Shield tunnel segment structure prestress system composition and construction method

Abstract

The invention discloses a shield tunnel segment structure prestress system composition and a construction method, belongs to the technical field of shield tunnel segment construction, and provides a method for arranging a prestress system in a shield tunnel segment and a systematic construction method for inserting prestress operation procedures in the tunneling process of a shield tunneling machine. And the technical blank in the field is filled. The construction method comprises the steps that the prestress system is arranged to be in a vertical ring shape and anchored to the inner wall of the duct piece in a crossed mode, and anchoring positions are symmetrically arranged; the operation procedure is as follows: a reserved hole channel and a cable force monitoring sensor are arranged when a duct piece is poured; the prestressed cable disc is transported to the to-be-assembled position in cooperation with the rhythm of tunneling a tunnel and assembling segments of a shield tunneling machine; prestressing tendons penetrate through the reserved hole channels; and the prestressing tendons are symmetrically tensioned to a design value and anchored. According to the construction method, a pre-stress system operation procedure is integrated aiming at an existing shield tunneling machine tunneling tunnel construction method, a pre-stress shield tunnel system construction method is formed, and the construction method has the advantages of being high in mechanization degree and good in construction quality.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel segment construction, and more particularly to a shield tunnel segment structure prestressed system composition and a construction method. Background Art

[0002] In recent years, prestressed systems have been gradually developed and applied to special engineering structures such as tunnels due to their superior reinforcement performance on concrete structures. In tunnel projects, reinforced concrete segments are often used as initial support. However, ordinary reinforced concrete segment structures are prone to cracking, water seepage, rust of connecting bolts, and difficulty in later maintenance. Therefore, introducing the prestressed system into the tunnel segment structure can remedy the above problems and comprehensively improve the bearing performance and durability of the segments.

[0003] The prestressing system of conventional prestressed concrete structures primarily consists of pre-buried channels, prestressed tendons, anchor clamps, and protective structures. The main construction methods for this prestressing system include four steps: channel pre-buried, tendon threaded through the channels, prestressed tensioning, and protective construction. However, existing shield tunneling methods do not incorporate prestressing system operating procedures, and existing shield machines lack prestressing construction facilities. Given the limited space, mechanized and interwoven operations, high safety risks, tight construction schedules, and high quality requirements, a systematic solution for shield tunnel prestressing system construction is necessary. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide a prestressed system structure and construction method for a shield tunnel segment structure.

[0005] The technical solution of the present invention is: a shield tunnel segment structure prestressed system structure and construction method, comprising the following steps:

[0006] Step 1. Conduct an overall layout design for the prestressing system of the shield tunnel segment structure. Based on the characteristics of the shield tunnel segment structure, the prestressing is arranged in a vertical ring and cross-anchored to the inner wall of the segment. To ensure uniform stress distribution, the number of prestressing cables and the anchoring positions of each segment ring should be arranged symmetrically. Based on the requirements of tunnel structure operation and maintenance, cable force monitoring sensors and spare channels are reserved on the segments. This means that the stress state of the segments can be monitored at any time during operation, and prestressing can be reapplied or replaced after a certain period of time. The overall layout plan of the tunnel segment prestressing monitoring system is as follows: To save costs, there is no need to monitor the cable force of each prestressing cable. Instead, they only need to be evenly spaced within the tunnel route section. At the same time, additional measuring points are set up in areas with sudden line changes, complex geology, and irregular loads.

[0007] Step 2. Prefabricate the prestressed pipe segments, set up reserved channels during the process of pouring concrete into the prestressed pipe segments, and set up cable force monitoring sensors in the reserved channels;

[0008] Step 3. Prestressed cables are made and rolled into prestressed cable drums;

[0009] Step 4. In coordination with the shield machine's entry into the tunnel and the assembly of the prestressed segments, the prestressed cable drums required for each ring of prestressed segments are loaded onto a transport train and transported along with the prestressed segments to the assembly location inside the tunnel;

[0010] Step 5. After assembling a ring of prestressed pipe segments, the prestressed strands in the prestressed cable drum are passed through the reserved holes of the prestressed pipe segments by a wire threading and pulling machine;

[0011] Step 6. Use two tensioning jacks to tension the two ends of the prestressed tendon synchronously to the designed prestressing value and anchor it;

[0012] Step 7. Carry out anti-corrosion treatment on the anchor head;

[0013] Step 8. Connect the lead of the cable force monitoring sensor to the demodulator to monitor the cable force.

[0014] As a further improvement, the cable force monitoring sensor is a magnetic flux sensor, and the number of the cable force monitoring sensors is 3, one of which is located at the diagonal of the anchor end, and the other two are located at the transition points of the two anchor end corners respectively.

[0015] Furthermore, in step 2, during the process of using concrete to cast the prestressed pipe segment, the corrugated pipe is placed in the prestressed pipe segment by tying the positioning steel bars to form the reserved channel, and a trumpet structure is provided at both ends of the corrugated pipe. The cable force monitoring sensor is nested on the outside of the corrugated pipe, and the spiral reinforcement is buried in the anchor end of the prestressed pipe segment. The anchor plate is buried in the anchor end of the prestressed pipe segment by using the reserved holes on the template and bolts.

[0016] Furthermore, in step 3, the prestressed bundle is prefabricated in a factory or manufactured on the construction site, that is, the steel strands are cut one by one according to the designed length, the number of steel strands is determined according to the size of the designed prestressing value, and then multiple steel strands are arranged into a bundle to obtain a prestressed bundle. Then, each bundle of prestressed bundles is individually wound into a prestressed cable drum using a traction head and a drum machine, and the prestressed cable drum is fixed for easy transportation.

[0017] Furthermore, in step 5, during construction, the prestressed cable drum is first loaded into the pay-off drum and hoisted to the position of the prestressed pipe segment that has just been assembled in the tunnel. Then, the threading and pulling machine is arranged above the reserved tunnel opening. The movement and fixation of the threading and pulling machine can be achieved by setting a small mechanical arm on the shield machine.

[0018] Start the wire threading and traction machine to transport the traction wire through the reserved channel and out from the channel opening below, connect the traction wire to the traction head of the prestressed bundle, and then start the wire threading and traction machine to reverse and pull the prestressed bundle through the reserved channel until the prestressed bundle passes through the reserved channel to the set working length.

[0019] Furthermore, in step 6, the graded synchronous tensioning is divided into three levels of uniform tensioning:

[0020] tensioning to 20% of the designed prestressing value, maintaining the first set time, and detecting whether the prestressing tendons and equipment are abnormal, and stopping tensioning if any abnormality is found;

[0021] tensioning to 60% of the designed prestressing value, maintaining the first set time, and detecting whether the prestressing tendons and equipment are abnormal, and stopping tensioning if any abnormality is found;

[0022] Tensioning is performed to 100% of the designed prestressing value; a first set time is maintained, and the prestressing tendons and equipment are checked for abnormalities, and tensioning is stopped if any abnormality is found.

[0023] Furthermore, the tensioning jack is an ultra-high pressure integrated jack, which integrates the tensioning tooling and the through-type jack into one. The movement and fixation of the tensioning jack can be achieved by arranging a small mechanical arm on the shield machine.

[0024] Furthermore, before tensioning, it is necessary to test whether the actual friction resistance of the reserved channel is consistent with the preset value during design, so as to determine whether the established effective prestressing force meets the design requirements; the details are as follows:

[0025] Before construction, a friction test is carried out by setting up a test segment with the same structure as the prestressed segment; or during construction, a friction test is carried out by selecting the reserved channel of the assembled first ring prestressed segment;

[0026] If the deviation between the actual duct friction resistance and the preset value is greater than the set deviation, it is necessary to report to the design unit for review to determine whether the tensioning control force needs to be adjusted to ensure that the effective stress established after tensioning is completed meets the design requirements.

[0027] Furthermore, if the prestressed tendons are anchored using a bonded prestressed system, grouting construction is required in step 7, using a dynamic serial grouting construction process to complete the automated mixing and grouting operations using a grouting trolley;

[0028] The specific construction process is as follows: install the anchor cover in advance during the interval between the assembly of the prestressed pipe segments, install the joint pipe at the grouting port of the reserved channel, install the valve on the joint pipe, and use the external pipeline to connect the adjacent reserved channels end to end to prepare for the work;

[0029] Then the grouting trolley is driven into the tunnel segment area to be grouting, the grouting pipe is connected to the joint pipe of the head end grouting port, the grouting pipe connected to the tunnel exhaust port is connected to the grouting cylinder, and the water and electricity lines are connected before the mixing and grouting can begin. The mixing and grouting process are automatically performed by the grouting trolley according to the set program;

[0030] After the slurry comes out from the vent of the last reserved channel, close the head grouting port, then connect the grouting pipe to the joint pipe of the tail grouting port to fill the grouting, and after the slurry comes out from the vent of the last reserved channel again, close the vent, and stabilize the pressure for the second set time according to the process requirements to complete the grouting of this group of channels;

[0031] The grouting trolley is driven out of the tunnel, and the joint pipe and valve can be removed during the interval after the slurry has initially solidified;

[0032] Pour or apply anti-corrosion materials at the anchor heads at both ends for anti-corrosion.

[0033] Furthermore, if the prestressed bundle is anchored using a non-bonded prestressed system or a finished cable prestressed system, then in step 7, an anchor cover is first installed, and then anti-corrosion material is poured or applied to the anchor heads at both ends for anti-corrosion.

[0034] Beneficial effects

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. The present invention provides a construction method for a tunnel segment prestressing system that can be industrialized, mechanized, and easily monitored and maintained. It greatly improves the bearing capacity and service life of the initial support concrete segments of the tunnel, while also being highly efficient, safe, and reliable.

[0037] 2. The tunnel segments of the present invention are prefabricated and assembled structures. The prestressed structure of the tunnel segments is designed to be arranged in an inner ring, which greatly improves the integrity of the segments. The self-stabilization of the entire ring of segments can be achieved by relying solely on prestressed bundles, without the need for connecting bolts, thereby improving the efficiency of assembly construction and saving material costs.

[0038] 3. The present invention arranges cable force monitoring sensors at selected locations, which can not only realize cable force calibration during the construction process to ensure construction quality, but also realize health monitoring during tunnel operation to extend the service life of the tunnel.

[0039] 4. The present invention realizes the mechanized continuous operation of the two processes of conveying the traction wire and traction of the prestressed bundle through the wire threading and traction machine, which greatly improves the construction efficiency.

[0040] 5. By using ultra-high-pressure integrated jacks, the present invention significantly reduces the overall dimensions of the tensioning device. The tensioning tooling and jacks are integrated into one, enabling one-time installation of the entire device in the hole, facilitating mechanized installation and greatly improving construction efficiency. Compared with conventional annular prestressed deflection tensioning technology, the deflection support is eliminated, saving the working length of the prestressed bundle, reducing the friction resistance of the tensioning device, lowering the installation difficulty and safety risks, and further improving installation efficiency. At the same time, the two ultra-high-pressure integrated jacks achieve precise control of the tensioning process through three-level uniform tensioning, improving construction quality and safety.

[0041] 6. The present invention fully conforms to the layout characteristics of the tunnel structure prestressed system through dynamic serial grouting, and can complete multi-channel grouting operations at one time within a limited window period during the shield machine excavation process, without the need for repeated installation and disassembly of grouting pipelines and mobile grouting facilities, greatly improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of the present invention;

[0043] Figure 2 It is a structural schematic diagram of the prestressed system in the present invention;

[0044] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0045] Figure 4 It is a structural diagram of the anchoring of the prestressed system in the present invention;

[0046] Figure 5 Schematic diagram of the prestressed bundle passing through the prestressed tube segment in the present invention;

[0047] Figure 6 Schematic diagram of cross anchoring of prestressed tendons in the present invention;

[0048] Figure 7 A schematic diagram of grouting in the present invention;

[0049] Figure 8 for Figure 7 Enlarged view of point B in the middle;

[0050] Figure 9 Schematic diagram of grouting in the present invention;

[0051] Figure 10 This is a schematic diagram of the locomotive connected to the grouting trolley in the present invention;

[0052] Figure 11 This is a schematic diagram of the main structure of the grouting trolley in the present invention;

[0053] Figure 12 It is a schematic diagram of the top view of the grouting trolley in the present invention.

[0054] Among them: 1- prestressed pipe segment, 2- cable force monitoring sensor, 3- prestressed bundle, 4- prestressed cable drum, 5- threading traction machine, 6- tensioning jack, 7- corrugated pipe, 8- bell mouth structure, 9- spiral reinforcement, 10- anchor plate, 11- pay-off drum, 12- traction wire, 14- tensioning tooling, 15- through-type jack, 16- grouting trolley, 17- anchor cover, 18- joint pipe, 19- valve, 20- external pipeline, 21- grouting pipe, 22- channel exhaust port, 23- grouting pipe, 24- grouting tube, 26- working anchor plate, 27- working clip, 28- steel strand, 29- guide wheel, 30- grouting pipe, 31- locomotive, 32- mobile platform Platform, 33-wheel, 34-control module, 35-high-speed stirring device, 36-low-speed stirring device, 37-feeding device, 38-loading arm, 39-weight sensor, 40-slurry discharge port, 41-slurry discharge control valve, 42-discharge port, 43-grouting pump, 44-pressure gauge, 45-grouting interface, 46-high-speed mixing drum, 47-high-speed motor, 48-low-speed mixing drum, 49-low-speed motor, 50-hopper, 51-feeding channel, 52-feeding motor, 53-feeding port, 54-column, 55-beam, 56-mobile trolley, 57-crane, 58-hanging rope, 59-grab, 60-rotating table, 61-storage area, 62-slurry storage drum. DETAILED DESCRIPTION

[0055] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0056] See Figures 1 to 12 In the present invention, according to the characteristics of the shield tunnel segment structure, the prestressing force is arranged in a vertical ring and cross-anchored to the inner wall of the prestressed segment 1. In order to ensure the uniformity of the structural force, the prestressing force quantity and anchoring position of each ring of the prestressed segment 1 should be arranged symmetrically, such as Figure 7 As shown, each ring of prestressed segments 1 is equipped with two prestressed strands 3, with the anchorage positions of the two strands 3 arranged symmetrically. Depending on the needs of tunnel structure operation and maintenance, cable force monitoring sensors and spare channels can be reserved on the prestressed segments 1. This allows the stress state of the prestressed segments 1 to be monitored at any time during operation, and prestressing can be reapplied or replaced after a certain period of time.

[0057] The shield tunnel segment structure prestressing system of the present invention comprises:

[0058] 1. The reserved channel formed by the bellows 7 is made of metal or plastic material and has the function of deformation compensation. For the prefabricated assembled structure, the bellows joint is designed as a bell-mouth structure 8 to facilitate the smooth passage of the prestressed bundle through the interface during the later threading.

[0059] 2. Anchor bearing member consisting of anchor plate 10 and spiral reinforcement 9;

[0060] 3. A cable force monitoring sensor 2 sleeved on the outside of the bellows 7;

[0061] 4. A prestressed bundle consisting of multiple (or one) smooth steel strands 28;

[0062] 5. Anchoring structure consisting of a porous working anchor plate 26 + a working clip 27 group;

[0063] 6. Anchor cover 17 made of steel or plastic;

[0064] 7. And special grouting materials with high strength and easy compaction.

[0065] The present invention provides a shield tunnel segment structure prestressing system structure and construction method, comprising the following steps:

[0066] Step 1. Conduct an overall layout design for the prestressing system of the shield tunnel segment structure. Based on the characteristics of the shield tunnel segment structure, the prestressing is arranged in a vertical ring and cross-anchored to the inner wall of the segment. To ensure uniform stress distribution, the number of prestressing cables and the anchoring positions of each segment ring should be arranged symmetrically. Based on the requirements of tunnel structure operation and maintenance, cable force monitoring sensors and spare channels are reserved on the segments. This means that the stress state of the segments can be monitored at any time during operation, and prestressing can be reapplied or replaced after a certain number of years. The overall layout plan for the tunnel segment prestressing monitoring system is as follows: To save costs, there is no need to monitor the cable force of each prestressing cable. Prestressing cables only need to be evenly spaced within the tunnel route section. Additional measuring points are set up in areas with sudden line changes, complex geology, and irregular loads.

[0067] Step 2. Prefabricate the prestressed pipe segment 1, set a reserved channel during the process of pouring concrete into the prestressed pipe segment 1, and install a cable force monitoring sensor 2 in the reserved channel;

[0068] Step 3. The prestressed bundle 3 is made into a cable and rolled into a prestressed cable drum 4;

[0069] Step 4. In coordination with the shield machine's progress in the tunnel and the assembly of the prestressed segments 1, the prestressed cable drums 4 required for each ring of prestressed segments 1 are loaded onto a transport train and transported along with the prestressed segments 1 to the assembly location inside the tunnel;

[0070] Step 5. After assembling a ring of prestressed segments 1, the prestressed strands 3 in the prestressed cable drum 4 are passed through the reserved holes of the prestressed segments 1 by the threading and pulling machine 5;

[0071] Step 6. Use two tensioning jacks 6 to tension the prestressed tendons 3 in stages and synchronously at both ends to the designed prestressing value and then anchor them;

[0072] Step 7. Carry out anti-corrosion treatment on the anchor head;

[0073] Step 8. Connect the lead of the cable force monitoring sensor 2 to the demodulator to monitor the cable force.

[0074] Of course, during the tensioning process of step 6, the cable tension of the prestressed tendon 3 can also be monitored in real time by the cable tension monitoring sensor 2 .

[0075] Specifically, the cable tension monitoring sensor 2 is a magnetic flux sensor, and there are three cable tension monitoring sensors 2. One of the cable tension monitoring sensors 2 is located at the diagonal point of the anchor end, which is the farthest position from the anchor end. The other two cable tension monitoring sensors 2 are located at the transition points of the two anchor end corners, which are stress concentration points. Through these three cable tension monitoring sensors 2, the stress state and health of the prestressed bundle 3 can be effectively monitored.

[0076] Of course, in the prestressed segments 1 of the entire tunnel, in order to save costs, there is no need to monitor the cable tension of each ring of prestressed bundles 3. It is sufficient to evenly arrange cable tension monitoring of a ring of prestressed bundles 3 at intervals within the section of the tunnel route. At the same time, additional cable tension monitoring points of prestressed bundles 3 can be added in areas with sudden changes in line shape, complex geology, or irregular loads, so as to effectively monitor the prestress of the prestressed segments 1 of the entire tunnel.

[0077] In step 2, during the process of using concrete to cast the prestressed pipe segment 1, the corrugated pipe 7 is placed in the prestressed pipe segment 1 by tying the positioning steel bars to form a reserved channel. The two ends of the corrugated pipe 7 are provided with a trumpet structure 8. The cable tension monitoring sensor 2 is nested on the outside of the corrugated pipe 7, and the spiral reinforcement 9 is buried in the anchor end of the prestressed pipe segment 1. The anchor plate 10 is buried in the anchor end of the prestressed pipe segment 1 by using the reserved holes on the template and bolts.

[0078] In step 3, the prestressed strands 3 are prefabricated in a factory or on-site. Factory prefabrication is preferred, as it offers a favorable environment, convenient operation, high efficiency, and greater precision. Steel strands are cut one by one according to the designed length, and the number of strands is determined based on the designed prestressing value. The strands are then braided into a bundle to form a prestressed strand 3. Each prestressed strand 3 is then individually wound into a prestressed cable drum 4 using a traction head and a reeling machine. The prestressed cable drum 4 is then secured for easy transport.

[0079] In step 5, when the bundle is threaded, first the prestressed cable drum 4 is loaded into the pay-off drum 11 (the pay-off drum 11 adopts the pay-off drum of the prior art) and hoisted to the position of the prestressed pipe segment 1 that has just been assembled in the tunnel. Then the threading traction machine 5 (the threading traction machine 5 adopts the prestressed bundle special threading traction machine of the prior art) is arranged above the reserved hole. The movement and fixation of the threading traction machine can be achieved by setting a small mechanical arm on the shield machine, such as Figure 5 shown.

[0080] The wire threading and traction machine 5 is started to convey the traction wire 12 through the reserved channel and out from the lower channel opening. The traction wire 12 is connected to the traction head of the prestressed bundle 3. Then, the wire threading and traction machine 5 is started to reverse and pull the prestressed bundle 3 through the reserved channel until the prestressed bundle 3 has passed through the reserved channel to the set working length. Among them, the lower channel opening and the wire pay-off drum 11 are both provided with guide wheels 29. The guide wheels 29 guide the traction wire 12 and the prestressed bundle 3 through, which can make the bundle threading smooth and with little resistance.

[0081] In step 6, two tensioning jacks 6 are used to tension the Figure 6 As shown in the figure, graded synchronous tensioning is divided into three levels of uniform tensioning:

[0082] Tensioning is performed to 20% of the designed prestressing value to play a pre-tightening role and maintained for the first set time. The prestressing tendon 3 and the equipment are checked for abnormalities. If any abnormality is found, tensioning is stopped.

[0083] Tensioning is performed to 60% of the designed prestressing value. At this time, the entire ring of prestressed segments 1 is tightened and maintained for the first set time. The prestressed bundles 3, the equipment, and the prestressed segments 1 are checked for abnormalities. If any abnormality is found, tensioning is stopped.

[0084] Tensioning is performed to 100% of the designed prestress value. At this point, the pressure is stabilized, and the prestressing tendon 3, the equipment, and the prestressing segment 1 are inspected for abnormalities. If any abnormality is detected, tensioning is stopped. The first set time is 1 to 5 minutes. This three-stage uniform tensioning ensures uniform control of the tensioning process, streamlines the process, and improves operational efficiency.

[0085] The tensioning jack 6 is an ultra-high-pressure integrated jack. Specifically, it integrates a tensioning tool 14 (including a limit plate and automatic tool anchor, both of which are currently available) and a through-type jack 15. The tensioning jack can be moved and fixed using a small robotic arm installed on the shield machine, facilitating mechanized installation and improving operational efficiency. The through-type jack 15 is an ultra-high-pressure jack. By increasing the rated oil pressure, the jack's size is significantly reduced, reducing the required working space and facilitating installation.

[0086] Before tensioning, it is necessary to test whether the actual friction resistance of the reserved channel (especially the curved prestressed channel) is consistent with the preset value during design. The channel friction resistance is the friction coefficient, so as to determine whether the established effective prestress meets the design requirements. The details are as follows:

[0087] Before construction, a friction test is carried out by separately setting up a test segment with the same structure as the prestressed segment 1; or during construction, a friction test is carried out by selecting the reserved channel of the assembled first ring prestressed segment 1;

[0088] If the deviation between the actual duct friction resistance (friction coefficient) and the preset value is greater than the set deviation, it is necessary to report to the design unit for review to determine whether the tensioning control force needs to be adjusted to ensure that the effective stress established after tensioning is completed meets the design requirements.

[0089] There are generally three types of anchoring methods for the prestressed tendons 3: a bonded prestressed system, an unbonded prestressed system, and a finished cable prestressed system.

[0090] If the prestressed tendons 3 are anchored by a bonded prestressed system, grouting construction is to be carried out in step 7 , using a dynamic serial grouting construction process, with the grouting trolley 16 completing the automated operations of mixing materials and grouting.

[0091] The specific construction process is as follows: using the intermittent time of assembling the prestressed pipe segments 1 in advance to install the anchor cover 17, installing the joint pipe 18 at the grouting port of the reserved channel, installing the valve 19 at the joint pipe 18, and providing grouting ports at both ends of the reserved channel, that is, installing the joint pipe 18 and the valve 19 at both ends of the reserved channel, and at the same time using the external pipe 20 to connect the head and tail (grouting ports at the head and tail) of multiple adjacent reserved channels to prepare for the work;

[0092] Then the grouting trolley 16 is driven into the tunnel segment area to be grouting, the grouting pipe 21 is connected to the joint pipe 18 (the valve 19 of the joint pipe 18) of the head end grouting port, the output end of the grouting trolley 16 is connected to the grouting pipe 21, the grouting pipe 23 connected to the channel exhaust port 22 is connected to the grouting tube 24, the grouting tube 24 is used to accommodate the waste slurry, the tail end grouting port of the last reserved channel is connected to the grouting tube 24 through the return grouting pipe 30, and the water and electricity lines are connected to start mixing and grouting. The mixing and grouting processes are automatically performed by the grouting trolley 16 according to the set program;

[0093] Each reserved channel is provided with a channel exhaust port 22 at the top. During the grouting process, except for the last channel exhaust port 22, the other channel exhaust ports 22 are closed after the slurry is discharged. After the channel exhaust port 22 of the last reserved channel (i.e. the last reserved channel in the slurry flow direction) is discharged, the head end grouting port is closed. Figure 9As shown, the grouting pipe 21 is then connected to the joint pipe 18 of the tail end grouting port for grouting. After the slurry is discharged from the vent 22 of the last reserved channel again, the vent 22 is closed. The pressure is stabilized for the second set time according to the process requirements to complete the grouting of this group of channels. The second set time is 5 to 10 minutes, so that the slurry can fill the reserved channels.

[0094] Drive the grouting trolley 16 out of the tunnel, that is, drive the grouting trolley 16 out of the tunnel by the locomotive 31. After the slurry initially solidifies, the joint pipe 18 and the valve 19 can be removed during the interval.

[0095] The anchor head positions at both ends are perfused or smeared with anticorrosive materials for anticorrosion, and the anticorrosive materials are made of oily or waxy materials. That is, anticorrosive materials are perfused in the anchor cover 17, or the outside of the anchor cover 17 is smeared with anticorrosive materials and wrapped.

[0096] If the prestressed tendons 3 are anchored using an unbonded prestressing system or a prestressed cable system, then in step 7, anchor caps 17 are first installed, and then anti-corrosion material is poured or applied to the anchor heads at both ends for corrosion protection. Specifically, the anti-corrosion material is poured into the anchor caps 17, or the anti-corrosion material is applied to the outside of the anchor caps 17 to wrap them.

[0097] In one embodiment, the grouting trolley 16 is as shown in FIG. Figure 10-12 As shown, the mobile platform 32 includes wheels 33 at its bottom. A control module 34, a high-speed stirring device 35, a low-speed stirring device 36, a loading device 37 for feeding the high-speed stirring device 35, and a loading arm 38 for feeding the loading device 37 are located on top of the mobile platform 32. The high-speed stirring device 35 is located above the low-speed stirring device 36 and is equipped with a weight sensor 39. A slurry discharge port 40 for discharging slurry into the low-speed stirring device 36 is located at its bottom, and a slurry discharge control valve 41 is provided at the discharge port 40. A discharge port 42 is provided at the bottom of the low-speed stirring device 36, and a grouting pump 43 is connected to the discharge port 42. The output end of the grouting pump 43 is equipped with a pressure gauge 44 and a grouting interface 45. The control module 34 is electrically connected to the high-speed stirring device 35, the low-speed stirring device 36, the loading device 37, the loading arm 38, the slurry discharge control valve 41, the grouting pump 43, the pressure gauge 44, and the weight sensor 39.

[0098] During grouting operation, the grouting interface 45 is connected to the grouting pipe 21 .

[0099] The wheels 33 are rail train wheels and can be connected in series with the material transport train 45 during shield machine operation as a power source. Of course, the wheels 33 can also be driven independently by their own power, i.e., the motor is driven to rotate by the control module 34.

[0100] Specifically, the high-speed stirring device 35 includes a high-speed stirring drum 46, a slurry discharge port 40 located at the bottom of the high-speed stirring drum 46, a weight sensor 39 located at the bottom of the high-speed stirring drum 46, and the high-speed stirring drum 46 is mounted on the top of the mobile platform 32 via a bracket (the bracket is not shown). The weight sensor 39 is on the top of the bracket and supports the high-speed stirring drum 46. The high-speed stirring drum 46 is provided with a high-speed stirring impeller. The top of the high-speed stirring drum 46 is provided with a high-speed motor 47 connected to the high-speed stirring impeller. The control module 34 is electrically connected to the high-speed motor 47. The high-speed stirring drum 46 is provided with a water inlet for connecting an external water pipe to inject water into the high-speed stirring drum 46. The water inlet is provided with a water valve, and the control module 34 is electrically connected to the water valve. The high-speed stirring device 35 is used to stir the powder and water into a slurry. The high-speed motor provides power. The weight sensor is used to control the water inlet and feed amount in the high-speed stirring drum. The slurry discharge port is used to discharge the stirred slurry into the low-speed stirring drum.

[0101] The low-speed stirring device 36 includes a low-speed stirring drum 48. A discharge port 42 is located at the bottom of the low-speed stirring drum 48. A low-speed stirring impeller is installed in the low-speed stirring drum 48. A low-speed motor 49 connected to the low-speed stirring impeller is installed at the top of the low-speed stirring drum 48. The control module 34 is electrically connected to the low-speed motor 49. The low-speed stirring device 36 is used to prevent slurry sedimentation, and the low-speed motor provides power. The discharge port 42 is used to transport the slurry into the grouting pump.

[0102] The grouting pump 43 is used to extract slurry, the pressure gauge 44 is used to measure and feedback the slurry pressure, and the grouting interface 45 is used to connect the slurry inlet of the channel 35 of the prestressed pipe segment 33 through the grouting pipe 43.

[0103] The feeding device 37 includes a hopper 50. The hopper 50 is a box-shaped structure for accommodating powder. A cover can be provided on the hopper 50 to prevent powder from flying during operation. A feeding channel 51 is provided at the bottom of the hopper 50, extending to the top of the high-speed stirring device 35. The feeding channel 51 is a pipeline structure used to transport powder from the hopper 50 to the high-speed stirring drum. An auger blade is provided within the feeding channel 51. A feeding motor 52 is provided at the top of the feeding channel 51 to drive the auger blade to rotate. The feeding motor 52 provides power for the powder transportation. A feeding port 53 is provided at the upper end of the feeding channel 51 for feeding material into the high-speed stirring device 35. The control module 34 is electrically connected to the feeding motor 52.

[0104] The loading arm 38 includes a column 54 mounted on top of the mobile platform 32. A crossbeam 55 is mounted on top of the column 54. The crossbeam 55 is located above the loading device 37. A mobile trolley 56 (similar to a crane or overhead crane) is mounted on the crossbeam 55. The mobile trolley 56 is equipped with a crane 57. The lower end of the rope 58 of the crane 57 is connected to a gripper 59 (manipulator) for grabbing the material bag. The control module 34 is electrically connected to the mobile trolley 56 and the crane 57. The gripper 59 is opened and closed manually or controlled by the control module 34.

[0105] A rotating platform 60 connected to the beam 55 is provided on the top of the column 54, or a rotating platform 60 connected to the column 54 is provided on the top of the mobile platform 32. The control module 34 is electrically connected to the rotating platform 60, so that the beam 55 can achieve horizontal rotation.

[0106] The mobile platform 32 on one side of the column 54 is provided with a storage area 61 for storing material bags. The top of the mobile platform 32 is also provided with a slurry storage barrel 62 for accommodating waste slurry. The slurry storage barrel 62 has the same function as the slurry support barrel 24, and there is no need to set up a slurry support barrel 24 separately.

[0107] The process of making slurry: connect the water and electricity lines of the mobile platform 32, use the loading arm 38 to grab the material bag, and then put the material into the loading device 37;

[0108] Input the slurry dosage, water-cement ratio, pressure, and stirring time parameters into the control module 34, and then start. The control module 34 controls the feeding device 37 to feed the high-speed stirring device 35 according to the slurry dosage and water-cement ratio, and stops feeding after the weight sensor 39 detects that enough material has been added. The control module 34 controls the water valve of the high-speed stirring device 35 to open and add water, and stops adding water after the weight sensor 39 detects that enough water has been added.

[0109] The control module 34 controls the high-speed stirring device 35 to perform high-speed stirring according to the stirring time. After the high-speed stirring is completed, the control module 34 controls the slurry discharge control valve 41 to open and put the stirred slurry into the low-speed stirring device 36. The control module 34 controls the low-speed stirring device 36 to continue stirring at a low speed to prevent the slurry from settling.

[0110] The grouting pump 43 is started to discharge the air and impurities in the grouting pipe 21 , and the waste liquid is discharged into the slurry storage barrel 62 .

[0111] Of course, in other embodiments, the grouting trolley 16 may also be a CNC grouting trolley using current technology.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A shield tunnel segment structure prestressing system composition and construction method, characterized in that: The following steps are involved: Step 1. Conduct an overall layout design for the prestressing system of the shield tunnel segment structure. Based on the characteristics of the shield tunnel segment structure, the prestressing is arranged in a vertical ring and cross-anchored to the inner wall of the segment. To ensure uniform stress distribution, the number of prestressing cables and the anchoring positions of each segment ring should be arranged symmetrically. Based on the requirements of tunnel structure operation and maintenance, cable force monitoring sensors and spare channels are reserved on the segments. This means that the stress state of the segments can be monitored at any time during operation, and prestressing can be reapplied or replaced after a certain period of time. The overall layout plan of the tunnel segment prestressing monitoring system is as follows: To save costs, there is no need to monitor the cable force of each prestressing cable. Instead, they only need to be evenly spaced within the tunnel route section. At the same time, additional measuring points are set up in areas with sudden line changes, complex geology, and irregular loads. Step 2. Prefabricate the prestressed pipe segment (1), set a reserved channel during the process of pouring the prestressed pipe segment (1) with concrete, and set a cable force monitoring sensor (2) in the reserved channel; Step 3. The prestressed bundle (3) is made into a cable and rolled into a prestressed cable drum (4); Step 4. In accordance with the rhythm of the shield machine entering the tunnel and assembling the prestressed segments (1), the amount of prestressed cable discs (4) required for one ring of prestressed segments (1) is loaded onto a material transport train each time and transported together with the prestressed segments (1) to the location to be assembled inside the tunnel; Step 5. After assembling a ring of prestressed pipe segments (1), the prestressed bundle (3) in the prestressed cable drum (4) is passed through the reserved channel of the prestressed pipe segment (1) by a wire threading and traction machine (5); Step 6. Using two tensioning jacks (6), the two ends of the prestressed bundle (3) are tensioned synchronously and graded to the designed prestressing value, and then anchored; Step 7. Carry out anti-corrosion treatment on the anchor head; Step 8. Connect the lead of the cable force monitoring sensor (2) to the demodulator to monitor the cable force.

2. A shield tunnel segment structure prestressing system structure and construction method according to claim 1, characterized in that: The cable force monitoring sensor (2) is a magnetic flux sensor, and the number of the cable force monitoring sensors (2) is three, one of which is located at the diagonal position of the anchoring end, and the other two cable force monitoring sensors (2) are respectively located at the transition points of the two anchoring end corners.

3. The shield tunnel segment structure prestressing system structure and construction method according to claim 2 is characterized in that: In step 2, during the process of using concrete to cast the prestressed pipe segment (1), a corrugated pipe (7) is placed in the prestressed pipe segment (1) by tying the positioning steel bars to form the reserved channel, a bell-mouth structure (8) is provided at both ends of the corrugated pipe (7), the cable force monitoring sensor (2) is nested outside the corrugated pipe (7), and a spiral rib (9) is embedded in the anchor end of the prestressed pipe segment (1), and an anchor plate (10) is embedded in the anchor end of the prestressed pipe segment (1) by using a reserved hole on the template and fixing with bolts.

4. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: In step 3, the prestressed bundle (3) is prefabricated in a factory or manufactured on the construction site, that is, the steel strands are cut one by one according to the designed length, the number of steel strands is determined according to the size of the designed prestressing value, and then the multiple steel strands are arranged into a bundle to obtain the prestressed bundle (3). Then, each bundle of the prestressed bundle (3) is individually wound up into a prestressed cable drum (4) using a traction head and a winding machine, and the prestressed cable drum (4) is fixed for easy transportation.

5. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: In step 5, during construction, the prestressed cable drum (4) is first loaded into the pay-off drum (11) and hoisted to the position of the prestressed pipe segment (1) that has just been assembled in the tunnel, and then the threading and pulling machine (5) is arranged above the reserved tunnel opening. The movement and fixation of the threading and pulling machine can be achieved by arranging a small mechanical arm on the shield machine; The wire threading traction machine (5) is started to convey the traction wire (12) through the reserved channel and out from the lower channel opening, the traction wire (12) is connected to the traction head of the prestressed bundle (3), and then the wire threading traction machine (5) is started to reversely pull the prestressed bundle (3) through the reserved channel until the prestressed bundle (3) passes through the reserved channel to a set working length.

6. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: In step 6, the graded synchronous tensioning is divided into three levels of uniform tensioning: Tensioning to 20% of the designed prestressing value, maintaining the first set time, and detecting whether the prestressed bundle (3) and the equipment are abnormal, and stopping tensioning if any abnormality occurs; Tensioning to 60% of the designed prestressing value, maintaining the first set time, and detecting whether the prestressing bundle (3) and the equipment are abnormal, and stopping tensioning if any abnormality occurs; Tensioning is performed to 100% of the designed prestressing value; a first set time is maintained, and the prestressing bundle (3) and the equipment are detected to see if there is any abnormality, and tensioning is stopped if any abnormality is found.

7. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: The tensioning jack (6) is an ultra-high pressure integrated jack. The tensioning jack (6) integrates the tensioning tooling (14) and the through-type jack (15) into one piece. The movement and fixation of the tensioning jack can be achieved by arranging a small mechanical arm on the shield machine.

8. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: Before tensioning, it is necessary to test whether the actual friction resistance of the reserved channel is consistent with the preset value during design, so as to determine whether the established effective prestressing force meets the design requirements; the details are as follows: Before construction, a friction test is carried out by separately setting a test segment with the same structure as the prestressed segment (1); or during construction, a friction test is carried out by selecting a reserved channel of the assembled first ring prestressed segment (1); If the deviation between the actual duct friction resistance and the preset value is greater than the set deviation, it is necessary to report to the design unit for review to determine whether the tensioning control force needs to be adjusted to ensure that the effective stress established after tensioning is completed meets the design requirements.

9. The shield tunnel segment structure prestressing system structure and construction method according to claim 1 is characterized in that: If the prestressed bundle (3) is anchored by a bonded prestressed system, grouting construction is performed in step 7, using a dynamic serial grouting construction process, and completing the automated operation of mixing materials and grouting by a grouting trolley (16); The specific construction process is as follows: using the intermittent time of assembling the prestressed pipe segments (1) in advance to install the anchor cover (17), installing the joint pipe (18) at the grouting port of the reserved channel, installing the valve (19) on the joint pipe (18), and simultaneously using the external pipe (20) to connect the adjacent multiple reserved channels end to end to prepare for the work; Then the grouting trolley (16) is driven into the tunnel segment area to be grouting, the grouting pipe (21) is connected to the joint pipe (18) of the head end grouting port, the grouting pipe (23) connected to the tunnel exhaust port (22) is connected to the grouting cylinder, and the water and electricity lines are connected to start mixing and grouting. The mixing and grouting processes are automatically performed by the grouting trolley (16) according to the set program; After the slurry is discharged from the duct exhaust port (22) of the last reserved duct, the head end grouting port is closed, and then the grouting pipe (21) is connected to the joint pipe (18) of the tail end grouting port for grouting, and after the slurry is discharged from the duct exhaust port (22) of the last reserved duct again, the duct exhaust port (22) is closed, and the pressure is stabilized for the second set time according to the process requirements to complete the grouting of the ducts of this group; The grouting trolley (16) is driven out of the tunnel, and after the slurry is initially solidified, the joint pipe (18) and the valve (19) can be removed during the interval; Pour or apply anti-corrosion materials at the anchor heads at both ends for anti-corrosion.

10. The shield tunnel segment structure prestressing system structure and construction method according to claim 1, characterized in that: If the prestressed bundle (3) is anchored by a non-bonded prestressed system or a finished cable prestressed system, then in step 7, the anchor cover (17) is first installed, and then the anti-corrosion material is poured or applied to the anchor heads at both ends for anti-corrosion.

Images