Anti-drag grouting method for ultra-long-distance pipe jacking construction of water supply pipeline

Abstract

The invention discloses a water supply pipeline ultra-long distance pipe jacking construction drag reduction grouting method. The method comprises the following steps that S1, construction preparation and system layout are conducted, specifically, the stress performance of a working well and the stress performance of a back wall are detected, and a pipe jacking machine and an intermediate jacking station are debugged; the adaptability of the prefabricated pipe joint, the grouting pipe and the sealing gasket is checked, and an intelligent grouting control system integrated with a friction resistance real-time monitoring and early warning module is arranged; the grouting pipe is fixed on the inner wall of the pipe joint in a buckling manner; and S2, cooperative jacking and grouting are conducted, specifically, a pipe jacking machine is started to conduct segmented jacking, and in the jacking process, thixotropic slurry is synchronously injected into an annular gap between the outer wall of the pipe joint and the soil body to form a lubricating sleeve. By constructing a systematic grouting resistance reduction system integrating intelligent monitoring, dynamic regulation and control and structural guarantee, the problems of insufficient jacking force, high pipeline damage risk, low construction efficiency and difficulty in environmental influence control caused by frictional resistance accumulation in ultra-long-distance pipe jacking construction are solved.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering construction, specifically relating to a grouting method for reducing drag during ultra-long-distance pipe jacking construction of water supply pipelines. Background Technology

[0002] Pipe jacking, a trenchless construction technique, is widely used in the laying of municipal water supply pipelines. Its basic principle is to use jacking equipment such as hydraulic cylinders to push prefabricated pipe sections into the soil section by section, starting from the working shaft, until they are connected in the receiving shaft to form an underground pipeline. This technology can effectively reduce damage to surface structures and environmental impact, and is particularly suitable for laying pipelines that cross obstacles such as highways, railways, buildings, and rivers.

[0003] With urban development, the distance of water supply pipelines is increasing daily, placing higher demands on ultra-long-distance pipe jacking construction technology. During the jacking process, enormous frictional resistance is generated between the outer wall of the pipe and the surrounding soil. This frictional resistance accumulates with the jacking distance, becoming a key factor limiting the jacking distance. Excessive frictional resistance not only requires the jacking equipment to provide extremely high jacking force, which may lead to insufficient equipment capacity or pressure failure of pipe sections, but also increases the risk of pipeline axis misalignment, joint seal failure, and even causes excessive soil disturbance and surface subsidence, directly threatening the safety and quality of the project.

[0004] To reduce jacking resistance, existing technologies typically employ drag-reducing grouting, which involves injecting thixotropic mud into the annular gap between the outer wall of the pipe section and the soil to form a mud sleeve, thereby transforming solid dry friction into liquid wet friction. However, in the practical application of ultra-long-distance pipe jacking construction for water supply pipelines, existing grouting methods still have significant shortcomings: First, the grouting process often fails to form a systematic and coordinated solution with pipe section structure design, jacking parameter control, and intermediate station setup, resulting in difficulty in maintaining a stable and continuous drag reduction effect; Second, under complex geological conditions and ultra-long distances, it is difficult to ensure that the grout is evenly distributed throughout the annular gap and forms effective support, which easily leads to grout loss, performance degradation, and abnormally increased local frictional resistance; Third, conventional pipe section interface sealing and grouting hole arrangement methods are insufficient to ensure the integrity and durability of the grout sleeve, and improper grouting pressure and control may also damage the pipeline sealing performance; Finally, existing technologies rely heavily on post-event monitoring for quality control of the grouting process, lacking a refined parameter management and feedback mechanism throughout the entire process, making it difficult to provide timely warnings and interventions for situations such as sudden increases in frictional resistance and abnormal ground settlement during construction.

[0005] Therefore, there is an urgent need in this field for a drag-reducing grouting method that can systematically solve the above problems and is applicable to ultra-long-distance pipe jacking construction of water supply pipelines, so as to effectively overcome the technical bottlenecks such as insufficient jacking force, high risk of pipeline damage, low construction efficiency and difficulty in controlling environmental impact caused by excessive friction. Summary of the Invention

[0006] To overcome the systematic deficiencies, uneven grout distribution, and lagging quality control of existing drag-reducing grouting technologies, which make it difficult to form a continuous, stable, and complete mud sleeve in ultra-long-distance pipe jacking construction and fundamentally solve the contradiction between the jacking force demand and the safety of the pipeline structure, a drag-reducing grouting method for ultra-long-distance pipe jacking construction of water supply pipelines is proposed.

[0007] The technical solution of this invention is: a grouting method for reducing drag during ultra-long-distance pipe jacking construction of water supply pipelines, comprising the following steps: S1. Construction preparation and system layout: Test the stress performance of the working well and the back wall, and debug the pipe jacking machine and the intermediate room; check the compatibility of the precast pipe sections, grouting pipes and sealing gaskets, and deploy an intelligent grouting control system with a real-time frictional resistance monitoring and early warning module; the grouting pipes are fixed to the inner wall of the pipe sections by snap-fit. S2. Coordinated jacking and grouting: Start the pipe jacking machine for segmented jacking. During the jacking process, thixotropic mud is injected into the annular gap between the outer wall of the pipe section and the soil to form a lubricating sleeve. During this process, the intelligent grouting control system dynamically adjusts the grouting parameters based on real-time jacking data, geological data and sensor feedback. S3. Pipe section splicing and sealing: After each pipe section is jacked in, the pipe sections are immediately spliced, and a sealing gasket is embedded at the pipe section interface. The sealing gasket is arranged to avoid the grouting hole position to ensure the interface sealing. S4. Curing and Grouting: During the jacking interval or after the jacking is completed, the injected grout is cured to form a stone body with a certain strength. Then the grout filling density is tested, and any gaps are filled by secondary grouting through the reserved grouting channel. S5. Effect Verification and Control: By monitoring changes in jacking force, calculating frictional resistance, and combining ground settlement data, the drag reduction and support effects are verified. If the expected results are not achieved, the grouting parameters or jacking parameters are dynamically adjusted.

[0008] Furthermore, in step S2, the dynamic control of grouting parameters specifically includes: dynamically adjusting the grouting pressure and grouting flow rate based on the real-time jacking speed and thrust data of the pipe jacking machine, so that the grouting volume matches the annular void volume and jacking speed; identifying geologically weak or easily collapsed sections based on the results of pre-ground radar detection, and carrying out pre-grouting reinforcement of the sections before the pipe jacking machine arrives.

[0009] Furthermore, the dynamic control of grouting parameters also includes: using data from soil pressure sensors and temperature sensors pre-embedded on the pipe section, and automatically optimizing the grouting pressure and grout mix ratio through a control algorithm to achieve closed-loop control of grouting parameters.

[0010] Furthermore, in step S2, the grout injection is pre-distributed through a conical transition structure set between the pipe jacking machine and the first pipe section; the outer surface of the conical transition structure is provided with a spiral guide groove, through which the grout is evenly coated into the annular gap during the jacking process; the conical angle of the conical transition structure is adapted to the outer diameter of the pipe jacking machine and the first pipe section, and its axial direction is provided with a grouting channel communicating with the guide groove.

[0011] Furthermore, the real-time friction resistance monitoring and early warning module of the intelligent grouting control system performs the following operations: establishing a real-time relationship model between the jacking force and the jacking distance to calculate the real-time friction resistance and setting an early warning threshold; when the actual friction resistance exceeds the early warning threshold, automatically starting the emergency grouting program, increasing the grouting volume or adjusting the grout properties; and intelligently starting the relay station at the corresponding location based on the distribution characteristics of the friction resistance along the pipeline.

[0012] Furthermore, in steps S2 and S4, an adaptive adjustment strategy for grout performance is adopted, specifically including: dynamically adjusting the grout viscosity according to the construction stage, using a low-viscosity formula to optimize fluidity during the continuous jacking stage, and using a high-viscosity formula to prevent grout loss during the jacking pause stage; adjusting the grout composition according to changes in formation characteristics, and adding fibers or plugging agents to the grout in highly permeable sand layers or fractured formations.

[0013] Furthermore, the secondary grouting in step S4 is performed using a dual-circuit grouting system, including a main grouting circuit and an auxiliary grouting circuit. The main grouting circuit is responsible for forming an initial lubrication sleeve during the jacking process, while the auxiliary grouting circuit focuses on grouting sections with complex geological conditions or severe grout loss.

[0014] Furthermore, both the main grouting circuit and the auxiliary grouting circuit are equipped with independent pressure control valves and flow metering devices, which can achieve differentiated control of grouting pressure and grouting volume based on geological survey data of different sections of the pipeline.

[0015] Furthermore, the effect verification described in step S5 specifically involves monitoring the pipe section's posture and stress using sensors deployed on the pipe section, and combining this with background analysis software to display in real time the wrapping status and support effect of the grout stone body on the pipeline, thereby generating a construction quality assessment report.

[0016] Furthermore, in step S1 and throughout the entire construction process, strict safety and environmental protection controls are implemented: protective facilities are installed at the working wellhead, and grouting and jacking equipment are regularly inspected; workers are equipped with full protective gear; environmentally friendly and biodegradable grout materials are selected, and waste grout generated during construction is collected and treated in a harmless manner. The grout leakage emergency treatment device is installed at the working wellhead and grouting equipment area.

[0017] The beneficial effects of this invention are: 1. This invention achieves dynamic and coordinated control of grouting parameters and jacking process by setting up an intelligent grouting control system and a real-time frictional resistance monitoring and early warning module. Based on real-time jacking data, geological information and sensor feedback, the system automatically adjusts the grouting pressure and flow rate to ensure that the grout injection volume matches the annular void volume and jacking speed, thereby forming a continuous and stable mud sleeve, effectively overcoming the systematic shortcomings of the prior art in maintaining the drag reduction effect. 2. By adopting a conical transition structure with spiral guide grooves on its outer surface, the grout is evenly coated into the annular gap between the outer wall of the pipe section and the soil during the jacking process, avoiding the problems of uneven grout distribution and abnormal increase in local frictional resistance. This structure enhances the integrity and support effect of the mud jacket by pre-distributing the grout, and reduces grout loss and performance degradation. 3. By using an adaptive adjustment strategy for grout performance and a dual-loop grouting system, the viscosity and composition of the grout are dynamically adjusted according to the construction stage and geological characteristics. Secondary grouting is carried out during the jacking interval or after completion, which further ensures the density of grout filling, solves the problem of easy grout loss under complex geological conditions, maintains the durability of the mud jacket, and reduces the jacking force requirement and the risk of pipeline damage. 4. By monitoring the jacking force, frictional resistance, and ground settlement in real time, and verifying the drag reduction effect with background analysis software, the system achieves refined quality control throughout the entire process. Once the frictional resistance exceeds the warning threshold, the system automatically initiates emergency grouting or intermediate injection, providing timely warnings and interventions, thereby improving construction safety and efficiency, and fundamentally alleviating the contradiction between insufficient jacking force and structural safety. Detailed Implementation

[0018] This invention provides a method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines, comprising the following steps: S1. Construction preparation and system layout: Test the stress performance of the working well and back wall, and debug the pipe jacking machine and intermediate room; check the compatibility of prefabricated pipe sections, grouting pipes and sealing gaskets, and deploy an intelligent grouting control system with a real-time frictional resistance monitoring and early warning module; the grouting pipes are fixed to the inner wall of the pipe sections by snap-fit. S2. Coordinated jacking and grouting: Start the pipe jacking machine to carry out segmented jacking. During the jacking process, thixotropic mud is injected into the annular gap between the outer wall of the pipe section and the soil to form a lubricating sleeve. During this process, the intelligent grouting control system dynamically adjusts the grouting parameters based on real-time jacking data, geological data and sensor feedback. S3. Pipe section splicing and sealing: After each pipe section is jacked in, the pipe sections are immediately spliced, and sealing gaskets are embedded at the pipe section joints. The sealing gaskets are arranged to avoid the grouting hole position to ensure the joint sealing. S4. Curing and Grouting: During the jacking interval or after the jacking is completed, the injected grout is cured to form a stone body with a certain strength. Then the grout filling density is tested, and any gaps are filled by secondary grouting through the reserved grouting channel. S5. Effect Verification and Control: By monitoring changes in jacking force, calculating frictional resistance, and combining ground settlement data, the drag reduction and support effects are verified. If the expected results are not achieved, the grouting parameters or jacking parameters are dynamically adjusted.

[0019] Furthermore, the dynamic control of grouting parameters specifically includes: dynamically adjusting the grouting pressure and grouting flow rate based on the real-time jacking speed and thrust data of the pipe jacking machine, so that the grouting volume matches the annular void volume and jacking speed; and identifying geologically weak or easily collapsed sections based on the results of pre-ground radar detection, and carrying out pre-grouting reinforcement of these sections before the pipe jacking machine arrives.

[0020] Furthermore, dynamic control of grouting parameters also includes: using data from soil pressure sensors and temperature sensors pre-embedded on the pipe sections, and automatically optimizing grouting pressure and grout mix ratio through control algorithms to achieve closed-loop control of grouting parameters.

[0021] Furthermore, the grout injection is pre-distributed through a conical transition structure set between the pipe jacking machine and the first pipe section; the outer surface of the conical transition structure is provided with a spiral guide groove, through which the grout is evenly coated into the annular gap during the jacking process; the conical angle of the conical transition structure is adapted to the outer diameter of the pipe jacking machine and the first pipe section, and its axial direction is provided with a grouting channel that communicates with the guide groove.

[0022] Furthermore, the real-time friction resistance monitoring and early warning module of the intelligent grouting control system performs the following operations: establishes a real-time relationship model between the jacking force and the jacking distance to calculate the real-time friction resistance and sets an early warning threshold; when the actual friction resistance exceeds the early warning threshold, it automatically starts the emergency grouting program, increases the grouting volume or adjusts the grout properties; and intelligently starts the relay station at the corresponding location based on the distribution characteristics of the friction resistance along the pipeline.

[0023] Furthermore, in steps S2 and S4, an adaptive adjustment strategy for grout performance is adopted, specifically including: dynamically adjusting the grout viscosity according to the construction stage, using a low-viscosity formula to optimize fluidity during the continuous jacking stage, and using a high-viscosity formula to prevent grout loss during the jacking pause stage; adjusting the grout composition according to changes in formation characteristics, and adding fibers or plugging agents to the grout in highly permeable sand layers or fractured formations.

[0024] Furthermore, in step S4, the secondary grouting is performed using a dual-circuit grouting system, including a main grouting circuit and an auxiliary grouting circuit. The main grouting circuit is responsible for forming an initial lubrication sleeve during the jacking process, while the auxiliary grouting circuit focuses on grouting sections with complex geological conditions or severe grout loss.

[0025] Furthermore, both the main grouting circuit and the auxiliary grouting circuit are equipped with independent pressure control valves and flow metering devices, which can achieve differentiated control of grouting pressure and grouting volume based on geological survey data of different sections of the pipeline.

[0026] Furthermore, in step S5, the effect verification is specifically achieved by monitoring the pipe section's posture and stress through sensors deployed on the pipe section, and by combining this with background analysis software to display in real time the wrapping status and support effect of the grout stone body on the pipeline, thereby generating a construction quality assessment report.

[0027] Furthermore, in step S1 and throughout the entire construction process, strict safety and environmental protection controls are implemented: protective facilities are installed at the working wellhead, and grouting and jacking equipment are regularly inspected; workers are equipped with full protective gear; environmentally friendly and biodegradable grout materials are selected, and waste grout generated during construction is collected and treated in a harmless manner; and grout leakage emergency treatment devices are installed at the working wellhead and grouting equipment area.

[0028] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0029] Example 1: Long-distance pipe jacking construction in gravel strata

[0030] S1: Construction Preparation and System Deployment Ground-penetrating radar combined with borehole exploration was used to accurately mark the distribution areas of sand and gravel particle sizes and the development zones of large pores. The pipe jacking machine was equipped with a wear-resistant cutterhead, and the spacing between intermediate sections was shortened by 20% compared to conventional methods. Spare grouting holes were added to the inner wall of the precast pipe sections, and the grouting pipes were fixed with double clamps and reinforced with protective sleeves. The intelligent grouting control system was set with a frictional resistance warning threshold of 12-18 kN / m².

[0031] S2: Coordinated jacking and grouting The jacking speed of the pipe jacking machine is controlled at 3-5 cm / min. The depth of the spiral guide channel with a conical transition structure is increased to 15 mm, and the channel width is increased to 20 mm, with a diversion hole at the end of the guide channel. The grouting pressure is increased by 30% compared to soft soil strata, and pulse grouting is used in sections with a porosity greater than 30%. Pre-grouting reinforcement is initiated 3 meters before reaching the high-porosity development zone, using cement-water glass dual-liquid grout.

[0032] S3: Pipe section splicing and sealing The pipe joints use double-layer sealing gaskets: an inner rubber gasket and an outer water-swellable sealing strip, with the two layers staggered. After assembly, the joint sealing is tested using ultrasonic testing.

[0033] S4: Curing and Grouting During the initial grout curing period, the strength of the stone mass was tested every 2 hours. Secondary grouting employed a dual-circuit grouting system, with the auxiliary grouting circuit equipped with a high-pressure grouting pump, and the grouting pressure controlled at 1.2-1.5 MPa. 2% fiber material was added to the grout.

[0034] S5: Effect Verification and Adjustment A core sampling test was added, with core samples taken every 50 meters. If voids were found in the core sample, a third grouting was immediately performed through a backup grouting hole.

[0035] Example 2: Close-range crossing construction in soft soil strata

[0036] S1: Construction Preparation and System Deployment Settlement observation points were added during the inspection of the back wall. The pipe jacking machine's attitude control system achieved an installation accuracy of ±2mm. The intelligent grouting control system was set with a ground settlement threshold of 5mm; exceeding this threshold automatically triggered control commands.

[0037] S2: Coordinated jacking and grouting The jacking speed is maintained at 2-4 cm / min. The cone angle of the conical transition structure is adjusted to 15°. The system receives data from the hydrostatic level in real time, and automatically increases the grouting pressure by 0.05 MPa when a settlement of 0.5 mm is detected. The grout uses a bentonite-CMC composite formula, and the viscosity is adjusted between 20-60 mPa·s according to the construction stage.

[0038] S3: Pipe section splicing and sealing Before splicing, clean the soft soil and impurities at the pipe section joints, and fix the pipe sections using mechanical pressing. Wrap the outside of the sealing gasket with non-woven fabric.

[0039] S4: Curing and Grouting For sections with excessive settlement, the auxiliary grouting circuit adopts a low-pressure, slow-injection method, increasing the grouting volume by 50% compared to the conventional method. 0.5% of an early-strength agent is added to the grout.

[0040] S5: Effect Verification and Adjustment The tiltmeter is used to monitor the pipe section's attitude, and settlement curves are generated using background software. If the settlement approaches the threshold, the jacking speed is immediately reduced and the grouting pressure is increased.

[0041] Example 3: Pipe jacking construction of large-diameter pipelines

[0042] S1: Construction Preparation and System Deployment The back wall adopts a composite structure of reinforced concrete and steel plate. The relay stations are arranged in groups of 80 meters, and each group is equipped with an independent grouting interface. Six grouting pipes are evenly distributed along the circumference of the inner wall of the precast pipe section, and each grouting pipe corresponds to an independent control valve.

[0043] S2: Coordinated jacking and grouting The conical transition structure adopts a split design, with six groups of spiral guide grooves on the outer surface, each corresponding to one of the six grouting pipes. Based on the real-time thrust of the pipe jacking machine, the grouting volume between each group of intermediate stations is adjusted synchronously. When the thrust exceeds 80% of the design value, auxiliary grouting between adjacent intermediate stations is automatically initiated.

[0044] S3: Pipe section splicing and sealing Flange-type splicing is used, with three sealing lines at the joint. A hydrostatic test is performed after splicing.

[0045] S4: Curing and Grouting For secondary grouting, micro-expansion cement grout is used, with the expansion rate controlled at 1%-2%. During the curing period, the expansion of the stones is monitored daily.

[0046] S5: Effect Verification and Adjustment Strain gauges and displacement sensors are installed on the pipe sections to monitor their stress and deformation. The background software generates a three-dimensional stress model and immediately adjusts the grouting parameters for the corresponding section when local stress concentration is detected.

[0047] Example 4: Pipe jacking construction in karst formations

[0048] S1: Construction Preparation and System Deployment A combination of ground-penetrating radar and borehole CT scans was used to accurately locate the karst caves. The pipe-jacking machine was equipped with a karst cave detection probe. An emergency grouting reserve pool was set up next to the working shaft.

[0049] S2: Coordinated jacking and grouting When the jacking reaches 5 meters into the karst cave, reduce the jacking speed to 1-2 cm / min and initiate pre-grouting. Small karst caves are filled with a cement-water glass two-component grout; large karst caves are first filled with crushed stone and then the grout is injected. A 3% (by mass) sealing agent is added to the grout.

[0050] S3: Pipe section splicing and sealing The pipe joints use metal-framed reinforced sealing gaskets, and after splicing, waterproof membrane is wrapped around the outside of the joints.

[0051] S4: Curing and Grouting The auxiliary grouting circuit adopts a fixed-point grouting mode, with specialized grouting holes set according to the distribution location of the karst caves. The secondary grouting is carried out in two stages: the first stage injects fast-setting grout, and the second stage injects conventional grout.

[0052] S5: Effect Verification and Adjustment The filling effect of the karst cave was verified by combining borehole sampling and radar scanning. If the karst cave was found to be incompletely filled, the emergency grouting reserve pool was immediately activated for supplementary filling.

[0053] Example 5: Long-distance pipe jacking construction in composite strata

[0054] S1: Construction Preparation and System Deployment For a 1200-meter-long complex geological project traversing clay, sand, and rock layers, an intelligent grouting control system was deployed. The system is pre-set with grouting parameter combinations for different geological formations, and the frictional resistance warning threshold is set to 8-15 kN / m² for each formation.

[0055] S2: Coordinated jacking and grouting The grout formula is automatically switched according to changes in the geological formation: a low-viscosity formula is used for clay layers, a medium-viscosity leak-proof formula is used for sand layers, and a high-viscosity early-strength formula is used for rock layers. The grouting pressure is dynamically adjusted between 0.2 and 1.0 MPa according to the geological characteristics.

[0056] S3: Pipe section splicing and sealing After each pipe section is advanced, it is immediately spliced ​​together. Sealing gaskets are selected from different materials based on geological conditions to ensure a tight seal at the joints.

[0057] S4: Curing and Grouting During the jacking intervals, the system automatically switches to a high-viscosity formula to prevent grout loss. After jacking is completed, a second grouting is applied to key sections such as the sand layer using a dual-circuit grouting system.

[0058] S5: Effect Verification and Control. By monitoring the changes in jacking force and calculating frictional resistance, the overall drag reduction rate was maintained above 65% throughout the jacking process. The final jacking force was reduced by about 40% compared to similar projects that did not use this method.

[0059] The working principle of this invention is based on a technical approach of intelligent sensing, dynamic control, and synergistic effects, achieving drag reduction by constructing a complete closed-loop control system. The specific working process is as follows: The intelligent grouting control system, as the core control unit, achieves intelligent sensing through the following methods: a thrust sensor monitors the thrust changes of the main jacking cylinder in real time; a jacking speed sensor collects the advancing speed of the pipe jacking machine; an earth pressure sensor detects the contact pressure between the pipe section and the surrounding soil; and a temperature sensor monitors the working environment temperature of the grout. This sensor data is transmitted in real time to the friction resistance real-time monitoring and early warning module. This module accurately calculates the friction resistance value using a real-time relationship model between the thrust and the jacking distance, and dynamically compares it with a preset threshold. When the system detects abnormal frictional resistance, it immediately activates a multi-level response mechanism: first, it automatically starts the emergency grouting program to increase the grouting volume or adjust the grout properties; at the same time, based on the distribution characteristics of frictional resistance along the pipeline, it intelligently activates the intermediate stations at the corresponding locations to achieve a reasonable distribution of the jacking force. At the execution level, the system achieves precise control through the following methods: the grouting pump delivers thixotropic slurry through the axial grouting channel of the conical transition structure. The slurry is evenly coated into the annular gap during the jacking process via a spiral guide groove, forming a complete lubrication sleeve. Based on the detection data from the ground-penetrating radar and real-time sensor feedback, the control system dynamically adjusts the grouting pressure and flow rate through control algorithms, ensuring a precise match between the grouting volume and the volume of the annular gap and the jacking speed. During the pipe section splicing process, sealing gaskets are precisely embedded in the interface grooves, and their placement strictly avoids the grouting holes to ensure interface sealing. The system automatically switches the grout formula according to the construction stage, using a low-viscosity formula during the continuous jacking stage to ensure fluidity, and switching to a high-viscosity grout formula during the jacking pause stage to prevent grout loss; Subsequent secondary grouting was carried out through the auxiliary grouting circuit of the dual-circuit grouting system, with key grouting implemented in sections with complex geological conditions or severe grout loss. Finally, data collected from sensors deployed on the pipe sections and ground settlement monitoring points were used to verify the drag reduction and support effects, completing a closed-loop management process from monitoring, decision-making, execution to verification. Through the coordinated work of the above-mentioned components, the entire system achieves real-time monitoring, early warning and dynamic control of frictional resistance during pipe jacking construction, effectively solving technical problems such as insufficient jacking force and high risk of pipeline damage caused by the accumulation of frictional resistance in ultra-long-distance pipe jacking construction.

Claims

1. A method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines, characterized in that, Includes the following steps: S1. Construction preparation and system layout: Test the stress performance of the working well and the back wall, and debug the pipe jacking machine and the intermediate room; check the compatibility of the precast pipe sections, grouting pipes and sealing gaskets, and deploy an intelligent grouting control system with a real-time frictional resistance monitoring and early warning module; the grouting pipes are fixed to the inner wall of the pipe sections by snap-fit. S2. Coordinated jacking and grouting: Start the pipe jacking machine for segmented jacking. During the jacking process, thixotropic mud is injected into the annular gap between the outer wall of the pipe section and the soil to form a lubricating sleeve. During this process, the intelligent grouting control system dynamically adjusts the grouting parameters based on real-time jacking data, geological data and sensor feedback. S3. Pipe section splicing and sealing: After each pipe section is jacked in, the pipe sections are immediately spliced, and a sealing gasket is embedded at the pipe section interface. The sealing gasket is arranged to avoid the grouting hole position to ensure the interface sealing. S4. Curing and Grouting: During the jacking interval or after the jacking is completed, the injected grout is cured to form a stone body with a certain strength. Then the grout filling density is tested, and any gaps are filled by secondary grouting through the reserved grouting channel. S5. Effect Verification and Control: By monitoring changes in jacking force, calculating frictional resistance, and combining ground settlement data, the drag reduction and support effects are verified. If the expected results are not achieved, the grouting parameters or jacking parameters are dynamically adjusted.

2. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, In step S2, the dynamic control of grouting parameters specifically includes: dynamically adjusting the grouting pressure and grouting flow rate based on the real-time jacking speed and thrust data of the pipe jacking machine, so that the grouting volume matches the annular void volume and jacking speed; identifying geologically weak or easily collapsed sections based on the results of pre-ground radar detection, and carrying out pre-grouting reinforcement of the sections before the pipe jacking machine arrives.

3. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 2, characterized in that, The dynamic control of grouting parameters also includes: using data from soil pressure sensors and temperature sensors pre-embedded on the pipe sections, and automatically optimizing the grouting pressure and grout mix ratio through a control algorithm to achieve closed-loop control of grouting parameters.

4. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, In step S2, the grout injection is pre-distributed through a conical transition structure set between the pipe jacking machine and the first pipe section; the outer surface of the conical transition structure is provided with a spiral guide groove, through which the grout is evenly coated into the annular gap during the jacking process; the conical angle of the conical transition structure is adapted to the outer diameter of the pipe jacking machine and the first pipe section, and its axial direction is provided with a grouting channel communicating with the guide groove.

5. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, The real-time friction resistance monitoring and early warning module of the intelligent grouting control system performs the following operations: establishes a real-time relationship model between the jacking force and the jacking distance to calculate the real-time friction resistance and sets an early warning threshold; when the actual friction resistance exceeds the early warning threshold, it automatically starts the emergency grouting program, increases the grouting volume or adjusts the grout properties; and intelligently starts the relay station at the corresponding location according to the distribution characteristics of the friction resistance along the pipeline.

6. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, In steps S2 and S4, an adaptive adjustment strategy for grout performance is adopted, specifically including: dynamically adjusting the grout viscosity according to the construction stage, using a low-viscosity formula to optimize fluidity during the continuous jacking stage, and using a high-viscosity formula to prevent grout loss during the jacking pause stage; adjusting the grout composition according to changes in formation characteristics, and adding fibers or plugging agents to the grout in highly permeable sand layers or fractured formations.

7. The method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, The secondary grouting in step S4 is performed using a dual-circuit grouting system, which includes a main grouting circuit and an auxiliary grouting circuit. The main grouting circuit is responsible for forming an initial lubrication sleeve during the jacking process, while the auxiliary grouting circuit focuses on grouting sections with complex geological conditions or severe grout loss.

8. A method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 7, characterized in that, Both the main grouting circuit and the auxiliary grouting circuit are equipped with independent pressure control valves and flow metering devices, which can achieve differentiated control of grouting pressure and grouting volume based on geological survey data of different sections of the pipeline.

9. A method for reducing drag during long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, The effect verification described in step S5 specifically involves monitoring the pipe section's posture and stress using sensors deployed on the pipe section, and combining this with background analysis software to display in real time the wrapping status and support effect of the grout stone body on the pipeline, thereby generating a construction quality assessment report.

10. A method for drag reduction grouting during ultra-long-distance pipe jacking construction of water supply pipelines according to claim 1, characterized in that, In step S1 and throughout the entire construction process, strict safety and environmental protection controls are implemented: protective facilities are installed at the working wellhead, and grouting and jacking equipment are regularly inspected; workers are equipped with full protective gear; environmentally friendly and biodegradable grout materials are selected, and waste grout generated during construction is collected and treated in a harmless manner. The grout leakage emergency treatment device is installed at the working wellhead and grouting equipment area.