inlet includes a cavity structure with a top opening surrounded by an inclined plate and two triangular plates. The cavity structure is opposite to the notch of the steel plate, and the upper end of the cavity structure is flush with the upper end of the steel plate.

[0010] Furthermore, after installing the anchor template in the above step five, high-strength fast-hardening grouting material is used for grouting and sealing. After the grout solidifies to the set time, the mold is removed, the anchor template is disassembled, the exposed length of the screw is removed, and the end surface is polished and leveled. After leveling, it is roughened and a layer of cement slurry is applied.

[0011] Furthermore, the above-mentioned grouting is carried out using T-beam end face processing lifting and pouring equipment. The T-beam end face processing lifting and pouring equipment includes a grouting head, a grouting pump, a telescopic cylinder, a pitching arm, a lifting arm and an electric turntable. The grouting head is connected to the grouting pump through a grouting pipe. The grouting head is fixedly connected to the cylinder rod end of the telescopic cylinder. The cylinder seat of the telescopic cylinder is fixedly connected to the pitching arm. The pitching arm is fixedly connected to the upper end of the lifting arm. The lower end of the lifting arm is fixedly connected to the electric turntable. The electric turntable is fixedly connected to the traveling trolley. The grouting pump is fixedly connected to the traveling trolley. A slurry storage tank is installed on the traveling trolley, and a stirring device is provided on the slurry storage tank.

[0012] Furthermore, a flexible anti-slurry plate is provided at one end of the cylinder rod of the grouting head close to the telescopic cylinder, and the anti-slurry plate can shield the grouting head after it is extended into the slurry inlet.

[0013] Furthermore, the above-mentioned pitch arm includes a pitch connector, a U-shaped slot plate and a pitch motor that drives the pitch connector to rotate. The pitch connector is rotatably connected to the pitch seat through a pitch rotation axis. The pitch seat is fixedly connected to the upper end of the lifting arm. The pitch motor is installed on the pitch seat and connected to the pitch rotation axis. The U-shaped slot plate is fixedly connected to the pitch connector at a distance away from the pitch axis. The U-shaped slot plate is provided with a strip-shaped through hole that is fixedly connected to the cylinder seat of the telescopic cylinder.

[0014] Furthermore, the above-mentioned lifting arm includes a lifting plate, two guide rods and an electric push rod. The lifting plate is used to connect the pitch arm, and is telescopically connected to two guide rods at both ends. The lower ends of the two guide rods are fixedly connected to the fixed seat, and the fixed seat is fixedly connected to the electric turntable. The rod end of the electric push rod is fixedly connected to the middle part of the bottom side of the lifting plate, and the body of the electric push rod is fixedly connected to the fixed seat.

[0015] Furthermore, the operation method of the tensioning machine in the above step 2 is as follows: the tensioning order of the positive bending moment steel strands of the main beam is N2→N3→N4→N1; the tensioning order of the negative bending moment steel strands of the pier top is: T1 steel strand from inside to outside; the anchor adopts a clip-type anchor, and its tensioning procedure is 0→initial stress 10%σcon→initial stress 20%σcon→σcon, σcon holding load for 5 minutes; the tensioning rate is controlled at 10-25% / min of the tensioning control force, and the stable pressure holding time after reaching the control stress is not less than 5 minutes; when the jacks used in the tensioning machine are tensioned, the allowable error of the synchronous tensioning force between the left and right jacks and the two ends is controlled within ±2%; when tensioning to the control stress, the accuracy of the tensioning control stress is controlled within ±1.5%; prestressing When the force is tensioned to the design value, the error between the actual elongation and the theoretical elongation is controlled within ±6%; after tensioning is completed and the jack and tool anchor are removed, check whether the notches of each steel strand at the tool anchor are flush. If not, it means there is a slippage phenomenon, and the slippage should be supplemented to reach the control stress; the total number of broken and slipped wires in the entire beam shall not exceed 1.0% of the total number of steel wires in the section, and there shall not be more than 1 broken wire in a bundle, and they shall not be on the same side; if the entire bundle or a large number of wires are slipped and broken, the anchor head shall be removed, and the steel bundle shall be replaced after inspection and re-tensioning; the prestressed tendons shall be anchored after the tensioning control stress reaches stability; for clip-type anchors, the top surfaces of the clips shall be flush after anchoring, the mutual misalignment shall not be greater than 2mm, and the height exposed outside the anchor shall not be greater than 4mm.

[0016] Furthermore, the above-mentioned duct grouting method steps are as follows:

[0017] 1) Anchorage sealing

[0018] Make a grouting cover according to the anchor model, and install the grouting cover and seal the anchor after the steel strand is cut;

[0019] 2) Slurry mixing

[0020] (1) Grouting equipment performance requirements

[0021] ① The grouting machine adopts the LJ-YJB1 circulating grouting system, which includes a high-speed grouting system, a grouting system, a control system and an automatic data acquisition system. The equipment should be able to automatically monitor and record the grouting process water-binder ratio, grouting pressure, stable pressure, stable time and grouting flow rate.

[0022] ② The speed of the mixer should not be less than 1000r / min, the shape of the stirring blade should match the speed, the linear speed of the blade should not be less than 10m / s and not more than 20m / s, and the mixing should be uniform within the specified time;

[0023] ③ The storage tank for temporary storage of slurry should have a stirring function, and the stirring speed should not exceed 500r / min; and a filter with a mesh size of no more than 3mm should be installed at the outlet of the storage tank;

[0024] ④ The volume of the mixer and slurry storage tank must be larger than the volume of the pipe bundle to be grouting. It is prohibited to add materials, stir and slurry at the same time;

[0025] ⑤ The grouting machine shall use a grouting pump that can operate continuously and can work at a constant pressure of more than 0.7 MPa. The minimum scale value of the pressure gauge shall not be greater than 0.1 MPa, and the maximum range shall ensure that the actual working pressure is within the range of 25% to 75% of its range. Air pressure grouting pumps shall not be used for grouting.

[0026] ⑥ In the event of an abnormality, the grouting machine has an automatic alarm function;

[0027] ⑦ The data protection function can effectively prevent construction personnel from modifying operating procedures or collected data. In the event of communication or equipment failure, emergency measures can be automatically taken to ensure data storage security.

[0028] ⑧ The water-cement ratio sensor, pressure sensor and flow sensor of the grouting machine should be verified or calibrated together with the high-speed grouting system, grouting system and control system as a whole. The verification or calibration cycle is 6 months;

[0029] (2) The performance indexes of post-tensioned prestressed duct grouting slurry are shown in the following table:

[0030]

[0031] (3) Slurry configuration

[0032] The grouting mix ratio is determined based on the laboratory test results. The materials used for grouting are weighed using automatic metering, with a metering error of less than ±1%. The design strength of the cement slurry is 50 MPa, and the slurry is prepared using Portland cement with a strength grade of 42.5 MPa.

[0033] Turn on the grouting trolley, first add 80% of the mixing water into the high-speed mixing barrel with a speed of 1000r / min, evenly add all the grouting agent, stir while adding, then evenly add all the cement, stir for 2 minutes after all the powder is added; then add the remaining 20% ​​of the mixing water and continue stirring for 2 minutes; then pass the filter composed of a filter mesh with a mesh size of no more than 3×3mm set at the outlet of the high-speed mixing barrel into the storage tank and stir continuously, test the fluidity of the slurry for 10 to 17 seconds, and press it into the channel only after passing the test, and make 3 groups of test pieces. The time interval between the end of cement slurry mixing and pressing into the pipeline shall not exceed 40 minutes; the grouting pressure is 0.5 to 0.7Mpa; the filling degree of the grouting should be until the other end of the channel is full and the exhaust hole discharges cement slurry with the same fluidity as the specified fluidity; after closing the slurry outlet, it is advisable to maintain a stable pressure period of not less than 0.5MPa, and the maintenance time of the stable pressure period should be 3 to 5 minutes;

[0034] 3) Intelligent grouting

[0035] The LJ-YJB1 circulating grouting system includes a system host, a measurement and control system, and a circulating grouting system. The slurry circulates continuously in a loop composed of prestressed pipes, a slurry making machine, and a grouting pump to exhaust the air in the pipe, promptly detect pipe blockage, and perform punching by increasing the pressure to discharge impurities and eliminate factors that lead to loose grouting. Precision pressure sensors are installed at the inlet and outlet of the pipe to monitor the pressure in real time, and provide real-time feedback to the system host for analysis and judgment. The measurement and control system adjusts the pressure according to the host's instructions to ensure that the prestressed pipe completes the grouting process under the constraints of the important indicators of slurry quality, pressure, and pressure stabilization time required by the construction technical specifications, ensuring that the grouting is full and dense. The system host judges the fullness of the pipe based on whether the pressure difference between the inlet and outlet remains constant within a certain period of time.

[0036] Furthermore, the hole is flushed before the above grouting, and the accumulated water in the hole is blown out with oil-free compressed air after flushing; the grouting is carried out slowly and evenly without interruption, and all the exhaust holes at the highest points are opened and closed one by one in sequence to ensure smooth exhaust in the hole, and the grouting of the same pipeline is carried out continuously and completed in one go; the prepared slurry is lower than 25°C, and cooling measures must be adopted during construction in high temperature seasons, or construction must be carried out in the morning or evening. The duration from the mixing of cement slurry to the injection into the hole shall not exceed 40 minutes, and the cement slurry shall remain in a fluid state before use and during the injection process. Cement slurry with reduced fluidity due to delayed use shall be used. , its fluidity shall not be increased by adding additional water; strengthen the cleaning and maintenance of grouting equipment, and there shall be no residue and water accumulation in the equipment after cleaning; during grouting operation, construction workers shall wear safety protection equipment correctly, grouting operators must wear protective glasses, and operators who transport cement and grouting agents shall wear protective masks; when grouting, each work team shall prepare and retain no less than 3 groups of test pieces with a size of 40mm×40mm×160mm, standard curing for 28d, and carry out compressive strength and flexural strength tests as the basis for quality assessment; after grouting, the grouting strength must reach 85% of the design strength when moving precast concrete components.

[0037] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention forms a circulating grouting process in the multiple corrugated pipes in the T-beam, and a sealed and fixed grouting cover is arranged at the anchor to ensure that the entire grouting is carried out stably, avoiding the problems of poor grouting quality and unstable grouting pressure caused by leakage, and the amount of slurry pressed in is 1.5 times the volume of the corrugated pipe, which can ensure sufficient grouting, make the slurry denser after solidification, and make the pipeline grouting fuller. The use of high-strength and fast-hardening grouting materials can achieve rapid solidification, and the entire process greatly improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of grouting end sealing structure;

[0039] Figure 2 This is a schematic diagram of installing the template at the left end of the T-beam;

[0040] Figure 3 It is a schematic diagram of the structure of the left end of the T beam;

[0041] Figure 4 for Figure 1 A schematic diagram of the enlarged structure of the middle part A;

[0042] Figure 5 This is a schematic diagram of the grouting equipment structure;

[0043] Figure 6 Schematic diagram of the pitch arm structure;

[0044] Figure 7 Schematic diagram of the mixing equipment structure;

[0045] Figure 8 This is a schematic diagram of the T-beam grouting equipment structure;

[0046] Figure 9 This is a schematic diagram of the layout of the connecting pipes at the left end of the T-beam;

[0047] Figure 10 This is a schematic diagram of the grouting equipment structure connected to the right end of the T-beam;

[0048] Figure 11 for Figure 8 The enlarged structural diagram at B in the middle;

[0049] Figure 12 This is a schematic diagram of the installation structure of the grouting cover from the left side. DETAILED DESCRIPTION

[0050] The invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1: Figures 1 to 12 As shown, a T-beam pre-tensioning, grouting and end-sealing integrated construction method comprises the following steps:

[0052] Step 1: An upper corrugated pipe 200, a middle corrugated pipe 300, and two lower corrugated pipes 400 are pre-installed in the T-beam 100 to form a channel. Both ends of the upper corrugated pipe 200, the middle corrugated pipe 300, and the two lower corrugated pipes 400 are fixedly connected with anchor seats 104. The anchor seats 104 are embedded in the T-beam 100 and remain fixed. A set amount of steel strands 500 are inserted into each channel and both ends pass through the anchor seats 104. The T-beam 100 is placed on a support stand 600.

[0053] Step 2: Prestressed anchors 106 are installed at both ends of the multiple steel strands 500 in each corrugated pipe. Two tensioning machines are used to symmetrically pre-tension the multiple steel strands 500 in each channel. The multiple steel strands are stopped after reaching the set prestress and set tensioning length. The anchors at both ends are pressed against and fixed to the anchor seats. The anchor seats support the prestressed steel strands. The excess steel strands outside the anchors are removed, and the pre-tensioned anchoring of the steel strands in the remaining channels is completed.

[0054] Step 3, grouting of the channel: After the prestressed anchorage of the steel strand, the grouting of the channel where the steel strand is placed should be completed within 48 hours. During the grouting process, the grouting ports set at the anchor seats at the ends of the four channels at one end of the T-beam are connected to the grouting machine, and the grouting ports at both ends of the other channels are connected in series, and finally return to the grouting machine to form a circulating grouting. A grouting cover is fixedly and sealed at the end of the anchor to ensure that the grouting volume in one channel is at least 1.5 times the volume of the corrugated pipe;

[0055] Step 4: After grouting is completed, high-strength fast-hardening grouting material is used to seal the two ends of the T-beam.

[0056] Furthermore, in the above step five, multiple anchor sealing templates are used to seal the anchors at each end of the T-beam. The multiple anchor sealing templates include an upper template, a middle template and a lower template. The upper template is the same as the middle template, and the lower template covers the grooves of the two anchors. The specific structure includes a steel plate 101 and a screw 102. The steel plate 101 covers the groove 103 at the entire anchor 106. Two screws 102 are used, and the inner ends are symmetrically fixedly connected to the threaded holes of the anchor seat 104. The outer ends pass through the steel plate 101 and are locked with nuts 107. A slurry inlet 105 is provided at the top of the steel plate 101. The slurry inlet 105 includes a cavity structure with a top opening surrounded by an inclined plate and two triangular plates. The cavity structure is opposite to the notch of the steel plate 101, and the upper end of the cavity structure is flush with the upper end of the steel plate 101. , fits into the groove of the anchor to form a casting cavity structure, which is convenient for casting, and uses the existing threaded holes to install screws to lock the template. The installation is convenient and quick, the connection is stable and reliable, and the template is simple to remove after casting. A triangular slurry inlet is set to facilitate the addition of high-strength and fast-hardening grouting materials into the casting cavity. The entire end face only requires three templates to complete the casting. The independent module also reduces the serious local leakage caused by the uneven end face. It also includes a collection tray 108 placed on the ground. The collection tray 108 is opposite to the sealing anchor template installed at the end of the T-beam, and can collect the slurry leaked from the sealing anchor template. Handrails are set at both ends of the collection tray for easy movement. Universal rollers with brake mechanisms are set at the bottom of the collection tray for easy movement, saving time and effort. It has a brake function and is also easy to position.

[0057] Furthermore, after installing the anchor template in the above step five, high-strength fast-hardening grouting material is used for grouting and sealing. After the grouting solidifies to the set time, the formwork is removed, the anchor template is disassembled, the exposed length of the screw is removed, and the end surface is polished and leveled. After leveling, it is roughened and a layer of cement slurry is applied to smooth the end surface. The screw is reserved inside, which can improve the supporting stability and reliability of the high-strength fast-hardening grouting material filled in the groove, and has better bite ability with the end of the T-beam.

[0058] During grouting, conventional practice is to manually carry out grouting by carrying a slurry bucket. However, when grouting the end of the T-beam, the T-beam is placed on a support frame, and the groove thereon is relatively high. Even the most vulnerable person needs to set up a platform or ladder to carry out grouting, which is time-consuming and labor-intensive, and has poor operational safety. To address this problem, the present application provides a lifting and pouring device for grouting. During grouting, a lifting and pouring device for treating the end face of the T-beam 200 is used for grouting. The lifting and pouring device for treating the end face of the T-beam 200 includes a grouting head 201, a grouting pump 202, a telescopic cylinder 203, a pitching arm 204, a lifting arm 205, and an electric turntable 206. 6. The grouting head 201 is connected to the grouting pump 202 through the grouting pipe 207. The grouting head 201 is fixedly connected to the cylinder rod end of the telescopic cylinder 203. The cylinder seat of the telescopic cylinder 203 is fixedly connected to the pitching arm 204. The pitching arm 204 is fixedly connected to the upper end of the lifting arm 205. The lower end of the lifting arm 205 is fixedly connected to the electric turntable 206. The electric turntable 206 is fixedly connected to the traveling trolley 208. The grouting pump 202 is fixedly connected to the traveling trolley 208. A slurry storage tank 209 is installed on the traveling trolley 208. The slurry storage tank 209 is provided with a stirring device 210. When in use, put the grouting material into the slurry storage tank and stir it. After stirring for the set time, control the walking trolley to the center position of the front side of the T-beam end, control the lifting arm to the set height according to the position of the groove, and then control the pitching arm to rotate downward to the set angle, control the walking trolley to approach the T-beam end, control the telescopic cylinder to extend, so that the grouting head extends into the grouting inlet, and start the grouting pump for grouting. During the grouting process, control the electric turntable to rotate within a small angle range, and ensure that the grouting head can swing freely in the grouting inlet. Through swinging, the grouting material can be more stably filled in the casting cavity, thereby improving the pouring rate of the grouting material. The performance stability and uniformity of the structure after solidification are improved. The grooves are grouted from bottom to top during the grouting process. After the grouting is completed, the walking trolley is controlled to enter the next T-beam end for grouting. The use of lifting casting equipment can realize the rapid grouting of a single end of the T-beam, improve the grouting efficiency, reduce labor intensity, and make the operation safer. The lifting, pitching and telescopic control can realize the precise docking of the grouting head. The installation of a visual recognition module makes it easier to automatically identify the slurry inlet according to the height, and then control the walking trolley, lifting arm, pitching arm and telescopic cylinder to perform corresponding actions, greatly improving the level of automation.

[0059] The telescopic cylinder 203 adopts a double-rod cylinder, and a mounting plate 221 is provided at the end of the double-rod to facilitate the installation of the grouting head. The double-rod cylinder is telescopic, and the telescopic effect is stable and reliable. It can resist the jet impact force of the grouting head under the pressure of the grouting pump, and the grouting is more stable.

[0060] The grouting head 201 is a hard plastic tube with a flat structure at the front end and a connecting plate 222 at the tail end. The connecting plate 222 is fixedly connected to the mounting plate 221. The grouting head 201 is connected to the grouting pipe 207 near the tail end. The flat head structure facilitates stable delivery into the casting cavity.

[0061] In order to prevent the slurry in the casting cavity from splashing onto the telescopic cylinder and other components during the grouting process, a splash-proof barrier is provided. That is, a flexible slurry-proof plate 211 is provided at one end of the cylinder rod of the grouting head 201 close to the telescopic cylinder 203. The slurry-proof plate 211 can block the grouting head 201 after it is inserted into the slurry inlet 105. By blocking the slurry splashing out of the slurry inlet, it can prevent it from flying onto the telescopic cylinder and other components, thereby affecting their service life.

[0062] To facilitate the installation of the telescopic cylinder, the pitch arm 204 includes a pitch connector 212, a U-shaped groove plate 213 and a pitch motor 215 that drives the pitch connector 212 to rotate. The pitch connector 212 is rotatably connected to the pitch seat 214 through the pitch rotation axis. The pitch seat 214 is fixedly connected to the upper end of the lifting arm 205. The pitch motor is mounted on the pitch seat 214 and connected to the pitch rotation axis. The U-shaped groove plate 213 is fixedly connected to the pitch connector 212 at a distance away from the pitch axis. The U-shaped groove plate 213 is provided with a strip-shaped through hole 216 that is fixedly connected to the cylinder seat of the telescopic cylinder 203. The structure provided by the U-shaped groove plate is convenient and quick to install the telescopic cylinder, and the strip through hole structure is also convenient for adjusting the position, and has a wider range of applications. The casing of the pitch motor is fixedly connected to one side of the pitch seat of the binaural structure, driving the pitch rotation axis to rotate, and then driving the pitch arm to pitch, thereby achieving the required angle control.

[0063] In order to stably lift and support the grouting head, telescopic cylinder and pitch arm, the lifting arm 205 includes a lifting plate 217, two guide rods 218 and an electric push rod 219. The lifting plate 217 is used to connect the pitch arm 204, and is telescopically connected with two guide rods 218 at both ends. The lower ends of the two guide rods 218 are fixedly connected to the fixed seat 220, and the fixed seat 220 is fixedly connected to the electric turntable 206. The rod end of the electric push rod 219 is fixedly connected to the middle part of the bottom side of the lifting plate 217, and the body of the electric push rod 219 is fixedly connected to the fixed seat 220. The electric push rod is used for lifting and driving, the lifting distance is accurate, and the support is stable and reliable. The double guide rods guide and have good directional stability. During the swinging and spraying process of the spray head, the lifting arm has better torsional resistance and better support stability.

[0064] The stirring device 210 includes an inner stirring shaft 224, a stirring sleeve 225, a lower stirring blade 226 and an upper stirring blade 227. The lower end of the stirring sleeve 225 is fixedly connected to a plurality of upper stirring blades 227. The plurality of upper stirring blades 227 are evenly arranged along the circumference of the lower end of the stirring sleeve 225. The inner stirring shaft 224 is rotatably connected to the stirring sleeve 225 and the lower end thereof extends out of the stirring sleeve 225 and is connected to a plurality of lower stirring blades 226. The plurality of lower stirring blades 226 are arranged along the inner stirring shaft 224. The lower end of the stirring sleeve 225 is evenly arranged in the circumferential direction, and the lower stirring blades 226 and the upper stirring blades 227 are arranged at intervals. The upper end of the stirring sleeve 225 is rotatably connected to the support frame 228, and the support frame 228 is rotatably connected to the top of the pulp storage tank 209 through a bearing. The upper end is extended and fixedly connected to the third gear 229. The second gear 230 meshing with the third gear 229 is fixedly connected to the drive shaft 231. The drive shaft 231 is rotatably connected to the top plate of the upper frame 232 through a bearing. The upper frame 232 The first gear 233 is fixedly connected to the support frame 228, and the first gear 233 meshing with the second gear 230 is fixedly connected to the motor shaft of the stirring motor 234. The stirring motor 234 is fixedly connected to the top of the upper frame 232 in an inverted manner. The upper end of the drive shaft 231 extends out of the upper frame 232 and is fixedly connected to a crank 235. The other end of the crank 235 is hinged to one end of a connecting rod 236. The other end of the connecting rod 236 is hinged to a hinge pin 238 on the rotating disk 237. The hinge pin 238 is away from the center of the rotating disk 237. The central arrangement is that the middle part of the rotating disk 237 is fixedly connected to the end of the stirring sleeve 225 extending out of the upper frame 232, and the stirring sleeve 225 and the upper frame 232 are rotatably connected through a bearing. The rotating disk 237, the crank 235, and the connecting rod 236 constitute a double crank mechanism, and the installation method can ensure that the stirring sleeve and the inner stirring shaft rotate in opposite directions. The above-mentioned double stirring shafts and the arrangement of the stirring blades with opposite rotation directions make the stirring effect better and reduce the possibility of solidification of the stirring slurry during flow.

[0065] Furthermore, the operation method of the tensioning machine in the above step 2 is as follows: the tensioning order of the positive bending moment steel strands of the main beam is N2→N3→N4→N1; the tensioning order of the negative bending moment steel strands of the pier top is: T1 steel strand from inside to outside; the anchor adopts a clip-type anchor, and its tensioning procedure is 0→initial stress 10%σcon→initial stress 20%σcon→σcon, σcon holding load for 5 minutes; the tensioning rate is controlled at 10-25% / min of the tensioning control force, and the stable pressure holding time after reaching the control stress is not less than 5 minutes; when the jacks used in the tensioning machine are tensioned, the allowable error of the synchronous tensioning force between the left and right jacks and the two ends is controlled within ±2%; when tensioning to the control stress, the accuracy of the tensioning control stress is controlled within ±1.5%; prestressing When the force is tensioned to the design value, the error between the actual elongation and the theoretical elongation is controlled within ±6%; after tensioning is completed and the jack and tool anchor are removed, check whether the notches of each steel strand at the tool anchor are flush. If not, it means there is a slippage phenomenon, and the slippage should be supplemented to reach the control stress; the total number of broken and slipped wires in the entire beam shall not exceed 1.0% of the total number of steel wires in the section, and there shall not be more than 1 broken wire in a bundle, and they shall not be on the same side; if the entire bundle or a large number of wires are slipped and broken, the anchor head shall be removed, and the steel bundle shall be replaced after inspection and re-tensioning; the prestressed tendons shall be anchored after the tensioning control stress reaches stability; for clip-type anchors, the top surfaces of the clips shall be flush after anchoring, the mutual misalignment shall not be greater than 2mm, and the height exposed outside the anchor shall not be greater than 4mm.

[0066] The grouting equipment used in the grouting process includes an LJ-YJB1 circulating grouting system, a grouting cover 301 and a connecting conduit 302. The grouting cover 301 is fixedly sealed at the end of the anchor 106. The connecting conduit 302 uses multiple roots, each of which is connected to the slurry ports of two anchor seats 104. The slurry ports are connected to the inside of the bellows. The LJ-YJB1 circulating grouting system includes a mixer 303 and a grouting machine 304. The slurry outlet of the grouting machine 304 is connected to the slurry port of the anchor seat 104 through a slurry inlet pipe 305. The slurry port of the anchor seat 104 is located at one end of the upper bellows 200. The slurry port at the other end of the bellows 200 is connected to the slurry port at that end of the right bellows in the lower two bellows 400 through the connecting conduit 302, the slurry port at the other end of the right bellows is connected to the slurry port at that end of the middle bellows 300, the slurry port at the other end of the middle bellows 300 is connected to the slurry port at that end of the left bellows in the lower two bellows 400, the slurry port at the other end of the left bellows in the lower two bellows 400 is connected to the mixer 303 through the slurry outlet pipe 306, the mixer 303 is connected to the grouting machine 304 through the pump and the pipeline, and the entire grouting equipment forms a circulating grouting.

[0067] The grouting cover 301 includes a steel casing 307, an end panel 308 and a sealing rubber pad 309. The outer end of the steel casing 307 is fixedly sealed and connected to the end panel 308. The end panel 308 is provided with two through holes 310. The two through holes 310 pass through two screws 311 to fix the grouting cover 301 to the anchor seat 104. The sealing rubber pad 309 is an annular structure with an annular groove 312 on one side. The sealing rubber pad 309 is sleeved on the end of the steel casing 307 through the annular groove 312. The parallel surface of the sealing rubber pad 309 is against the end face of the anchor 106 near the edge. The grouting cover of this structure is easy to assemble and disassemble, and utilizes the threaded holes on the existing anchor plate and is directly locked with screws. The connection is reliable and stable, and can withstand stable connection under high pressure. The addition of a sealing rubber pad can improve the sealing effect and avoid poor slurry pressurization stability caused by leakage.

[0068] Furthermore, the above-mentioned duct grouting method steps are as follows:

[0069] 1) Anchorage sealing

[0070] Make a grouting cover according to the anchor model, and install the grouting cover and seal the anchor after the steel strand is cut;

[0071] 2) Slurry mixing

[0072] (1) Grouting equipment performance requirements

[0073] ① The grouting machine adopts the LJ-YJB1 circulating grouting system, which includes a high-speed grouting system, a grouting system, a control system and an automatic data acquisition system. The equipment should be able to automatically monitor and record the grouting process water-binder ratio, grouting pressure, stable pressure, stable time and grouting flow rate.

[0074] ② The speed of the mixer should not be less than 1000r / min, the shape of the stirring blade should match the speed, the linear speed of the blade should not be less than 10m / s and not more than 20m / s, and the mixing should be uniform within the specified time;

[0075] ③ The storage tank for temporary storage of slurry should have a stirring function, and the stirring speed should not exceed 500r / min; and a filter with a mesh size of no more than 3mm should be installed at the outlet of the storage tank;

[0076] ④ The volume of the mixer and slurry storage tank must be larger than the volume of the pipe bundle to be grouting. It is prohibited to add materials, stir and slurry at the same time;

[0077] ⑤ The grouting machine shall use a grouting pump that can operate continuously and can work at a constant pressure of more than 0.7 MPa. The minimum scale value of the pressure gauge shall not be greater than 0.1 MPa, and the maximum range shall ensure that the actual working pressure is within the range of 25% to 75% of its range. Air pressure grouting pumps shall not be used for grouting.

[0078] ⑥ In the event of an abnormality, the grouting machine has an automatic alarm function;

[0079] ⑦ The data protection function can effectively prevent construction personnel from modifying operating procedures or collected data. In the event of communication or equipment failure, emergency measures can be automatically taken to ensure data storage security.

[0080] ⑧ The water-cement ratio sensor, pressure sensor and flow sensor of the grouting machine should be verified or calibrated together with the high-speed grouting system, grouting system and control system as a whole. The verification or calibration cycle is 6 months;

[0081] (2) The performance indexes of post-tensioned prestressed duct grouting slurry are shown in the following table:

[0082]

[0083] (3) Slurry configuration

[0084] The grouting mix ratio is determined based on the laboratory test results. The materials used for grouting are weighed using automatic metering, with a metering error of less than ±1%. The design strength of the cement slurry is 50 MPa, and the slurry is prepared using Portland cement with a strength grade of 42.5 MPa.

[0085] Turn on the grouting trolley, first add 80% of the mixing water into the high-speed mixing barrel with a speed of 1000r / min, evenly add all the grouting agent, stir while adding, then evenly add all the cement, stir for 2 minutes after all the powder is added; then add the remaining 20% ​​of the mixing water and continue stirring for 2 minutes; then pass the filter composed of a filter mesh with a mesh size of no more than 3×3mm set at the outlet of the high-speed mixing barrel into the storage tank and stir continuously, test the fluidity of the slurry for 10 to 17 seconds, and press it into the channel only after passing the test, and make 3 groups of test pieces. The time interval between the end of cement slurry mixing and pressing into the pipeline shall not exceed 40 minutes; the grouting pressure is 0.5 to 0.7Mpa; the filling degree of the grouting should be until the other end of the channel is full and the exhaust hole discharges cement slurry with the same fluidity as the specified fluidity; after closing the slurry outlet, it is advisable to maintain a stable pressure period of not less than 0.5MPa, and the maintenance time of the stable pressure period should be 3 to 5 minutes;

[0086] 3) Intelligent grouting

[0087] The LJ-YJB1 circulating grouting system includes a system host, a measurement and control system, and a circulating grouting system. The slurry circulates continuously in a loop composed of prestressed pipes, a slurry making machine, and a grouting pump to exhaust the air in the pipe, promptly detect pipe blockage, and perform punching by increasing the pressure to discharge impurities and eliminate factors that lead to loose grouting. Precision pressure sensors are installed at the inlet and outlet of the pipe to monitor the pressure in real time, and provide real-time feedback to the system host for analysis and judgment. The measurement and control system adjusts the pressure according to the host's instructions to ensure that the prestressed pipe completes the grouting process under the constraints of the important indicators of slurry quality, pressure, and pressure stabilization time required by the construction technical specifications, ensuring that the grouting is full and dense. The system host judges the fullness of the pipe based on whether the pressure difference between the inlet and outlet remains constant within a certain period of time.

[0088] Furthermore, the hole is flushed before the above grouting, and the accumulated water in the hole is blown out with oil-free compressed air after flushing; the grouting is carried out slowly and evenly without interruption, and all the exhaust holes at the highest points are opened and closed one by one in sequence to ensure smooth exhaust in the hole, and the grouting of the same pipeline is carried out continuously and completed in one go; the prepared slurry is lower than 25°C, and cooling measures must be adopted during construction in high temperature seasons, or construction must be carried out in the morning or evening. The duration from the mixing of cement slurry to the injection into the hole shall not exceed 40 minutes, and the cement slurry shall remain in a fluid state before use and during the injection process. Cement slurry with reduced fluidity due to delayed use shall be used. , its fluidity shall not be increased by adding additional water; strengthen the cleaning and maintenance of grouting equipment, and there shall be no residue and water accumulation in the equipment after cleaning; during grouting operation, construction workers shall wear safety protection equipment correctly, grouting operators must wear protective glasses, and operators who transport cement and grouting agents shall wear protective masks; when grouting, each work team shall prepare and retain no less than 3 groups of test pieces with a size of 40mm×40mm×160mm, standard curing for 28d, and carry out compressive strength and flexural strength tests as the basis for quality assessment; after grouting, the grouting strength must reach 85% of the design strength when moving precast concrete components.

[0089] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A T-beam pre-tensioning, grouting and end-sealing integrated construction method, characterized by: The method comprises the following steps: Step 1: Pre-install an upper corrugated pipe, a middle corrugated pipe, and two lower corrugated pipes in the T-beam to form a channel. Both ends of the upper corrugated pipe, the middle corrugated pipe, and the lower corrugated pipe are fixedly connected with anchor seats. The anchor seats are embedded in the T-beam and remain fixed. A set amount of steel strands are inserted into each channel and both ends pass through the anchor seats; Step 2: Prestressed anchors are installed at both ends of the multiple steel strands in each corrugated pipe. Two tensioning machines are used to symmetrically pre-tension the multiple steel strands in each channel. The multiple steel strands are stopped after reaching the set prestress and set tensioning length. The anchors at both ends are pressed against and fixed to the anchor seats. The anchor seats support the prestressed steel strands. The excess steel strands outside the anchors are removed, and the pre-tensioned anchoring of the steel strands in the remaining channels is completed. Step 3, grouting of the channel: After the prestressed anchorage of the steel strand, the grouting of the channel where the steel strand is placed should be completed within 48 hours. During the grouting process, the grouting ports set at the anchor seats at the ends of the four channels at one end of the T-beam are connected to the grouting machine, and the grouting ports at both ends of the other channels are connected in series, and finally return to the grouting machine to form a circulating grouting. A grouting cover is fixedly and sealed at the end of the anchor to ensure that the grouting volume in one channel is at least 1.5 times the volume of the corrugated pipe; Step 4: After grouting is completed, high-strength fast-hardening grouting material is used to seal the two ends of the T-beam.

2. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 1, characterized in that: In step five, multiple anchor sealing templates are used to seal the anchors at each end of the T-beam. The anchor sealing template includes a steel plate (101) and a screw (102). The steel plate (101) covers the entire groove (103) at the anchor (106). Two screws (102) are used, and the inner ends are symmetrically fixedly connected to the threaded holes of the anchor seat (104). The outer ends pass through the steel plate (101) and are locked with nuts. A slurry inlet (105) is provided at the top of the steel plate (101). The slurry inlet (105) includes a cavity structure with a top opening surrounded by an inclined plate and two triangular plates. The cavity structure is opposite to the notch of the steel plate (101), and the upper end of the cavity structure is flush with the upper end of the steel plate (101).

3. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 2, characterized in that: After installing the anchor template in step five, use high-strength fast-hardening grouting material for grouting and sealing. After the grout solidifies for the set time, remove the mold, disassemble the anchor template, remove the exposed length of the screw, and polish and level the end surface. After leveling, chisel the surface and apply a layer of cement slurry.

4. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 3, characterized in that: During grouting, a T-beam end surface treatment lifting and pouring device is used for grouting. The T-beam end surface treatment lifting and pouring device comprises a grouting head (201), a grouting pump (202), a telescopic cylinder (203), a pitching arm (204), a lifting arm (205) and an electric turntable (206). The grouting head (201) is connected to the grouting pump (202) through a grouting pipe (207). The grouting head (201) is fixedly connected to the cylinder rod end of the telescopic cylinder (203). The cylinder seat is fixedly connected to the pitching arm (204), the pitching arm (204) is fixedly connected to the upper end of the lifting arm (205), the lower end of the lifting arm (205) is fixedly connected to the electric turntable (206), the electric turntable (206) is fixedly connected to the walking trolley (208), the grouting pump (202) is fixedly connected to the walking trolley (208), a slurry storage tank (209) is installed on the walking trolley (208), and a stirring device (210) is provided on the slurry storage tank (209).

5. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 4, characterized in that: A flexible anti-slurry plate (211) is provided at one end of the cylinder rod of the grouting head (201) close to the telescopic cylinder (203). The anti-slurry plate (211) can shield the grouting head (201) after it extends into the slurry inlet (105).

6. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 2, characterized in that: The pitch arm (204) comprises a pitch connector (212), a U-shaped slot plate (213) and a pitch motor (215) for driving the pitch connector (212) to rotate. The pitch connector (212) is rotatably connected to a pitch seat (214) via a pitch rotation axis. The pitch seat (214) is fixedly connected to the upper end of the lifting arm (205). The pitch motor is mounted on the pitch seat (214) and connected to the pitch rotation axis. The U-shaped slot plate (213) is fixedly connected to the pitch connector (212) at a distance away from the pitch axis. The U-shaped slot plate (213) is provided with a strip-shaped through hole (216) fixedly connected to the cylinder seat of the telescopic cylinder (203).

7. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 6, characterized in that: The lifting arm (205) comprises a lifting plate (217), two guide rods (218) and an electric push rod (219). The lifting plate (217) is used to connect the pitching arm (204). The two guide rods (218) are telescopically connected at both ends. The lower ends of the two guide rods (218) are fixedly connected to a fixed seat (220). The fixed seat (220) is fixedly connected to the electric turntable (206). The rod end of the electric push rod (219) is fixedly connected to the middle part of the bottom side of the lifting plate (217). The body of the electric push rod (219) is fixedly connected to the fixed seat (220).

8. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 1, characterized in that: The operation method of the tensioning machine in step 2 is as follows: the tensioning order of the positive bending moment steel strands of the main beam is N2→N3→N4→N1; the tensioning order of the negative bending moment steel strands of the pier top is: T1 steel strand from inside to outside; the anchor adopts a clip-type anchor, and its tensioning procedure is 0→initial stress 10%σcon→initial stress 20%σcon→σcon, σcon holding load for 5 minutes; the tensioning rate is controlled at 10-25% / min of the tensioning control force, and the stable pressure holding time after reaching the control stress is not less than 5 minutes; the tensioning machine When tensioning with jacks, the allowable error of the synchronous tensioning force between the left and right jacks and the jacks at both ends is controlled within ±2%; when tensioning to the control stress, the accuracy of the tensioning control stress is controlled within ±1.5%; when the prestressing is tensioned to the design value, the error between the actual extension and the theoretical extension is controlled within ±6%; after tensioning is completed and the jacks and tool anchors are removed, check whether the notches of each steel strand at the tool anchor are flush. If not, it indicates a slippage phenomenon, and the slipped strand should be re-tensioned to achieve the control stress; The total number of broken and slipped wires in the entire beam shall not exceed 1.0% of the total number of steel wires in that section, and no more than one wire shall be broken in a bundle, and the wires shall not be on the same side; if an entire bundle or a large number of wires are slipped or broken, the anchor head shall be removed, and the steel bundle shall be re-tensioned after inspection and replacement; the prestressed tendons shall be anchored after the tensioning control stress reaches stability; for clip-type anchors, the top surfaces of the clips shall be flush after anchoring, the mutual misalignment shall not be greater than 2mm, and the height exposed outside the anchor shall not be greater than 4mm.

9. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 1, characterized in that: The steps for grouting the duct are as follows: 1) Anchorage sealing Make a grouting cover according to the anchor model, and install the grouting cover and seal the anchor after the steel strand is cut; 2) Slurry mixing (1) Grouting equipment performance requirements ① The grouting machine adopts the LJ-YJB1 circulating grouting system, which includes a high-speed grouting system, a grouting system, a control system and an automatic data acquisition system. The equipment should be able to automatically monitor and record the grouting process water-binder ratio, grouting pressure, stable pressure, stable time and grouting flow rate. ② The speed of the mixer should not be less than 1000r / min, the shape of the stirring blade should match the speed, the linear speed of the blade should not be less than 10m / s and not more than 20m / s, and the mixing should be uniform within the specified time; ③ The storage tank for temporary storage of slurry should have a stirring function, and the stirring speed should not exceed 500r / min; and a filter with a mesh size of no more than 3mm should be installed at the outlet of the storage tank; ④ The volume of the mixer and slurry storage tank must be larger than the volume of the pipe bundle to be grouting. It is prohibited to add materials, stir and slurry at the same time; ⑤ The grouting machine shall use a grouting pump that can operate continuously and can work at a constant pressure of more than 0.7 MPa. The minimum scale value of the pressure gauge shall not be greater than 0.1 MPa, and the maximum range shall ensure that the actual working pressure is within the range of 25% to 75% of its range. Air pressure grouting pumps shall not be used for grouting. ⑥ In the event of an abnormality, the grouting machine has an automatic alarm function; ⑦With data protection function; ⑧ The water-cement ratio sensor, pressure sensor and flow sensor of the grouting machine should be verified or calibrated together with the high-speed grouting system, grouting system and control system as a whole. The verification or calibration cycle is 6 months; (2) The performance indexes of post-tensioned prestressed duct grouting slurry are shown in the following table: (3) Slurry configuration The grouting mix ratio is determined based on the laboratory test results. The materials used for grouting are weighed using automatic metering, with a metering error of less than ±1%. The design strength of the cement slurry is 50 MPa, and the slurry is prepared using Portland cement with a strength grade of 42.5 MPa. Turn on the grouting trolley, first add 80% of the mixing water into the high-speed mixing barrel with a speed of 1000r / min, evenly add all the grouting agent, stir while adding, then evenly add all the cement, stir for 2 minutes after all the powder is added; then add the remaining 20% ​​of the mixing water and continue stirring for 2 minutes; then pass the filter composed of a filter mesh with a mesh size of no more than 3×3mm set at the outlet of the high-speed mixing barrel into the storage tank and stir continuously, test the fluidity of the slurry for 10 to 17 seconds, and press it into the channel only after passing the test, and make 3 groups of test pieces. The time interval between the end of cement slurry mixing and pressing into the pipeline shall not exceed 40 minutes; the grouting pressure is 0.5 to 0.7Mpa; the filling degree of the grouting should be until the other end of the channel is full and the exhaust hole discharges cement slurry with the same fluidity as the specified fluidity; after closing the slurry outlet, it is advisable to maintain a stable pressure period of not less than 0.5MPa, and the maintenance time of the stable pressure period should be 3 to 5 minutes; 3) Intelligent grouting The LJ-YJB1 circulating grouting system includes a system host, a measurement and control system, and a circulating grouting system. The slurry circulates continuously in a loop composed of prestressed pipes, a slurry making machine, and a grouting pump to exhaust the air in the pipe, promptly detect pipe blockage, and perform punching by increasing the pressure to discharge impurities and eliminate factors that lead to loose grouting. Precision pressure sensors are installed at the inlet and outlet of the pipe to monitor the pressure in real time, and provide real-time feedback to the system host for analysis and judgment. The measurement and control system adjusts the pressure according to the host's instructions to ensure that the prestressed pipe completes the grouting process under the constraints of the important indicators of slurry quality, pressure, and pressure stabilization time required by the construction technical specifications, ensuring that the grouting is full and dense. The system host judges the fullness of the pipe based on whether the pressure difference between the inlet and outlet remains constant within a certain period of time.

10. The method for pre-tensioning, grouting and end-sealing a T-beam according to claim 9, characterized in that: Before grouting, flush the channel, and blow out the accumulated water in the channel with oil-free compressed air after flushing; grouting should be carried out slowly and evenly without interruption, and all the exhaust holes at the highest points should be opened and closed one by one to ensure smooth exhaust in the channel. Grouting of the same pipeline should be carried out continuously and completed in one go; the prepared slurry should be below 25°C. Cooling measures must be taken during construction in high temperature seasons, or construction should be carried out in the morning or evening. The time from mixing the cement slurry to pressing it into the hole should not exceed 40 minutes. The cement slurry should remain in a fluid state before use and during the injection process. Cement slurry with reduced fluidity due to delayed use should not be grouting. Add extra water to increase its fluidity; strengthen the cleaning and maintenance of grouting equipment, and there should be no residue or water accumulation in the equipment after cleaning; during grouting operation, construction workers must wear safety protection equipment correctly, grouting operators must wear protective glasses, and operators who transport cement and grouting agents must wear protective masks; when grouting, each work team should prepare and retain no less than 3 groups of test pieces with a size of 40mm×40mm×160mm, standard curing for 28 days, and conduct compressive strength and flexural strength tests as the basis for quality assessment; after grouting, the grouting strength must reach 85% of the design strength when moving precast concrete components.

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