CN111928014A - Pipe jacking engineering construction method - Google Patents

Abstract

The invention discloses a pipe jacking engineering construction method, which comprises the following construction steps: the method comprises the following steps of measurement lofting, working pit construction, starting base installation and pipe jacking machine hoisting, back wall and oil cylinder support installation, tunnel portal double-curtain rubber installation, tunnel portal breaking construction, pipe joint prefabrication and transportation, pipe joint turning over and well descending, pipe jacking, resistance reduction construction, relay station construction, alloy steel cutter follow-up replacement, replacement grouting and pipe jacking machine entering and exiting. The construction method can overcome the problems of safety protection of excavation before the construction of the pipe, water drainage in the pipe and the like in the prior art, can realize circulation of fresh air in the pipe, discharge of toxic gas and deviation rectification control of the position of the pipeline, can improve the construction efficiency, saves the construction cost, and can safely and efficiently promote the progress of the construction.

Description

Pipe jacking engineering construction method

Technical Field

The invention relates to the technical field of building construction, in particular to a pipe jacking engineering construction method.

Background

In recent years, with the advance of old city reconstruction, many construction projects are located in regions with dense houses, large population mobility and complex traffic conditions in urban areas. Designed as a buried tunnel. Due to the complicated engineering geology, more old pipe networks, hard rocks and abundant underground water, the tunnel underground excavation construction period is too long and the danger is high, so the scheme of pipe jacking construction is feasible. However, the construction of the project by using the jacking pipe has the following technical difficulties:

firstly, the pipeline is positioned in the plain soil filling layer, so that the rainwater is large in summer and autumn, and the plain soil filling is easy to collapse when the pipeline is excavated in front of the pipe in a rainy period, so that the safety protection before the pipe is excavated is a key point and is also a difficult point. The excavation before the pipe in the rainy period of the plain soil filling layer may cause water accumulation in the pipe, and the construction of workers in the pipe is influenced.

Moreover, working wells (starting wells) are arranged at two ends of each long pipeline section, and a receiving well is arranged in the middle of each long pipeline section, so that the long pipeline section is jacked from two ends to the middle of each long pipeline section, certain pipeline section is jacked from a high position to a low position, water accumulation in the pipeline is easily caused, and therefore, the key point is to well drain water in the pipeline.

In addition, some unexplored pipelines may exist underground, so that a mechanical earth-removing process cannot be adopted during jacking construction, earth can be removed only before a manual pipe is adopted, and fresh air circulation and toxic gas exhaust in the pipe are key points during construction.

Finally, safe power utilization during lighting in the pipe is also the key point of consideration during construction. The deviation correction control of the pipeline position is a work key point and is also a difficult point. The working well and the receiving well are permanent structures as inspection wells, and the key point is that the seams of the well walls are waterproof.

In the prior art, when the problems are met, a better technical effect is difficult to obtain, and the improvement on the prior construction method is necessary.

Disclosure of Invention

The invention aims to provide a pipe jacking engineering construction method to overcome the defects of the existing construction method.

The technical scheme of the invention is as follows:

a pipe jacking engineering construction method comprises the following construction steps: the method comprises the following steps of measurement lofting, working pit construction, starting base installation and pipe jacking machine hoisting, back wall and oil cylinder support installation, tunnel portal double-curtain rubber installation, tunnel portal breaking construction, pipe joint prefabrication and transportation, pipe joint turning over and well descending, pipe jacking, resistance reduction construction, relay station construction, alloy steel cutter follow-up replacement, replacement grouting and pipe jacking machine entering and exiting.

Wherein, the pipe coupling stands up, goes into the well and includes: the pipe joints are vertically stacked on the field before going into the shaft, and are turned over for 90 degrees on the ground in advance before going into the shaft, the pipe joints are horizontally placed on the ground, and then the shaft operation is carried out; after the pipe joints are stably hoisted to the ground from the carriage by the crane, the pipe joints are hoisted in a turnover mode on the ground by adopting a hoisting mode; when the pipe joint is turned over, the main lifting hook of the truck crane lifts the pipe joint in a balanced manner, when the pipe joint is lifted to 1-2 m high, the auxiliary hook lifts the socket at the lower part of the pipe joint and slowly lifts the pipe joint, and simultaneously the main hook slowly hooks down until the pipe joint rotates by 90 degrees and is transversely placed on the ground.

Further, the method for measuring jacking of the jacking pipe comprises the following steps:

1) erecting a Suguano LT402L and a long-distance 500m laser theodolite in the jacking axis direction of a pipeline in a working well, and enabling a base platform to be only independently connected with a structural bottom plate of the working well, wherein the height of the instrument is consistent with the zero position of a measuring optical target in a pipe jacking machine; otherwise, it cannot be in contact with any other device;

2) the laser theodolite sends out a laser beam consistent with the designed axis of the pipeline and the gradient of the pipeline through manual measurement and calculation and directly strikes a measuring light target in the pipe jacking machine, and a rear viewpoint is attached to a side wall by a 50-by-50 mm reflector plate; the laser stably tracks and measures the optical target while the machine head and the pipe joint move, whether the advancing direction of the machine head is jacked according to the designed axis and the gradient of the pipeline or not is visually seen on the measuring optical target in the jacking process, and if a deviation is found, a jacking driver timely performs reverse deviation correction according to deviation data on the measuring optical target.

Further, the drag reduction construction comprises the following steps: the pipe joint waxing and drag reduction method comprises the following steps: pouring paraffin into an electric heating wax melting pot → heating to melt and boiling → putting a brush on the surface of the pipe joint → airing → spraying coal gas to heat the paraffin, so that the paraffin on the surface of the pipe joint is evenly and smoothly aired → storing → descending a well for transportation → installing the pipe joint.

Compared with the prior art, the construction method can overcome the problems of safety protection of excavation before the construction of the pipe, water drainage in the pipe and the like in the prior art, can realize circulation of fresh air in the pipe, discharge of toxic gas and deviation rectification control of the position of the pipeline, can improve the construction efficiency, saves the engineering cost, and can safely and efficiently promote the engineering progress.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the following examples.

Example 1:

the pipe jacking construction of a certain project comprises the following construction steps: the method comprises the following steps of measurement lofting, working pit construction, starting base installation and pipe jacking machine hoisting, back wall and oil cylinder support installation, tunnel portal double-curtain rubber installation, tunnel portal breaking construction, pipe joint prefabrication and transportation, pipe joint turning and well descending, pipe jacking, resistance reduction construction, relay station construction, alloy steel cutter follow-up replacement, replacement grouting and pipe jacking machine entering and exiting.

1 measurement lofting

And (4) adopting a measurement control network which is approved by a measurement supervision engineer to perform construction lofting, fixing a protected control point, and frequently rechecking. The working pit is positioned by a total station, the theodolite is used for pipeline center line control, and the level is used for elevation control.

And (3) guiding the ground coordinate point into the underground well by adopting a direct guiding method, and establishing an underground pipe jacking tunneling use control point in a branch wire mode by utilizing the coordinate point embedded in the pithead and the measurement control network control point.

When the measuring device is installed, the measuring instrument is separated from the pit bottom and the pit wall of the working pit, and the situation that the positions are displaced due to the application of jacking force during construction and are inconsistent with the initial position, and errors are easy to generate is avoided.

Before starting the push pipe, the axis and the elevation of the tunneling machine head are measured, and the measured data are fed back in time for adjustment. The original data record in the jacking construction is continuous, real and complete, and the record form is clearly filled.

And (4) after the jacking of each section of pipeline is finished, retesting, and drawing a pipeline jacking track graph (comprising pipeline height, direction, jacking force curve and the like).

2 construction of working pit

(1) The working pit is a working place for pipe jacking construction. The position thereof can be determined according to the following conditions:

1) when the pipe is pushed in one direction, the pipe is selected at the downstream end of the pipe to facilitate drainage;

2) considering the terrain and soil conditions, and making the back of the available original soil;

3) the working pit has a certain safety distance with the pipeline and the building which are possibly passed through;

4) a place close to water and a power supply;

5) the working well does not affect ground traffic and the like.

(2) Size of the working pit

The working pit has enough space and working surface to ensure the pipe laying, the installation of jacking equipment and the operation space, the length and width of the pit bottom are the clearance size of 8m multiplied by 6.5m, and the depth is 1m deeper than the bottom of the pipe jacking.

3 initial base installation and pipe jacking machine hoisting

The size of the main machine of the push bench is large, and the weight of the whole push bench reaches 75 t. The main machine of the push bench can be directly hoisted by the whole machine without turning over, the top of the main machine is provided with four hoisting lugs, the main machine is processed after leaving the factory, and the quality meets the standard requirement.

4 back wall and oil cylinder bracket installation

(1) Design of back rest

The rear backrest is divided into two blocks, and the size of the single rear backrest is 3440mm in width, 6300mm in height and 450mm in thickness; the back rest is mainly formed by fully welding the stiffening plates and the surrounding panels, and the back rest is fully welded by 20mm steel plates. The longitudinal and transverse spacing of the stiffening steel plate is 200 mm.

(2) Main technical parameters

Technical parameters of steel back

Firstly, adopting Q345B steel as welding material;

secondly, the built-in stiffening plates are made of 20mm steel plates, and the center distance between the longitudinal stiffening plates and the transverse stiffening plates is 200 mm;

thirdly, the wrapping steel plate is a 20mm steel plate;

fourthly, all the joints are fully welded.

The rear back wall and the oil cylinder bracket are both installed in place by adopting an QYU80t crawler crane, and are accurately positioned and leveled by measuring personnel in the installation process; the axial line of the jacking oil cylinder and the axial line of the tunnel must be in high consistency, and the stress state of the pipe joint and the base and the magnitude of jacking force are greatly influenced during later jacking.

The back wall needs to be installed in advance, provides counter force for pipe jacking pushing, adopts 2 units of 200t oil cylinders to push the pipe jacking machine into the tunnel portal, and provides space for installing the oil cylinder support.

5-hole door double-curtain rubber installation

The opening water stop ring is arranged at the reserved opening of the working well and has the function of preventing underground water, sand and contact mud from flowing to the working well from the gap between the pipe joint and the water stop ring. Double curtain rubber water stop rings and compression rings can be adopted.

6-hole door breaking construction

The soil body is reinforced by adopting three-axis stirring construction, the reinforcing and coring effect is better, the coring hole site has no underground water, and the portal pile body is broken from top to bottom.

7 pipe joint prefabrication and transportation

The pipe joint is prefabricated by adopting an outsourcing mode, a pipe joint steel reinforcement cage is processed by adopting a seam welder in a prefabrication plant, and the whole steel mould cast-in-place concrete construction, manual insertion type vibration and steam maintenance are adopted. And the pipe joints are transported by adopting a flat plate trailer at night, one pipe is loaded in each 3 sections of pipes, and the pipe joints are horizontally placed on the trailer, so that the transportation safety of the pipe joints is ensured.

8 pipe joint turning over and well descending

In order to facilitate transportation and stacking, the pipe joints are vertically stacked on the field before being put into the shaft, and before being put into the shaft, the pipe joints are required to be turned over for 90 degrees on the ground in advance, laid on the ground horizontally and then put into the shaft. After the crane stably lifts the pipe joint from the carriage to the ground, the pipe joint needs to be lifted in a lifting mode on the ground in a turning-over mode. When the pipe joint is turned over, the main lifting hook of the truck crane lifts the pipe joint in a balanced manner, when the pipe joint is lifted to 1-2 m high, the auxiliary hook lifts the socket at the lower part of the pipe joint and slowly lifts the hook, meanwhile, the main hook slowly hooks down until the pipe joint rotates for 90 degrees and is transversely placed on the ground, when the pipe joint goes into a well, the steel wire rope transversely penetrates through the inside of the pipe joint, the protection device is installed at the bell mouth part to prevent the steel wire rope from being damaged, the truck crane is used for going into the well to operate, and the socket direction is ensured to be the jacking direction of the jacking pipe.

9 jacking pipe jacking

(1) Laser guide system

The main equipment of the measuring system is as follows: suguano LT402L laser theodolite (500m), measuring target and monitor.

Measuring the system function: monitoring the axial deviation of the push head in the push pipe construction process.

(2) Measuring method

1) A Suguano LT402L laser theodolite with the length of 500m is erected in the jacking axis direction of a pipeline in a working well, a base platform (with the length of 1m, the width of 1m and the height of 0.8m) is required to be only independently connected with a structural bottom plate of the working well, and the height of the laser theodolite is consistent with the zero position of a measuring light target in a pipe jacking machine. The instrument support can also be made of a steel pipe with the diameter of 180-220 mm (the central line of the steel pipe is consistent with that of the tunnel). In addition, the laser theodolite can not be in contact with any other equipment, so that the vibration or the movement of the other equipment can not cause the vibration of the base platform, which can indirectly cause the instability of the laser theodolite and the inaccuracy of the measured data.

2) The laser theodolite sends out a laser beam consistent with the designed axis of the pipeline and the gradient of the pipeline through manual measurement and calculation and directly strikes a measuring light target in the pipe jacking machine, and a rear view point is pasted on a side wall by a 50-by-50 mm reflector plate (the zero position of the reflector plate is consistent with the center of the tunnel). The head and the pipe joint move forward continuously during jacking, the laser stably tracks and measures the optical target while the head and the pipe joint move, whether the advancing direction of the head jacks according to the design axis and the gradient of the pipeline can be visually seen on the measuring optical target in the jacking process, and if deviation occurs, a jacking driver can perform reverse deviation correction according to deviation data on the measuring optical target in time.

(3) Deviation rectification of push bench

The main equipment is as follows: the system comprises a deviation rectifying jack, an oil pump station, a displacement sensor and an inclinometer.

Function II: and controlling the advancing direction of the pipe jacking machine head in pipe jacking construction.

(4) Soil pressure tunneling slurry slag

The top pipe is driven in a soil pressure balance mode, muck enters the stirring box through a gate of the screw conveyor and then is pumped to the ground surface separation system through the mud pump and the pipeline, after mud and slag are separated, one part of mud is used for mud-water conveying circulation through the mud inlet pipe, and the other part of mud is separated into muck and clear water through the centrifugal machine.

10 drag reduction construction

(1) Pipe joint waxing and drag reduction

In order to reduce the peripheral friction resistance of the jacking pipe, the whole pipeline needs to be waxed to reduce the resistance so as to increase the jacking distance. The construction adopts the whole body of the pipeline to be waxed, and adopts the granular industrial paraffin (No. 54 semi-refined paraffin) to wax the whole body of the outer side of the pipeline with the thickness of 0.5 mm.

(2) Pipe joint waxing construction step

Pouring the paraffin wax into an electric heating paraffin melting pot → heating to melt and boiling → putting the paraffin wax on the surface of the pipe joint by a brush → airing → spraying and heating the paraffin wax by coal gas to ensure that the paraffin wax on the surface of the pipe joint is uniform and smooth → airing → storing → descending a well for transportation → installing the pipe joint.

(3) Lubricating drag reduction mud

1) Synchronous grouting drag reduction

The synchronous grouting material at the tail end of the head of the jacking pipe is required to have high viscosity, small water loss and good stability; the slurry replenishing material for replenishing the loss of the peripheral slurry of the pipeline requires smaller viscosity and larger fluidity. Thixotropic slurry in the jacking pipe adopts single-liquid grouting, and the composition materials prepared in the construction site comprise bentonite, soda ash, CMC and water.

In the jacking process, the thixotropic slurry needs to be frequently injected to reduce jacking resistance. The shape and arrangement of the grouting holes: arranging a thixotropic slurry grouting hole at the front end of the pipe joint, wherein the number of the thixotropic slurry grouting holes is 4, the grouting holes are Dg25 steel pipes and are arranged at 90 degrees, and a slurry sleeve is formed on the outer wall of each pipe through continuous slurry pressing.

The thixotropic slurry pipe is arranged behind the push bench, 4 sections of pipes are arranged behind the push bench, each section of pipe is provided with the thixotropic slurry pipe, and a complete slurry sleeve is formed on the outer wall of each pipe section. And 2 sections of the subsequent pipe joints, namely 1 pipe joint at each interval, are provided one for replenishing the slurry to the slurry sleeve.

(4) Grouting construction

a grouting pressure

And during synchronous grouting, the pressure of slurry in the stratum is required to be greater than the sum of the static water and soil pressures at the point, so that the stratum is filled as much as possible and is not easy to split. When the grouting pressure is overlarge, the slurry disturbs the stratum on the outer wall of the pipe joint, so that the ground surface is raised and slurry leakage at a shallow section can occur; when the grouting pressure is too low, the grouting speed is too low, the filling is insufficient, the integrity of the slurry sleeve is damaged, and the resistance increase and the overlarge ground surface settlement are easy to occur. According to calculation and experience, the theoretical grouting pressure of the grouting orifice of the engineering pipe joint is 0.12-0.15 MPa. In the pushing process, the grouting pressure and the grouting amount can be properly adjusted according to the monitoring data of the ground deformation.

b amount of grouting

The general grouting amount is 2-3 times of the annular gap at the periphery of the pipeline, and according to calculation and experience, the external grouting amount of each section of pipeline is 1.2-1.8 m 3;

the pulp supplementing quantity is as follows: the amount of the slurry is controlled to be 0.15 times of the building clearance, and the slurry is supplemented to the periphery of each section of pipeline by 0.1-0.12 m3 according to calculation and experience.

c grouting time and rate

The synchronous grouting speed is preferably matched with the jacking speed, and the total grouting amount in each cycle is preferably injected uniformly at a constant speed according to the jacking speed of the push bench. The grouting pump adopts a BW-250 type slurry pump, and the minimum flow is 35L/min. According to the construction experience of the related shield tunnel, the pushing speed of the pipe jacking machine is predicted to be about 40mm/min, the pushing of the pipe jacking machine in a loop needs about 60 minutes, the calculation is carried out according to 1200L of slurry injected after each section of pipe wall, and the slurry injection pump needs to continuously inject the slurry for 34 minutes, namely synchronous slurry injection is carried out according to the pushing speed of 73 mm/min. But the actual grouting speed and the tunneling speed need to be continuously adjusted and determined according to the field situation.

d standard of end of grouting

The double control standard of grouting pressure and grouting amount is adopted, namely when the grouting pressure reaches a set value or the grouting amount reaches a calculated amount, the grouting is considered to meet the requirement, but the grouting amount is preferably controlled mainly in the actual operation process.

e grouting effect inspection

Stopping grouting after the grouting pressure reaches a designed pressure value;

the grouting pressure does not reach the design pressure value, but the grouting amount reaches the design grouting amount;

thirdly, judging whether grouting is needed to be continued according to the monitoring condition;

judging whether to supplement the slurry or not according to the statistical result of the variation data of the jacking force, and performing secondary reinforcing grouting for the unsatisfied requirements.

The order of pulp replenishment must be maintained from back to front. The slurry can be supplemented once a day on the slurry supplementing section after being jacked in the range of one hundred meters. The specific method comprises the following steps: and (4) performing grout replenishment by opening and closing a valve and grouting time by a technician in the hole.

11 Relay station construction

(1) Relay station main equipment and function

Consists of a small jack, a hydraulic pump station and an outer shell.

The relay station is used for propelling the whole section of pipeline in a segmented manner, so that the main pushing force is reduced. The relay station consists of 10 jacks of 300KN, and the thrust is 2400 KN.

(2) Working principle and layout distance of relay station

The outer sleeve is pushed forwards to be pushed out by the extending action of the small jack of the relay station, after the outer sleeve pushes the pipe section forwards for a certain distance, the pipe is pushed to move by the rear main jack or the next relay station, the small jack retracts to reset, the pipe section is pushed by the continuous reciprocating motion, and the whole section of the pipe is pushed forwards.

The working principle of the relay station is as follows: when the relay station is placed, the first relay station is placed at the front part, and when the total thrust of the backseat reaches 40-60% of the total thrust of the relay station, the first relay station is placed; theoretically, one relay station is arranged when the total thrust reaches 70-80% of the total thrust of the relay station, and relay jacking of the relay station is started when the total thrust reaches 90% of the total thrust of the main jack.

As the jacking pipe has huge jacking force in rocks, in order to prevent the damage of the pipe, four relay stations are installed in the actual construction process, wherein the first relay station is 20m behind the machine head, the second relay station is placed at 60 meters, the third relay station is placed at 100 meters, and the fourth relay station is placed at 120 meters.

(3) In-hole relay station handling

Dismantling a jack in the relay station;

welding a single layer of reinforcing mesh sheets with the phi of 8 and the interval of 200 multiplied by 200 mm;

and thirdly, spraying C30 mixed soil.

(4) Replacement in-hole relay station

1) Preparation work for replacement relay station

The replacement of the relay station is a construction operation with great risk, corresponding preparation work must be done before the replacement of the relay station, and necessary conditions are created for the orderly operation of the replacement of the relay station. The key points are as follows:

before replacing the relay station, the receiving wellhead is lifted vertically without obstacles in the range of the channel, and the control of the operation field is ensured.

And secondly, preparing 1 truck crane, gas cutting equipment, electric welding equipment, electric picks, hoists, jacks and other equipment for dismantling, performing necessary inspection and debugging, ensuring that the equipment works normally, and controlling the equipment.

Preparing materials such as the steel wire rope and the shackle, ensuring that the strength, the tension and the like of the materials meet the requirements of safe dismantling operation, obtaining the qualified guarantee of manufacturers and realizing the controllability of the materials.

And fourthly, chiseling away the mortar in the hoisting hole of each section of the pipe joint, and cleaning the mortar blocks in the hole.

Preparing organization and labor resources for completing the operation of replacing the relay station, wherein the labor resources have the related experience of replacing the relay station, good safety awareness and collective concept, and ensure the controllability of personnel.

2) Method for replacing relay station

Firstly, when the push bench completely ejects out of the receiving hole door, an installation operator timely removes the first section pipe and the connecting bolt of the push bench, and arranges a professional hoisting team to hoist the push bench out of the receiving well.

Secondly, after the pipe jacking is dismantled, the pipe joint is continuously pushed forwards until the pipe joint of the second section is pushed out 1/3, and the pushing operation is suspended.

And thirdly, symmetrically welding pull lugs on two sides of the pipe joint, fixing one end of the chain block on the receiving base, fixing the other end of the chain block on the pull lugs, and symmetrically and forcibly pulling the chain block until the first pipe joint and the second pipe joint are completely separated. A crane may be used to coordinate the pipe section separation operation.

And fourthly, penetrating the steel wire rope into the pipe joint, hoisting the pipe joint out by using an 80t truck crane, sending the pipe joint onto a flat car prepared in advance, and fixing the pipe joint by using a chain block. And transporting to the original working well for replacement.

And fifthly, properly cleaning the disassembled pipe joints in the working well, and timely arranging operators to replace the pipe joints if the wedge-shaped sealing rings are damaged.

And sixthly, removing the 2-5 pipe joints by analogy.

12 alloy steel cutter replacement

Because this section of push pipe geology is hard and the condition is complicated, prop about 100m need be changed once, include: hobs, scrapers, edge scrapers, tear scrapers, and the like.

13 replacement grouting

(1) Replacement grouting construction scheme

1) Mounting and grouting;

2) debugging grouting equipment: after the grouting equipment is installed, a specially-assigned person checks the grouting equipment, and then a water pressing test is carried out;

3) stirring slurry: during the transition period of the pipe jacking machine, the slurry is stirred manually on the ground by using a stirring barrel while stirring. The slurry is cement paste.

4) And (3) checking the quality of the slurry: the quality of the slurry is detected by a baume densitometer, and if the slurry does not meet the requirements, the slurry is re-prepared.

5) Grouting: performing post-pipe wall replacement grouting by adopting a ground pipe jacking slurry injection system; and taking down the grouting hose, replacing all grouting holes with the counter-thread and grouting ball valves, opening all the ball valves before grouting, closing the ball valves after replacing cement paste, and performing replacement from a lower position to a higher position.

6) And (3) grouting effect inspection:

grouting pressure control: the replacement grouting pressure is controlled to be 1.0-1.5 bar under the general condition; if the replacement grouting effect is not good, the grouting pressure can be properly increased.

Controlling the grouting quantity: when the replacement grouting amount reaches 0.24m 3/linear meter or the mud discharged from the pipe joint reserved hole is observed to be basically all cement paste, the grouting hole ball valve can be closed, and the replacement of the next pipe section is continued.

14 push bench goes in and out hole

(1) Soil body reinforcement of hole opening before hole outlet of pipe jacking machine

According to the progress condition of the jacking pipe, in order to ensure that the heading machine can smoothly enter the receiving well, water and soil are prevented from flowing into the receiving well along a building gap between the tool pipe and a well ring after the heading machine goes out of a hole, and the smooth construction of the in-well joint is ensured. If the geology is poor, before the heading machine reaches the receiving well, grouting reinforcement can be carried out on the soil body at the hole opening, the reinforcement range is within 5m before the hole opening, and the distance between the periphery of the hole opening and the outer side of the pipeline is 2-3 m.

(2) Re-check measurement of push bench state

Rechecking before the development machine enters the receiving well, measuring the position of the pipe push bench, which is an important basis for confirming the pipe push state, evaluating the state of the development machine when the development machine goes out of the hole, and drawing up the construction axis and the construction scheme, etc., so that the development machine is always implemented according to the preset scheme in the construction of the stage, and enters the receiving well accurately in a good state.

(3) Chiseling brick wall sealing door

(4) Receiving pit of push bench

After the receiving well brick wall sealing door is damaged, the tunneling machine head is required to quickly and continuously jack the pipe joint, and the hole exiting time is shortened as soon as possible. After the whole heading machine enters the tunnel, the machine head and the concrete pipe joint are separated as soon as possible, and the pipe joint and the joint of the receiving well are processed according to the design requirements, so that the water and soil loss is reduced.

The operation requirements are as follows:

the pipe end treatment after the development machine enters the soil layer meets the following regulations: a pipe-jacking tunneling machine entering the receiving pit and a pillow cushion should be arranged at the lower part of the pipe end; the length of the two ends of the pipeline exposed in the working pit is not less than 0.5m, and no interface is required; the end of the reinforced concrete pipeline is required to be poured with a concrete foundation in time.

In the whole process of jacking the pipeline, the advancing direction of the pipe-jacking tunneling machine is controlled, the reason and the development trend of deviation are analyzed according to the measurement result, and the deviation rectifying measures are determined.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (4)

1. A pipe jacking engineering construction method is characterized by comprising the following construction steps: the method comprises the following steps of measurement lofting, working pit construction, starting base installation and pipe jacking machine hoisting, back wall and oil cylinder support installation, tunnel portal double-curtain rubber installation, tunnel portal breaking construction, pipe joint prefabrication and transportation, pipe joint turning over and well descending, pipe jacking, resistance reduction construction, relay station construction, alloy steel cutter follow-up replacement, replacement grouting and pipe jacking machine entering and exiting.

2. The pipe jacking project construction method according to claim 1, characterized in that: the pipe joint turning over and well descending comprise: the pipe joints are vertically stacked on the field before going into the shaft, and are turned over for 90 degrees on the ground in advance before going into the shaft, the pipe joints are horizontally placed on the ground, and then the shaft operation is carried out; after the pipe joints are stably hoisted to the ground from the carriage by the crane, the pipe joints are hoisted in a turnover mode on the ground by adopting a hoisting mode; when the pipe joint is turned over, the main lifting hook of the truck crane lifts the pipe joint in a balanced manner, when the pipe joint is lifted to 1-2 m high, the auxiliary hook lifts the socket at the lower part of the pipe joint and slowly lifts the hook, meanwhile, the main hook slowly hooks down until the pipe joint rotates 90 degrees and is transversely placed on the ground, when the pipe joint goes into a well, the steel wire rope transversely penetrates through the inside of the pipe joint, a protection device is installed at the socket part, the truck crane is used for running into the well, and the socket direction is ensured to be the jacking direction of a jacking pipe.

3. The pipe jacking project construction method according to claim 1, characterized in that: the method for measuring jacking of the jacking pipe comprises the following steps:

1) erecting a Suguano LT402L and a long-distance 500m laser theodolite in the jacking axis direction of a pipeline in a working well, wherein a base platform can only be independently connected with a structural bottom plate of the working well, and the height of the laser theodolite is consistent with the zero position of a measuring optical target in a pipe jacking machine; otherwise, it cannot be in contact with any other device;

2) the laser theodolite sends out a laser beam consistent with the designed axis of the pipeline and the gradient of the pipeline through manual measurement and calculation and directly strikes a measuring light target in the pipe jacking machine, and a rear viewpoint is attached to a side wall by a 50-by-50 mm reflector plate; the laser stably tracks and measures the optical target while the machine head and the pipe joint move, whether the advancing direction of the machine head is jacked according to the designed axis and the gradient of the pipeline or not is visually seen on the measuring optical target in the jacking process, and if a deviation is found, a jacking driver timely performs reverse deviation correction according to deviation data on the measuring optical target.

4. The pipe jacking project construction method according to claim 1, characterized in that: the drag reduction construction comprises the following steps: the pipe joint waxing and drag reduction method comprises the following steps: pouring the paraffin into an electric heating paraffin melting pot → heating to melt and boiling → putting the paraffin on the surface of the pipe joint by a brush → airing → spraying and heating the paraffin by coal gas so that the paraffin on the surface of the pipe joint is uniform and smooth → airing → storing → descending a well and transporting → installing the pipe joint.