Water-rich sand layer complex geology pipe jacking construction mud concentration closed-loop regulation and environmental protection construction method
Patent Information
- Application Number
- CN202610988527.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-10-27
Smart Images
Figure CN122977470A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of trenchless construction technology, specifically a closed-loop control method for mud concentration and an environmentally friendly construction method for pipe jacking construction in complex geological conditions with water-rich sand layers. Background Technology
[0002] In the construction of urban underground pipe networks, pipe jacking is widely used in water supply, drainage, gas, and heating pipeline projects due to its advantages of minimal impact on surface traffic and less excavation disturbance. However, in water-rich sandy geological conditions, where the stratum permeability is high, the sand grain size distribution is wide, and the groundwater dynamics are complex, traditional pipe jacking construction faces the following two prominent problems.
[0003] Traditional pipe jacking construction relies heavily on manual experience to mix slurry and uses it extensively in a repetitive manner, lacking effective slurry-sand separation devices and dynamic concentration control methods. During construction, the sand content of the slurry is generally high, and the slurry density and viscosity fluctuate significantly, making it difficult to maintain stable support pressure at the tunnel face. This leads to safety risks such as quicksand, piping, tunnel face instability, and even excessive ground settlement, posing a significant threat to the safety and quality of pipe jacking construction in water-rich sandy layers. At the same time, traditional processes have low slurry recycling rates and generate large amounts of waste slurry and solid waste; dust, noise, and vibration control measures are inadequate during construction; and when the project passes through sensitive areas such as hospitals, main roads, and adjacent water bodies, it is extremely difficult to simultaneously meet the requirements of green environmental protection and zero-pollution construction.
[0004] In summary, existing technologies have significant shortcomings in both precise control of mud concentration during pipe jacking construction in water-rich sandy layers and environmentally friendly construction in sensitive areas. There is an urgent need to develop a pipe jacking construction method that can achieve closed-loop control of mud concentration throughout the entire process, ensure safe and stable construction, and achieve green and low-emission construction. Summary of the Invention
[0005] To address the aforementioned problems in existing technologies, this invention provides a closed-loop control method for mud concentration and an environmentally friendly construction method for pipe jacking in complex geological conditions with water-rich sand layers. By constructing a closed-loop mud concentration control system through mud grading and separation, real-time online monitoring, intelligent concentration control, and closed-loop return, a collaborative control system for jacking construction is established, which is linked to multi-dimensional environmental protection control measures to achieve safe, efficient, and green construction of pipe jacking projects in water-rich sand layers.
[0006] The present invention employs a closed-loop control method for mud concentration and an environmentally friendly construction method for pipe jacking construction in complex geological conditions with water-rich sand layers, comprising: Step S1: The sand-containing mud generated by the pipe jacking machine cutting operation is discharged to the mud and sand separation system outside the working well through the slurry discharge pipeline. First, the coarse sand particles are removed by the vibrating screen, and then the slurry after screening is sent to the hydrocyclone to further separate the fine sand particles. The separated sand and slag are dehydrated and dried and then stored in a centralized pile.
[0007] Step S2: Install sensors at key nodes of the mud system pipeline to monitor the mud specific gravity, viscosity, sand content and pipeline pressure in real time. The monitoring data is automatically transmitted to the intelligent control unit, and personnel are arranged to manually sample and verify the data every 30 minutes.
[0008] Step S3: Dynamically adjust the mud concentration based on monitoring data and manual verification results. When the mud concentration is too low, add bentonite to the mud conditioning tank. When the mud concentration is too high, add water to dilute the mud. Adjust the mud specific gravity or viscosity target value according to the sand particle size distribution and water content characteristics of the strata to keep all mud indicators stable within the preset range.
[0009] Step S4: The purified mud that has been regulated to meet the standards is pumped from the purified mud tank to the working face through a slurry pump at a return pressure 0.02 to 0.05 MPa higher than the static water and soil pressure, so as to maintain the stability of the working face pressure curtain and realize the closed-loop recycling of mud; when the purified mud tank is insufficient, the backup mud tank is activated to supplement it.
[0010] Step S5 involves coordinating the jacking speed, axis correction, and mud return pressure of the pipe jacking machine to dynamically stabilize the pressure curtain at the working face, suppress quicksand and piping, and control ground subsidence.
[0011] Step S6 involves precise control of dust, noise, and vibration at the construction site; specific anti-seepage and water-stopping measures are taken for construction sections near rivers or canals; and the dried sand and slag separated in step S1 are utilized as resources.
[0012] Furthermore, the preset control parameters for the mud in step S3 are: specific gravity 1.1-1.3 g / cm³, viscosity 18-25 s, and sand content less than 3%; when traversing a coarse sand layer, the specific gravity of the mud is adjusted to 1.10-1.15 g / cm³; when traversing a fine sand layer, the viscosity of the mud is controlled at 20-25 s.
[0013] Furthermore, in step S1, the amplitude of the vibrating screen is controlled at 3-5 mm to separate and remove coarse sand particles with a particle size of not less than 0.075 mm; the feed pressure of the hydrocyclone is controlled at 0.15-0.3 MPa to further separate fine sand particles with a particle size of less than 0.075 mm.
[0014] Furthermore, in step S3, when the mud concentration is too low, the amount of bentonite added to the mud conditioning tank is 5-10 kg / m³; when the mud concentration is too high, clean water is added to the mud to dilute it until all indicators reach the preset control range.
[0015] Furthermore, in step S5, the jacking speed of the pipe jacking machine is controlled at 5-10 cm / h, the single axis correction amount does not exceed 5 mm, and the ground settlement is controlled within 30 mm.
[0016] Furthermore, in step S4, the mud recycling rate is no less than 90%; the mud system is sequentially set up with a sand-containing mud tank, a purified mud tank, and a spare mud tank to form a three-level circulating storage system to ensure the continuity of mud supply.
[0017] Furthermore, in step S6, the dried sand and slag, after passing inspection, are used for pipeline trench backfilling and other processes, thereby realizing the resource utilization of solid waste and reducing the amount of solid waste transported and discharged.
[0018] Furthermore, in step S6, dust control measures include enclosing the construction area, hardening roads, and regularly watering to reduce dust; noise control prioritizes the use of low-noise equipment and restricts high-noise operation periods at night; vibration control is achieved by strictly controlling the jacking speed and hydraulic system operating parameters.
[0019] Furthermore, the seepage prevention and water-stopping measures in step S6 include: setting up seepage prevention curtains or isolation walls in the construction section near the river or canal, and laying seepage prevention linings on the ground mud pools to prevent construction mud from leaking and polluting the surrounding water bodies.
[0020] Furthermore, in step S2, the online monitoring sensor and the intelligent control unit are linked together. When the monitoring data deviates from the control index range, the intelligent control unit automatically triggers the bentonite dosing device or the water dilution device to respond. The results are manually reviewed every 30 minutes to verify the accuracy of automatic control in real time, ensuring that all mud indicators remain within the preset control range.
[0021] Compared with existing technologies, this invention fundamentally solves the industry problem of high sand content, large concentration fluctuations, and difficulty in precise control of mud concentration in water-rich sandy layer pipe jacking construction by constructing a closed-loop mud concentration control system that closely coordinates the series-connected separation of vibrating screen and hydrocyclone, real-time online monitoring, and intelligent concentration regulation. The mud specific gravity can be stably controlled at 1.1-1.3 g / cm³, viscosity at 18-25 s, and sand content below 3%. The pressure curtain at the tunnel face is stable and reliable, effectively curbing the risks of quicksand, piping, and tunnel face instability, and fully ensuring the safety of the stratum and surrounding structures. Through coordinated control of jacking speed, axis correction, and mud return pressure, the disturbance and settlement deformation of the stratum are significantly reduced. The settlement of the stratum can be stably controlled within 30 mm, and the single axis correction does not exceed 5 mm. The construction precision and safety reliability are greatly improved, which can meet the construction requirements of complex working conditions such as crossing buildings and dense pipeline areas; the mud recycling rate is not less than 90%, the mud consumption is greatly reduced, the overall construction cost can be reduced by 10% to 15%, and the construction period can be shortened by 8% to 12% accordingly, resulting in significant economic benefits; the dried sand and slag are used on-site for pipeline trench backfilling and other processes, realizing the resource utilization of solid waste. Combined with the precise control of dust, noise and vibration at the construction site and special anti-seepage and water-stopping measures for sections near water bodies, a green and environmentally friendly construction system covering the entire construction process is constructed. It can fully meet the construction requirements of zero pollution, zero safety accidents and zero environmental disputes when crossing sensitive areas such as hospitals, main roads and adjacent water bodies. The social and environmental benefits are outstanding and it has high promotion and application value. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a diagram illustrating the method steps of the present invention; Figure 2 This is a diagram of the guide rail installation site in an embodiment of the present invention; Figure 3 This is a field diagram of the pressure-bearing steel plate and hydraulic cylinder of the rear wall in an embodiment of the present invention; Figure 4 This is a field diagram of the hole-stopping device in an embodiment of the present invention; Figure 5 This is a field diagram of the two-stage separation system of vibrating screen and hydrocyclone in an embodiment of the present invention; Figure 6 This is a field diagram of the dynamic closed-loop monitoring of mud concentration in an embodiment of the present invention. Detailed Implementation
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0026] The embodiments of the present invention will be further described in detail below with reference to specific engineering examples.
[0027] This invention is applied in practice based on the pipe jacking section of the raw water pipeline project of Suyu Chengbei Water Plant (total length 542m, pipeline burial depth 19m). The project passes through Jingtou Hospital, Santaishan Avenue and is close to Luomahu Second Main Canal. It is a typical water-rich sandy layer pipe jacking project in a sensitive area with complex geological conditions and strict environmental protection requirements.
[0028] Before construction, a mud-sand separation system was installed outside the working well. The system consisted of a vibrating screen and a hydrocyclone connected in series. During the commissioning phase, the amplitude of the vibrating screen was set to 3-5 mm, and the feed pressure of the hydrocyclone was adjusted to 0.15-0.3 MPa to ensure that the system could effectively separate sand particles with a diameter of not less than 0.075 mm. A three-stage mud storage system was set up, including a sand-containing mud tank, a purified mud tank, and a spare mud tank.
[0029] During pipe jacking construction, the sand-containing slurry generated by the pipe jacking machine is automatically discharged to the sand-containing slurry pool through the slurry discharge pipeline, and then enters the coarse separation stage of the vibrating screen. The coarse sand is intercepted on the vibrating screen and discharged to the sand storage area. The slurry after screening is pumped into the hydrocyclone by the slurry pump for fine sand separation. The fine sand discharged from the underflow of the hydrocyclone enters the dewatering device for drying, and the clear liquid overflowing from the hydrocyclone flows into the purified slurry pool.
[0030] The outlet of the purification mud tank is equipped with a densitometer, a viscosity sensor, and a sand content detector to monitor the mud specific gravity, viscosity, sand content, and pipeline pressure in real time. All data are automatically transmitted to the intelligent control unit. At the same time, dedicated technicians manually verify the mud viscosity and sand content every 30 minutes using manual testing methods such as the Marshall funnel method. The two methods are mutually verified to ensure the accuracy of monitoring.
[0031] When the intelligent control unit determines that the mud concentration is below the preset lower limit, it automatically starts the bentonite dosing device, adding bentonite to the slurry mixing tank at a dosage of 5-10 kg / m³. When the mud concentration exceeds the preset upper limit, it automatically opens the water dilution valve for adjustment. When construction crosses a coarse sand layer, the target mud specific gravity is adjusted to 1.10-1.15 g / cm³ to enhance the support pressure at the working face. When crossing a fine sand layer, the target viscosity is adjusted to 20-25 s to enhance the mud suspension and sand-carrying capacity, ensuring that the mud specific gravity is always maintained within the control range of 1.1-1.3 g / cm³, viscosity 18-25 s, and sand content below 3%.
[0032] The purified mud is pumped from the purification mud tank back to the tunnel face of the pipe jacking machine at a pressure 0.02–0.05 MPa higher than the measured static water and soil pressure on site. This forms a stable pressure curtain at the tunnel face, preventing groundwater and sand particles from intruding into the tunnel face. The return pressure is adjusted in conjunction with the jacking speed, the switching of the earth pressure / slurry balance mode, and the axis correction operation. The jacking speed is controlled at 5–10 cm / h, and the single axis correction amount does not exceed 5 mm. Through full-process surface settlement monitoring, the ground settlement is controlled within 30 mm throughout the entire construction process.
[0033] The mud recycling rate is no less than 90%. After drying, the sand and slag are tested and qualified, and then used on-site for backfilling pipeline trenches to reduce the amount of solid waste transported and discharged. Dust is controlled by enclosure measures in the construction area. Low-noise equipment is given priority and high-noise operation periods at night are restricted. The impact of construction vibration on the surrounding environment is reduced by controlling the jacking speed and hydraulic system parameters. In the construction section near the Luoma Lake Second Main Canal, seepage prevention curtains are set up and seepage prevention linings are laid on the ground mud pits to ensure that the mud does not leak and pollute the surrounding water bodies.
[0034] After the project was completed, a comprehensive evaluation showed that the construction achieved zero safety accidents, zero pollution, and zero environmental disputes. All ground settlement control standards were met. After review by industry experts, the technology of this invention reached the leading level in China and has significant value for engineering promotion and application.
[0035] It should be noted that the specific methods by which each module performs operations in the system described in the above embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.
[0036] Finally, it should be noted that although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A closed-loop control method for mud concentration and an environmentally friendly construction method for pipe jacking in complex geological conditions with water-rich sand layers, characterized in that, Includes the following steps: Step S1: The sand-containing mud generated by the pipe jacking machine cutting operation is discharged to the mud and sand separation system outside the working well through the slurry discharge pipeline. First, the coarse sand particles are removed by the vibrating screen, and then the slurry after screening is sent to the hydrocyclone to further separate the fine sand particles. The separated sand and slag are dewatered, dried and then stored in a centralized pile. Step S2: Install sensors at key nodes of the mud system pipeline to monitor the mud specific gravity, viscosity, sand content and pipeline pressure in real time. The monitoring data is automatically transmitted to the intelligent control unit, and personnel are arranged to manually sample and verify the data every 30 minutes. Step S3: Dynamically adjust the mud concentration based on monitoring data and manual verification results. When the mud concentration is too low, add bentonite to the mud mixing tank. When the mud concentration is too high, add water to dilute the mud. Adjust the mud specific gravity or viscosity target value according to the sand particle size distribution and water content characteristics of the strata to keep all mud indicators stable within the preset range. Step S4: The purified mud that has been regulated to meet the standards is pumped from the purified mud tank to the working face through a slurry pump at a return pressure 0.02 to 0.05 MPa higher than the static water and soil pressure, so as to maintain the stability of the working face pressure curtain and realize the closed-loop recycling of mud; when the purified mud tank is insufficient, the backup mud tank is activated to supplement it. Step S5: Coordinate the operation of the pipe jacking machine's jacking speed, axis correction amount, and mud return pressure to dynamically stabilize the pressure curtain at the working face, suppress quicksand and piping, and control ground subsidence. Step S6 involves precise control of dust, noise, and vibration at the construction site; specific anti-seepage and water-stopping measures are taken for construction sections near rivers or canals; and the dried sand and slag separated in step S1 are utilized as resources.
2. The method according to claim 1, characterized in that, In step S3, the preset control parameters for the mud are: specific gravity 1.1-1.3 g / cm³, viscosity 18-25 s, and sand content less than 3%; when crossing a coarse sand layer, the specific gravity of the mud is adjusted to 1.10-1.15 g / cm³; when crossing a fine sand layer, the viscosity of the mud is controlled at 20-25 s.
3. The method according to claim 1, characterized in that, In step S1, the amplitude of the vibrating screen is controlled at 3-5 mm to separate and remove coarse sand particles with a particle size of not less than 0.075 mm; the feed pressure of the hydrocyclone is controlled at 0.15-0.3 MPa to further separate fine sand particles with a particle size of less than 0.075 mm.
4. The method according to claim 1, characterized in that, In step S3, when the mud concentration is too low, add 5-10 kg / m³ of bentonite to the mud mixing tank; when the mud concentration is too high, add water to dilute the mud until all indicators reach the preset control range.
5. The method according to claim 1, characterized in that, In step S5, the jacking speed of the pipe jacking machine is controlled at 5-10 cm / h, the single axis correction amount does not exceed 5 mm, and the ground settlement is controlled within 30 mm.
6. The method according to claim 1, characterized in that, In step S4, the mud recycling rate shall not be less than 90%; the mud system shall be set up with sand-containing mud tank, purified mud tank and spare mud tank in sequence to form a three-level circulation storage system to ensure the continuity of mud supply.
7. The method according to claim 1, characterized in that, In step S6, the dried sand and slag, after passing the test, are used for pipeline trench backfilling and other processes, realizing the resource utilization of solid waste and reducing the amount of solid waste transported and discharged.
8. The method according to claim 1, characterized in that, In step S6, dust control measures include enclosing the construction area, hardening roads, and regularly watering to reduce dust; noise control prioritizes the use of low-noise equipment and restricts high-noise operation periods at night; vibration control is achieved by strictly controlling the jacking speed and hydraulic system operating parameters.
9. The method according to claim 1, characterized in that, The seepage prevention and water-stopping measures in step S6 include: setting up seepage prevention curtains or isolation walls in the construction section near the river or canal, and laying seepage prevention linings on the ground mud pools to prevent construction mud from leaking and polluting the surrounding water bodies.
10. The method according to claim 2, characterized in that, In step S2, the online monitoring sensor and the intelligent control unit work together. When the monitoring data deviates from the control index range, the intelligent control unit automatically triggers the bentonite dosing device or the water dilution device to respond. The results are manually checked every 30 minutes to verify the accuracy of the automatic control in real time, ensuring that all mud indicators remain within the preset control range.