Pipe jacking machine receiving construction method

Abstract

The application relates to a pipe jacking machine receiving construction method, which comprises the following steps: constructing a foundation pit retaining structure at a preset receiving well position, making the foundation pit retaining structure form a closed foundation pit retaining system, and keeping the soil in the foundation pit of the receiving well in an unexcavated state; controlling the pipe jacking machine to advance from a working well to the foundation pit retaining structure, and cutting through the foundation pit retaining structure to enter the range of the foundation pit retaining structure; plugging the gap between the shell of the pipe jacking machine and the foundation pit retaining structure; layer-by-layer excavating the soil in the foundation pit of the receiving well, and installing a temporary supporting device in the foundation pit during the excavation process; and hoisting the pipe jacking machine out of the receiving well after the soil is excavated to a design elevation. The application relies on the closed system formed by the foundation pit retaining structure and the in-situ soil support in the pit, can receive the pipe jacking machine without waiting for the completion of the main body structure of the receiving well, does not need to reinforce the soil at the end before receiving, and enables the pipe jacking machine to directly enter the unexcavated soil area in the foundation pit retaining structure.

Description

Technical Field

[0001] This application relates to the field of pipe jacking construction, and in particular to a method for receiving a pipe jacking machine. Background Technology

[0002] Pipe jacking, as a trenchless underground pipeline laying technology, has been widely used in urban water supply and drainage, gas, and power and communication underground pipeline projects due to its significant advantages such as minimal interference with surface traffic and low disturbance to the surrounding environment. In the core procedures of pipe jacking construction, the receiving well stage is a critical node that determines the success or failure of the construction, directly affecting the overall project schedule, cost, and construction safety.

[0003] Currently, traditional pipe jacking machine receiving construction generally follows a fixed procedural logic of "receiving shaft main structure construction → end soil reinforcement → pipe jacking machine reception → pipe jacking machine hoisting out". However, this traditional process has many prominent technical defects in practical applications: First, the process connection is rigid. If the receiving shaft is affected by factors such as land acquisition and demolition, underground pipeline relocation, or limited construction site, resulting in a delay in the construction period, it will directly block the pipe jacking machine's advancement process, causing construction stagnation and overall project delays, increasing construction costs. Second, the construction cost is high and the process is cumbersome. End soil reinforcement requires a large amount of additional materials, equipment, and labor, and the reinforcement quality is easily constrained by geological conditions, posing a safety risk of reinforcement failure. Third, the construction flexibility is poor. The receiving shaft and pipe jacking construction are mutually restrictive, making it difficult to adapt to projects with complex geology, sensitive surrounding environment, or tight schedules. Fourth, safety risk control is difficult. Inadequate reinforcement can easily lead to end soil heave, collapse, or even deformation of the retaining structure, threatening the safety of personnel and surrounding structures.

[0004] In view of the shortcomings of the traditional process, there is currently no construction method that can break the traditional process logic and achieve safe reception of the pipe jacking machine without the need for prior construction of the main structure of the receiving well and the reinforcement of the end soil. Summary of the Invention

[0005] This application provides a method for receiving pipe jacking machines, which can solve the problem that traditional pipe jacking receiving methods require the construction of the main structure of the receiving well and the reinforcement of the end head, resulting in delays in the construction period and high costs.

[0006] This application provides a method for receiving a pipe jacking machine during construction, which includes: Construct a retaining structure for the foundation pit at the predetermined receiving well location, so that the retaining structure forms a closed foundation pit retaining system and keeps the soil inside the receiving well foundation pit in an unexcavated state. The pipe jacking machine is controlled to advance from the working shaft to the foundation pit retaining structure, and after cutting through the foundation pit retaining structure, it enters the area of ​​the foundation pit retaining structure; Seal the gap between the outer shell of the pipe jacking machine and the foundation pit retaining structure; The soil in the receiving well pit is excavated in layers, and temporary support devices are installed in the pit during the excavation process. After the soil is excavated to the design elevation, the pipe jacking machine will be lifted out of the receiving well.

[0007] In one embodiment, the foundation pit retaining structure adopts any one or more combinations of diaphragm walls, single-row piles, double-row piles, gravity retaining walls, and interlocking piles. Within the area through which the pipe jacking machine cuts through the foundation pit retaining structure, the reinforcing steel of the foundation pit retaining structure is made of glass fiber reinforced plastic.

[0008] In one embodiment, during the construction of the foundation pit retaining structure at the preset receiving well location, dewatering treatment and monitoring point deployment are completed. When constructing the foundation pit retaining structure at the preset receiving well location, the depth of penetration and rigidity of the foundation pit retaining structure must meet the following requirements: the foundation pit retaining structure must withstand the jacking force of the pipe jacking machine, the soil pressure outside the foundation pit, and the groundwater pressure when the soil inside the pit is not excavated.

[0009] In one embodiment, the pipe jacking machine is controlled to advance from the working shaft to the foundation pit retaining structure, and after cutting through the foundation pit retaining structure, it enters the area within the foundation pit retaining structure, specifically including: Control the pipe jacking machine to advance directionally along the designed axis and monitor its advancing attitude; When the pipe jacking machine advances to the outside of the foundation pit retaining structure, it stops and cuts the foundation pit retaining structure, so that the pipe jacking machine enters the unexcavated original soil area in the receiving well foundation pit, until it is completely within the scope of the foundation pit retaining structure.

[0010] In one embodiment, sealing the gap between the outer shell of the pipe jacking machine and the foundation pit retaining structure includes: temporarily sealing the gap by any one or a combination of grouting, quick-setting concrete, and sealing airbags.

[0011] In one embodiment, the soil within the receiving well foundation pit is excavated in layers, specifically including: The original soil in the receiving well pit is excavated from the periphery of the pipe jacking machine outwards in a layered and symmetrical manner.

[0012] In one embodiment, the excavation layer thickness is determined according to geological conditions, with the layer thickness in soft soil being less than or equal to 1.5m, and the layer thickness in sandy soil and silty clay soil being less than or equal to 2.0m. The temporary support device is a combination of steel supports and steel walers; When excavating the soil in the receiving well pit in layers, temporary support devices are installed for each layer of soil excavated. The displacement of the retaining structure, the attitude of the pipe jacking machine and the water level outside the pit are monitored, and the excavation speed and the timing of the installation of temporary support devices are adjusted according to the monitoring data.

[0013] In one embodiment, after the pipe jacking machine is lifted out of the receiving shaft, the method further includes: Construction of the main structure of the receiving well, completion of the bottom slab, side walls and top slab of the receiving well, simultaneous removal of temporary support devices, and completion of interface treatment and foundation pit backfilling.

[0014] In one embodiment, before constructing the retaining structure of the foundation pit at the predetermined receiving well location, the method further includes: Conduct geological surveys of the construction site to obtain the physical and mechanical parameters of the soil layers; The embedment depth and stiffness of the foundation pit retaining structure are determined based on the physical and mechanical parameters of the soil layer.

[0015] In one implementation, lifting the pipe jacking machine out of the receiving shaft specifically includes: After cleaning the bottom of the foundation pit, a crane and lifting equipment were used to lift the pipe jacking machine out of the receiving well.

[0016] The beneficial effects of the technical solutions provided in this application include: This application provides a method for receiving a pipe jacking machine. Because the receiving process relies on the closed system formed by the foundation pit retaining structure and the original soil support within the pit, the pipe jacking machine can be received without waiting for the completion of the main structure of the receiving shaft. This reduces waiting time and eliminates the need for pre-received soil reinforcement, allowing the pipe jacking machine to directly enter the unexcavated soil area within the retaining structure. Simultaneously, by sealing gaps to prevent soil erosion, and in conjunction with layered excavation and the installation of temporary support devices, the reinforcement process is eliminated while ensuring the stability of the foundation pit retaining structure and controllable pipe jacking machine posture. This achieves safe reception and lifting of the pipe jacking machine in the unexcavated state of the receiving shaft foundation pit, ensuring that the pipe jacking progress is not constrained by the construction progress of the receiving shaft, and separating the pipe jacking machine reception from the main structure construction of the receiving shaft. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of the pipe jacking machine receiving construction method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the support plan layout of the pipe jacking receiving well provided in an embodiment of this application; Figure 3 for Figure 2 Schematic diagram of section 1-1; Figure 4 for Figure 2 Schematic diagram of section 2-2.

[0019] In the diagram: 1. Excavation pit retaining structure; 2. Pipe jacking machine; 3. Temporary support device. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] This application provides a method for receiving pipe jacking machines, which can solve the problem in related technologies that traditional pipe jacking receiving requires the construction of the main structure of the receiving well and the reinforcement of the end, resulting in a delay in the construction period and a high cost.

[0022] This application provides a method for receiving a pipe jacking machine during construction, which includes: 101: Construct the foundation pit retaining structure 1 at the preset receiving well location, so that the foundation pit retaining structure 1 forms a closed foundation pit retaining system, and keeps the soil in the receiving well foundation pit in an unexcavated state. 102: Control the pipe jacking machine 2 to advance from the working shaft to the foundation pit retaining structure 1, and cut through the foundation pit retaining structure 1 before entering the area of ​​the foundation pit retaining structure 1; 103: Seal the gap between the outer shell of the pipe jacking machine 2 and the foundation pit retaining structure 1; 104: Excavate the soil in the receiving well pit in layers, and install temporary support devices 3 in the pit during the excavation process; 105: After the soil is excavated to the design elevation, the pipe jacking machine 2 will be lifted out of the receiving well.

[0023] The core technical problem this application aims to solve is: how to break away from the traditional construction logic of "first constructing the main structure of the receiving well, then reinforcing the end soil, and finally receiving the pipe jacking machine 2," and achieve safe reception of the pipe jacking machine 2 when the receiving well pit is unexcavated, the main structure is not constructed, and there is no end reinforcement. This also solves the problem of pipe jacking construction stalling due to delays in the receiving well's construction period, simplifying construction procedures, reducing costs, and improving construction safety and flexibility. Because the receiving process of the pipe jacking machine 2 relies on the closed system formed by the pit retaining structure 1 and the support of the original soil within the pit, the receiving of the pipe jacking machine 2 can be carried out without waiting for the completion of the main structure of the receiving well. This reduces waiting time and eliminates the need for end soil reinforcement before reception, allowing the pipe jacking machine 2 to directly enter the unexcavated soil area within the retaining structure. Meanwhile, by sealing the gaps to prevent soil erosion, and in conjunction with layered excavation and the installation of temporary support devices 3, the reinforcement process is eliminated while ensuring the stability of the foundation pit retaining structure 1 and the controllable attitude of the pipe jacking machine 2. This enables the safe reception and hoisting of the pipe jacking machine 2 in the unexcavated state of the receiving well foundation pit, so that the progress of pipe jacking is not constrained by the construction progress of the receiving well, and the process of receiving the pipe jacking machine 2 and the construction of the main structure of the receiving well are separated.

[0024] Before constructing the foundation pit retaining structure 1 at the preset receiving well location in step 101, the method further includes: Conduct geological surveys of the construction site to obtain the physical and mechanical parameters of the soil layers; The depth and stiffness of the retaining structure 1 for the foundation pit are determined based on the physical and mechanical parameters of the soil.

[0025] Specifically, a comprehensive geological survey of the construction site is conducted first. This survey, through on-site drilling and sampling and laboratory geotechnical testing, clarifies the geological parameters within the foundation pit area, including soil layer distribution patterns, physical and mechanical properties, and groundwater level distribution, providing data support for the selection of the retaining structure. In addition, underground pipeline detection is required, employing a combination of geophysical scanning and manual trench excavation to determine the location and depth of underground pipelines, identify pipeline types, materials, and routes, and create a detailed pipeline distribution map. Based on the detection results, the retaining structure design is optimized, adjusting the arrangement of retaining piles or wall thickness to avoid important pipeline protection areas, preventing damage to underground pipelines during retaining structure construction, ensuring the safe operation of surrounding municipal facilities during the construction of the retaining system, preventing secondary disasters such as leakage or collapse caused by pipeline rupture from affecting the stability of the foundation pit, providing fundamental conditions for the quality of the retaining structure wall, reducing uncertainties during construction, and ensuring the integrity of the closed retaining structure system.

[0026] By combining on-site drilling and sampling with indoor geotechnical tests, the geological distribution, soil properties, and groundwater burial conditions of the construction area were determined. The physical and mechanical parameters of the soil layers, including key indicators such as soil weight, internal friction angle, cohesion, and permeability coefficient, were accurately obtained, providing basic data support for the design of the retaining structure.

[0027] Based on the obtained physical and mechanical parameters of the soil layers, the embedment depth and cross-sectional stiffness of the foundation pit retaining structure 1 are calculated and determined. The design of the retaining structure (embedded depth and stiffness) must meet the requirement that, in the unexcavated state of the soil inside the pit, it can independently withstand the active earth pressure outside the foundation pit, the groundwater pressure, and the jacking force generated when the pipe jacking machine 2 advances through the retaining structure. Through overturning resistance, heave resistance, and deformation calculations, it is ensured that the retaining structure does not experience excessive displacement or instability during the receiving of the pipe jacking machine 2, ensuring that the foundation pit retaining system forms a closed and stable protective structure that meets the stress requirements in the unexcavated state.

[0028] Step 101: First, based on the design dimensions of the receiving well, the site geological survey report, and the environmental distribution of surrounding buildings, underground pipelines, etc., the specific construction scope and structural form of the foundation pit retaining structure 1 are comprehensively determined. The foundation pit retaining structure 1 is constructed at the pre-designated receiving well location, forming a closed foundation pit retaining system that effectively blocks the connection between water and soil inside and outside the pit. During this construction phase, the soil inside the receiving well pit remains in its original, unexcavated state, using the undisturbed soil as a temporary support medium for the initial receiving stage of the pipe jacking machine 2, avoiding the risk of soil stress release and pit bottom heave caused by premature excavation.

[0029] In this embodiment, the specific type of the foundation pit retaining structure 1 can be flexibly selected according to the actual engineering conditions, adopting any one or more combinations of diaphragm walls, single-row piles, double-row piles, gravity retaining walls, and interlocking piles. To address the special process requirements of the pipe jacking machine 2, within the area where the pipe jacking machine 2 cuts through the foundation pit retaining structure 1, the reinforcing steel of the foundation pit retaining structure 1 is made of glass fiber reinforced plastic (GFRP). GFRP is machinable and its strength meets the retaining requirements. The cutterhead of the pipe jacking machine 2 can directly cut through the retaining structure in this area during the advancement process, without the need for pre-existing mechanical demolition of the retaining structure, thus achieving a seamless connection between the pipe jacking machine 2 and the retaining structure.

[0030] During the construction of the retaining structure 1 at the pre-designated receiving well location, dewatering and monitoring point deployment were carried out simultaneously. Dewatering was used to control the groundwater level below the bottom of the pit, preventing water and sand inrush during the construction of the retaining structure and ensuring the quality of the retaining structure wall and the effectiveness of joint sealing. Monitoring point deployment was used to collect real-time data on the deformation and settlement of the retaining structure and the surrounding environment, ensuring the safety of the surrounding environment. The prior implementation of dewatering and monitoring measures created stable soil and water conditions for the subsequent reception of the pipe jacking machine 2, ensuring controllable construction quality of the retaining structure.

[0031] When constructing the retaining structure 1 at the pre-designated receiving well location, the embedment depth and cross-sectional stiffness of the retaining structure 1 must be determined through specific calculations. The embedment depth and stiffness of the retaining structure 1 must meet the following requirements: The retaining structure 1 must withstand the jacking force of the pipe jacking machine 2, the earth pressure outside the pit, and the groundwater pressure when the soil inside the pit is not excavated. By increasing the embedment depth and improving the structural stiffness, it is ensured that the retaining system does not experience excessive displacement or structural damage at the moment the pipe jacking machine 2 cuts in, maintaining the overall stability of the pit and preventing ground subsidence accidents caused by the failure of the retaining structure.

[0032] In step 102: Control the pipe jacking machine 2 to advance from the working shaft to the foundation pit retaining structure 1, and cut through the foundation pit retaining structure 1 before entering the area of ​​the foundation pit retaining structure 1, specifically including steps 1021-1022: Step 1021: Control the pipe jacking machine 2 to advance along the designed axis and monitor the advancing posture; In step 1021, the pipe jacking machine 2 advances along the designed axis trajectory, which has been pre-measured and verified to ensure it coincides with the centerline of the working shaft and the receiving shaft, forming a continuous advancement path. During advancement, an automated measurement system consisting of a laser guidance system and attitude monitoring equipment collects real-time data on the advancement direction deviation, elevation settlement, and three-dimensional attitude angles of the pipe jacking machine 2. The laser beam is projected onto the target inside the machine to generate deviation readings. The monitoring data is fed back to the central control system at a high frequency, and the advancement parameters are adjusted in a timely manner according to the deviation threshold, including the main jacking thrust, the cutterhead rotation torque, and the extension and retraction stroke of the correction jacks, to ensure that the pipe jacking machine 2 can accurately advance to the preset receiving area of ​​the receiving shaft foundation pit retaining structure 1, avoiding the cumulative error caused by long-distance advancement that leads to the receiving position deviating from the design center. A uniform speed jacking strategy is maintained during advancement to reduce disturbance to the surrounding soil, ensure that the axis accuracy meets the receiving requirements, and record advancement data for traceability, forming a complete advancement log.

[0033] When the pipe jacking machine 2 advances to the outside of the receiving well foundation pit retaining structure 1, step 1022 is executed: when the pipe jacking machine 2 advances to the outside of the foundation pit retaining structure 1, it stops, cuts the foundation pit retaining structure 1, so that the pipe jacking machine 2 enters the unexcavated original soil area in the receiving well foundation pit, until it completely enters the area of ​​the foundation pit retaining structure 1.

[0034] Specifically, the jacking operation is first stopped, and the pre-set receiving position of the retaining structure is re-verified to ensure that the center of the cutterhead coincides with the center of the receiving area, preventing the expansion of damage to the retaining structure due to cutting position deviation. For the retaining structure within the jacking excavation range, its internal steel reinforcement is made of glass fiber reinforced plastic (GFRP), a material that is machinable and has sufficient strength to meet the retaining requirements. It can be directly cut and removed by the cutterhead of the jacking machine 2 without additional mechanical crushing, avoiding the impact of the demolition operation on the overall stability of the retaining structure and the resulting vibration risks. Then, the cutterhead of the jacking machine 2 is started to rotate, applying axial thrust to cut the retaining structure, allowing the jacking machine 2 to slowly enter the undisturbed soil area within the receiving well pit. During this process, the undisturbed soil maintains its natural stress state, and the arching effect of the soil provides temporary support for the jacking machine 2, preventing the machine head from sinking or shifting. The cutting process of the retaining structure must be carried out smoothly to avoid severe vibration affecting the stability of the retaining system. The cutterhead cutting speed should be matched with the jacking speed to ensure a smooth cutting surface and reduce voids.

[0035] The pipe jacking machine 2 continues to advance until it is completely within the retaining structure 1 of the foundation pit, completing the reception and positioning of the pipe jacking machine 2. The standard for determining the depth of the pipe jacking machine 2 entering the foundation pit is: the main body of the pipe jacking machine 2 is completely located within the closed area of ​​the retaining structure, with sufficient space left at the tail to meet the needs of subsequent soil excavation and hoisting of the lifting equipment. This position ensures that the pipe jacking machine 2 is within the safety protection circle formed by the retaining structure, avoiding exposure to water and soil pressure outside the pit before soil excavation, and providing a stable parking platform for subsequent processes, ensuring structural safety and operational feasibility during the reception process. After being received and positioned, the pipe jacking machine 2 is in a static standby state, waiting for the instruction to excavate the soil in layers within the pit. At this time, the gap between the outer shell of the pipe jacking machine 2 and the retaining structure has not yet been sealed and is in a pending state, reserving operating conditions for the subsequent gap sealing process. The parking position of the pipe jacking machine 2 in the pit needs to comprehensively consider the size of the foundation pit and the working radius of the hoisting equipment to ensure that no secondary handling is required during the hoisting operation, improving construction efficiency, while ensuring the stability of the machine body and preventing displacement during the waiting period for excavation.

[0036] After the pipe jacking machine 2 is received and positioned, an annular gap is formed between the outer shell of the pipe jacking machine 2 and the foundation pit retaining structure 1 due to the cutting operation. This gap directly connects the water and soil system inside and outside the foundation pit, resulting in a significant water and soil pressure difference. To prevent soil erosion, the gap between the outer shell of the pipe jacking machine 2 and the foundation pit retaining structure 1 needs to be quickly sealed immediately. Based on the above embodiment, in this embodiment, sealing the gap between the outer shell of the pipe jacking machine 2 and the foundation pit retaining structure 1 includes: temporarily sealing the gap using any one or a combination of grouting, quick-setting concrete, and sealing airbags.

[0037] Grouting material is injected under pressure into the depths of the gaps, filling tiny voids and solidifying to form a water-stopping curtain; quick-setting concrete rapidly solidifies at the gaps to form a rigid support structure, resisting external soil pressure; sealing airbags, after inflating, adhere tightly to the gap walls to achieve immediate water-stopping isolation, suitable for conditions with a high risk of water inrush. When multiple methods are used in combination, airbags are typically used first to block the water flow path, followed by concrete injection to enhance overall sealing and strength, ensuring a tight seal and sufficient compressive strength.

[0038] During the sealing process, it is essential to ensure that the sealing body can withstand the soil and water pressure outside the excavation pit, preventing soil and groundwater from seeping into the retaining structure through gaps. If the gaps are not sealed tightly, high-pressure water and soil can easily breach the sealing body, potentially causing soil inrush, collapse, and other safety hazards, thus ensuring the sealing and stability of the excavation pit retaining system. The sealing operation must be completed while the pipe jacking machine is stationary to avoid mechanical vibration affecting the solidification of the sealing material, forming a stable temporary water-stop barrier. This creates a dry and safe environment for subsequent operations within the pit, ensuring the overall stress balance of the retaining structure in the undisturbed state and preventing stress release from the soil due to gap leakage.

[0039] After sealing is completed, the sealed area is inspected to ensure there is no leakage or loosening before proceeding to the next step. The inspection includes observing the surface of the sealing body for signs of water seepage, testing the strength of the sealing body, and tapping to check for hollow or loose areas. Only after the integrity of the sealing structure is verified, ensuring effective water and soil isolation inside and outside the pit, can excavation work begin. This ensures subsequent construction is safe and controllable, meets the overall process requirements of the pipe jacking machine receiving construction method, achieves seamless connection between procedures, and guarantees construction safety in the unexcavated state of the receiving well pit.

[0040] Based on the above embodiments, in this embodiment, the soil in the receiving well foundation pit is excavated in layers, specifically including: The excavation of the undisturbed soil within the receiving shaft pit is carried out in a layered and symmetrical manner, progressing from the periphery of the pipe jacking machine 2 outwards. The excavation sequence gradually expands from the periphery of the pipe jacking machine 2 outwards, prioritizing the soil beneath and around the machine to allow for future lifting operations and prevent premature excavation of the central area, which could cause the retaining structure to shift inwards and compress the pipe jacking machine 2. The symmetrical excavation method ensures balanced soil pressure release on both sides of the pit, preventing uneven displacement of the retaining structure due to unilateral excavation and protecting the already positioned pipe jacking machine 2 from the unloading of soil within the pit. The excavation of the undisturbed soil must maintain a smooth transition of the soil's natural stress state, minimizing disturbance and ensuring the stability of the excavation face. This prevents localized collapses that could affect the safety of the pipe jacking machine 2 and maintains the temporary support function of the soil within the pit during the excavation process.

[0041] The excavation layer thickness is determined based on geological conditions. In soft soil areas, the layer thickness is less than or equal to 1.5m, while in sandy soil and silty clay areas, it is less than or equal to 2.0m. In soft soil areas, the soil has poor self-stability and significant rheological characteristics. Thinner layer thicknesses shorten the exposure time of each layer, reducing the risk of pit bottom heave and retaining structure deformation, and preventing support failure due to soil creep. In sandy soil or silty clay areas, the soil has a certain degree of self-stability, allowing for appropriately increased layer thicknesses to improve excavation efficiency and reduce the frequency of support installation. Layer thickness control must be combined with the excavation equipment's operational capabilities to ensure that each layer is removed completely in one go, avoiding repeated excavation that could loosen the soil at the pit bottom. Geological conditions are dynamically confirmed based on the preliminary survey report and the actual soil layers revealed during excavation, ensuring that layering parameters match the actual strata. Excavation with excessive thickness is strictly prohibited, as it could lead to excessive stress on the retaining structure.

[0042] During excavation, temporary support devices 3 are constructed simultaneously within the foundation pit. Temporary support device 3 is a combination of steel supports and steel walers. The spacing and stiffness of the temporary supports must meet the deformation resistance requirements of the retaining structure. After each layer of soil is excavated, the corresponding temporary support device 3 is immediately installed to prevent excessive displacement or deformation of the retaining structure. The steel walers are horizontally arranged along the inner side of the retaining structure, closely fitting it to evenly transfer soil pressure to the steel supports. Pre-applied axial forces are applied to both ends of the steel supports to offset some of the retaining structure deformation and enhance the initiative of the support system. Support installation must closely follow the excavation face; over-excavation before support is strictly prohibited. This ensures that the exposure time of the retaining structure in the unsupported state is minimized, maintaining the overall stability of the foundation pit retaining system in the undisturbed state, preventing plastic deformation of the retaining structure due to delayed support, and ensuring that the support system and retaining structure work together effectively.

[0043] During the layered excavation of the soil within the receiving shaft foundation pit, the displacement of the retaining structure, the attitude of the pipe jacking machine 2, and the water level outside the pit are monitored. The excavation speed and the timing of the installation of temporary support devices 3 are adjusted based on the monitoring data. During excavation, the horizontal displacement and settlement of the retaining structure, the attitude of the pipe jacking machine 2, the groundwater level outside the pit, and soil settlement are monitored in real time, establishing a data acquisition and feedback mechanism. The monitoring data serves as the basis for construction decisions. When the displacement rate of the retaining structure exceeds the warning value, the excavation speed is reduced or excavation is suspended and the support is densified; when the attitude of the pipe jacking machine 2 deviates, the excavation symmetry is adjusted to correct the force balance; when the water level outside the pit drops abnormally, the integrity of the cutoff wall is checked. Adjusting the excavation speed and the timing of support installation based on the monitoring data ensures construction safety, achieves information-based construction management, guarantees the structural safety and surrounding environmental stability of the receiving shaft foundation pit during soil excavation, and meets the overall process requirements of the pipe jacking machine 2 receiving construction method.

[0044] If groundwater seepage occurs during excavation, it will be drained promptly using methods such as sump drainage and wellpoint dewatering. The sump is located at the lowest point of the pit, and submersible pumps will be used to pump out accumulated surface water. Wellpoint dewatering will be deployed around the perimeter of the pit to lower the groundwater level below the excavation surface, and water level changes will be monitored in real time. This ensures the soil within the pit remains dry, preventing groundwater soaking that could soften and cause collapse, maintaining the self-stabilizing capacity of the excavation surface, preventing quicksand or piping caused by excessive soil moisture content, ensuring the safety of the layered excavation work surface and the effectiveness of temporary support installation, ensuring continuous excavation, meeting the environmental requirements of the pipe jacking machine 2 for receiving the machine and subsequent main structure construction, preventing water damage from affecting the positioning of the pipe jacking machine 2, and ensuring the working environment within the pit meets construction standards.

[0045] In step 105, the pipe jacking machine 2 is lifted out of the receiving well, which specifically includes: cleaning the bottom of the foundation pit and using a crane with lifting equipment to lift the pipe jacking machine 2 out of the receiving well.

[0046] After the soil in the receiving shaft is excavated to the design elevation, the remaining soil and debris at the bottom of the pit must be thoroughly cleaned to fully expose the bottom of the pipe jacking machine 2, ensuring that the lifting equipment can smoothly pass through the reserved lifting holes or binding positions at the bottom of the pipe jacking machine 2. The bottom cleaning area must cover the projected area of ​​the pipe jacking machine 2 and the surrounding working space to prevent soil accumulation from affecting the lifting balance, provide a stable working foundation for the lifting equipment, and avoid the machine body tilting during lifting due to uneven ground.

[0047] A crane, in conjunction with lifting equipment, will be used to disassemble or lift the pipe jacking machine 2 entirely out of the receiving shaft. The lifting plan will be determined based on the weight of the pipe jacking machine 2, the size of the pit, and the lifting capacity of the crane. If the pit space is sufficient and the crane's rated lifting capacity meets the requirements, lifting it entirely will be preferred to reduce subsequent assembly steps. If space or equipment capacity is limited, the pipe jacking machine 2 will be disassembled into modules such as the cutterhead, front shield, middle shield, and rear shield, and lifted out separately. Specialized wire ropes or chains will be used for lifting equipment, reliably connected to the lifting lugs of the pipe jacking machine 2 to ensure uniform stress at the connection points, prevent slippage or structural damage during lifting, and ensure the stability of the lifting process.

[0048] During the lifting process, operate slowly to avoid collisions between the pipe jacking machine 2 and the foundation pit retaining structure 1 and temporary supports, ensuring the safe lifting of the pipe jacking machine 2. A trial lift should be conducted initially to confirm braking performance and center of gravity stability before formal lifting. The lifting path must be planned in advance to avoid the steel supports and steel walers installed within the foundation pit. Maintain a low and stable speed during movement to prevent the machine from swinging and impacting the retaining structure wall or temporary support system, avoiding damage to the completed retaining structure or causing support instability. After the pipe jacking machine 2 is completely removed from the foundation pit area, place it in the designated storage area and complete the equipment removal work in the receiving shaft to free up the working surface for subsequent main structure construction.

[0049] Based on the above embodiments, in this embodiment, after the pipe jacking machine 2 is lifted out of the receiving well, the method further includes: constructing the main structure of the receiving well, completing the construction of the bottom plate, side walls and top plate of the receiving well, simultaneously dismantling the temporary support device 3, and completing the interface treatment and backfilling of the foundation pit.

[0050] Before the foundation slab is constructed, a cushion layer and a waterproof layer are laid. The side wall reinforcement is connected to the reserved reinforcement of the foundation pit retaining structure 1 to ensure that the main structure and the retaining system form an integral load-bearing structure. During the construction of the top slab, holes for subsequent pipeline access must be reserved. The concrete pouring of the main structure must be carried out continuously to ensure the structural density and impermeability, forming a permanent receiving well space to replace the temporary retaining system and bear the long-term load.

[0051] During construction, temporary supports within the foundation pit are removed simultaneously, following the principle of "support first, remove later." This means that steel supports and walers at the corresponding locations can only be removed after the main structure's concrete strength has reached the design requirements. The removal process is carried out in stages to avoid sudden stress changes in the retaining structure caused by unloading all at once. This ensures that the main structure can gradually bear the soil pressure outside the foundation pit, maintaining its stability until backfilling is completed, and preventing excessive deformation of the retaining structure due to premature support removal.

[0052] After completing the joint treatment of the jacking pipe sections, waterproof sealing was applied to the junction of the jacking pipe and the sidewall of the receiving shaft. The gaps were filled with caulking material and a water-stop ring was installed to prevent groundwater from seeping into the shaft along the outer wall of the pipe, ensuring the waterproof performance of the receiving shaft structure. Subsequently, the foundation pit was backfilled using low-permeability cohesive soil, compacted in layers to the design elevation, restoring the original ground surface. Finally, the entire jacking pipe receiving and receiving shaft construction process was completed, achieving permanent connection between the jacking tunnel and the receiving shaft, restoring the ground environment, and ensuring the project's delivery and use.

[0053] In summary, this application effectively resolves the conflict between construction schedules by reconstructing the construction process logic. Traditional processes require the construction of the receiving well's main structure and end reinforcement before receiving the pipe jacking machine 2, resulting in a rigid workflow. This invention eliminates the need for prior construction of the receiving well's main structure; only the foundation pit retaining structure 1 needs to be completed before receiving the pipe jacking machine 2. Even if the receiving well's construction is delayed due to various factors, it will not hinder the pipe jacking machine 2's advancement. The pipe jacking machine 2 can directly enter the undisturbed soil area within the unexcavated foundation pit, effectively avoiding delays caused by mutual constraints between pipe jacking construction and receiving well construction. The construction of the receiving well's main structure is moved to after the pipe jacking machine 2 is lifted out, significantly improving the flexibility of construction organization, substantially shortening the overall project duration, decoupling the time between pipe jacking advancement and foundation pit construction, and ensuring that the critical path is not constrained by the receiving well's civil engineering progress.

[0054] This application eliminates the end-point reinforcement process, reducing construction costs and time. Traditional methods require soil mixing or jet grouting reinforcement at the end points. This application uses the foundation pit retaining structure 1 to form a closed protective system, replacing the traditional end-point soil reinforcement process. This eliminates the need for reinforcement materials, equipment, and labor, significantly reducing construction costs. Fiberglass reinforced plastic bars are used in specific areas of the retaining structure, allowing the pipe jacking machine 2 cutterhead to directly cut through them without prior demolition. This also reduces the time consumption associated with reinforcement processes, simplifies the construction process, improves construction efficiency, and avoids the acceptance risk caused by uneven end-point reinforcement quality. Both economic efficiency and timeliness are optimized, eliminating the waste and disposal of reinforcement materials.

[0055] This application demonstrates high construction safety and controllable risks. The closed foundation pit retaining structure 1 withstands external soil and water pressure, and the gap between the pipe jacking machine 2 and the retaining structure is quickly sealed using grouting or quick-setting concrete to prevent soil inrush and collapse. Layered excavation of the soil, combined with temporary support, controls the deformation of the retaining structure, and information-based monitoring provides real-time feedback of displacement data. Multiple safeguards effectively avoid safety hazards such as soil inrush and collapse that may arise from the failure of traditional end reinforcement, ensuring the safety and controllability of the pipe jacking machine 2 reception and foundation pit excavation processes. The pipe jacking machine 2 is received in undisturbed soil, where the soil arching effect provides temporary support, resulting in good posture stability and reducing the likelihood of displacement or damage, thus ensuring the safety of the equipment and structure. Monitoring data guides the dynamic adjustment of construction parameters.

[0056] This application boasts strong adaptability and a wide range of applications. It can adapt to various geological conditions, including soft soil, sandy soil, and silty clay, by adjusting the excavation layer thickness to suit different geological formations. It is compatible with different types of pipe jacking machines, such as slurry balance pipe jacking machines and earth pressure balance pipe jacking machines, with adjustable cutting and propulsion parameters. It is also compatible with various foundation pit support methods, including diaphragm walls, single-row piles, double-row piles, gravity retaining walls, and interlocking piles. It can meet the pipe jacking construction needs of various complex conditions, such as urban centers, sensitive surrounding environments, and tight construction schedules. Its practicality is extremely high, and the support and excavation schemes can be flexibly combined according to specific engineering conditions, adapting to various underground space development scenarios.

[0057] This application presents a simple and highly feasible process. The construction steps are clearly defined, covering aspects such as retaining wall construction, pipe jacking, gap sealing, layered excavation, and main structure construction. No complex specialized equipment is required; existing pipe jacking and foundation pit construction equipment, such as conventional pipe jacking machines, cranes, and excavators, can be used. The process flow is easy to master and facilitates on-site application. Standardized operating procedures reduce operational errors, ensure smooth transitions between processes, lower the technical threshold, and facilitate large-scale replication and application in similar pipe jacking receiving projects, thereby improving the industry's construction technology level. The equipment is highly versatile, easy to schedule, and adaptable to various sites.

[0058] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0059] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for receiving and constructing a pipe jacking machine, characterized in that, It includes: Construct a foundation pit retaining structure (1) at the preset receiving well location, so that the foundation pit retaining structure (1) forms a closed foundation pit retaining system and keeps the soil inside the receiving well foundation pit in an unexcavated state. Control the pipe jacking machine (2) to advance from the working well to the foundation pit retaining structure (1), and cut through the foundation pit retaining structure (1) and enter the area of ​​the foundation pit retaining structure (1); Seal the gap between the outer shell of the pipe jacking machine (2) and the pit retaining structure (1); The soil in the receiving well pit is excavated in layers, and temporary support devices are installed in the pit during the excavation process (3). After the soil is excavated to the design elevation, the pipe jacking machine (2) is lifted out of the receiving well.

2. The pipe jacking machine receiving construction method as described in claim 1, characterized in that: The foundation pit retaining structure (1) adopts any one or more combinations of underground continuous wall, single row pile, double row pile, gravity retaining wall and interlocking pile; Within the range through which the pipe jacking machine (2) cuts through the foundation pit retaining structure (1), the steel bars of the foundation pit retaining structure (1) are made of glass fiber reinforced plastic bars.

3. The pipe jacking machine receiving construction method as described in claim 1, characterized in that: When constructing the foundation pit retaining structure (1) at the preset receiving well location, dewatering treatment and monitoring point layout are completed; When constructing the foundation pit retaining structure (1) at the preset receiving well location, the depth of the foundation pit retaining structure (1) into the soil and its rigidity satisfy the following: the foundation pit retaining structure (1) can withstand the jacking force of the pipe jacking machine (2), the soil pressure outside the foundation pit and the groundwater pressure when the soil inside the pit is not excavated.

4. The pipe jacking machine receiving construction method as described in claim 1, characterized in that, The control of the pipe jacking machine (2) to advance from the working shaft to the foundation pit retaining structure (1), and to cut through the foundation pit retaining structure (1) and enter the area of ​​the foundation pit retaining structure (1), specifically including: Control the pipe jacking machine (2) to advance along the designed axis and monitor the advancing posture; When the pipe jacking machine (2) advances to the outside of the foundation pit retaining structure (1), it stops and cuts the foundation pit retaining structure (1) so that the pipe jacking machine (2) enters the unexcavated original soil area in the foundation pit of the receiving well until it is completely within the scope of the foundation pit retaining structure (1).

5. The pipe jacking machine receiving construction method as described in claim 1, characterized in that: The gap between the outer shell of the pipe jacking machine (2) and the foundation pit retaining structure (1) is sealed, including: using any one or a combination of grouting, quick-setting concrete, and sealing airbags to temporarily seal the gap.

6. The pipe jacking machine receiving construction method as described in claim 1, characterized in that, The soil within the receiving well foundation pit was excavated in layers, specifically including: The original soil in the foundation pit of the receiving well is excavated from the periphery of the pipe jacking machine (2) to the outside of the foundation pit in a layered and symmetrical manner.

7. The pipe jacking machine receiving construction method as described in claim 6, characterized in that: The excavation layer thickness is determined according to geological conditions. The layer thickness in soft soil is less than or equal to 1.5m, and the layer thickness in sandy soil and silty clay soil is less than or equal to 2.0m. The temporary support device (3) is a combination of steel support and steel waler; When excavating the soil in the receiving well foundation pit in layers, temporary support devices (3) are installed for each layer of soil excavated. The displacement of the retaining structure, the attitude of the pipe jacking machine (2) and the water level outside the pit are monitored. The excavation speed and the timing of the installation of the temporary support devices (3) are adjusted according to the monitoring data.

8. The pipe jacking machine receiving construction method as described in claim 1, characterized in that, After the pipe jacking machine (2) is lifted out of the receiving well, the method further includes: Construction of the main structure of the receiving well, completion of the construction of the bottom slab, side walls and top slab of the receiving well, simultaneous removal of temporary support devices (3), and completion of interface treatment and foundation pit backfilling.

9. The pipe jacking machine receiving construction method as described in claim 1, characterized in that, Before constructing the foundation pit retaining structure (1) at the preset receiving well location, the method further includes: Conduct geological surveys of the construction site to obtain the physical and mechanical parameters of the soil layers; The depth and stiffness of the foundation pit retaining structure (1) are determined based on the physical and mechanical parameters of the soil layer.

10. The pipe jacking machine receiving construction method as described in claim 1, characterized in that, Lifting the pipe jacking machine (2) out of the receiving well, specifically including: Clean the bottom of the foundation pit and use a crane with lifting equipment to lift the pipe jacking machine (2) out of the receiving well.

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