Rectangular pipe jacking machine construction method for improving construction accuracy

Abstract

The application relates to the technical field of tunnel construction, and discloses a construction method of a rectangular pipe jacking machine capable of improving construction precision. The method aims at solving the technical problems in the prior art, such as water leakage at the starting well and receiving well, stratum collapse caused by the retreat of the pipe jacking machine after pipe joint jacking, easy deflection of the pipe jacking machine, and jacking difficulty of the pipe jacking machine caused by the easy formation of mud cakes on the cutter head of the pipe jacking machine. The method comprises the following steps: construction preparation before pipe jacking of the pipe jacking machine: installing a water stop device at a starting well portal, installing a starting device, and hoisting the pipe jacking machine; pipe jacking construction of a starting section of the pipe jacking machine: breaking the surrounding structure of the starting well, jacking the pipe jacking machine and filling the bin, and cutting the soil body; pipe jacking construction of a normal section of the pipe jacking machine: pushing the pipe jacking machine forward; and pipe jacking construction of a receiving section of the pipe jacking machine. The method further comprises a step of removing mud cakes, and a mud cake removing device is connected with a pressure monitoring mechanism. The method improves construction safety and construction efficiency, eliminates the deviation of the working face from the source, and is rapid and convenient to debug.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel construction, in particular to a construction method of a rectangular pipe jacking machine for improving construction accuracy. BACKGROUND

[0002] With the rapid development of urban construction, the demand for urban underground space development is becoming larger and larger, and accordingly, the construction demand and purpose of the stratum are becoming more and more diversified. Not only is this the case for urban underground space, but in recent years, the trend of safety and green development in many underground construction fields such as mine development and coal mining is becoming more and more urgent. Based on such actual needs, higher requirements are put forward for the construction method. How to effectively implement stratum treatment construction or geological improvement construction, how to extend the construction operation to the predetermined position in the stratum, and how to better protect the stratum after excavation and development, only with the current existing underground construction method, it is still not convenient and effective for construction and treatment.

[0003] The prior art Chinese patent document 202210217795 discloses a construction method of a shield machine entering a portal arch top pipe. The shield machine starting well counterforce device is installed, the counterforce device design height is installed at the distance of the top pipe design depth to the base pit bottom + 500mm ± 50mm; the portal height of the shield machine drilling is measured and positioned; the top pipe construction machine is installed; the top pipe construction operation is carried out; after the construction is completed, the top pipe grouting is carried out in time; the measurement monitoring points are laid after the grouting is completed; the shield machine and other mechanical hoisting and drilling work are carried out; the top pipe stability in the process of the shield machine drilling is monitored in time.

[0004] However, the above-mentioned scheme has at least the following technical problems in the implementation process: the starting well and the receiving well portal are prone to water leakage, the stratum collapses after the pipe joint is jacked and the pipe jacking machine retreats, the pipe jacking machine is prone to deflection, and the pipe jacking machine cutter head is prone to mud cake, causing the pipe jacking machine to be difficult to jack. SUMMARY

[0005] In view of the above technical problems, the present application provides a construction method of a rectangular pipe jacking machine for improving construction accuracy, which solves the technical problems of water leakage of the starting well and the receiving well portal, stratum collapse after the pipe joint is jacked and the pipe jacking machine retreats, deflection of the pipe jacking machine, and mud cake of the pipe jacking machine cutter head causing the pipe jacking machine to be difficult to jack.

[0006] According to one aspect of the present application, a construction method of a rectangular pipe jacking machine for improving construction accuracy is provided, comprising the following steps:

[0007] S1: preparation work and initial ring construction

[0008] A water stop device is installed at the portal of the starting shaft, a starting device is installed in the starting shaft, a pipe jacking machine is hoisted, the surrounding structure of the starting shaft is broken layer by layer from bottom to top, and the construction site is cleaned, and the size of the broken part is not less than the size of the steel ring of the portal; after the construction site is cleaned, the pipe jacking machine is hoisted and jacked forward, the jacking is stopped after the pipe jacking machine is jacked forward by 0.5-1 ring pipe piece width distance, and the thixotropic mud is delivered to the soil bin at the machine head, and the filling height is not less than half of the equipment height;

[0009] S2: normal section jacking construction of the pipe jacking machine

[0010] Forward tunneling of the pipe jacking machine: after filling, the pipe jacking machine continues to cut soil along the jacking axis and forward jacking, and the rotation speed of the screw conveyor is adjusted to control the soil bin pressure P of the pipe jacking machine, so that the active earth pressure Pa < P < passive earth pressure Pp,

[0011] During the tunneling process, it also includes a step of removing mud cake, which includes:

[0012] Mud cake detection: a mud outlet is installed on the working face, a thixotropic mud / low-density mud is connected through a mud pipeline, the mud pipeline is driven through a hydraulic circuit, a pressure detection device is connected on each branch of the hydraulic circuit, when the pressure value of one or more of them rises, it is determined that mud cake phenomenon occurs, and when the values rise in an arithmetic sequence, it is determined that the working face is unbalanced;

[0013] Mud pipeline conversion and variable flow cleaning: the pipe jacking machine stops tunneling, the mud pipeline is opened, the cutter head mud cake is washed, and the pressure values return to normal;

[0014] Balancing adjustment of the shield working face stress: the pressure detection device is connected to a general controller, the output end of the general controller is connected to a display screen, the general controller controls the flow valve of the hydraulic circuit, and the oil pressure of each hydraulic circuit is adjusted to realize reverse balancing of the working face pressure;

[0015] During the tunneling process, it also includes jacking axis correction, the general controller is also electrically connected to an observation platform, the observation platform is arranged in the starting shaft of the pipe jacking machine, an automatic leveling level is installed on the observation platform, a laser theodolite is installed on the automatic leveling level, a laser emitter is installed on the telescope of the laser theodolite, and a laser detector is arranged on the measuring platform in the shell of the pipe jacking machine; the jacking axis correction step includes: the laser theodolite is centered and leveled on the automatic leveling level, at this time the laser beam is the reference guide line of the jacking axis, at the beginning of construction, the receiving target center of the laser detector coincides with the laser spot emitted by the laser emitter, the laser detector indicates zero, after the pipe jacking machine starts tunneling, the machine head deviates, the laser spot emitted by the laser emitter deviates from the receiving target center of the laser detector, the general controller gives a deviation control signal, and then the pipe jacking machine head direction is corrected, so that the pipe jacking machine head advances along the direction of the laser beam;

[0016] Pipe section installation: Before each pipe section is installed, the water stop is installed in advance. The pipe section is hoisted by a crawler crane. The pipe section is installed concentrically and coaxially with the pipe jacking machine. After each ring of pipe sections is pushed, the pipe jacking machine stops advancing. The oil cylinder of the pipe jacking machine is retracted to leave space for hoisting the next ring of pipe sections. The next ring of pipe sections is hoisted in front of the jacking iron of the oil cylinder and is installed along the jacking axis.

[0017] Installation of the retreat prevention device: After jacking is completed, the retreat prevention device is installed on both sides of the base.

[0018] S3: Construction of the pipe receiving section

[0019] Installation of the receiving base and the water stop device: The position of the hole portal is measured. The pipe jacking machine receiving base is installed in the receiving well according to the elevation of the pipe jacking machine. The water stop device is installed at the hole portal of the receiving well.

[0020] Breaking the receiving well enclosure and receiving the pipe jacking machine: When the cutter head of the pipe jacking machine is 0.5-1 ring pipe piece width away from the receiving well enclosure, stop jacking, break the protection structure at the hole portal of the receiving well and clean the construction site.

[0021] After the construction site is cleaned, the pipe jacking machine is advanced to be received by the receiving well. The pipe sections are welded to the hole ring. A hydraulic slurry is used to fill the gap between the pipe sections and the hole ring to fix the pipe sections and reduce water and soil loss.

[0022] Separation of the pipe jacking machine from the pipe sections and sealing of the hole portal: After the pipe sections are fixed, the pipe jacking machine is separated from the pipe sections. The hole portal is sealed by using a hole portal plate.

[0023] The water stop device installed at the starting well portal in S1 and the water stop device installed at the receiving well portal in S4 both have flanges. The water stop devices are connected to the starting well and the receiving well through the flanges. The water stop device includes a rubber water stop ring (1) and a plurality of rubberized fabric plates (2) connected by bolts. A plurality of corresponding screw holes are reserved on the rubber water stop ring (1) and the rubberized fabric plates (2).

[0024] The starting device in S1 includes a starting base (7). An equal-height track (8) parallel to the jacking axis is installed on the starting base (7). A launching rack (9) and a steel backrest (10) are connected to the track. A starting counterforce frame is cast in concrete or installed in the gap between the steel backrest (10) and the lining wall of the starting well.

[0025] The hoisting of the pipe jacking machine in S1 includes the following steps:

[0026] (1) The front cylinder lower assembly and the front cylinder upper assembly are hoisted in sequence. The front cylinder lower assembly and the front cylinder upper assembly are fixed firmly to the track. Both the front cylinder lower assembly and the front cylinder upper assembly are provided with sockets.

[0027] (2) Hoist the rear cylinder lower assembly, the bolt conveyor and the rear cylinder upper assembly in sequence, and the rear cylinder lower assembly and the rear cylinder upper assembly are both provided with sealing rubber rings corresponding to the sockets;

[0028] (3) Apply lithium-based lubricating grease to the sockets and the sealing rubber rings evenly, and use the main jacking cylinder or the auxiliary jacking cylinder to push the rear cylinder lower assembly into the front cylinder lower assembly and push the rear cylinder upper assembly into the front cylinder upper assembly, and control the pushing speed to realize that the sealing rubber rings enter the sockets;

[0029] The front cylinder lower assembly, the front cylinder upper assembly, the rear cylinder lower assembly and the rear cylinder upper assembly are all parallel to the jacking axis.

[0030] The pipe jacking machine is also provided with a deviation prevention measure during the forward pushing process in S2, and the deviation prevention measure comprises the following steps: connecting a large-tonnage hand-operated hoist through a hoist in one side of the pipe jacking machine / the well wall, tightening the chain while the pipe jacking machine is pushed, welding a stop block on the outer shell of the pipe jacking machine, and cooperating with the foundation pit guide rail to prevent the pipe jacking machine from deviating; and the pipe jacking machine is connected with the front two pipe sections to prevent the head of the pipe jacking machine from deviating.

[0031] The stop-retreating device in S2 comprises a plurality of struts (3), a plurality of pins (4) and a plurality of pin seats (5) matched with the pins (4), the struts (3) are welded on the base, the pins (4) are inserted into the hoisting holes of the pipe sections (6) and are fixedly installed in cooperation with the pin seats (5), and the retreating force generated by the pipe sections (6) is transmitted to the struts (3) of the stop-retreating device in sequence through the pins (4) and the pin seats (5).

[0032] The pipe section friction reduction step is further included before the installation of the pipe section in S2, the pipe section friction reduction step comprises injecting thixotropic mud on the outside of the pipe section on the inside of the pipeline to form a circle of friction reduction mud sleeve around the pipeline to reduce the frictional resistance between the soil and the pipeline; and the thixotropic mud comprises bentonite, water, soda ash, CMC (PAM) and emulsified oil.

[0033] The receiving well pipe jacking machine disassembly step is further included after S3, and the receiving well pipe jacking machine disassembly step comprises:

[0034] (1) dismounting the connecting components between the split parts of the pipe jacking machine; (2) hoisting the front cylinder upper part out of the receiving working well; (3) dismounting the support frame of the mud cake installation and cleaning device; (4) hoisting the rear cylinder upper part out of the receiving working well; (5) hoisting the screw conveyor out of the receiving working well; (6) hoisting the rear cylinder lower part out of the receiving working well; and (7) hoisting the front cylinder lower part out of the receiving working well.

[0035] The beneficial effects of the present application are as follows:

[0036] The construction safety and construction efficiency are improved, and the post-construction maintenance cost is reduced.

[0037] Setting water stop device installs the starting well hole mouth and the receiving well hole mouth, prevents the outside soil and the wall mud from rushing into the starting well and the receiving well, and causes the serious quality safety accident;

[0038] Setting retreat stop device, the retreat force of the pipe section is transmitted to the retreat stop device, preventing the pipe section from retreating after jacking to cause the stratum collapse, so as to stabilize the pipe section;

[0039] Taking the deflection prevention measure, preventing the pipe jacking machine from deflecting, and avoiding the accident;

[0040] The on-off mud flow channel is convenient for forming or cleaning the mud cake or the detail control of the modified mud, and is convenient for the maintenance and maintenance of the later equipment; the design of the inner and outer pipes is convenient for realizing or stirring the excavated soil to form the thixotropic mud, or the flushing effect of the cutter head of the pipe jacking machine, and is not in conflict with each other and is independently used at different times; the guide groove is convenient for better flushing and stirring the rod by low-density grouting;

[0041] Setting pipe section friction reduction, reducing jacking resistance and ground settlement;

[0042] Setting starting device, so as to bear various loads in the pipe jacking machine jacking process, while the starting well does not displace, deform and settle;

[0043] The automatic leveling leveler is automatically leveled on the observation table, and the performance is stable;

[0044] The laser theodolite guides the laser beam emitted by the laser into the telescope barrel of the laser theodolite, so that the laser beam is emitted along the collimation axis direction, and the laser theodolite is used as a reference to carry out line marking, positioning and angle and slope measurement, and corrects the direction of the pipe jacking machine head, so that the pipe jacking machine head advances along the direction of the laser beam, and the degree of automation is high;

[0045] The laser emits laser, and the light quality is pure and the spectrum is stable; the laser beam hits the laser detection instrument light target of the tunneling machine, the position of the point on the light target is observed to judge the height and left-right deviation of the tunneling, the laser detection instrument receives the laser emitted by the laser and detects the incident angle and position of the laser, the measurement is stable, the precision is high, and the laser detection instrument is convenient and practical. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is the water stop device structure schematic diagram in the application;

[0047] Figure 2 It is the starting device structure schematic diagram in the application;

[0048] Figure 3 It is the retreat device structure schematic diagram in the application;

[0049] Figure 4 It is the grouting pipe group explosion effect perspective view in the application;

[0050] Figure 5 is a sectional view of the structure of the grouting pipe group in another working state in the application;

[0051] Figure 6 is a sectional view of the structure of the grouting pipe group in another working state in the application;

[0052] Names of components in the figure: 1, rubber water stop ring; 2, rubber cord fabric plate; 3, support; 4, pin; 5, pin seat; 6, pipe joint; 7, starting base; 8, track; 9, launching rack; 10, steel backrest; 11, external modified mud pipe; 12, internal flushing pipe; 13, through hole; 14, positioning slide; 15, positioning sliding groove. DETAILED DESCRIPTION

[0053] The preferred embodiments of the application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the application, and are not used to limit the application. Example 1

[0054] This example discloses a construction method of a rectangular pipe jacking machine for improving construction accuracy, referring to Figures 1 to 6 , comprising the following steps:

[0055] S1: preparation work and initial ring construction

[0056] A water stop device is installed at the starting well opening, a starting device is installed in the starting well, the pipe jacking machine is hoisted, the starting well enclosure structure is broken layer by layer from bottom to top, and the construction site is cleaned up, and the broken size is not less than the size of the steel ring at the opening; after the construction site is cleaned up, the pipe jacking machine is hoisted and jacked forward, the jacking is stopped after jacking for 0.5-1 ring pipe piece width distance, the thixotropic mud is transported to the machine head soil bin, and the filling height is not less than half of the equipment height;

[0057] S2: jacking construction of the normal section of the pipe jacking machine

[0058] Pipe jacking machine forward excavation: after filling, continue to jacking the pipe jacking machine along the jacking axis to cut the soil, and adjust the rotating speed of the screw conveyor to control the soil bin pressure P of the pipe jacking machine, so as to achieve the condition of active earth pressure Pa < P < passive earth pressure Pp,

[0059] During the excavation process, it also includes the working step of removing the mud cake, and the working step of removing the mud cake includes:

[0060] Mud cake detection: a mud outlet is installed on the working face, the thixotropic mud / low density mud is connected through the mud pipeline, the mud pipeline is driven by the hydraulic circuit, and the pressure detection device is connected on each branch of the hydraulic circuit; when the pressure value of one or more of them rises, it is determined that the mud cake phenomenon occurs; when the numerical value rises in an arithmetic sequence, it is determined that the working face is unbalanced.

[0061] Mud pipeline conversion, variable flow cleaning: the pipe jacking machine stops tunneling, opens the mud pipeline, realizes the flushing of the cutter head mud cake, and returns to the pressure value;

[0062] Balanced adjustment of the stress of the shield tunnel face: the pressure detection device is connected to the general controller, the output end of the general controller is connected to the display screen, the general controller controls the hydraulic circuit flow valve, and the oil pressure of each hydraulic circuit is adjusted to realize the reverse balanced adjustment of the tunnel face pressure;

[0063] During the tunneling process, the top jacking axis deviation correction is also included, and the observation platform is also electrically connected to the general controller, the observation platform is arranged in the launching shaft of the pipe jacking machine, an automatic leveling level is installed on the observation platform, a laser theodolite is installed on the automatic leveling level, a laser is installed on the telescope of the laser theodolite, and a laser detector is arranged on the measuring platform in the pipe jacking machine shell; the working steps of the top jacking axis deviation correction include: the laser theodolite is centered and leveled on the automatic leveling level, at this time the laser beam is the reference guide line of the top jacking axis, at the beginning of construction, the receiving target center of the laser detector coincides with the laser spot emitted by the laser, the laser detector indicates zero, after the pipe jacking machine starts tunneling, the machine head deviates, the laser spot emitted by the laser deviates from the receiving target center of the laser detector, the general controller gives a deviation control signal, and then the machine head direction of the pipe jacking machine is corrected, so that the machine head of the pipe jacking machine advances along the direction of the laser beam;

[0064] Installation of pipe sections: before each pipe section is installed, a water stop strip / water stop ring is installed in advance, a crawler crane is used to hoist the pipe section, and the pipe section is installed concentrically and coaxially with the pipe jacking machine; after each ring of pipe sections is pushed and pressed, the pipe jacking machine stops advancing, the oil cylinder of the pipe jacking machine retracts, leaving space for hoisting the next ring of pipe sections, hoisting the next ring of pipe sections in front of the top iron of the oil cylinder, and installing the pipe sections along the top jacking axis;

[0065] Installation of the retreat stop device: after the jacking is completed, the retreat stop device is installed on both sides of the base;

[0066] S3: Construction of the pipe receiving section

[0067] Installation of the receiving base and the water stop device: measure the position of the hole portal, install the pipe jacking machine receiving base in the receiving well according to the elevation of the pipe jacking machine, and install the water stop device at the hole portal of the receiving well;

[0068] Breaking the receiving well enclosure structure and receiving the pipe jacking machine in the receiving well: when the cutter head of the pipe jacking machine is 0.5-1 ring pipe piece width away from the receiving well enclosure structure, stop jacking, break the protection structure of the receiving well hole portal and clean the construction site;

[0069] After the construction site is cleaned, the pipe jacking machine advances to the receiving well, the pipe sections are welded to the hole ring, and water-hardening slurry is used to fill the gap between the pipe sections and the hole ring to fix the pipe sections and reduce water and soil loss;

[0070] Separate the pipe jacking machine from the pipe joint, and block the hole door: after the pipe joint is fixed, the pipe jacking machine is separated from the pipe joint, and the hole door plate is used to block the receiving well hole door.

[0071] The S1 water stop device is installed at the starting well hole, and the S4 water stop device is installed at the receiving well hole. Flanges are reserved at the starting well hole and the receiving well hole. The water stop device is connected to the starting well and the receiving well through the flanges. The water stop device includes a rubber water stop ring (1) and a plurality of rubberized fabric plates (2) connected by bolts. A plurality of corresponding screw holes are reserved on the rubber water stop ring (1) and the rubberized fabric plates (2).

[0072] The S1 starting device includes a starting base (7). An equal-height track (8) parallel to the jacking axis is installed on the starting base (7). A launching frame (9) and a steel backrest (10) are connected to the track. The concrete is poured and the starting counterforce frame is installed in the gap between the steel backrest (10) and the lining wall of the starting well.

[0073] The hoisting of the pipe jacking machine in S1 includes the following steps:

[0074] (1) Hoist the front cylinder lower assembly and the front cylinder upper assembly in sequence, and fix the front cylinder lower assembly and the track firmly. Both the front cylinder lower assembly and the front cylinder upper assembly are provided with sockets.

[0075] (2) Hoist the rear cylinder lower assembly, the bolt conveyor, and the rear cylinder upper assembly in sequence. Both the rear cylinder lower assembly and the rear cylinder upper assembly are provided with sealing rubber rings corresponding to the sockets.

[0076] (3) Uniformly apply lithium-based lubricating grease at the sockets and the sealing rubber rings. Use the main jacking oil cylinder or the auxiliary oil cylinder to push the rear cylinder lower assembly into the front cylinder lower assembly and the rear cylinder upper assembly into the front cylinder upper assembly. Control the pushing speed to make the sealing rubber rings enter the sockets.

[0077] The front cylinder lower assembly, the front cylinder upper assembly, the rear cylinder lower assembly, and the rear cylinder upper assembly are all parallel to the jacking axis.

[0078] During the forward pushing process of the pipe jacking machine in S2, a deviation prevention measure is also provided. The deviation prevention measure includes: connecting a large-tonnage hand-operated hoist to the pipe jacking machine side / lifting between the well walls, tightening the chain while the pipe jacking machine is pushing / a welding block on the pipe jacking machine shell, cooperating with the foundation pit guide rail to prevent the pipe jacking machine from deviating; and connecting the pipe jacking machine and the previous two pipe joints into one body to prevent the pipe jacking machine head from deviating.

[0079] The deviation prevention measure includes:

[0080] Looking forward from the rear cylinder of the pipe jacking machine, the position distribution of the correction oil cylinder is determined. At this time:

[0081] If the pipe jacking machine head is tilted upward, the lower group of oil cylinders is extended, the left and right side oil cylinders are followed, and the upper side oil cylinders are locked.

[0082] If the machine head of the pipe jacking machine is tilted downward, the upper group of oil cylinders is extended, the left and right side oil cylinders follow, and the lower side oil cylinders are locked;

[0083] If the machine head of the pipe jacking machine is tilted to the left, the right group of oil cylinders is extended, the upper and lower side oil cylinders follow, and the left side oil cylinders are locked;

[0084] If the machine head of the pipe jacking machine is tilted to the right, the left group of oil cylinders is extended, the upper and lower side oil cylinders follow, and the right side oil cylinders are locked;

[0085] If deviations occur in the upper / lower and left / right directions at the same time, the upper / lower deviation is corrected first, and then the left / right deviation is corrected.

[0086] The S2 stop device comprises a plurality of struts (3), a plurality of pins (4), and a plurality of pin seats (5) matched with the pins (4). The struts (3) are welded on the base, the pins (4) are inserted into the hoisting holes of the pipe sections (6), and the pipe sections (6) are fixedly installed in cooperation with the pin seats (5). The retraction force generated by the pipe sections (6) is sequentially transmitted to the struts (3) of the stop device through the pins (4) and the pin seats (5).

[0087] Before the S2 installation of the pipe section, a pipe section friction reduction step is further included. The pipe section friction reduction step comprises injecting a thixotropic mud on the outside of the pipe section on the inside of the pipeline to form a ring of friction reduction mud around the pipeline, thereby reducing the frictional resistance between the soil and the pipeline. The thixotropic mud comprises bentonite, water, soda ash, CMC (PAM), and emulsified oil.

[0088] The mud ratio (in kg / m3) is shown in the following table

[0089] The friction reduction mud mixing ratio table (unit: kg / m3)

[0090] Serial number Bentonite Water Soda ash CMC (PAM) Emulsified oil 1 200～250 350 2.5～4.5 1.5～2.5 2 350 800 5 3 7

[0091] In particular, it further includes a combined mud system composed of a sleeve. In the combined mud system, mud modification during tunneling, cleaning, early warning and treatment of mud cake are realized. Furthermore, in the cleaning process of the mud cake, a specific step of judging whether the working face is inclined by pressure is introduced synchronously. The inducement of the initial inclination is eliminated, and the stable operation of the equipment is ensured as a whole.

[0092] The S3 further includes a pipe jacking machine disassembly step in a receiving well. The pipe jacking machine disassembly step in the receiving well comprises:

[0093] (1) removing the connecting components between the split parts of the pipe jacking machine; (2) hoisting the upper part of the front cylinder out of the receiving working well; (3) disassembling the support frame of the mud cake cleaning device; (4) hoisting the upper part of the rear cylinder out of the receiving working well; (5) hoisting the screw conveyor out of the receiving working well; (6) hoisting the lower part of the rear cylinder out of the receiving working well; (7) hoisting the lower part of the front cylinder out of the receiving working well.

[0094] While there have been described herein the preferred embodiments of the present application, various modifications and changes can be suggested to one skilled in the art, and it is intended that the application be constructed as including all such modifications and changes as fall within the scope of the application. It is therefore desired that what is, within the scope of the appended claims and their equivalents, be regarded as falling within the scope of the present application.

[0095] It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A construction method for a rectangular pipe jacking machine with improved construction accuracy, characterized by: The steps include: S1: Preparation and initial construction Install a water-stop device at the launch well entrance, install the launch device inside the launch well, hoist the pipe jacking machine, and demolish the launch well enclosure structure layer by layer from bottom to top and clean the construction site. The demolished size should be no smaller than the size of the portal steel ring. After cleaning the construction site, hoist the pipe jacking machine and push it forward. After pushing 0.5-1 ring of pipe segment width, stop pushing and transport thixotropic mud into the machine head soil bin. The filling height should be no less than half of the equipment height. S2: Pipe jacking machine normal section jacking construction The pipe jacking machine advances forward: after filling the bunker, it continues to advance along the jacking axis to cut the soil, and controls the bunker pressure P of the pipe jacking machine by adjusting the speed of the screw conveyor to achieve active soil pressure Pa<P<passive soil pressure Pp. The excavation process also includes a step of removing the mud cake, which includes: Mud cake detection: A mud outlet is installed on the tunnel face, connected to the contact-variable mud / low-density mud through a mud pipe. The mud pipe is driven by a hydraulic circuit, and each branch of the hydraulic circuit is connected to a pressure detection device. When one or more pressure values ​​increase, mud cake is determined to be present. When the values ​​increase in an arithmetic progression, it is determined that the tunnel face is under unbalanced force. Mud pipeline conversion, variable flow rate cleaning: the pipe jacking machine stops excavation, opens the mud pipeline, and realizes the flushing of mud cake on the cutter head until the pressure values ​​drop; Force balance adjustment of shield tunnel face: the pressure detection device is connected to the main controller, the output end of the main controller is connected to the display screen, the main controller controls the flow valve of the hydraulic circuit, and regulates the oil pressure of each hydraulic circuit to achieve reverse balance of tunnel face pressure; The excavation process also includes correction of the jacking axis. The main controller is also electrically connected to an observation platform, which is arranged in the starting shaft of the pipe jacking machine. An automatic leveling level is installed on the observation platform, a laser theodolite is installed on the automatic leveling level, a laser is installed on the telescope of the laser theodolite, and a laser detector is arranged on the measuring platform in the casing of the pipe jacking machine. The step of correcting the jacking axis includes: centering and leveling the laser theodolite and mounting it on the automatic leveling level. At this time, the laser beam is the reference guide line of the jacking axis. At the beginning of construction, the receiving target center of the laser detector coincides with the laser spot emitted by the laser, and the laser detector indicates zero. After the pipe jacking machine starts excavation, the machine head deviates, and the laser spot emitted by the laser deviates from the receiving target center of the laser detector. The main controller gives a deviation control signal, thereby correcting the orientation of the pipe jacking machine head, so that the pipe jacking machine head moves along the direction of the laser beam. Install pipe segments: Before installing each pipe segment, pre-install water stop strips / water stop rings. Use a crawler crane to lift the pipe segment. When installing the pipe segment, keep it concentric and coaxial with the pipe jacking machine. After pushing each pipe segment, the pipe jacking machine stops advancing and the oil cylinder of the pipe jacking machine retracts, leaving space for lifting the next pipe segment. Lift the next pipe segment to the front of the top iron of the oil cylinder and install the pipe segment along the jacking axis. Install the anti-retraction device: After the jacking is completed, install the anti-retraction device on both sides of the base; S3: Construction of the pipe jacking receiving section Install the receiving base and water-stop device: Measure the tunnel portal position, install the pipe jacking machine receiving base in the receiving well according to the elevation of the pipe jacking machine, and install the water-stop device at the receiving well portal; Remove the receiving well enclosure structure and the receiving well pipe jacking machine: When the pipe jacking machine cutterhead is 0.5-1 segment width away from the receiving well enclosure structure, stop jacking, remove the receiving well door protection structure and clean up the construction site; After the construction site is cleaned, the pipe jacking machine is pushed into the receiving well to receive the pipe, weld the pipe segment to the hole ring, and use hydraulic slurry to fill the gap between the pipe segment and the hole ring to fix the pipe segment and reduce soil erosion; Separate the pipe jacking machine from the pipe section and seal the tunnel door: After the pipe section is fixed, the pipe jacking machine is separated from the pipe section and the tunnel door plate is used to seal the receiving well tunnel door.

2. The method for constructing a rectangular pipe jacking machine with improved construction accuracy according to claim 1, wherein: The water-stop device in S1 is installed at the starting well hole, and the water-stop device in S3 is installed at the receiving well hole. Flanges are reserved for the starting well hole and the receiving well hole. The water-stop device is connected to the starting well and the receiving well respectively through the flanges. The water-stop device includes a rubber water-stop ring (1) and a plurality of rubber curtain plates (2) connected by bolts. A plurality of corresponding screw holes are reserved on the rubber water-stop ring (1) and the rubber curtain plates (2).

3. The construction method of a rectangular pipe jacking machine for improving construction accuracy according to claim 1, characterized in that: The launching device in S1 includes a launching base (7), a contour track (8) parallel to the jacking axis is installed on the launching base (7), a launching frame (9) and a steel backrest (10) are connected to the track, and concrete is poured / installed in the gap between the steel backrest (10) and the inner lining wall of the launching shaft.

4. The construction method of a rectangular pipe jacking machine for improving construction accuracy according to claim 1, characterized in that: The hoisting pipe jacking machine in S1 includes the following steps: (1) Hoist the front barrel lower assembly and the front barrel upper assembly in sequence, and secure the front barrel lower assembly to the track; both the front barrel lower assembly and the front barrel upper assembly are provided with sockets; (2) Hoist the rear barrel lower assembly, bolt conveyor, and rear barrel upper assembly in sequence. The rear barrel lower assembly and rear barrel upper assembly are both provided with sealing rubber rings corresponding to the sockets; (3) Apply lithium-based grease evenly on the socket and the sealing rubber ring, use the main top cylinder or auxiliary cylinder to push the rear tube lower assembly into the front tube lower assembly, and push the rear tube upper assembly into the front tube upper assembly, and control the pushing speed to ensure that the sealing rubber ring enters the socket; The front barrel lower component, the front barrel upper component, the rear barrel lower component and the rear barrel upper component are all parallel to the jacking axis.

5. The construction method of a rectangular pipe jacking machine with improved construction accuracy according to claim 1, wherein: During the forward advancement of the pipe jacking machine in S2, anti-deflection measures are also provided; the anti-deflection measures include: climbing on one side of the pipe jacking machine / connecting a large-tonnage hand winch between the well walls, tightening the chain while the pipe jacking machine is advancing / welding a block on the outer casing of the pipe jacking machine, cooperating with the foundation pit guide rail to prevent the pipe jacking machine from deflecting; and connecting the pipe jacking machine with the first two sections of pipe to prevent the head of the pipe jacking machine from deflecting.

6. The construction method of a rectangular pipe jacking machine for improving construction accuracy according to claim 1, characterized in that: The anti-recoil device in S2 comprises a plurality of pillars (3), a plurality of pins (4), and a plurality of pin seats (5) matched with the pins (4). The pillars (3) are welded to the base, and the pins (4) are inserted into the hanging holes of the pipe sections (6) and fixedly installed with the pin seats (5). The backward force generated by the pipe sections (6) is sequentially transmitted to the pillars (3) of the anti-recoil device through the pins (4) and the pin seats (5).

7. The construction method of a rectangular pipe jacking machine for improving construction accuracy according to claim 1, characterized in that: Before installing the pipe joint in S2, the step of reducing pipe joint friction is also included. The step of reducing pipe joint friction includes injecting thixotropic mud into the outer side of the pipe joint inside the pipeline to form a circle of friction-reducing mud sleeve around the pipeline to reduce the frictional resistance between the soil and the pipeline; the thixotropic mud includes bentonite, water, soda ash, polyacrylamide, and emulsified oil.

8. The construction method of a rectangular pipe jacking machine for improving construction accuracy according to claim 1, characterized in that: After S3, the process also includes the step of dismantling the receiving well pipe jacking machine, and the process of dismantling the receiving well pipe jacking machine includes: (1) Remove the connecting parts between the two parts of the pipe jacking machine; (2) Lift the upper part of the front barrel out of the receiving working well; (3) Remove the support frame for installing the mud cake cleaning device; (4) Lift the upper part of the rear barrel out of the receiving working well; (5) Lift the screw conveyor out of the receiving working well; (6) Lift the lower part of the rear barrel out of the receiving working well; (7) Lift the lower part of the front barrel out of the receiving working well.

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