CN116677389A - Construction method for recycling seafloor water of mini-tunnel pipe jacking machine - Google Patents

Abstract

The invention relates to the technical field of tunnel construction, in particular to a construction method for recovering from submarine water of a micro tunnel pipe-jacking machine, which is characterized in that a temporary non-drainage receiving well is formed by carrying out temporary cofferdam construction at a preset recovery position of a target sea area, then the front end of the micro tunnel pipe-jacking machine is controlled to be tunneled to the temporary non-drainage receiving well and to be in a state to be received, then the micro tunnel pipe-jacking machine is subjected to internal pressure test before recovery, then a sealing door is closed, the pipe-jacking machine and an underwater recovery module are controlled to be all driven into the temporary non-drainage receiving well, so that the micro tunnel pipe-jacking machine is in a state to be recovered, finally the underwater recovery module is separated from a precast concrete pipe section, and the micro tunnel pipe-jacking machine is recovered through the temporary non-drainage receiving well, so that the invention can directly realize the purpose of recovering the micro tunnel pipe-jacking machine from submarine water without building a cofferdam or building the non-drainage cofferdam as the receiving well when the invention is implemented.

Description

Construction method for recycling seafloor water of mini-tunnel pipe jacking machine

Technical Field

The invention relates to the technical field of tunnel construction, in particular to a construction method for recovering seafloor water of a mini-tunnel push bench.

Background

In the current urban infrastructure construction process, the micro tunnel pipe jacking machine technology is widely applied to underground pipeline construction projects of industries such as underground water taking, drainage pipelines, underground power transmission pipelines, petroleum and natural gas, and the like, particularly in sea-free areas, the technology can solve the environmental problem possibly caused by open-air excavation of coastlines, has extremely wide application range, and is especially suitable for pipeline construction from continents to oceans, such as petroleum and natural gas pipelines, sewage plant drainage pipelines, seawater desalination plant drainage pipelines, and the like.

In the related art, when a miniature tunnel pipe jacking machine is adopted to apply a seawater diversion pipeline, the initiation and the reception of the pipe jacking machine are key construction steps, and a receiving well is usually arranged in seawater for recycling the pipe jacking machine. The construction of cofferdam in seawater is greatly influenced by geological conditions under the seabed of a construction area, if a drainage cofferdam is constructed to receive a pipe pushing jack in a dry environment, the water stopping construction difficulty, leakage risk and cost of the cofferdam are high, and the construction period is long.

Disclosure of Invention

The invention mainly aims to provide a construction method for recovering the seawater of a miniature tunnel push bench from the seawater, which aims to solve the problem that the push bench is recovered underwater by not building a cofferdam or building a non-drainage cofferdam to be used as a receiving well when the push bench is used for constructing a seawater diversion pipeline in the related technology.

In order to achieve the above object, in a first aspect, the present invention provides a construction method for recovering from underwater of a mini-tunnel pipe-jacking machine, the mini-tunnel pipe-jacking machine includes a pipe-jacking machine and an underwater recovery module set in sequence, the rear end of the underwater recovery module is abutted with a precast concrete pipe joint, a sealing door is arranged at one end of the precast concrete pipe joint abutted with the underwater recovery module, and a water injection bin is formed between the underwater recovery module and the sealing door;

the construction method for recycling the submarine water of the mini-tunnel push bench comprises the following steps of:

performing temporary cofferdam construction at a preset recovery position of a target sea area to form a temporary non-drainage receiving well;

controlling tunneling construction of the micro tunnel pipe pushing bench to the preset recovery position, so that the front end of the pipe pushing bench enters the temporary non-drainage receiving well and is in a state to be received;

performing a recovery front internal pressure test on the micro tunnel pipe pushing jack;

closing the sealing door;

controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the micro tunnel push bench to be in a state to be recovered;

and separating the underwater recovery module from the precast concrete pipe section, and recovering the micro tunnel pipe jacking machine through the temporary non-drainage receiving well.

Optionally, the step of performing temporary cofferdam construction at a preset recovery position of the target sea area to form a temporary non-drainage receiving well includes:

performing measurement construction in a target sea area to determine the preset recovery position;

setting up a temporary construction platform at the preset recovery position;

a plurality of steel pipe piles and steel sheet piles are applied to the preset recovery position on the temporary construction platform to form a current cofferdam;

a transverse support is applied to the inner side of the current cofferdam, and dredging construction is carried out on the area in the current cofferdam to a preset elevation;

applying underwater back cover concrete with target thickness at the preset elevation and erecting a rail;

filling sand materials with preset thickness on the surface of the underwater bottom sealing concrete, completing the construction of the temporary cofferdam, and forming the temporary non-drainage receiving well; and the top elevation of the sand is higher than that of the mini-tunnel push bench.

Optionally, after the step of filling sand materials with a preset thickness on the surface of the underwater bottom sealing concrete to complete the temporary cofferdam construction and form the temporary non-drainage receiving well, the method further comprises the following steps:

and lifting the cofferdam steel pipe pile opposite to the travelling route of the mini-tunnel pipe pushing jack to be flush with the top elevation of the sand material, so as to form an opening for the mini-tunnel pipe pushing jack to enter the temporary cofferdam.

Optionally, the step of controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to make the mini tunnel push bench in a state to be recovered comprises the following steps:

controlling the tunneling construction of the front end of the pipe pushing jack to the preset recovery position according to preset parameters; the rear end of the push bench and the sealing door are both positioned in the submarine geology outside the temporary cofferdam;

and checking the sealing performance of the underwater recovery module, and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered.

Optionally, the mini tunnel push bench comprises a plurality of sealing positions and a plurality of valves;

the step of checking the sealing performance of the underwater recovery module and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered comprises the following steps:

checking the sealing state of each sealing position of the micro tunnel pipe pushing jack;

closing each valve in the micro tunnel push bench;

Controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well;

and removing sand in the temporary non-drainage receiving well so that the mini tunnel pipe jacking machine is exposed in seawater and is in a to-be-received state.

Optionally, a plurality of sections of precast concrete pipe sections are spliced in sequence to form a drainage tunnel;

after the step of closing each of the valves in the mini-tunnel push bench, further comprising:

and performing secondary grouting construction on the outer wall of the water diversion tunnel.

Optionally, the mini tunnel push bench further comprises a plurality of hinge positions;

the step of removing sand in the temporary cofferdam so that the micro tunnel pipe jacking machine is exposed in seawater and is in a state to be received comprises the following steps:

removing sand in the temporary cofferdam so as to expose the micro tunnel pipe jacking machine in seawater;

fixing each hinge position of the micro tunnel pipe jacking machine;

and installing a lifting device on the micro tunnel pipe pushing jack so that the micro tunnel pipe pushing jack is in a state to be received.

Optionally, the step of performing the pressure test before recycling on the mini tunnel push bench includes:

Installing a compressed air device in the sealed cabin, and installing a pressure gauge at the sealed door; the pressure gauge is communicated with a compressed air connection port of the compressed air device;

supplying compressed air with a preset pressure into the sealed cabin through the sealing door;

recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement;

and stopping supplying compressed air and removing the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

Optionally, after the step of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement, the method further includes:

when the pressure change curve does not meet the preset requirement, checking and repairing the air leakage position of the micro tunnel pipe jacking machine;

and repeatedly executing the steps of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement, and stopping supplying air and dismantling the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

Optionally, a stroke oil cylinder is arranged in the underwater recovery module, and the stroke oil cylinder is abutted with one end of the water diversion tunnel, on which the sealing door is arranged;

The step of separating the underwater recovery module from the precast concrete pipe section and recovering the mini tunnel push bench through the temporary non-drainage receiving well comprises the following steps:

and driving the stroke oil cylinder to separate the underwater recovery module from the precast concrete pipe section, and recovering the micro tunnel pipe jacking machine.

According to the technical scheme, temporary cofferdam construction is carried out at a preset recovery position of a target sea area to form a non-drainage temporary non-drainage receiving well, then tunneling construction of the mini tunnel pipe jacking machine is controlled to the preset recovery position, the front end of the pipe jacking machine enters the temporary non-drainage receiving well and is in a state to be received, before-recovery internal pressure test is carried out on the mini tunnel pipe jacking machine, then a sealing door is closed, the pipe jacking machine and the underwater recovery module are controlled to all drive into the temporary non-drainage receiving well, so that the mini tunnel pipe jacking machine is in the state to be recovered, finally, the underwater recovery module is separated from a prefabricated concrete pipe section, and the mini tunnel pipe jacking machine is recovered through the temporary non-drainage receiving well, so that the purpose of recovering the mini tunnel pipe jacking machine in sea water can be achieved without building a cofferdam or building the non-drainage cofferdam to be used as the receiving well when the mini tunnel pipe jacking machine is concretely implemented, and construction efficiency is improved. The problems that in the related art, a water-stop construction difficulty, leakage risk and cost of a cofferdam are high, a construction period is long and the like due to the fact that a drainage cofferdam is built to receive a push bench in a dry environment are solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a construction method for recovering from the bottom water of a micro tunnel push bench according to an embodiment of the present invention;

fig. 2 is a flowchart of step S100 illustrated in fig. 1;

fig. 3 is a flowchart of step S300 illustrated in fig. 1;

fig. 4 is a detailed flowchart of step S500 illustrated in fig. 1;

fig. 5 is a flowchart of step S524 illustrated in fig. 4.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the mechanisms in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is correspondingly changed.

In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

The inventive concept of the present invention is further elucidated below in connection with some embodiments.

The invention provides a construction method for recycling submarine water of a mini-tunnel pipe jacking machine.

As shown in fig. 1 to 5, an embodiment of the method for recovering and constructing the bottom water of the mini-tunnel push bench according to the present invention is provided.

In this embodiment, referring to fig. 1-5, the construction method for recovering the micro-tunnel pipe-jacking machine from the ocean water includes a pipe-jacking machine and an underwater recovery module set in sequence, wherein the tail end of the underwater recovery module is abutted with a precast concrete pipe joint, a sealing door is arranged at one end of the precast concrete pipe joint abutted with the underwater recovery module, and a water injection cabin is formed between the underwater recovery module and the sealing door;

the construction method for recycling the submarine water of the mini-tunnel push bench comprises the following steps:

s100, performing temporary cofferdam construction at a preset recovery position of a target sea area to form a temporary non-drainage receiving well;

in the embodiment, a receiving well is built in the sea, the sea bed water level is-11 mPD, the laying pipeline water level, namely, the receiving water level of the pipe pushing equipment is-26 mPD, and-11 mPD to-26 mPD are all argillic soil layers, in order to realize underwater pipe pushing equipment recovery, after the pipe pushing equipment is tunneled to reach a designated position, sea mud covered above the pipe pushing equipment is removed, pipe pushing equipment recovery hoisting can be carried out, a temporary cofferdam is built in the sea for receiving the pipe pushing equipment, drainage is not required during the temporary cofferdam building, the functions are that the sea mud at the periphery of the cofferdam flows into the bottom of the receiving well, the plane size of the cofferdam meets the space requirement required by pipe pushing equipment recovery, and then cofferdam design and construction building are carried out according to geological conditions. In order to meet the requirement of receiving the push bench, the receiving well needs to consider the arrangement of a reserved receiving hole when being constructed, and the main construction steps of the receiving well comprise (1) constructing an offshore temporary construction platform according to measurement and positioning; (2) C, applying and punching a steel pipe pile and a steel sheet pile surrounding the weir to a designed position on the temporary construction platform to form a cofferdam; (3) Installing a cofferdam inner side support, and removing sea mud in the cofferdam by using a construction ship until the sea mud is 1.5 meters below the flat water (-26 mPD) of the receiving pipe jacking machine; (4) The bottom of the cofferdam falls to be 1m thick and is subjected to bottom sealing coagulation under water for supporting the push bench from sinking; (5) Backfilling sand in the cofferdam to design flat water (-21 mPD), wherein the sand is generally 2 meters higher than the pipe pushing machine and is used for balancing pushing force when the pipe pushing machine enters a receiving well; (6) According to the design requirement, 8 pipe pushing machine well side wall weir steel pipe piles are pulled up until the pile bottom level water is-21 mPD, an inlet cofferdam opening of the pipe pushing machine of about 5mx5m is formed, and the receiving well cofferdam is built.

S200, controlling tunneling construction of the mini tunnel pipe pushing bench to a preset recovery position, so that the front end of the pipe pushing bench enters a temporary non-drainage receiving well and is in a state to be received;

in this embodiment, the push bench is constructed by circulating jacking until the push bench is tunneled to a specified position outside the receiving well structure, then the tunnel formed by raising the steel pipe pile is led into the receiving well, the push bench is pushed into the receiving well in cooperation with the concrete push bench and stopped at a correct position, and after confirming that the position and mileage of the push bench are correct, the preparation work of recovering the push bench can be started. After the pipe pushing machine enters the receiving well, the tunneling speed of the pipe pushing machine needs to be controlled to be slowed down, and meanwhile, the tunneling mileage of the pipe pushing machine is closely monitored, so that on one hand, the pipeline laying length is ensured to be carried out according to the design requirement, and on the other hand, the first pipe section is prevented from entering the receiving well to be too long (more than 50% of the pipe section length), and risks are brought to the subsequent underwater recovery of the pipe pushing machine.

S300, carrying out recovery front internal pressure test on the micro tunnel pipe pushing jack;

in this embodiment, in order to ensure that the pipe push bench does not leak water and water logging equipment, before the pipe push bench is separated from the precast concrete pipe section, a pressure test needs to be performed on the recovery bin, so as to ensure the sealing effect of the recovery module sealing assembly. The main step of the pressure test is that (1) a compressed air device is arranged in the end pipe of the receiving well pipe section; (2) Installing a pressure gauge on the pipe joint sealing door and connecting a compressed air connecting channel; (3) Opening a valve port at a connecting channel in the sealing door partition plate to apply 0.5bar of compressed air into the push bench; (4) Observing and recording a pressure curve (pressure gauge), wherein the pressure curve is usually used for ensuring that the push bench is watertight, pressurizing for at least 12 hours, if the pressure curve does not pass the compressed air test, finding out a leakage point and sealing, and repeating the compressed air test until the pressure curve is qualified (maintaining 0.5bar pressure); (5) After the pressure test is successfully completed, the ball valve at the compressed air connecting channel is closed, the compressed air pipeline is disconnected, the pressure gauge is disassembled, and the compressed air connecting channel is sealed, so that the compressed air connecting channel is watertight. After the compressed air test is finished, the redundant equipment in the joint is required to be removed as soon as possible, various screw tightening operations are carried out on the sealing door partition plate, the tightness of the sealing door partition plate is ensured, and then the separation of the recovery module at the rear end of the push bench and the sealing door partition plate is carried out within 12 hours.

The hydraulic pipeline connection of the hydraulic jack in the underwater recovery module is completed underwater by a diver, and the operation process comprises the steps of (1) removing a cover plate on a reserved terminal block at the top of the underwater recovery module, (2) removing a blind plug from a wiring terminal, connecting a hydraulic pipeline, and using the blind plug as an oil feeding pushing jack, (3) removing the blind plug from a junction box, and connecting the hydraulic pipeline, and using the blind plug as an oil return withdrawing jack. The connecting terminal is used for connecting a hydraulic pipeline, is an air pipe connecting terminal, the inside of the connecting terminal is connected with the warehouse of the push bench, and detects and corrects the pressure in the warehouse of the push bench when the connecting terminal is used for connecting an air pipe, and the air pipe connecting method is consistent with the oil pipe connecting; and secondly, water is injected between the recovery module and the pipe joint sealing door through the connection air throat, and the recovery module is realized through an air pipe connecting terminal.

The water injection between the recovery module and the sealing door is a key process before the separation operation of the pipe pushing jack and the concrete pipe joint, the water injection function is to extrude the gas in the corresponding bin, and the water pressure balance inside and outside the bin is kept through the water injection, so that the separation operation is performed in an isobaric environment, if the air exhaust water injection work is not performed, the recovery bin can generate larger suction force during the separation operation, the water can rapidly enter the recovery chamber, the equipment is possibly damaged, and the underwater suction force is extremely unfavorable for the work of underwater divers and must be avoided. Connecting pipelines/hoses to the connecting terminals, wherein in the process, the tail ends of the two pipelines are higher than the water surface, (2) ensuring that a diver opens a ball valve for connecting the pipelines after leaving a dangerous area, (3) fixing the pipelines above the water surface, and exhausting and ventilating the area between a recycling module bin and a concrete pipe joint sealing door; (4) And placing the pipeline under water, and injecting water into the area between the recycling module bin and the concrete pipe joint sealing door.

After the previous working procedures are finished, the separation operation can be carried out, the front part of the push bench is ensured to have no material before the separation operation, and then the push bench is pushed out of the pipeline, and the push bench can be realized by forming a pit in front of the tool bit if necessary. The separation operation is realized by a professional operating the hydraulic jack ejection cylinder of the recovery module through oil pressure equipment on a working ship, in the process, the hydraulic jack is checked with assistance of a diver, the hydraulic cylinder is ensured to be fully extended and the pipe pushing jack is completely released from the tunnel pipe joint, when the pipe pushing jack is determined to be completely pushed away from the pipe joint, the separation jack needs to be retracted, and the diver is assisted to ensure that the jack is fully retracted.

Before the separation operation is carried out, the suspended weight distribution cross beam is connected with each pipe joint of the equipment, and meanwhile, the cross beam is suspended by using the floating crane, and when the completion of the separation operation is confirmed, the pipe jacking machine can be suspended from the receiving well by using the floating crane, so that the construction of underwater recovery of the pipe jacking machine is realized.

S400, closing the sealing door;

in the embodiment, after tunneling the pipe push bench to a designed position, the preparation work before equipment recovery can be carried out, and the method comprises the steps of (1) checking the cleanliness and damage condition of all sealing door assemblies and the surfaces of sealing elements, replacing the sealing elements according to actual conditions as required to ensure the sealing effect, (2) fully retracting a steering cylinder to fill a main driver with oil, and simultaneously closing a ball valve to seal a driving device, (3) closing all slurry pipe feeding and discharging gate valves, disconnecting feeding and discharging pipelines at a recovery module partition plate, disconnecting all electric and hydraulic pipelines, and sealing all openings on the recovery module partition plate; (4) And (5) secondary grouting is carried out on the outer wall of the precast concrete pipe joint, the integrity of the paved pipeline is enhanced, all pipeline facilities in the pipeline are removed after grouting is finished, and the pipeline is cleaned out, (5) backfilled sand in the receiving well is removed, so that the pipe jacking machine is exposed in the sea water at the bottom of the vertical shaft.

After the preparation work is finished, the connection screw among all the equipment pipe joints of the pipe push bench is locked, so that all the bin pipe joints of the pipe push bench are connected into a whole, the pipe joints comprise a main driving bin, a steering bin, a power bin, an air pressure bin, a recovery module bin and the like, the fastening work is carried out by a professional in a pipeline paved through a pipe push bench from the rear end of the pipe push bench to enter the equipment, the fastening and sealing effect is ensured in the process, and the tightness and the impermeability among the bin pipe joints are ensured.

In the whole recycling operation process, the main pushing jack of the pushing system in the departure well is required to always output pushing force to the tail end of the pipe joint, and meanwhile, the thrust ring is required to be always locked on the prefabricated concrete pipe joint to generate back pressure so as to prevent the concrete pipe joint or the warehouse pipe joint from being disconnected in the recycling operation process.

S500, controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered;

when the push bench is assembled in a departure well, each bin pipe joint is provided with a hanging ring which is used for connecting a hanging weight distribution beam. Before tunneling operation is started after the pipe jacking assembly is completed, the hanging ring on the pipe joint of the equipment is removed, and the equipment is blocked by wax and a special cap, so that tunneling and pushing are ensured to be carried out smoothly. After the underwater recovery preparation work in the receiving well is finished, the hanging rings are required to be reinstalled on the pipe joints of all the bins, the underwater installation of the hanging rings is carried out under water by a diver, the main steps are that after the cap is removed, lower screws of the hanging rings are screwed on reserved holes of the pipe joints of the bins, after the installation of the hanging rings is finished, special distribution cross beams are connected with the hanging rings, lifting ship hanging hooks are connected with the distribution cross beams and used as lifting recovery push bench, the distribution cross beams of the lifting and the weight of the push bench are required to be comprehensively designed and determined by combining the distribution of the hanging rings, I-shaped steel is generally adopted, each equipment bin is ensured to be directly connected with the cross beams, and the problem that the equipment bin is not bent and water seepage is caused due to uneven stress in the process of the equipment bin is ensured.

S600, separating the underwater recovery module from the precast concrete pipe section, and recovering the miniature tunnel push bench through the temporary non-drainage receiving well.

According to the technical scheme, temporary cofferdam construction is carried out at the preset recovery position of a target sea area to form a temporary non-drainage receiving well, tunneling construction of the micro tunnel pipe-jacking machine is controlled to the preset recovery position, the front end of the pipe-jacking machine enters the temporary non-drainage receiving well and is in a state to be received, internal pressure test before recovery is carried out on the micro tunnel pipe-jacking machine, then a sealing door is closed, the pipe-jacking machine and the underwater recovery module are controlled to all drive into the temporary non-drainage receiving well, so that the micro tunnel pipe-jacking machine is in the state to be recovered, finally, the underwater recovery module is separated from a prefabricated concrete pipe section, and the micro tunnel pipe-jacking machine is recovered through the temporary non-drainage receiving well.

In some embodiments, performing temporary cofferdam construction at a predetermined recovery location in a target sea area to form a temporary non-drainage receiving well includes:

s110, measuring construction is carried out in a target sea area to determine a preset recovery position;

s120, building a temporary construction platform at a preset recovery position;

s130, a plurality of steel pipe piles and steel sheet piles are applied to a preset recovery position on a temporary construction platform to form a current cofferdam;

s140, performing transverse support on the inner side of the current cofferdam, and dredging and constructing an area in the current cofferdam to a preset elevation;

s150, applying underwater back cover concrete with target thickness at a preset elevation and erecting a rail;

it should be specifically and explicitly stated that in this embodiment, the purpose of the application of the underwater concrete is to provide sufficient support for the receiving of the mini-tunnel push bench and the underwater recovery module, so as to avoid the hidden troubles of instability or capsizing of the push bench and the underwater recovery module caused by insufficient hardness of the seabed bedrock or the seabed. In this embodiment, the target thickness of the example is at least 1m.

S160, filling sand materials with preset thickness on the surface of the underwater bottom sealing concrete, completing temporary cofferdam construction, and forming a temporary non-drainage receiving well; wherein, the top elevation of sand material is higher than the top elevation of miniature tunnel push bench.

In some embodiments, the surface of the underwater back cover concrete is filled with sand material with a preset thickness, and after the step of completing temporary cofferdam construction and forming a temporary non-drainage receiving well, the method further comprises the following steps:

s170, lifting the steel pipe pile opposite to the micro tunnel pipe jacking machine to be flush with the top elevation of the sand material, so as to form an opening for the micro tunnel pipe jacking machine to enter the temporary cofferdam.

In some embodiments, the step of controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to make the mini tunnel push bench in a state to be recovered comprises the following steps:

s510, controlling tunneling construction of the pipe push bench to a preset recovery position according to preset parameters; the rear end of the push bench and the sealing door are positioned in the submarine geology outside the temporary cofferdam;

s520, checking the sealing performance of the underwater recovery module, and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered.

In some embodiments, the mini-tunnel push bench includes a plurality of sealing locations and a plurality of valves;

the step of checking the sealing performance of the underwater recovery module and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered comprises the following steps:

S521, checking the sealing state of each sealing position of the micro tunnel pipe jacking machine;

s522, closing each valve in the micro tunnel pipe pushing bench;

s523, controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well;

s524, removing sand in the temporary non-drainage receiving well so that the mini tunnel pipe jacking machine is exposed in seawater and is in a to-be-received state.

In some specific embodiments, the precast concrete pipe joints are spliced in sequence to form a drainage tunnel;

after the step of closing each valve in the mini tunnel push bench, the method further comprises the following steps:

s525, performing secondary grouting construction on the outer wall of the precast concrete pipe joint drainage tunnel.

In some embodiments, the mini-tunnel push bench further comprises a plurality of hinge locations;

the step of removing sand in the temporary cofferdam so as to expose the mini tunnel pipe jacking machine in seawater and in a state to be received comprises the following steps:

s524a, removing sand in the temporary cofferdam so as to expose the micro tunnel pipe jacking machine in the sea water;

s524b, fixing all hinge positions of the micro tunnel pipe jacking machine;

s524c, installing a lifting device on the micro tunnel pipe pushing jack so as to enable the micro tunnel pipe pushing jack to be in a state to be received.

In some embodiments, the step of performing a pre-recovery internal pressure test on the mini-tunnel push bench comprises:

s310, installing a compressed air device in a sealed bin and installing a pressure gauge at a sealing door; the pressure gauge is communicated with a compressed air connection port of the compressed air device;

s320, supplying compressed air with preset pressure into the sealed cabin through the sealing door;

s330, recording and judging whether a pressure change curve of the pressure gauge meets preset requirements;

and S340, stopping supplying the compressed air and dismantling the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

In some embodiments, after the step of recording and determining whether the pressure change curve of the pressure gauge meets the preset requirement, the method further includes:

s350, checking and repairing the air leakage position of the micro tunnel pipe jacking machine when the pressure change curve does not meet the preset requirement;

s360, repeatedly executing the steps of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement, and stopping supplying air and dismantling the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

In some specific embodiments, a stroke oil cylinder is arranged in the underwater recovery module and is abutted with one end of the diversion tunnel, where the sealing door is arranged;

Separating the underwater recovery module from the precast concrete pipe section, and recovering the mini-tunnel push bench through the temporary non-drainage receiving well, wherein the method comprises the following steps of:

and the underwater recovery module is separated from the precast concrete pipe section by the driving stroke oil cylinder, and the miniature tunnel pipe jacking machine is recovered.

In some specific embodiments, the micro-tunnel construction is a process of constructing a small tunnel in underground non-excavation drilling by using a micro-tunnel pipe jacking machine, and is commonly used for paving an underground pipeline, and a pipe jacking process or a segment lining process can be selectively adopted for paving the tunnel pipeline according to the diameter of the tunnel. In the current urban infrastructure construction process, the micro-tunnel pipe jacking machine tunneling technology is widely applied to underground pipeline construction engineering in industries such as underground water taking, drainage pipelines, underground power transmission pipelines, petroleum and natural gas, and the like, particularly in sea-free areas, and can solve all environmental problems possibly caused by open-air excavation of coastlines, and the technology has extremely wide application range, particularly in pipeline construction from continents to oceans, such as petroleum and natural gas pipelines, sewage plant drainage pipelines, seawater desalination drainage pipelines, and the like.

When the miniature tunnel pipe-jacking construction method is adopted for laying the land-to-sea submarine pipeline, the pipe-jacking machine is started and received as a key construction step, a starting well and a receiving well are usually required to be built according to engineering design and used for pipe-jacking machine starting and receiving construction, the starting well is located in a land area, the construction mode is relatively traditional, the receiving well is located in the sea, the construction difficulty of the cofferdam constructed in seawater is much greater than that of the receiving well in the land area, the construction difficulty is greatly influenced by geological conditions under the seabed in the construction area, if the drainage cofferdam is constructed for receiving the pipe-jacking machine in a dry environment, the water-stopping construction difficulty and risk coefficient of the cofferdam are both high, and the cost is high. With the development of the pipe push bench technology, the pipe push bench recovery can be realized under water without building a cofferdam or building a non-drainage cofferdam to be used as a receiving well.

In the construction engineering of a sea hydration light factory, two sea water pipelines are required to be constructed from land to sea for taking sea water and discharging strong brine, the project is constructed by adopting a micro-tunnel pipe jacking technology, wherein when the water taking pipeline is constructed, the actual condition of the project is considered, and the construction is carried out by adopting a method for recovering a pipe jacking machine under water. The invention provides experience reference for the construction project of the underwater recovery push bench similar to the submarine land-to-sea push bench construction by introducing key procedures and key control points in the construction and construction process of the recovery push bench in the submarine water of a certain seawater desalination light factory.

(1) And customizing the pipe jacking machine for underwater recovery. The pipe pushing machine is selected to be recycled underwater, and the assembly is required to be customized and additionally installed during equipment selection, design, production and manufacture, wherein the first is an underwater recycling module, and the second is a sealing door arranged at the front end of the top pipe joint.

(2) And constructing a non-drainage cofferdam receiving well. When the submarine pipe jacking pipeline is positioned in a non-stone rock stratum and a muddy soil layer, the non-drainage cofferdam is built to serve as a receiving well, the pipe jacking machine is recovered underwater, and the non-drainage cofferdam is used for blocking sea mud from flowing into the receiving well.

(3) The environmental protection efficiency is high. The non-drainage cofferdam is built in seawater, the water stopping requirement of the cofferdam is avoided, the cofferdam temporary engineering is few, the construction efficiency is high, grouting water stopping construction is avoided, and the influence on the marine ecological environment is small.

When a sea pipeline is built, a pipe jacking construction method is adopted, a departure well is built on land, pipe jacking machine assembly and pipe jacking equipment pushing construction are carried out in a dry environment, the pipe jacking machine needs to be recovered after the pipe jacking machine passes through the sea floor to reach a designated position, unlike the conventional cofferdam building method, the pipe jacking machine does not need to be built in a wet environment in seawater, a diver is used for separating the pipe jacking machine from a pipe joint on the sea floor, a lifting hook is arranged on the pipe jacking machine in the seawater, the lifting hook is connected with a special lifting distribution beam (lifting appliance), and the pipe jacking machine is recovered from water through a floating crane ship.

In order to separate the underwater push bench from the coagulation pipeline, special arrangement is needed when the push bench is selected, firstly, an underwater recovery module is additionally arranged at the rear end of the push bench, as shown in fig. 1, an independently driven hydraulic pushing system is arranged in the recovery module, and secondly, a special sealing door is additionally arranged at the front end of a first pipe section of the push bench. The separation operation principle of the underwater pipe pushing jack and the concrete pipe joint is that the underwater recovery module bin hydraulic oil pipe is connected (the outside of the pipe pushing jack bin is connected) by a diver, and after the oil pipe is connected, an operator controls the hydraulic jack in the module on a working ship to separate the pipe pushing jack from the concrete pipe joint.

The method comprises the steps of constructing a receiving well in the sea, wherein the sea bed leveling is-11 mPD, laying pipelines, namely, the receiving leveling of the push bench is-26 mPD, and the-11 mPD-26mPD are all argillic soil layers, removing sea mud covered on the push bench after tunneling of the push bench reaches a designated position for realizing underwater recovery of the push bench, and then recovering and hoisting the push bench. In order to meet the requirement of receiving the push bench, the receiving well needs to be considered to reserve the setting of the receiving hole when being constructed, and the main construction steps of the receiving well comprise; (1) Building an offshore temporary construction platform according to the measurement and positioning; (2) Installing a side support inside the cofferdam, and removing sea mud in the cofferdam by using a construction ship until receiving flat water (-26 mPD) of a pipe push bench is 1.5 meters below; (4) The bottom of the cofferdam falls to be 1m thick and is subjected to bottom sealing coagulation under water for supporting the push bench from sinking; (5) Sand is filled in the cofferdam until the water is designed to be flat (-21 mPD), and the water is generally 2 meters higher than the pipe pushing machine, so that the water is used as balanced pushing force when the pipe pushing machine enters a receiving well; (6) According to the design requirement, 8 TBM side wall weir steel pipe piles are lifted to the pile bottom level of-21 mPD, an inlet cofferdam opening of the pipe pushing jack of about 5mx5m is formed, and the receiving well cofferdam is built.

And (3) performing circulating jacking construction on the pipe-jacking machine until the tunneling of the pipe-jacking machine reaches a designated position outside a receiving vertical shaft structure, pumping up 8 pipe-jacking machine well-entering side wall weir steel pipe piles to the pile bottom flat water of-21 mPD according to design requirements to form a pipe-jacking machine inlet cofferdam opening of about 5mx5m, improving an inlet tunnel formed by a steel pipe in the process of constructing a receiving well cofferdam to enter a receiving well, pushing the pipe-jacking machine into the receiving well in cooperation with the pipe-jacking machine, stopping at a correct position, and starting the preparation work of recovering the pipe-jacking machine after confirming the position and mileage of the pipe-jacking machine. After the pipe pushing machine enters the receiving well, the tunneling speed of the pipe pushing machine needs to be controlled to be slowed down, and meanwhile, the tunneling mileage of the pipe pushing machine is closely monitored, so that on one hand, the pipeline laying length is ensured to be carried out according to the design requirement, and on the other hand, the first pipe section is prevented from entering the receiving well to be too long (more than 50% of the pipe section length), and risks are brought to the subsequent underwater recovery of the pipe pushing machine.

After the pipe jacking machine is tunneled to a designed position, preparation work before equipment recovery can be carried out, and the pipe jacking machine comprises (1) checking the cleanliness and damage condition of all sealing door assemblies and the surfaces of sealing elements, and replacing the sealing elements according to actual conditions to ensure a sealing effect; (3) Closing all slurry pipe feeding and discharging gate valves, disconnecting the feeding and discharging pipeline at the position of the recovery module partition board, disconnecting all electric and hydraulic pipelines, sealing and recovering all openings on the module partition board, (4) performing secondary grouting on the outer wall of the precast concrete pipe joint, reinforcing the integrity of the paved pipeline, removing all pipeline facilities in the pipeline after grouting is finished, and cleaning out the pipeline, (5) removing backfilled sand in the receiving well, so that the pipe jacking machine is exposed in the sea water at the bottom of the vertical shaft.

After the preparation work is finished, the connection screw among all the equipment pipe joints of the pipe pushing machine is locked, so that all the bin pipe joints of the pipe pushing machine are connected into a whole, the pipe joints comprise a main driving bin, a steering bin, a power bin, an air pressure bin recycling module bin and the like, the fastening work is carried out by a professional in a pipeline paved through a pipe pushing machine from the rear end of the pipe pushing machine to enter the equipment, the fastening and sealing effect is ensured in the process, and the tightness and the impermeability among the bin pipe joints are ensured.

In the whole recycling operation process, the main pushing jack of the pushing system in the departure well is required to always output pushing force to the tail end of the pipe joint, and meanwhile, the thrust ring is required to be always locked on the precast concrete pipe joint to generate back pressure so as to prevent the pipe joint or the bin pipe joint from being disconnected in the recycling operation process.

When the push bench is assembled in a departure well, each bin pipe joint is provided with a hanging ring which is used for connecting a hanging weight distribution beam. Before tunneling operation is started after the pipe jacking assembly is completed, the hanging ring on the pipe joint of the equipment is removed, and the equipment is blocked by wax and a special cap, so that tunneling and pushing are ensured to be carried out smoothly. After the underwater recovery preparation work in the receiving well is finished, the hanging rings are required to be reinstalled on the pipe joints of all the bins, the underwater installation of the hanging rings is carried out under water by a diver, the main steps are that after the cap is removed, lower screws of the hanging rings are screwed on reserved holes of the pipe joints of the bins, after the installation of the hanging rings is finished, special distribution cross beams are connected with the hanging rings, lifting ship hanging hooks are connected with the distribution cross beams and used for hanging away the recovered pipe pushing machine, the distribution cross beams of the hanging weight distribution are required to be combined with the comprehensive design of the hanging rings, I-shaped steel is generally adopted, each equipment bin is ensured to be directly connected with the cross beams, and the problem that the equipment bin is not bent and water seepage is caused due to uneven stress in the process of transferring is ensured.

In order to ensure that the tunneller is free from water leakage and water immersion equipment, a pressure test is required to be carried out on the recovery bin before the pipe pushing jack is separated from the precast concrete pipe section, so that the sealing effect of the recovery module sealing assembly is ensured. The main step of the pressure test is that (1) a compressed air device is arranged in the end pipe of the receiving well pipe section; (2) Installing a pressure gauge on the pipe joint sealing door and connecting a compressed air connecting channel; (3) Opening a valve port at a connecting channel in the sealing door partition plate to apply 0.5bar of compressed air into the tunnel boring machine; (4) Observing and recording a pressure curve (manometer), typically to ensure that the heading machine is watertight, pressurizing for at least 12 hours if the machine fails the compressed air test, finding a leak and sealing it, repeating the compressed air test until it is acceptable (maintaining 0.5bar pressure); (5) After the pressure test is successfully completed, the ball valve at the compressed air connecting channel is closed, the compressed air pipeline is disconnected, the pressure gauge is disassembled, and the compressed air connecting channel is sealed, so that the compressed air connecting channel is watertight. After the compressed air test is finished, the redundant equipment in the joint is required to be removed as soon as possible, various screw tightening operations are carried out on the sealing door partition plate, the tightness of the sealing door partition plate is ensured, and then the separation of the pipe jacking machine recovery module and the sealing door partition plate is carried out within 12 hours.

The hydraulic pipeline connection of the hydraulic driving jack in the underwater recovery module is completed underwater by a diver, and the operation process is that (1) a cover plate on a reserved terminal block at the top of the underwater recovery module is disassembled; (2) The blind plug is detached from the wiring terminal and then connected with the hydraulic pipeline to be used as an oil feeding pushing jack; (3) The blind plug is detached from the junction box and then connected with a hydraulic pipeline to serve as an oil return withdrawing jack. The connecting terminal is used for connecting a hydraulic pipeline and is an air pipe connecting terminal, the inside of the connecting terminal is connected with the chamber of the push bench, and the pressure in the chamber of the push bench is detected and corrected during recycling construction, so that the sealing and the water tightness are ensured; meanwhile, the connecting terminal is used for connecting the air pipe, the air pipe connecting method is consistent with the oil pipe connecting, and the air pipe connecting method has the advantages that when the pipe jacking machine needs to be reserved in water for a long time, the air pressure inside the pipe jacking machine is kept/corrected to be about 0.5bar through the air pipe, so that the internal equipment is prevented from being damaged, and the air pipe is connected with a bin of the pipe jacking machine through the connecting terminal; and secondly, water is injected between the recovery module and the pipe joint sealing door through the connection air throat, and the recovery module is realized through an air pipe connecting terminal.

The water injection between the recovery module and the sealing door is a key process before the separation operation of the pipe pushing jack and the concrete pipe joint, the water injection function is to extrude the gas in the corresponding bin, and the water pressure balance inside and outside the bin is kept through the water injection, so that the separation operation is performed in an isobaric environment, if the air exhaust water injection work is not performed, the recovery bin can generate larger suction force during the separation operation, the water can rapidly enter the recovery chamber, the equipment is possibly damaged, and meanwhile, the underwater suction force is extremely unfavorable for the work of underwater divers and must be avoided. Connecting the pipeline/hose to the connecting terminal, and ensuring that the tail ends of the two pipelines are higher than the water surface in the process; (2) A ball valve for ensuring that a diver opens a connecting pipeline after leaving a dangerous area, wherein (3) the pipeline 3 is fixed above the water surface, and the area between a chamber of the recovery module and a pipe joint sealing door is subjected to exhaust ventilation; (4) And placing the pipeline under water, and injecting water into the area between the recycling module bin and the pipe joint sealing door.

After the previous working procedures are finished, the separation operation can be carried out, the fact that no material exists before the pipe pushing machine is ensured before the separation operation, and then the pipe pushing machine is pushed out of a pipeline, and the separation operation can be realized by forming a pit in front of a cutter head when needed. The separation operation is realized by a professional operating the hydraulic jack ejection cylinder of the recovery module through oil pressure equipment on a working ship, in the process, the hydraulic jack is checked with assistance of a diver, the hydraulic cylinder is ensured to be fully extended and the pipe pushing jack is completely released from the tunnel pipe joint, when the pipe pushing jack is determined to be completely pushed away from the pipe joint, the separation jack needs to be retracted, and the diver is assisted to ensure that the jack is fully retracted.

Before the separation operation is carried out, the suspended weight distribution cross beam is connected with each pipe joint of the pipe pushing jack, meanwhile, the cross beam is suspended by using the floating crane, and when the completion of the separation operation is confirmed, the pipe pushing jack can be lifted off from the receiving well by using the floating crane, so that the underwater recovery pipe pushing jack construction is realized.

When the miniature tunnel pipe-jacking machine is used for land-to-sea pipe-jacking construction, a specific module is selected and additionally arranged during pipe-jacking machine type selection, pipe-jacking machine recovery is allowed to be carried out underwater, compared with the mode of constructing a drainage cofferdam in muddy sea bed seawater, the construction of a non-drainage cofferdam receiving well is simple, a cofferdam supporting structure is greatly reduced, the requirements of cofferdam water stop in a cement-rich environment are avoided, the construction risks of cofferdam water stop and water leakage are avoided, the construction efficiency is greatly improved, the construction period cost advantage is obvious, compared with the mode of constructing a sea water drainage cofferdam, the construction cost of the cofferdam can be saved by 40%, the cost of the pipe-jacking machine additionally arranged under water recovery module is quite low compared with the cost of cofferdam construction, and the comprehensive view of the construction method is very suitable for receiving the pipe-jacking machine under the condition of a sea bottom muddy soil layer and has very high economic benefit.

When the pipe pushing bench is recycled underwater, no or only a non-drainage cofferdam is needed to be built, the risks of water stopping and water leakage of the drainage cofferdam are avoided, the common water stopping and water leakage treatment mode is grouting reinforcement soil, namely, a large amount of chemical slurry is injected under the seabed around the cofferdam to solidify and reinforce the soil, the grouting range and grouting effect are greatly controlled in the construction process, the influence on the marine environment is great, and the construction area is located in a coral protection area, and when recycling construction is carried out, the grouting water stopping construction process can be avoided, the influence on the marine environment is reduced to the minimum, and good environmental protection benefits are achieved; in addition, the construction technology of the underwater recovery pipe pushing jack is strong, the successfully implemented construction scheme has a model leading effect in the industry, and can promote the further popularization and application of the underwater recovery pipe pushing jack technology while cultivating the talents of professional technology, so that the method has good social benefits.

The invention is successfully applied to the first-stage engineering of a certain seawater desalination plant. Project engineering comprises two submarine water taking and draining pipelines, the project is built by adopting a micro-tunnel tunneling pipe jacking lining mode, wherein the inner diameter of the water taking pipeline is 2.5 m and the length of the water taking pipeline is 330 m, the pipe jacking machine is used for discharging water and leveling water by-26.0 mPD, the water taking pipeline passes through silt, sediment and rock layers for many times through geological survey, the water taking pipeline is a composite geological condition, meanwhile, a water taking pipeline receiving well is positioned on the sediment layer, the engineering amount of a drainage cofferdam receiving well is large, the difficulty is high, the safety risk coefficient is high, the influence on the marine environment is large, after comprehensive consideration, the project adopts a non-drainage cofferdam (seabed-12.0 mPD and pipe jacking machine discharging-26 mPD), namely a wet well mode, and is used for underwater recovery pipe jacking machine, and the cofferdam is built for blocking sea mud from entering the receiving well without considering the drainage function.

Currently, a water intake pipeline for pipe jacking construction is already built, and a first underwater recovery pipe jacking machine construction scheme in a certain area is successfully realized.

According to the technical scheme, temporary cofferdam construction is carried out at the preset recovery position of a target sea area to form a temporary non-drainage receiving well, tunneling construction of the micro tunnel pipe-jacking machine is controlled to the preset recovery position, the front end of the pipe-jacking machine enters the temporary non-drainage receiving well and is in a state to be received, internal pressure test before recovery is carried out on the micro tunnel pipe-jacking machine, then a sealing door is closed, the pipe-jacking machine and the underwater recovery module are controlled to all drive into the temporary non-drainage receiving well, so that the micro tunnel pipe-jacking machine is in the state to be recovered, finally, the underwater recovery module is separated from a prefabricated concrete pipe section, and the micro tunnel pipe-jacking machine is recovered through the temporary non-drainage receiving well.

The foregoing description is only of the optional embodiments of the present invention, and is not intended to limit the scope of the invention, and all the equivalent structural changes made by the description of the present invention and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the invention.

Claims (10)

1. The construction method for recovering the micro-tunnel pipe-jacking machine from the sea floor water is characterized in that the micro-tunnel pipe-jacking machine comprises a pipe-jacking machine and an underwater recovery module which are sequentially arranged, the rear end of the underwater recovery module is in butt joint with a precast concrete pipe joint, a sealing door is arranged at one end of the precast concrete pipe joint, which is in butt joint with the underwater recovery module, and a water injection bin is formed between the underwater recovery module and the sealing door;

the construction method for recycling the submarine water of the mini-tunnel push bench comprises the following steps of:

performing temporary cofferdam construction at a preset recovery position of a target sea area to form a temporary non-drainage receiving well;

controlling tunneling construction of the micro tunnel pipe pushing bench to the preset recovery position, so that the front end of the pipe pushing bench enters the temporary non-drainage receiving well and is in a state to be received;

Performing a recovery front internal pressure test on the micro tunnel pipe pushing jack;

closing the sealing door;

controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the micro tunnel push bench to be in a state to be recovered;

and separating the underwater recovery module from the precast concrete pipe section, and recovering the micro tunnel pipe jacking machine through the temporary non-drainage receiving well.

2. The method for constructing the recovery of the micro-tunnel push bench from the ocean bottom water according to claim 1, wherein the step of performing the temporary cofferdam construction at the preset recovery position of the target ocean area to form the temporary non-drainage receiving well comprises the steps of:

performing measurement construction in a target sea area to determine the preset recovery position;

setting up a temporary construction platform at the preset recovery position;

a plurality of steel pipe piles and steel sheet piles are applied to the preset recovery position on the temporary construction platform to form a current cofferdam;

a transverse support is applied to the inner side of the current cofferdam, and dredging construction is carried out on the area in the current cofferdam to a preset elevation;

applying underwater back cover concrete with target thickness at the preset elevation and erecting a rail;

Filling sand materials with preset thickness on the surface of the underwater bottom sealing concrete, completing the construction of the temporary cofferdam, and forming the temporary non-drainage receiving well; and the top elevation of the sand is higher than that of the mini-tunnel push bench.

3. The construction method for recycling seafloor water of a mini tunnel push bench according to claim 2, wherein sand material with a preset thickness is filled on the surface of the underwater bottom sealing concrete, the temporary cofferdam construction is completed, and the step of forming the temporary non-drainage receiving well further comprises:

and lifting the cofferdam steel pipe pile opposite to the travelling route of the mini-tunnel pipe pushing jack to be flush with the top elevation of the sand material, so as to form an opening for the mini-tunnel pipe pushing jack to enter the temporary cofferdam.

4. The method for construction of recovery from sea floor water of a mini-tunnel push bench according to claim 3, wherein the step of controlling the push bench and the underwater recovery module to all travel into the temporary non-drainage receiving well so that the mini-tunnel push bench is in a state to be recovered comprises:

controlling the tunneling construction of the front end of the pipe pushing jack to the preset recovery position according to preset parameters; the rear end of the push bench and the sealing door are both positioned in the submarine geology outside the temporary cofferdam;

And checking the sealing performance of the underwater recovery module, and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered.

5. The method for recovering and constructing the micro-tunnel push bench from the ocean bottom water according to claim 4, wherein the micro-tunnel push bench comprises a plurality of sealing positions and a plurality of valves;

the step of checking the sealing performance of the underwater recovery module and controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well so as to enable the mini tunnel push bench to be in a state to be recovered comprises the following steps:

checking the sealing state of each sealing position of the micro tunnel pipe pushing jack;

closing each valve in the micro tunnel push bench;

controlling the push bench and the underwater recovery module to all drive into the temporary non-drainage receiving well;

and removing sand in the temporary non-drainage receiving well so that the mini tunnel pipe jacking machine is exposed in seawater and is in a to-be-received state.

6. The construction method for recycling the seafloor water of the mini-tunnel pipe jacking machine according to claim 5, wherein a plurality of sections of the precast concrete pipe sections are spliced in sequence to form a drainage tunnel;

After the step of closing each of the valves in the mini-tunnel push bench, further comprising:

and performing secondary grouting construction on the outer wall of the water diversion tunnel.

7. The method for construction and recovery of the micro-tunnel push bench from the ocean bottom water according to claim 6, wherein the micro-tunnel push bench further comprises a plurality of hinge positions;

the step of removing sand in the temporary cofferdam so that the micro tunnel pipe jacking machine is exposed in seawater and is in a state to be received comprises the following steps:

removing sand in the temporary cofferdam so as to expose the micro tunnel pipe jacking machine in seawater;

fixing each hinge position of the micro tunnel pipe jacking machine;

and installing a lifting device on the micro tunnel pipe pushing jack so that the micro tunnel pipe pushing jack is in a state to be received.

8. The method for construction of recovery from sea floor water of a micro-tunnel bench according to claim 7, wherein the step of performing the test of the pressure before recovery on the micro-tunnel bench comprises:

installing a compressed air device in the sealed cabin, and installing a pressure gauge at the sealed door; the pressure gauge is communicated with a compressed air connection port of the compressed air device;

Supplying compressed air with a preset pressure into the sealed cabin through the sealing door;

recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement;

and stopping supplying compressed air and removing the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

9. The method for recovering and constructing the micro-tunnel push bench from the ocean bottom water according to claim 8, wherein after the step of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement, further comprising:

when the pressure change curve does not meet the preset requirement, checking and repairing the air leakage position of the micro tunnel pipe jacking machine;

and repeatedly executing the steps of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirement, and stopping supplying air and dismantling the compressed air device and the pressure gauge when the pressure change curve meets the preset requirement.

10. The construction method for recovering the micro-tunnel pipe jacking machine from the sea floor water, as set forth in claim 9, wherein a stroke oil cylinder is arranged in the underwater recovery module, and is abutted with one end of the diversion tunnel where the sealing door is arranged;

The step of separating the underwater recovery module from the precast concrete pipe section and recovering the mini tunnel push bench through the temporary non-drainage receiving well comprises the following steps:

and driving the stroke oil cylinder to separate the underwater recovery module from the precast concrete pipe section, and recovering the micro tunnel pipe jacking machine.