Micro-tunneling pipe jacking machine and method for recovering a pipe under water

Abstract

This invention relates to the field of tunnel construction technology, and in particular to a method for recovering a micro tunnel jacking machine in seabed water. The method involves constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drained receiving well. The micro tunnel jacking machine is then controlled to advance to the temporary non-drained receiving well and is placed in a ready-to-be-recovered state. An internal pressure test is then performed on the micro tunnel jacking machine before recovery. The sealing door is then closed, and the jacking machine and the underwater recovery module are all driven into the temporary non-drained receiving well, thus placing the micro tunnel jacking machine in a ready-to-be-recovered state. Finally, the underwater recovery module is detached from the precast concrete pipe section, and the micro tunnel jacking machine is recovered through the temporary non-drained receiving well. This invention allows for the direct recovery of a micro tunnel jacking machine in seabed water without the need for a cofferdam or by constructing a non-drained cofferdam as a receiving well.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for recovering a micro tunnel jacking machine in underwater. Background Technology

[0002] In the current process of urban infrastructure construction, micro tunnel jacking technology is widely used in underground water intake, drainage pipelines, underground power transmission lines, and underground pipeline construction projects in industries such as oil and gas. Especially in coastal areas, this technology can solve the environmental problems that may be caused by open-pit excavation along the coastline. Its application scope is extremely wide, especially in the construction of pipelines from the mainland to the ocean, such as oil and gas pipelines, sewage treatment plant discharge pipelines, and seawater desalination plant intake and drainage pipelines.

[0003] In related technologies, when using micro tunnel boring machines (MTMs) to construct seawater diversion pipelines, the starting and receiving of the MTMs are key construction steps. Typically, receiving wells are set up in the seawater to retrieve the MTMs. Constructing cofferdams in seawater is significantly affected by the geological conditions beneath the seabed in the construction area. If a drainage cofferdam is built to receive the MTMs in a dry environment, the difficulty of water-stopping construction, the risk of leakage, and the cost are all high, and the construction period is long. Summary of the Invention

[0004] The main objective of this invention is to provide a construction method for recovering a micro tunnel jacking machine in the seabed, aiming to solve the problem of underwater recovery of the machine when using a pipe jacking machine to construct a seawater diversion pipeline, without building a cofferdam or by building a non-drainage cofferdam as a receiving well.

[0005] To achieve the above objectives, in a first aspect, the present invention proposes a construction method for underwater recovery of a micro tunnel jacking machine. The micro tunnel jacking machine includes a jacking machine and an underwater recovery module arranged sequentially. The rear end of the underwater recovery module abuts against a precast concrete pipe section, and a sealing door is provided at the end of the precast concrete pipe section that abuts against the underwater recovery module. A water injection chamber is formed between the underwater recovery module and the sealing door.

[0006] The underwater recovery method for the micro-tunnel jacking machine includes the following steps:

[0007] Temporary cofferdams were constructed at the pre-designated recovery location in the target sea area to form temporary non-drainage receiving wells;

[0008] Control the micro tunnel jacking machine to excavate to the preset recovery position, so that the front end of the jacking machine enters the temporary non-drainage receiving well and is in a waiting-to-receive state;

[0009] The internal pressure of the micro tunnel jacking machine was tested before it was recovered.

[0010] Close the sealing door;

[0011] Control the pipe jacking machine and the underwater recovery module to drive into the temporary non-drainage receiving well so that the micro tunnel pipe jacking machine is in a state ready for recovery.

[0012] The underwater recovery module is detached from the precast concrete pipe section, and the micro tunnel jacking machine is recovered through the temporary non-drainage receiving well.

[0013] Optionally, the step of constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drainage receiving well includes:

[0014] Surveying and construction work will be carried out in the target sea area to determine the preset recovery location;

[0015] A temporary construction platform was erected at the predetermined recycling location;

[0016] Several steel pipe piles and steel sheet piles are driven into the preset recovery location on the temporary construction platform to form the current cofferdam.

[0017] Lateral supports are installed on the inner side of the current cofferdam, and the area within the current cofferdam is dredged to the preset elevation.

[0018] At the preset elevation, underwater sealing concrete of target thickness is applied and track is erected.

[0019] A sand material of a predetermined thickness is filled on the surface of the underwater sealing concrete to complete the construction of the temporary cofferdam and form the temporary non-drainage receiving well; wherein, the top elevation of the sand material is higher than the top elevation of the micro tunnel jacking machine.

[0020] Optionally, after the step of filling the surface of the underwater sealing concrete with sand of a predetermined thickness to complete the construction of the temporary cofferdam and form the temporary non-drainage receiving well, the method further includes:

[0021] The cofferdam steel pipe piles directly opposite the travel path of the micro tunnel jacking machine are raised to be level with the top elevation of the sand material, forming an opening that allows the micro tunnel jacking machine to enter the temporary cofferdam.

[0022] Optionally, the step of controlling the pipe jacking machine and the underwater recovery module to all enter the temporary non-drainage receiving well, so that the micro tunnel jacking machine is in a ready-to-be-recovered state, includes:

[0023] According to preset parameters, the front end of the pipe jacking machine is controlled to tunnel to the preset recovery position; wherein the rear end of the pipe jacking machine and the sealing door are both located in the seabed geology outside the temporary cofferdam;

[0024] Check the sealing performance of the underwater recovery module and control the pipe jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well so that the micro tunnel pipe jacking machine is in a ready-to-be-recovered state.

[0025] Optionally, the miniature tunnel jacking machine includes multiple sealing positions and multiple valves;

[0026] The step of checking the sealing performance of the underwater recovery module and controlling the pipe jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well, so that the micro tunnel jacking machine is in a ready-to-be-recovered state, includes:

[0027] Check the sealing status of each of the sealing positions of the miniature tunnel jacking machine;

[0028] Close all valves in the miniature tunnel jacking machine;

[0029] Control the pipe jacking machine and the underwater recovery module to drive into the temporary non-drainage receiving well;

[0030] The sand in the temporary non-drainage receiving well is removed so that the micro tunnel jacking machine is exposed in the seawater and is ready to be received.

[0031] Optionally, multiple precast concrete pipe sections are sequentially spliced ​​to form a water diversion tunnel;

[0032] Following the step of closing each of the valves in the miniature tunnel jacking machine, the method further includes:

[0033] Secondary grouting was carried out on the outer wall of the water diversion tunnel.

[0034] Optionally, the miniature tunnel jacking machine also includes multiple articulated positions;

[0035] The step of removing the sand from the temporary cofferdam to expose the micro-tunnel jacking machine in seawater and place it in a ready-to-receive state includes:

[0036] Remove the sand from the temporary cofferdam to expose the micro-tunnel jacking machine to the seawater.

[0037] The hinge positions of the micro tunnel jacking machine are fixed.

[0038] A lifting device is installed on the micro tunnel jacking machine to put the micro tunnel jacking machine in a ready-to-receive state.

[0039] Optionally, the step of performing an internal pressure test on the micro tunnel jacking machine before recovery includes:

[0040] A compressed air device is installed inside the sealed chamber, and a pressure gauge is installed at the sealed door; wherein the pressure gauge is connected to the compressed air connection port of the compressed air device;

[0041] Compressed air with a preset pressure is supplied into the sealed chamber through the sealed door;

[0042] Record and determine whether the pressure change curve of the pressure gauge meets the preset requirements;

[0043] When the pressure change curve meets the preset requirements, the supply of compressed air is stopped and the compressed air device and the pressure gauge are removed.

[0044] Optionally, after the step of recording and determining whether the pressure change curve of the pressure gauge meets the preset requirements, the method further includes:

[0045] If the pressure change curve does not meet the preset requirements, then check and repair the air leakage location of the micro tunnel jacking machine.

[0046] Repeat the steps of recording and determining whether the pressure change curve of the pressure gauge meets the preset requirements, and when the pressure change curve meets the preset requirements, stop the air supply and remove the compressed air device and the pressure gauge.

[0047] Optionally, the underwater recovery module is equipped with a stroke cylinder, which abuts against one end of the water diversion tunnel where the sealing door is located;

[0048] The step of detaching the underwater recovery module from the precast concrete pipe section and recovering the micro tunnel jacking machine through the temporary non-drainage receiving well includes:

[0049] The hydraulic cylinder is driven to detach the underwater recovery module from the precast concrete pipe section and recover the micro tunnel jacking machine.

[0050] This invention addresses the challenges of constructing a temporary cofferdam at a predetermined recovery location in the target sea area, creating a non-draining temporary receiving well. A micro-tunnel jacking machine is then controlled to advance to the predetermined recovery location, ensuring its tip enters the temporary non-draining receiving well and is ready for recovery. A pre-recovery internal pressure test is then performed on the micro-tunnel jacking machine. The sealing door is then closed, and the jacking machine and the underwater recovery module are fully driven into the temporary non-draining receiving well, placing the micro-tunnel jacking machine in a ready-to-recovery state. Finally, the underwater recovery module is detached from the precast concrete pipe section, and the micro-tunnel jacking machine is recovered through the temporary non-draining receiving well. This invention allows for the recovery of micro-tunnel jacking machines underwater without the need for a cofferdam, or with the construction of a non-draining cofferdam serving as the receiving well, thus improving construction efficiency. It also solves the problems of related technologies that require constructing drainage cofferdams in dry environments for receiving jacking machines, which involve high difficulty in cofferdam construction, leakage risks, and costs, as well as long construction periods. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0052] Figure 1 This is a flowchart illustrating a method for recovering a micro tunnel jacking machine in underwater seabed, as exemplified by one embodiment of the present invention.

[0053] Figure 2 for Figure 1 The flowchart of step S100 in the example is shown;

[0054] Figure 3 for Figure 1 The flowchart of step S300 in the example is shown below;

[0055] Figure 4 for Figure 1 A detailed flowchart of step S500 in the example;

[0056] Figure 5 for Figure 4 The flowchart for step S524 in the example is shown.

[0057] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0059] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the mechanisms in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0062] The inventive concept of the present invention will be further explained below with reference to some specific embodiments.

[0063] This invention proposes a construction method for recovering a micro tunnel jacking machine in underwater conditions.

[0064] like Figures 1 to 5 As shown, an embodiment of the underwater recovery construction method of the micro tunnel jacking machine of the present invention is presented.

[0065] In this embodiment, please refer to Figures 1-5The method for underwater recovery of a micro tunnel jacking machine includes a jacking machine and an underwater recovery module arranged in sequence. The tail end of the underwater recovery module abuts against a precast concrete pipe section, and a sealing door is provided at the end of the precast concrete pipe section that abuts against the underwater recovery module. A water injection chamber is formed between the underwater recovery module and the sealing door.

[0066] The underwater recovery method for miniature tunnel jacking machines includes the following steps:

[0067] S100. Construct a temporary cofferdam at the pre-designated recovery location in the target sea area to form a temporary non-drainage receiving well;

[0068] In this embodiment, a receiving well is constructed in the sea. The seabed level is -11 mPD, and the level for laying the pipeline, i.e., the receiving level for the pipe jacking machine, is -26 mPD. The area from -11 mPD to -26 mPD consists of muddy soil. To achieve underwater recovery of the pipe jacking machine, the sea mud covering the pipe jacking machine must be removed after the machine reaches the designated position before it can be recovered and hoisted. Therefore, a temporary cofferdam needs to be constructed in the sea for receiving the pipe jacking machine. This temporary cofferdam does not require drainage during construction; its function is to prevent sea mud from flowing into the bottom of the receiving well. The cofferdam's planar dimensions should meet the space requirements for pipe jacking machine recovery. Subsequently, the cofferdam is designed and constructed according to the geological conditions. To meet the requirements of receiving the pipe jacking machine, the receiving well needs to be designed with a reserved receiving opening. The main construction steps of the receiving well described in this invention include: (1) building a temporary offshore construction platform according to the measurement and positioning; (2) driving cofferdam steel pipe piles and steel sheet piles on the temporary construction platform to the design position to form a cofferdam; (3) installing the inner lateral support of the cofferdam and using a construction vessel to remove the marine mud in the cofferdam to 1.5 meters below the horizontal water level (-26mPD) of the receiving pipe jacking machine; (4) laying a 1-meter-thick underwater sealing concrete at the bottom of the cofferdam to support the pipe jacking machine from sinking; (5) backfilling sand in the cofferdam to the design horizontal water level (-21mPD), generally 2 meters higher than the pipe jacking machine, to balance the jacking force when the pipe jacking machine enters the receiving well; (6) according to the design requirements, raising 8 pipe jacking machine entry side cofferdam steel pipe piles to the bottom of the piles to the horizontal water level of -21mPD, forming a pipe jacking machine entrance cofferdam opening of about 5m x 5m, and the receiving well cofferdam construction is completed.

[0069] S200: Control the micro tunnel jacking machine to advance to the preset recovery position, so that the front end of the jacking machine enters the temporary non-drainage receiving well and is in a waiting-to-receive state;

[0070] In this embodiment, the pipe jacking machine performs cyclic jacking construction until it reaches the designated position outside the receiving shaft structure. Then, it enters the receiving shaft through an entrance tunnel formed by raised steel pipe piles. The pipe jacking machine, in conjunction with concrete jacking, propels the pipe into the receiving shaft and stops in the correct position. After confirming the position and mileage of the pipe jacking machine are correct, preparations for its retrieval can begin. It is important to note that after the pipe jacking machine enters the receiving shaft, its excavation speed must be controlled and slowed down. Simultaneously, the mileage of the pipe jacking machine must be closely monitored to ensure that the pipeline laying length meets design requirements and to prevent the first pipe section from entering the receiving shaft too long (exceeding 50% of the original length), which could pose a risk to subsequent underwater retrieval of the pipe jacking machine.

[0071] S300, Perform internal pressure test on the micro tunnel jacking machine before recovery;

[0072] In this embodiment, to ensure that the pipe jacking machine does not leak or become waterlogged, a pressure test is required on the recovery chamber before separating the pipe jacking machine from the precast concrete pipe section to ensure the sealing effect of the sealing components of the recovery module. The main steps of the pressure test are: (1) Install a compressed air device in the pipe at the end of the receiving well section; (2) Install a pressure gauge on the sealing door of the pipe section and connect it to the compressed air connection channel; (3) Open the valve port at the connection channel in the sealing door partition to apply 0.5 bar of compressed air into the pipe jacking machine; (4) Observe and record the pressure curve (pressure gauge). Usually, to ensure that the pipe jacking machine does not leak, it is necessary to pressurize for at least 12 hours. If the compressed air test fails, the leak point must be found and sealed, and the compressed air test must be repeated until it is qualified (maintain 0.5 bar air pressure); (5) After successfully completing the pressure test, close the ball valve at the compressed air connection channel, disconnect the compressed air pipeline, remove the pressure gauge, and seal the compressed air connection channel to make it impermeable to water. After the compressed air test is completed, excess equipment in the joint should be removed as soon as possible, and all screws on the sealing door partition should be tightened to ensure its sealing. The separation of the recovery module at the rear end of the pipe jacking machine from the sealing door partition should be carried out within 12 hours.

[0073] The hydraulic pipeline connection of the hydraulic jack in the underwater recovery module is completed by the diver underwater. The operation process is as follows: (1) Remove the cover plate on the reserved terminal block on the top of the underwater recovery module; (2) Remove the blind plug from the terminal block and then connect the hydraulic pipeline for oil supply to push out the jack; (3) Remove the blind plug from the junction box and then connect the hydraulic pipeline for oil return to retract the jack. The terminal block is used to connect hydraulic lines and is an air pipe terminal block. Internally, it connects to the tunnel jacking machine's chamber. It is used to detect and correct the pressure inside the tunnel jacking machine's chamber during recovery operations, ensuring it is watertight. Simultaneously, the terminal block is used to connect air pipes. The air pipe connection method is the same as the hydraulic pipe connection. One function is to maintain / correct the internal air pressure of the tunnel jacking machine at approximately 0.5 bar when the machine needs to remain submerged for extended periods, ensuring the internal equipment is not damaged. This is achieved by connecting the terminal block, which connects internally to the tunnel jacking machine's chamber. Secondly, it allows water to be injected between the recovery module and the pipe section sealing door via an air hose, also achieved through the air pipe terminal block.

[0074] Water injection between the recovery module and the sealing door is a key process before the separation of the pipe jacking machine and the concrete pipe section. The purpose of water injection is to squeeze out the gas in the corresponding chamber and maintain the water pressure balance inside and outside the chamber, so that the separation operation can be carried out in an isobaric environment. If the venting and water injection work is not carried out, a large suction force will be generated in the recovery chamber during the separation operation, and water will enter the recovery chamber rapidly, which may damage the equipment. At the same time, the underwater suction force is extremely unfavorable to the underwater diver's work and must be avoided. The construction steps of water injection are as follows: (1) Connect the pipeline / hose to the terminal block, and ensure that the ends of both pipelines are above the water surface during the process; (2) Ensure that the diver opens the ball valve connecting the pipeline after leaving the danger zone; (3) Fix the pipeline above the water surface and ventilate the area between the recovery module chamber and the sealing door of the concrete pipe section; (4) Put the pipeline underwater and inject water into the area between the recovery module chamber and the sealing door of the concrete pipe section.

[0075] Once the above preliminary procedures are completed, the separation operation can begin. Before separation, ensure there is no material in front of the pipe jacking machine before pushing it out of the pipe. If necessary, this can be achieved by creating a recess in front of the cutter head. The separation operation is carried out by professionals on the workboat using hydraulic equipment to operate the hydraulic jacks of the recovery module to extend the cylinders. During the process, divers assist in checking and ensuring that the hydraulic cylinders are fully extended and that the pipe jacking machine has been completely released from the tunnel section. Once it is confirmed that the pipe jacking machine has completely pushed away from the tunnel section, the separation jacks need to be retracted, and divers assist in ensuring that the jacks are completely retracted.

[0076] Before the separation operation, the lifting distribution beam needs to be connected to each pipe section of the equipment. At the same time, a floating crane is used to hold the beam. Once the separation operation is confirmed to be completed, the floating crane can be used to lift the pipe jacking machine from the receiving well, thus realizing the underwater recovery of the pipe jacking machine.

[0077] S400, Close the sealing door;

[0078] In this embodiment, after the pipe jacking machine has been excavated to the design position, preparations for equipment recovery can be carried out, including: (1) checking the cleanliness and damage of all sealing door components and sealing surfaces, and replacing the sealing components as needed to ensure the sealing effect; (2) fully retracting the steering cylinder, filling the main drive with oil, and closing the ball valve to seal the drive device; (3) closing all mud pipe inlet and outlet gate valves, disconnecting the inlet and outlet pipeline connections at the recovery module partition, disconnecting all electrical and hydraulic pipelines, and sealing all openings on the recovery module partition; (4) performing secondary grouting on the outer wall of the precast concrete pipe section to strengthen the integrity of the pipeline, removing all pipeline facilities inside the pipeline after grouting, and cleaning out the pipeline; (5) removing the backfilled sand in the receiving well so that the pipe jacking machine is exposed in the seawater at the bottom of the shaft.

[0079] After the preparation work is completed, the next step is to tighten the connecting screws between the pipe sections of the pipe jacking machine, so that the pipe sections of the pipe jacking machine are connected into a whole, including the main drive chamber, steering chamber, power chamber, air pressure chamber and recovery module chamber. The tightening work is carried out by professional personnel who enter the equipment from the rear end of the pipe jacking machine through the pipes laid by the pipe jacking. During the process, it is necessary to ensure the tightening and sealing effect, and ensure that the pipe sections between the chambers are airtight and watertight.

[0080] Throughout the recovery operation, the main thrust jack of the jacking system in the launching well must continuously output thrust to the end of the pipe section, while the thrust ring must always be locked on the precast concrete pipe section to generate back pressure and prevent the concrete pipe section or the compartment pipe section from breaking during the recovery operation.

[0081] The S500, the control pipe jacking machine, and the underwater recovery module all drove into the temporary non-drainage receiving well so that the micro tunnel pipe jacking machine was in a state ready for recovery.

[0082] During the assembly of the pipe jacking machine at the launching shaft, each compartment pipe section is equipped with a lifting ring for connecting the load-bearing distribution beam. Before the tunneling operation begins after the pipe jacking machine is assembled, the lifting rings on the equipment pipe sections must be removed and sealed with wax and special caps to ensure smooth tunneling and jacking. After the underwater recovery preparation work in the receiving shaft is completed, the lifting rings need to be reinstalled on each compartment pipe section. The underwater installation of the lifting rings is carried out by divers. The main steps are to remove the caps and tighten the screws on the lower part of the lifting rings into the reserved holes on the compartment pipe sections. After the lifting rings are installed, the special distribution beam is connected to the lifting rings, and the hook of the crane is connected to the distribution beam for lifting the pipe jacking machine away for recovery. The load-bearing distribution beam needs to be comprehensively designed based on the distribution of the lifting rings and the weight of the pipe jacking machine. Generally, I-beams are used to ensure that each equipment compartment is directly connected to the beam, ensuring that the equipment compartments do not bend or leak due to uneven stress during transportation.

[0083] S600: The underwater recovery module is detached from the precast concrete pipe section, and the micro tunnel jacking machine is recovered through a temporary non-drainage receiving well.

[0084] This invention's technical solution involves constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drained receiving well. A micro-tunnel jacking machine is then controlled to advance to the predetermined recovery location, ensuring its front end enters the temporary non-drained receiving well and is ready for recovery. An internal pressure test is then performed on the micro-tunnel jacking machine before recovery. The sealing door is then closed, and the jacking machine and the underwater recovery module are all driven into the temporary non-drained receiving well, placing the micro-tunnel jacking machine in a ready-to-recovery state. Finally, the underwater recovery module is detached from the precast concrete pipe section, and the micro-tunnel jacking machine is recovered through the temporary non-drained receiving well. This invention allows for the direct recovery of a micro-tunnel jacking machine from the seabed without the need for a cofferdam, or by constructing a non-drained cofferdam as the receiving well. This improves construction efficiency and solves the problems of constructing drainage cofferdams in dry environments, which involve high difficulty in cofferdam construction, leakage risks, and costs, as well as long construction periods.

[0085] In some specific embodiments, the step of constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drainage receiving well includes:

[0086] S110. Conduct surveying and construction in the target sea area to determine the preset recovery location;

[0087] S120. Construct a temporary construction platform at the pre-designated recycling location;

[0088] S130. Drive several steel pipe piles and steel sheet piles at the preset recovery location on the temporary construction platform to form the current cofferdam;

[0089] S140. Construct lateral supports on the inner side of the current cofferdam and dredge the area within the current cofferdam to the preset elevation.

[0090] S150. Construct underwater sealing concrete of target thickness at the preset elevation and erect the track.

[0091] It should be specifically and clearly stated that, in this embodiment, the purpose of constructing underwater concrete is to provide sufficient support for the micro-tunnel jacking machine and the underwater recovery module, avoiding potential risks such as instability or overturning of the jacking machine and the underwater recovery module due to insufficient hardness of the seabed or bedrock. In this embodiment, the target thickness is at least 1 meter.

[0092] S160. Fill the surface of the underwater sealing concrete with sand of a preset thickness to complete the construction of a temporary cofferdam and form a temporary non-drainage receiving well; wherein the top elevation of the sand is higher than the top elevation of the micro tunnel jacking machine.

[0093] In some specific embodiments, after the step of filling the surface of the underwater bottom sealing concrete with sand of a predetermined thickness to complete the construction of the temporary cofferdam and form a temporary non-drainage receiving well, the method further includes:

[0094] S170. Raise the steel pipe pile directly opposite the micro tunnel jacking machine to the same level as the top of the sand material, forming an opening that allows the micro tunnel jacking machine to enter the temporary cofferdam.

[0095] In some specific embodiments, the step of controlling the pipe jacking machine and the underwater recovery module to all enter the temporary non-drainage receiving well, so that the micro-tunnel jacking machine is in a ready-to-be-recovered state, includes:

[0096] S510. According to the preset parameters, control the tunneling machine to advance to the preset recovery position; wherein, the rear end of the tunneling machine and the sealing door are located in the seabed geology outside the temporary cofferdam;

[0097] S520. Check the sealing performance of the underwater recovery module and control the pipe jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well so that the micro tunnel pipe jacking machine is in a ready-to-be-recovered state.

[0098] In some specific embodiments, the miniature tunnel jacking machine includes multiple sealing positions and multiple valves;

[0099] The steps for checking the sealing performance of the underwater recovery module and controlling the tunnel jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well, so that the micro tunnel jacking machine is in a ready-to-be-recovered state, include:

[0100] S521. Check the sealing status of each sealing position of the miniature tunnel jacking machine;

[0101] S522. Close all valves in the mini tunnel jacking machine;

[0102] S523, control the pipe jacking machine and underwater recovery module to all drive into the temporary non-drainage receiving well;

[0103] S524. Remove the sand from the temporary non-drainage receiving well so that the micro tunnel jacking machine is exposed in the seawater and ready for reception.

[0104] In some specific embodiments, precast concrete pipe sections are spliced ​​together sequentially to form a water diversion tunnel;

[0105] After closing all valves in the miniature tunnel jacking machine, the following steps are also included:

[0106] S525. Secondary grouting construction shall be carried out on the outer wall of the precast concrete pipe section water diversion tunnel.

[0107] In some specific embodiments, the micro tunnel jacking machine also includes multiple articulated positions;

[0108] The steps of removing sand from the temporary cofferdam to expose the micro-tunnel jacking machine in the seawater, placing it in a ready-to-receive state, include:

[0109] S524a. Remove the sand from the temporary cofferdam to expose the micro-tunnel jacking machine to the seawater.

[0110] S524b, Fix each hinge position of the miniature tunnel jacking machine;

[0111] S524c. Install a lifting device on the micro tunnel jacking machine to put the micro tunnel jacking machine in a ready-to-receive state.

[0112] In some specific embodiments, the step of performing an internal pressure test on a micro tunnel jacking machine before recovery includes:

[0113] S310. Install a compressed air device in the sealed chamber and a pressure gauge at the sealed door; wherein the pressure gauge is connected to the compressed air connection port of the compressed air device;

[0114] S320: Compressed air with a preset pressure is supplied into the sealed chamber through the sealed door;

[0115] S330. Record and determine whether the pressure change curve of the pressure gauge meets the preset requirements;

[0116] S340. When the pressure change curve meets the preset requirements, stop supplying compressed air and remove the compressed air device and pressure gauge.

[0117] In some specific embodiments, after recording and determining whether the pressure change curve of the pressure gauge meets the preset requirements, the method further includes:

[0118] S350. When the pressure change curve does not meet the preset requirements, check and repair the air leakage location of the micro tunnel jacking machine.

[0119] S360, Repeat the steps of recording and judging whether the pressure change curve of the pressure gauge meets the preset requirements, and when the pressure change curve meets the preset requirements, stop the air supply and remove the compressed air device and pressure gauge.

[0120] In some specific embodiments, the underwater recovery module is equipped with a stroke cylinder, which abuts against one end of the water diversion tunnel where a sealing door is located;

[0121] The steps of detaching the underwater recovery module from the precast concrete pipe section and recovering the micro-tunnel jacking machine through a temporary non-drainage receiving well include:

[0122] The drive stroke cylinder detaches the underwater recovery module from the precast concrete pipe section and recovers the micro tunnel jacking machine.

[0123] In some specific embodiments, microtunnel construction is the process of constructing small tunnels underground without excavation using a microtunnel jacking machine. It is commonly used for laying underground pipelines. Depending on the tunnel diameter, either pipe jacking or segment lining techniques can be selected for tunnel and pipeline laying. In current urban infrastructure construction, microtunnel jacking technology is widely used in underground water intake, drainage pipelines, underground power transmission lines, and underground pipeline construction projects in industries such as oil and gas. Especially in coastal areas, this technology can solve all the environmental problems that may result from open-pit excavation along the coastline. Its applicability is extremely wide, particularly in pipeline construction from the mainland to the ocean, such as oil and gas pipelines, sewage treatment plant discharge pipelines, and seawater desalination drainage pipelines.

[0124] When using microtunneling to lay subsea pipelines from land to sea, the launching and receiving of the jacking machine are crucial construction steps. Typically, launching and receiving shafts need to be built according to the engineering design. Launching shafts are located on land, and their construction methods are relatively traditional. However, receiving shafts are located in the sea, and constructing cofferdams in the seawater for use as receiving shafts is much more difficult than on land. This is significantly affected by the geological conditions beneath the seabed in the construction area. If a drainage cofferdam is built to receive the jacking machine in a dry environment, the difficulty and risk of cofferdam sealing construction are both high, and the cost is also high. With the development of jacking machine technology, it is now possible to recover the jacking machine underwater without constructing a cofferdam or with a non-drainage cofferdam.

[0125] In the construction of a seawater desalination plant, two seawater pipelines need to be built from land to the ocean for seawater intake and concentrated brine discharge. The project employs micro-tunneling technology for construction. During the construction of the water intake pipeline, considering the actual project conditions, the method of underwater recovery of the pipe jacking machine was chosen. This invention mainly introduces the key procedures and control points in the underwater recovery of the pipe jacking machine during the construction of a seawater desalination plant, providing experience and reference for similar projects involving underwater recovery of pipe jacking machines during land-to-sea pipe jacking construction.

[0126] (1) Customize the pipe jacking machine for underwater recovery. If the pipe jacking machine is to be recovered underwater, the following components need to be customized during the equipment selection, design and manufacturing process: one is the underwater recovery module, and the other is the sealing door set at the front end of the top pipe section.

[0127] (2) Constructing a non-drainage cofferdam receiving well. When the subsea pipe jacking pipeline is located in non-rocky rock layers and muddy soil layers, a non-drainage cofferdam is constructed as a receiving well to recover the pipe jacking machine underwater. The function of the non-drainage cofferdam is to prevent marine mud from flowing into the receiving well.

[0128] (3) High environmental protection efficiency. Constructing non-drainage cofferdams in seawater avoids the need for cofferdam water-stopping, requires fewer temporary cofferdam works, has high construction efficiency, avoids grouting water-stopping construction, and has little impact on the marine ecological environment.

[0129] When constructing the pipeline to the sea, the pipe jacking method is adopted. The starting shaft is built on land, and the pipe jacking machine is assembled and the pipe jacking equipment is pushed in a dry environment. After the pipe jacking machine crosses the seabed and reaches the designated position, it needs to be retrieved. Unlike the conventional cofferdam construction method, the pipe jacking machine does not need to be built in the wet environment of seawater. Divers separate the pipe jacking machine from the pipe section on the seabed, and a hook is installed on the pipe jacking machine in the seawater. The hook is connected to a specially made lifting distribution beam (lifting device), and the pipe jacking machine is retrieved from the water by a floating crane.

[0130] To achieve separation between the underwater pipe jacking machine and the concrete pipeline, special arrangements are required when selecting the pipe jacking machine. Firstly, an underwater recovery module must be installed at the rear end of the pipe jacking machine. Figure 1 As shown, the recovery module is equipped with an independently driven hydraulic jacking system, and a special sealing door is installed at the front end of the first pipe section. The principle of separating the underwater pipe jacking machine from the concrete pipe section is as follows: the underwater recovery module is connected to the hydraulic oil pipe by the diver (connected outside the pipe jacking machine compartment). After the oil pipe is connected, the operator operates the hydraulic jacks inside the module on the workboat to separate the pipe jacking machine from the concrete pipe section.

[0131] A receiving well is constructed in the sea. The seabed level is -11mPD, and the level of the pipe laying level, i.e., the receiving level of the pipe jacking machine, is -26mPD. Both -11mPD and -26mPD are muddy soil layers. In order to realize the underwater recovery of the pipe jacking machine, the sea mud covering the pipe jacking machine must be removed after the pipe jacking machine has reached the designated position before the pipe jacking machine can be recovered and hoisted. For this reason, a temporary cofferdam needs to be built in the sea for the pipe jacking machine to receive. The construction of this temporary cofferdam does not require drainage. Its function is to prevent the sea mud around the cofferdam from flowing into the bottom of the receiving well. The plane dimensions of the cofferdam should meet the space requirements for the recovery of the pipe jacking machine. Then, the cofferdam is designed and constructed according to the geological conditions. To meet the requirements of receiving the pipe jacking machine, the receiving well needs to be designed with the setting of a reserved receiving opening. The main construction steps of the receiving well described in this invention include: (1) building a temporary offshore construction platform according to the measurement and positioning; (2) driving cofferdam steel pipe piles and steel sheet piles on the temporary construction platform to the design position to form a cofferdam; (3) installing the inner lateral support of the cofferdam and using a construction vessel to remove the sea mud in the cofferdam to 1.5 meters below the horizontal water level (-26mPD) of the receiving pipe jacking machine; (4) laying a 1-meter-thick underwater sealing concrete at the bottom of the cofferdam to support the pipe jacking machine from sinking; (5) filling the cofferdam with sand to the design horizontal water level (-21mPD), generally 2 meters higher than the pipe jacking machine, to balance the jacking force when the pipe jacking machine enters the receiving well; (6) according to the design requirements, raising 8 TBM entry side cofferdam steel pipe piles to the bottom of the piles to the horizontal water level of -21mPD, forming a pipe jacking machine entrance cofferdam opening of about 5m x 5m, and the receiving well cofferdam construction is completed.

[0132] The pipe jacking machine will advance in a cyclical manner until it reaches the designated position outside the receiving shaft structure. Then, according to design requirements, eight steel pipe piles of the pipe jacking machine's entry side cofferdam will be raised to a depth of -21m PD at the bottom of the piles, forming an approximately 5m x 5m entrance cofferdam opening for the pipe jacking machine. During the completion of the receiving shaft cofferdam construction, the steel pipe forming the entrance tunnel will be raised and enter the receiving shaft. The pipe jacking machine will then advance into the receiving shaft and stop in the correct position. After confirming that the position and mileage of the pipe jacking machine are correct, preparations for its retrieval can begin. It is important to note that after the pipe jacking machine enters the receiving shaft, its excavation speed must be controlled and slowed down. Simultaneously, the mileage of the pipe jacking machine must be closely monitored to ensure that the pipeline laying length meets design requirements and to prevent the first pipe section from entering the receiving shaft too long (exceeding 50% of the original length), which could pose a risk to subsequent underwater retrieval of the pipe jacking machine.

[0133] After the pipe jacking machine has been excavated to the design position, preparations for equipment recovery can be carried out, including: (1) checking the cleanliness and damage of all sealing door components and sealing surfaces, and replacing the sealing components as needed to ensure the sealing effect; (2) fully retracting the steering cylinder, filling the main drive with oil, and closing the ball valve to seal the drive device; (3) closing all mud pipe inlet and outlet gate valves, disconnecting the inlet and outlet pipeline connections at the recovery module partition, disconnecting all electrical and hydraulic pipelines, and sealing all openings on the recovery module partition; (4) performing secondary grouting on the outer wall of the precast concrete pipe section to strengthen the integrity of the pipeline, removing all pipeline facilities inside the pipeline after grouting, and cleaning out the pipeline; (5) removing the backfilled sand in the receiving well so that the pipe jacking machine is exposed in the seawater at the bottom of the shaft.

[0134] After the preparation work is completed, the next step is to tighten the connecting screws between the pipe sections of the pipe jacking machine, so that the pipe sections of the pipe jacking machine are connected into a whole, including the main drive chamber, steering chamber, power chamber, air pressure chamber, recovery module chamber, etc. The tightening work is carried out by professional personnel who enter the equipment from the rear end of the pipe jacking machine through the pipes laid by the pipe jacking. During the process, it is necessary to ensure the tightening and sealing effect, and ensure that the pipe sections of the chambers are airtight and watertight.

[0135] Throughout the recovery operation, the main jack of the jacking system in the launching well must continuously output jacking force to the end of the pipe section. At the same time, the thrust ring must always be locked on the precast concrete pipe section to generate back pressure and prevent the pipe section or compartment pipe section from breaking during the recovery operation.

[0136] During the assembly of the pipe jacking machine at the launching shaft, each compartment pipe section is equipped with a lifting ring for connecting the load-bearing distribution beam. Before the tunneling operation begins after the pipe jacking machine is assembled, the lifting rings on the equipment pipe sections must be removed and sealed with wax and special caps to ensure smooth tunneling and jacking. After the underwater recovery preparation work in the receiving shaft is completed, the lifting rings need to be reinstalled on each compartment pipe section. The underwater installation of the lifting rings is carried out by divers underwater. The main steps are to remove the caps and tighten the screws under the lifting rings onto the pre-drilled holes in the compartment pipe sections. After the lifting rings are installed, the special distribution beam is connected to the lifting rings, and the crane hook is connected to the distribution beam for use in lifting and recovering the pipe jacking machine. The load-bearing distribution beam needs to be designed and determined in combination with the distribution of the lifting rings and the weight of the pipe jacking machine. Generally, I-beams are used to ensure that each equipment compartment is directly connected to the beam, ensuring that the equipment compartments do not bend or leak due to uneven stress during transportation.

[0137] To ensure that the tunnel boring machine does not leak or become submerged in water, a pressure test is required on the recovery chamber before separating the jacking machine from the precast concrete pipe section to ensure the sealing effect of the sealing components of the recovery module. The main steps of the pressure test are: (1) Install a compressed air device in the pipe at the end of the receiving well section; (2) Install a pressure gauge on the sealing door of the pipe section and connect it to the compressed air connection channel; (3) Open the valve port at the connection channel in the sealing door partition to apply 0.5 bar of compressed air into the tunnel boring machine; (4) Observe and record the pressure curve (pressure gauge). Usually, to ensure that the tunnel boring machine does not leak water, it should be pressurized for at least 12 hours. If the machine fails the compressed air test, find the leak and seal it, repeat the compressed air test until it passes (maintain 0.5 bar air pressure); (5) After successfully completing the pressure test, close the ball valve at the compressed air connection channel, disconnect the compressed air pipeline, remove the pressure gauge, and seal the compressed air connection channel to make it impermeable to water. After the compressed air test is completed, excess equipment in the joint should be removed as soon as possible, and all screws on the sealing door partition should be tightened to ensure its sealing. The separation of the pipe jacking machine recovery module from the sealing door partition should be carried out within 12 hours.

[0138] The hydraulic pipeline connection of the hydraulic drive jack in the underwater recovery module is completed by the diver underwater. The operation process is as follows: (1) Remove the cover plate on the reserved terminal block on the top of the underwater recovery module; (2) Remove the blind plug from the terminal block and then connect the hydraulic pipeline for oil supply to push out the jack; (3) Remove the blind plug from the junction box and then connect the hydraulic pipeline for oil return to retract the jack. The terminal block is used to connect hydraulic lines and is an air pipe terminal block. Internally, it connects to the tunnel jacking machine's chamber. It is used during recovery operations to detect and correct the pressure inside the tunnel jacking machine's chamber, ensuring it is watertight. Simultaneously, the terminal block is used to connect air pipes. The air pipe connection method is the same as the hydraulic pipe connection. One function is to maintain / correct the internal air pressure of the tunnel jacking machine at approximately 0.5 bar when the machine needs to remain submerged for extended periods, ensuring the internal equipment is not damaged. This is achieved by connecting the terminal block, which connects internally to the tunnel jacking machine's chamber. Secondly, it is used to inject water between the recovery module and the pipe section sealing door via an air hose, also achieved through the air pipe terminal block.

[0139] Water injection between the recovery module and the sealing door is a key process before the separation of the pipe jacking machine and the concrete pipe section. The purpose of water injection is to squeeze out the gas in the corresponding chamber and maintain the water pressure balance inside and outside the chamber, so that the separation operation can be carried out in an isobaric environment. If the venting and water injection work is not carried out, a large suction force will be generated in the recovery chamber during the separation operation, and water will enter the recovery chamber rapidly, which may damage the equipment. At the same time, the underwater suction force is extremely unfavorable to the underwater diver's work and must be avoided. The construction steps of water injection work are as follows: (1) Connect the pipeline / hose to the terminal block, and ensure that the ends of the two pipelines are above the water surface during the process; (2) Ensure that the diver opens the ball valve connecting the pipeline after leaving the danger zone; (3) Fix pipeline 3 above the water surface and ventilate the area between the recovery module chamber and the sealing door of the pipe section; (4) Put the pipeline underwater and inject water into the area between the recovery module chamber and the sealing door of the pipe section.

[0140] Once the above preliminary procedures are completed, the separation operation can begin. Before separation, ensure there is no material in front of the pipe jacking machine, and then push it out of the pipe. If necessary, this can be achieved by creating a recess in front of the cutter head. The separation operation is carried out by professionals on the workboat using hydraulic equipment to operate the hydraulic jacks of the recovery module to extend the cylinders. During the process, divers assist in checking and ensuring that the hydraulic cylinders are fully extended and that the pipe jacking machine has been completely released from the tunnel section. Once it is confirmed that the pipe jacking machine has completely pushed away from the tunnel section, the separation jacks need to be retracted, and divers assist in ensuring that the jacks are completely retracted.

[0141] Before the separation operation, the lifting distribution beam needs to be connected to each pipe section of the pipe jacking machine. At the same time, a floating crane is used to lift the beam. Once the separation operation is confirmed to be completed, the floating crane can be used to lift the pipe jacking machine from the receiving well, thus realizing the underwater recovery of the pipe jacking machine.

[0142] When performing onshore-to-offshore micro-tunnel jacking construction, the selection of the jacking machine includes the addition of a specific module that allows for underwater jacking machine recovery. Compared to constructing drainage cofferdams in silty seabeds for jacking machine recovery, the non-drainage cofferdam receiving shaft is simpler to construct, significantly reduces the cofferdam support structure, and avoids the need for water-stopping requirements in cement-rich environments. This eliminates the construction risks associated with water-stopping and leakage, greatly improving construction efficiency and offering significant advantages in terms of time and cost. Calculations show that this invention can save 40% of the cofferdam construction cost compared to building a seawater drainage cofferdam, while the cost of adding an underwater recovery module to the jacking machine is much lower than the cost savings from cofferdam construction. Overall, this method is highly suitable for receiving jacking machines in seabed silty soil conditions and offers significant economic benefits.

[0143] When using an underwater pipe jacking machine for recovery, it is unnecessary or only necessary to construct a non-drainage cofferdam, avoiding the risks of water leakage associated with constructing a drainage cofferdam. The usual method for water sealing and leakage treatment involves grouting to reinforce the soil, which involves injecting a large amount of chemical grout into the seabed around the cofferdam to solidify and reinforce the soil. This construction process is extremely difficult to control in terms of grouting range and effect, and has a significant impact on the marine environment, especially when the construction area is located in a coral reef protection zone. Using this invention for recovery construction can avoid the grouting water sealing process, minimizing the impact on the marine environment and providing excellent environmental benefits. Furthermore, the underwater pipe jacking machine construction technology is highly specialized, and successfully implemented construction schemes serve as models and guides in the industry. While cultivating professional technical personnel, it can also promote the further application of underwater pipe jacking machine technology, resulting in significant social benefits.

[0144] This invention has been successfully applied in the first phase of a seawater desalination plant project. The project included the construction of two subsea water intake and drainage pipelines, which were constructed using a micro-tunneling and pipe jacking method. The water intake pipeline has an inner diameter of 2.5 meters and a length of 330 meters. The pipe jacking machine excavated 26.0 mPD of seabed. Geological surveys revealed that the water intake pipeline traversed layers of silt, sediment, and rock, presenting complex geological conditions. Furthermore, the water intake pipeline receiving well was located in a sediment layer. Constructing a drainage cofferdam for the receiving well would have been a large-scale, challenging, and high-risk undertaking, with significant impact on the marine environment. After comprehensive consideration, the project adopted a non-drainage cofferdam (12.0 mPD at seabed, 26 mPD at pipe jacking machine excavation), or "wet well," method for underwater recovery of the pipe jacking machine. The cofferdam was constructed to prevent marine mud from entering the receiving well, without considering drainage functionality.

[0145] Currently, the water intake pipeline for the pipe jacking construction has been completed, and the underwater recovery of the pipe jacking machine has been successfully achieved for the first time in a certain region.

[0146] This invention's technical solution involves constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drained receiving well. A micro-tunnel jacking machine is then controlled to advance to the predetermined recovery location, ensuring its front end enters the temporary non-drained receiving well and is ready for recovery. An internal pressure test is then performed on the micro-tunnel jacking machine before recovery. The sealing door is then closed, and the jacking machine and the underwater recovery module are all driven into the temporary non-drained receiving well, placing the micro-tunnel jacking machine in a ready-to-recovery state. Finally, the underwater recovery module is detached from the precast concrete pipe section, and the micro-tunnel jacking machine is recovered through the temporary non-drained receiving well. This invention allows for the direct recovery of a micro-tunnel jacking machine from the seabed without the need for a cofferdam, or by constructing a non-drained cofferdam as the receiving well. This improves construction efficiency and solves the problems of constructing drainage cofferdams in dry environments, which involve high difficulty in cofferdam construction, leakage risks, and costs, as well as long construction periods.

[0147] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for recovering a miniature tunnel jacking machine in underwater seabed, characterized in that, The micro tunnel jacking machine includes a jacking machine and an underwater recovery module arranged in sequence. The rear end of the underwater recovery module abuts against a precast concrete pipe section, and a sealing door is provided at the end of the precast concrete pipe section that abuts against the underwater recovery module. A water injection chamber is formed between the underwater recovery module and the sealing door. The underwater recovery method for the micro-tunnel jacking machine includes the following steps: Temporary cofferdams were constructed at the pre-designated recovery location in the target sea area to form temporary non-drainage receiving wells; Control the micro tunnel jacking machine to excavate to the preset recovery position, so that the front end of the jacking machine enters the temporary non-drainage receiving well and is in a waiting-to-receive state; The internal pressure of the micro tunnel jacking machine was tested before it was recovered. Close the sealing door; Control the pipe jacking machine and the underwater recovery module to drive into the temporary non-drainage receiving well, so that the micro tunnel pipe jacking machine is in a state ready for recovery; The underwater recovery module is detached from the precast concrete pipe section, and the micro tunnel jacking machine is recovered through the temporary non-drainage receiving well. Water is injected between the recovery module and the sealing door to squeeze out the gas in the corresponding compartment, and the water pressure inside and outside the compartment is kept balanced by water injection so that the separation operation can be carried out in a medium-pressure environment. The step of performing an internal pressure test on the micro tunnel jacking machine before recovery includes: A compressed air device is installed inside the sealed chamber, and a pressure gauge is installed at the sealed door; wherein the pressure gauge is connected to the compressed air connection port of the compressed air device; Compressed air with a preset pressure is supplied into the sealed chamber through the sealed door; Record and determine whether the pressure change curve of the pressure gauge meets the preset requirements; When the pressure change curve meets the preset requirements, the supply of compressed air is stopped and the compressed air device and the pressure gauge are removed. After the step of recording and determining whether the pressure change curve of the pressure gauge meets the preset requirements, the method further includes: If the pressure change curve does not meet the preset requirements, then check and repair the air leakage location of the micro tunnel jacking machine. Repeat the steps of recording and determining whether the pressure change curve of the pressure gauge meets the preset requirements, and when the pressure change curve meets the preset requirements, stop the air supply and remove the compressed air device and the pressure gauge; The underwater recovery module is equipped with a stroke cylinder, which abuts against one end of the water diversion tunnel where the sealing door is located. The step of detaching the underwater recovery module from the precast concrete pipe section and recovering the micro tunnel jacking machine through the temporary non-drainage receiving well includes: The stroke cylinder is driven to detach the underwater recovery module from the precast concrete pipe section and recover the micro tunnel jacking machine; The water injection work construction steps are as follows: (1) Connect the pipeline / hose to the terminal block, and ensure that the ends of both pipelines are above the water surface during the process; (2) Ensure that the diver opens the ball valve connecting the pipeline after leaving the danger zone; (3) Fix the pipeline above the water surface and ventilate the area between the recovery module chamber and the concrete pipe section sealing door; (4) Put the pipeline underwater and inject water into the area between the recovery module chamber and the concrete pipe section sealing door.

2. The underwater recovery construction method for a micro-tunnel jacking machine as described in claim 1, characterized in that, The step of constructing a temporary cofferdam at a predetermined recovery location in the target sea area to form a temporary non-drainage receiving well includes: Surveying and construction work will be carried out in the target sea area to determine the preset recovery location; A temporary construction platform was erected at the predetermined recycling location; Several steel pipe piles and steel sheet piles are driven into the preset recovery location on the temporary construction platform to form the current cofferdam. Lateral supports are installed on the inner side of the current cofferdam, and the area within the current cofferdam is dredged to the preset elevation. At the preset elevation, underwater sealing concrete of target thickness is applied and track is erected. A sand material of a predetermined thickness is filled on the surface of the underwater sealing concrete to complete the construction of the temporary cofferdam and form the temporary non-drainage receiving well; wherein the top elevation of the sand material is higher than the top elevation of the micro tunnel jacking machine.

3. The underwater recovery construction method for a micro tunnel jacking machine as described in claim 2, characterized in that, After the step of filling the surface of the underwater sealing concrete with sand of a predetermined thickness to complete the construction of the temporary cofferdam and form the temporary non-drainage receiving well, the method further includes: The steel pipe piles of the cofferdam directly opposite the travel route of the micro tunnel jacking machine are raised to the same level as the top elevation of the sand material, forming an opening that allows the micro tunnel jacking machine to enter the temporary cofferdam.

4. The underwater recovery construction method for a micro tunnel jacking machine as described in claim 3, characterized in that, The step of controlling the pipe jacking machine and the underwater recovery module to all enter the temporary non-drainage receiving well, so that the micro tunnel jacking machine is in a ready-to-be-recovered state, includes: According to preset parameters, the front end of the pipe jacking machine is controlled to tunnel to the preset recovery position; wherein the rear end of the pipe jacking machine and the sealing door are both located in the seabed geology outside the temporary cofferdam; Check the sealing performance of the underwater recovery module and control the pipe jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well so that the micro tunnel pipe jacking machine is in a ready-to-be-recovered state.

5. The underwater recovery construction method for a micro-tunnel jacking machine as described in claim 4, characterized in that, The miniature tunnel jacking machine includes multiple sealing positions and multiple valves; The step of checking the sealing performance of the underwater recovery module and controlling the pipe jacking machine and the underwater recovery module to enter the temporary non-drainage receiving well, so that the micro tunnel jacking machine is in a ready-to-be-recovered state, includes: Check the sealing status of each of the sealing positions of the miniature tunnel jacking machine; Close all valves in the miniature tunnel jacking machine; Control the pipe jacking machine and the underwater recovery module to drive into the temporary non-drainage receiving well; The sand in the temporary non-drainage receiving well is removed so that the micro tunnel jacking machine is exposed in the seawater and is ready to be received.

6. The underwater recovery construction method for a micro-tunnel jacking machine as described in claim 5, characterized in that, Multiple precast concrete pipe sections are sequentially spliced ​​to form a water diversion tunnel; Following the step of closing each of the valves in the miniature tunnel jacking machine, the method further includes: Secondary grouting was carried out on the outer wall of the water diversion tunnel.

7. The underwater recovery construction method for a micro tunnel jacking machine as described in claim 6, characterized in that, The miniature tunnel jacking machine also includes multiple hinged positions; The step of removing the sand from the temporary cofferdam to expose the micro-tunnel jacking machine in seawater and place it in a ready-to-receive state includes: Remove the sand from the temporary cofferdam to expose the micro-tunnel jacking machine to the seawater. The hinge positions of the micro tunnel jacking machine are fixed. A lifting device is installed on the micro tunnel jacking machine to put the micro tunnel jacking machine in a ready-to-receive state.

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