Slurry balance shield circulation reduced scale experiment equipment under simulated large-diameter shield working condition

Abstract

The invention discloses slurry balance shield circulation scale experimental equipment under a simulated large-diameter shield working condition. The slurry balance shield circulation scale experimental equipment comprises an experimental bin, a simulated cutterhead stirring system and a circulation system. On one hand, on the basis of slurry balance shield circulation formed by a simulation experiment, the safe migration speed of particles generated by a large-diameter shield and an ultra-large-diameter shield at different geological environment propulsion rates in a slurry pipeline can be determined, so that the shield is guided, the circulation stagnant discharge probability is reduced, and secondary abrasion of accumulated slag to a cutter is reduced; meanwhile, visualized observation is conducted on bottom accumulated slag of a cutterhead muddy water bin in different modes, quantitative calculation and evaluation are conducted on the slag accumulation proportion, and a supporting basis is found for further research on the contribution degree of bottom accumulated slag to peripheral cutter abrasion; and on the other hand, the experimental characteristics of the experimental parameter reduced scale restart state on the conditions such as diameters of particles generated by different geologies, progressive decrease or progressive increase modes of blocks and the like are studied, and continuous synchronization capability is provided for continuous classification of geological particles and block reduced scale experiments.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield equipment, and particularly relates to a reduced-scale experimental device for slurry balance shield circulation under the condition of simulating large-diameter shield working conditions. Background Art

[0002] With the increase of domestic large-diameter shield, extra-large-diameter slurry shield projects, the geological environment faced by shield construction is becoming more and more complex. When the shield cutterhead tunnels in a complex geological environment, the cut blocks and particulate matters are re-aggregated under the combined action of factors such as cohesion, pressure, and turbulence, and are adsorbed and sedimented in the slurry chamber, on the surface of the cutterhead, and at the slag outlet, resulting in a series of problems such as slag accumulation in the slurry pressure chamber, secondary wear at the bottom edge of the cutterhead, blockage of the circulation channel and slag outlet, and abnormal shield tunneling parameters, which seriously affect the safe progress of the project.

[0003] In order to solve the problem of re-aggregation, sediment adsorption of the cut blocks and particulate matters formed by factors such as cohesion, pressure, and turbulence, the shield equipment usually adopts large-diameter direct drainage pipelines in the front shield slurry chamber, and coordinates the slurry specific gravity parameters with large flow velocities to carry the slag. The slag is transferred from the slurry chamber into the large-diameter direct drainage pipeline and then sent out of the working surface through a pipeline pump. For example, in multiple complex geological conditions such as crossing highly permeable sand layers, soil-rock composite strata, full-section hard rock strata, karst strata, and regional faults; strata such as soft upper and hard lower, slightly weathered and moderately weathered granite, fault zones, boulders, liquefied sand layers; soil-rock composite (soft upper and hard lower) strata, tuff strata, granite strata, and at the same time, the tunnel also crosses multiple fault fracture zones with many joints, fissures, and large water content, etc. Due to the high-pressure and invisible environment under normal operation of slurry circulation construction and the extremely complex geological conditions, it is impossible to directly and completely reflect the movement and accumulation of the excavated muck in the chamber. At the same time, circulation stagnation often occurs. Once stagnation occurs, it is often necessary to open the chamber for maintenance under good formation conditions, which is not only inconvenient to operate, but also has high construction risks. In addition, it has a greater impact on the construction period. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a brand-new reduced-scale experimental device for slurry balance shield circulation under the condition of simulating large-diameter shield working conditions.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0006] A reduced-scale experimental device for slurry balance shield circulation under the condition of simulating large-diameter shield working conditions, which includes:

[0007] An experimental chamber with a sealed pressure inside the chamber of at least 6 bar, and simulating the slurry working conditions formed by a large-diameter shield inside the chamber. The experimental chamber includes a slurry chamber and an air-cushion chamber arranged front and back based on a gate plate extending from the top to the bottom. A confluence port is formed between the bottom of the gate plate and the bottom wall of the experimental chamber. The slurry chamber and the air-cushion chamber are connected through the confluence port, and visual observation holes are provided on the bottom side walls of the slurry chamber and / or the air-cushion chamber.

[0008] A simulated cutterhead stirring system, which is located inside the air-cushion chamber and rotates around the front-back direction to form a moving stir.

[0009] A circulation system, which includes a slurry discharge pipeline assembly, a slurry inlet pipeline assembly, and a slurry treatment unit. The slurry treatment unit includes a slurry sieve and a slurry processor. The slurry discharge pipeline assembly is connected to the slurry chamber. The slurry sieve is used for multi-stage screening of particles in the slurry. The slurry processor is connected to the slurry outlet of the slurry sieve and performs separation and screening treatment based on the slurry to form slurry with a specific gravity and viscosity meeting the experimental requirements. The slurry inlet pipeline assembly is connected to the slurry outlet of the slurry processor and respectively returns to the slurry chamber and the air-cushion chamber based on flow control to constitute a slurry balance shield circulation.

[0010] Preferably, the experimental chamber is a rectangular pressure chamber. Briefly, a rectangular pressure balance air-cushion slurry chamber, which is converted from a circular shape to a square shape, combined with the simulated cutterhead stirring inside the chamber, forms a complete widened boundary space. The incoming slurry, rock slag, and clay rotate with the cutterhead in the rectangular pressure chamber, and the fluid flows towards the slag discharge port. The flowing sediment and adsorbed and aggregated particulate matter, in the rectangular state, based on the visual observation holes, view the deposition and dispersion law of particulate matter outside the circular rotation range of rock slag and clay. At the same time, the probability of circulation stagnation and discharge is reduced.

[0011] According to a specific implementation and preferred aspect of the present invention, the gate plate is parallel to the bottom wall, and the distance between the two is 1 / 12 to 1 / 8 of the downward extension length of the gate plate. Based on the chamber working conditions simulated by the gate plate, it is relatively close to the working conditions of large-diameter, large-diameter shield, and extra-large-diameter shield, so as to guide the slurry balance shield circulation according to the experimental results and reduce the incidence of circulation stagnation and discharge.

[0012] According to another specific implementation and preferred aspect of the present invention, the simulated cutterhead stirring system includes a stirring shaft extending along the front-back direction, stirring blades installed on the stirring shaft, and a power unit for driving the stirring shaft to rotate self. Based on the moving stir formed by the simulated cutterhead stirring system, the slurry inside the chamber rotates with the cutterhead in the simulated tunneling mode, realizing the restoration of operation actions. The movement characteristics of the solid-liquid two-phase flow turbulence of the slurry, rock slag, clay, and slurry in the slurry chamber are restored, and physical participation is carried out on the complete evolution of the incoming slurry, rock slag, clay, flowing sediment, adsorption aggregation, and movement actions in the chamber under the rotation of the cutterhead structure for different geological particulate matters.

[0013] Preferably, the stirring paddle comprises a stirring ring fixed on the stirring shaft and a plurality of stirring blades distributed circumferentially around the stirring ring, wherein the stirring ring is concentric with the stirring shaft, and the plurality of stirring blades are located on the same side of the stirring ring.

[0014] Furthermore, the stirring ring is relatively close to the gate, and the stirring blades extend backward. Generally, the stirring blades have 6 sets of blades, which are fixed to the stirring ring by welding. The overall diameter of the cutter disc is about 2m, and the stirring shaft is connected to the cutter disc rotation motor to drive the cutter disc to rotate.

[0015] Furthermore, the bottom of the stirring paddle is close to the bottom wall of the experimental chamber, and the stirring zone is partially aligned with the confluence. Generally, the bottom of the stirring paddle is kept 10 cm away from the chamber wall, as long as the stirring machine does not get stuck.

[0016] According to another specific implementation and preferred aspect of the present invention, the slurry discharge pipeline assembly includes a self-draining pipeline connected to the mud and water bin, wherein the self-draining pipeline is aligned with the confluence port, and the mud and water mixture is discharged to the mud screener based on the pressure of the experimental bin. In short, the mud and water mixture with no direction and irregular movement, mutual mixing between fluid particles, and random changes in parameters such as velocity and pressure in time and space is led to the slurry discharge main pipeline through a pipeline, and the inertial gravity generated by the flow velocity of the pipeline body and the mud in the pressure bin impact the mud and water in the bin to maintain the mud and water migration outlet, and the straight discharge pipeline discharges the slurry to form an attraction and entanglement, and the mud and water mixture connected to the mud and water bin is discharged, forming a self-adaptive same-diameter self-discharge mechanism.

[0017] According to another specific implementation and preferred aspect of the present invention, the mud screen includes a feed screen, a particle grading screening assembly, and a lower hopper, wherein the mud and water mixture discharged from the mud and water bin is separated from solid to liquid from top to bottom. In short, the mud screen consists of a three-layer structure, the top of the top structure is a screen (feed screen), which mainly intercepts fixed particles with large particle sizes; the particle grading screening assembly, which mainly performs graded screening based on the components in the mud and water to complete solid-liquid separation; the lower hopper guides the separated mud and water into the mud processor below, and also removes the screened solid particles by cleaning.

[0018] In addition, the slurry inlet pipeline assembly includes a slurry inlet main pipe connected to the mud and water outlet of the mud processor, a slurry inlet pump installed on the slurry inlet main pipe, a first slurry inlet branch pipe and a second slurry inlet branch pipe connected to the slurry inlet main pipe and respectively connected to the mud and water bin and the air cushion bin, wherein the connecting end of the first slurry inlet branch pipe is located at the top of the mud and water bin; the connecting end of the second slurry inlet branch pipe is located on the side wall of the air cushion bin and faces the simulated knife disc mixing system.

[0019] Preferably, the mud purifier separates mud by receiving vibration screening, removes impurities and useless particles, makes the performance of the mud meet the requirements of experimental specific gravity and viscosity, provides stable and high-quality mud, reduces experimental errors and failures caused by mud problems, realizes the recycling of mud, reduces the preparation amount of new mud, and ensures the smooth progress of the experiment. The mud purification system of the shield circulation experiment platform is mainly used to process and purify the mud used in shield construction to ensure the performance and reuse of the mud and environmental protection.

[0020] Preferably, the circulation system further includes a screw feeder, wherein the feeding end of the screw feeder is inserted into the confluence port from the side wall of the air cushion bin, the discharging end forms a transfer bin, and the transfer bin is communicated with the slurry discharging pipeline assembly. In short, the circulation system is composed of a slurry inlet pipeline and a slurry discharging pipeline. The slurry inlet pipeline is connected to a slurry pump, and the slurry and the put slag are fed into the slurry water bin and the air cushion bin through the slurry pump. The slurry discharging pipeline is divided into two types. One type is that the rectangular slurry water bin is connected to a screw conveyor and then to the slurry discharging pipe to the screening system, and the other type is that the rectangular slurry water bin is connected to a direct discharging pipeline and then accesses the main slurry discharging pipeline. That is, this experimental equipment can simulate the turbulent flow of the solid-liquid two-phase flow in the mud pressure chamber during the rotation of the cutter head, and the conveying characteristics generated by the ultimate settling velocity of rock slag and clay produced under different geological conditions in the turbulent flow environment of the solid-liquid two-phase flow. It can obtain the boundary effect in the rectangular bin pressure mode, master the law of sedimentation and stagnant discharge inside the slurry water bin, and can study the two-phase flow conveying characteristics through two access pipeline conveying systems of direct discharge and short screw. Through the corresponding visible bin plates, sensors, and flow meters, the dynamic monitoring of the movement characteristics, sedimentation rate, and pipeline resistance characteristics of rock slag and clay in the solid-liquid two-phase turbulent flow in the mud pressure chamber, the transportation discharge outlet, and the pipeline part can be realized. Secondly, determine the safe transportation speed of particulate matter in the slurry pipeline generated by the propulsion speed of the super-large shield in different geological environments, and the matching support basis for the use of the two transportation interfaces of direct discharge and short screw in the shield machine facing different geologies. Build the best pipeline transportation experimental function. It can also study the experimental characteristics of the scale-down restart state of experimental parameters on the diameter of particulate matter and the decreasing or increasing mode of the block stage generated by different geologies, and provide continuous synchronization ability for the continuous classification of geological particulate matter and block scale-down experiments.In short, as the depth changes, the pressure increases, the shield cutter head rotates and stirs, and the circulation carries slag, consuming energy, which prompts the deep ground and deep sea shield to operate in a cycle. Through the shield circulation test chamber, the underground high-pressure space area that is invisible and intangible to the current domestic shield technology is covered by large-diameter, large-diameter shield, and ultra-large-diameter shield. Under the pressure of the slag mud-water mixture generated by the shield, the shield circulation test chamber is composed of an air cushion chamber and a mud-water chamber. It has a 6Bar high-pressure adaptability and is designed through a scaled model to experiment. Verify the application of the world's leading shield equipment technology, use a complete set of experimental technology to tackle the technical difficulties of deep-sea and deep-ground shields, study the experience model of slurry shield and earth pressure shield equipment operation, and deeply explore the shield equipment in large-diameter coverage of complex geological environments. The experimental device puts block particles representing different geological and combined geological proportions in the experimental process, and conducts theoretical and applied technical research on the movement characteristics of stone ballast particles in the air cushion slurry circulation system and short spiral slurry circulation system shield circulation. The air cushion mud water circulation system and the short spiral mud water circulation system are switched to carry out mud water pressure particle circulation and slag experiments in the same geological mode. The unique design monitors and observes the turbulence effect of the core mud water bin of the shield and Newton's theory, supported by the pressure fusion combination effect. The current world shield, large diameter, large diameter shield, and ultra-large diameter shield technology research gap are simulated. The energy efficiency of the two circulation slag carrying mode shield equipment is compared, and the development performance experiment improves the feasibility support of equipment technology extension. Large diameter, large diameter shield, and ultra-large diameter shield equipment face different and long-distance complex and invisible geological conditions in the deep sea and deep earth, and due to space limitations, current scientific researchers and shield equipment design and manufacturing manufacturers can only make extended technical solutions to the situations that arise. At present, shield equipment does not have the ability to switch between the air cushion mud water circulation system and the short spiral mud water circulation system at the same time. When large diameter or even large diameter shield and ultra-large diameter shield equipment encounter complex geological conditions, it provides an optional solution for how to safely improve the shield efficiency and save energy, thereby enhancing practicality.

[0021] In addition, the control system: 1. Mud transportation demand monitoring: Real-time monitoring of parameters such as mud flow rate, pressure, and concentration during shield tunneling construction through sensors to determine the current transportation demand. 2. Control signal generation: Comparing the monitored parameters with preset working indicators, the control system generates corresponding control signals. 3. Speed control of the pump: Controlling the rotational speed of the mud pump to adjust the transportation flow rate and pressure of the mud. For example, when the flow rate is insufficient, increase the pump speed; otherwise, decrease the speed. 4. Valve adjustment: Adjusting the flow direction and flow rate distribution of the mud by controlling the valve opening on the pipeline to ensure appropriate mud supply to each working area. 5. Pressure balance control: Maintaining the pressure balance in the pipeline to prevent pipeline damage or poor mud transportation caused by excessive or too low pressure. 6. Feedback and correction: Continuously receiving new monitoring data and correcting and optimizing the control signals according to the actual operating conditions to achieve precise and stable control of the mud pipeline. 7. Fault monitoring and protection: Real-time monitoring of the operating status of the system. Once a fault is detected, such as pump overload or pipeline blockage, timely protective measures are taken to stop the operation of relevant equipment and issue an alarm. It consists of a control electrical box and the electrical circuits of each system's electrical equipment. The circuits of each system are connected to the main control electrical box, and electrical appliances, circuit breakers, relays, contactors, etc. required for each system are installed inside the electrical box. Monitoring system: 1. Flow monitoring: Measuring the flow rate of mud, muck, etc. in the circulation system using a flowmeter. 2. Pressure monitoring: Monitoring the pressure at different positions in the circulation pipeline through pressure sensors, including inlet pressure, outlet pressure, local pressure, etc. 3. Concentration monitoring: Measuring the concentration of solid particles in the circulation using a concentration meter to understand the transportation situation of the muck. 4. Temperature monitoring: Monitoring the temperature of key parts in the circulation system to prevent overheating. 5. Speed monitoring: The rotational speed of the circulation pump, etc. 6. Image monitoring: Using a camera to collect real-time images of key parts of the experimental platform to visually observe the phenomena during the experimental process. 7. Data acquisition and transmission: Transmitting the data collected by various sensors to the data processing center in real time. 8. Data processing and analysis: Processing, calculating, and analyzing the collected data to generate relevant charts and reports to provide data support for experimental research. 9. Alarm system: When the monitored parameters exceed the set safety range or normal range, an alarm signal is issued to remind the operator to take measures. 10. Control system interface: Connecting to the control system of the experimental platform to realize the interaction of monitoring data and control instructions, so as to adjust and control the experimental platform according to the monitoring results. Through this set of monitoring systems, the operating characteristics and laws of the shield circulation system can be understood more deeply, providing a scientific basis for the improvement and optimization of shield tunneling construction technology. Geological particle feeding and control system: 1. Particle storage container: Used to store geological particles to be fed. The size and capacity of the container are designed according to specific requirements. 2. Conveyor mechanism transports the particles from the storage container to the feeding port. 3. Feeding port: Controls the position and direction of particle feeding.Control system: It includes sensors, controllers, and actuators, and is used to monitor and control the speed, quantity, and timing of the delivery. At the same time, tracer particles are delivered to a specific area to track the path and speed of the muddy water movement. According to the specific geological conditions and the properties of the particles, the accuracy and effectiveness of the delivery are ensured. The geological particle delivery system is a system device for accurately delivering particles in a specific geological and engineering application environment.

[0022] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0023] In existing extra-large diameter slurry shields, the cut blocks and particulate matters re-aggregate under the influence of factors such as adhesion force, pressure, and turbulent flow, and sediment adsorption occurs. Usually, large-diameter direct drainage pipelines are set in the slurry sump of the front shield of the shield equipment. The slurry specific gravity parameter is coordinated with a large flow rate to carry the slag, and it is transferred from the slurry sump into the large-diameter direct drainage pipeline and then sent out of the working surface through a pipeline pump. However, with the change of the geological layer, and the tunnel also passes through multiple fault fracture zones with many joints, fractures, and large water content and other complex working conditions. Due to the high-pressure and invisible environment during the normal operation of the slurry circulation construction, and the extremely complex geological conditions, it is impossible to directly and completely reflect the movement and accumulation of the muck excavated during tunneling in the chamber. At the same time, the slurry circulation stagnation and drainage often occur. And once the stagnation and drainage occur, it is often necessary to open the chamber for maintenance under good formation conditions, which is not only inconvenient to operate but also has a high construction risk. In addition, it has a greater impact on the construction period and other deficiencies. And the present application solves various deficiencies of the existing structure through the overall design of the slurry balance shield circulation scale-down experimental equipment under the simulated large-diameter shield working conditions. After adopting the slurry balance shield circulation scale-down experimental equipment under the simulated large-diameter shield working conditions, the experimental equipment can simulate the turbulent flow of the solid-liquid two-phase flow in the slurry pressure chamber when the cutter head rotates, and generate the conveying characteristics of the limit settling velocity of the rock slag and clay generated under different geological conditions in the turbulent flow environment of the solid-liquid two-phase flow. It can obtain the boundary effect in the rectangular chamber pressure mode, master the law of sediment deposition and stagnation and drainage inside the slurry sump. At the same time, through the corresponding visible cabin plate, it realizes the dynamic monitoring of the movement characteristics, deposition rate, and pipeline resistance characteristics of the rock slag and clay in the slurry pressure chamber, the movement discharge port, and the pipeline part in the turbulent flow of the solid-liquid two-phase flow. Therefore, on the one hand, based on the slurry balance shield circulation formed by the simulation experiment, the present invention can determine the safe transportation speed of the particulate matters in the slurry pipeline during the propulsion rate of the extra-large shield in different geological environments, so as to guide the actual shield, reduce the probability of slurry circulation stagnation and drainage, and further reduce the secondary wear of the peripheral cutters caused by more accumulated slag at the bottom. At the same time, the model experiment can observe the accumulated slag situation at the bottom through the visualization window, visually observe the accumulated slag at the bottom of the cutter head slurry sump under different modes, quantitatively calculate and evaluate the accumulated slag ratio, and find a supporting basis for further studying the contribution of the accumulated slag at the bottom to the wear of the peripheral cutters; on the other hand, study the experimental parameter scale-down restart state for the experimental characteristics of conditions such as the diameter of the particulate matters generated by different geological conditions and the decreasing or increasing mode of the block stage, etc., to provide continuous synchronous ability for the continuous classification of geological particulate matters and block scale-down experiments. Brief Description of the Drawings

[0024] The following further describes the present invention in detail with reference to the drawings and specific embodiments:

[0025] Figure 1 The front view schematic diagram of the slurry balance shield circulation scale-down experimental equipment for Embodiment 1;

[0026] Figure 2Front view schematic diagram of the slurry balance shield circulation scaled - down experimental equipment for Example 2;

[0027] Figure 3 Front view schematic diagram of the slurry balance shield circulation scaled - down experimental equipment for Example 3;

[0028] Wherein: 1. Experimental chamber; 10. Gate plate; 11. Visual observation hole; 1a. Slurry chamber; 1b. Air cushion chamber; 2. Simulated cutter head stirring system; 20. Stirring shaft; 21. Stirring paddle; 210. Stirring ring; 211. Stirring blade; 22. Power unit; 3. Circulation system; 30. Slurry discharge pipeline assembly; 300. Self - discharge pipeline; 31. Inlet slurry pipeline assembly; 310. Inlet slurry main pipe; 311. Inlet slurry pump; 312. First inlet slurry branch pipe; 313. Second inlet slurry branch pipe; 32. Mud treatment unit; 320. Mud sieve; a. Feeding sieve; b. Particle size distribution screening assembly; c. Discharge hopper; 321. Mud processor; 33. Screw feeder; 34. Transfer bin; p. Discharge pipeline. Detailed implementation manners

[0029] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] In the present invention, unless otherwise clearly defined or limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the invention, unless otherwise clearly defined or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath", and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature is at a lower horizontal level than the second feature.

[0034] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0035] Embodiment 1

[0036] As Figure 1 shown, the scaled-down experimental equipment for slurry balance shield circulation under the condition of simulating large-diameter shield in this embodiment includes an experimental chamber 1, a simulated cutter head stirring system 2, and a circulation system 3.

[0037] Specifically, the internal sealed pressure of the experimental chamber 1 is 6 bar, and the slurry condition formed by the simulated large-diameter shield is simulated inside the chamber. The experimental chamber 1 includes a slurry chamber 1a and an air cushion chamber 1b arranged front and back, which are separated by a gate plate 10 extending from the top to the bottom. A confluence port is formed between the bottom of the gate plate 10 and the bottom wall of the experimental chamber 1. The slurry chamber 1a and the air cushion chamber 1b are communicated with each other through the confluence port, and visual observation holes 11 are provided on the bottom side walls of the slurry chamber 1a and / or the air cushion chamber 1b.

[0038] In this example, the experimental chamber 1 is a rectangular pressure chamber. Briefly, the rectangular pressure-balanced air-cushion slurry chamber is converted from the original circular shape to a square shape, combined with the simulated cutterhead stirring inside the chamber, forming a complete widened boundary space. The incoming slurry, rock debris, and clay rotate with the cutterhead in the rectangular pressure chamber, and the fluid flows towards the slag discharge port. The flowing sediment and adsorbed and aggregated particulate matter, in the rectangular state, based on the visual observation hole, the deposition and dispersion law of particulate matter outside the circular rotation range of rock debris and clay can be observed, while reducing the probability of circulating stagnation and discharge. The gate 10 is parallel to the bottom wall, and the distance between the two is 1 / 12 to 1 / 8 of the downward extension length of the gate 10 (generally, the value is 1 / 10). Based on the chamber conditions simulated by the gate 10, it is relatively close to the large-diameter shield conditions, so as to guide the slurry balance shield circulation according to the experimental results and reduce the incidence of circulating stagnation and discharge.

[0039] The simulated cutterhead stirring system 2 is located inside the air-cushion chamber 1b and rotates around the front-back direction to form a moving stirring. In this example, the simulated cutterhead stirring system 2 includes a stirring shaft 20 extending along the front-back direction, stirring paddles 21 installed on the stirring shaft 20, and a power device 22 (conventional motor or electric motor) that drives the stirring shaft 20 to rotate self-reliantly. Based on the moving stirring formed by the simulated cutterhead stirring system, the slurry inside the chamber rotates with the cutterhead under the simulated tunneling mode, realizing the restoration of the operation actions, restoring the movement characteristics of the slurry, rock debris, clay, and slurry in the solid-liquid two-phase flow turbulence inside the slurry chamber, and participating in the in-kind evolution of the flowing sediment, adsorption and aggregation, and complete movement actions of the incoming slurry, rock debris, and clay in the pressure chamber under the rotation of the cutterhead structure for different geological particulate matters. The stirring paddle 21 includes a stirring ring 210 fixed on the stirring shaft 20 and multiple groups of stirring blades 211 circumferentially distributed around the stirring ring 210. Among them, the stirring ring 210 is concentric with the stirring shaft 20, and the multiple groups of stirring blades 211 are located on the same side of the stirring ring 210. The stirring ring 210 is relatively close to the gate 10, and the stirring blades 211 extend backward. Generally, there are 6 groups of fan blades for the stirring blades, which are fixed on the stirring ring 210 by welding. The overall diameter of the cutterhead is about 2m, and the stirring shaft 20 is connected to the cutterhead rotation motor to drive the cutterhead to rotate. Further, the bottom of the stirring paddle 21 is close to the bottom wall of the experimental chamber 1, and the stirring area is partially aligned with the confluence port. Generally, the bottom of the stirring paddle 21 maintains a distance of 10 cm from the chamber wall, as long as there is no phenomenon of stirring jamming.

[0040] The circulation system 3 includes a slurry discharge pipeline assembly 30, a slurry inlet pipeline assembly 31, and a mud processing unit 32, wherein the mud processing unit 32 includes a mud screener 320 and a mud processor 321, the slurry discharge pipeline assembly 30 is connected to the mud and water bin 1a, the mud screener 320 is used for multi-stage screening of particles in the mud, the mud processor 321 is connected to the mud and water outlet of the mud screener 320, and is based on the mud and water separation and screening treatment to form mud and water with a specific gravity and viscosity that meet the experimental requirements; the slurry inlet pipeline assembly 31 is connected to the mud and water outlet of the mud processor 321, and based on flow control, it flows back to the mud and water bin and the air cushion bin respectively to form a mud balance shield circulation.

[0041] The slurry discharge pipeline assembly 30 includes a self-draining pipeline 300 connected to the mud and water bin 1a, wherein the self-draining pipeline 300 is aligned with the confluence, and discharges the mud and water mixture to the mud screener based on the pressure of the experimental bin 1. In short, the mud and water mixture with no direction and irregular movement, mixed between fluid particles, and parameters such as velocity and pressure with random changes in time and space is led to the slurry discharge main pipeline through a pipeline, and the inertial gravity generated by the flow velocity of the pipeline body and the mud in the pressure bin impact the mud and water in the bin, keep the mud and water moving to the discharge port, and the straight discharge pipeline discharges the slurry to form an attraction and entanglement, and the mud and water mixture connected to the mud and water bin is discharged, forming a self-adaptive same-diameter self-discharge mechanism.

[0042] The slurry inlet pipeline assembly 31 includes a slurry inlet main pipe 310 connected to the mud and water outlet of the mud processor 321, a slurry inlet pump 311 installed on the slurry inlet main pipe 310, a first slurry inlet branch pipe 312 and a second slurry inlet branch pipe 313 connected to the slurry inlet main pipe 310 and respectively connected to the mud and water bin 1a and the air cushion bin 1b, wherein the connecting end of the first slurry inlet branch pipe 312 is located at the top of the mud and water bin 1a; the connecting end of the second slurry inlet branch pipe 313 is located on the side wall of the air cushion bin 1b and facing the simulated knife disc mixing system 2.

[0043] The mud sieve 320 includes a feeding sieve a, a particle size grading and screening assembly b, and a discharging hopper c. Among them, the mud-water mixture discharged from the mud-water sump 1a is subjected to solid-liquid separation from top to bottom. Briefly speaking, the mud sieve consists of a three-layer structure. The upper part of the top layer structure is a screen (feeding sieve), which mainly intercepts large-particle-size fixed particles; the particle size grading and screening assembly mainly conducts grading and screening based on the components in the mud-water to complete solid-liquid separation; the discharging hopper guides the separated mud-water into the mud processor below, and at the same time removes the screened solid particles through cleaning. The mud purifier 321 (a product purchased externally in the market) separates the mud through receiving vibration screening, removes impurities and useless particles, makes the performance of the mud meet the experimental specific gravity and viscosity requirements, provides stable and high-quality mud, and reduces experimental errors and failures caused by mud problems. It realizes the recycling of mud, reduces the preparation amount of new mud, and ensures the smooth progress of the experiment. The mud purification system of the shield circulation experiment platform is mainly used to process and purify the mud used in shield construction to ensure the performance and reuse of the mud and environmental protection.

[0044] In addition, the control system: 1. Mud transportation demand monitoring: Real-time monitoring of parameters such as mud flow rate, pressure, and concentration during shield tunneling construction through sensors to determine the current transportation demand. 2. Control signal generation: Comparing the monitored parameters with the preset working indicators, the control system generates corresponding control signals. 3. Speed control of the pump: Controlling the rotation speed of the mud pump to adjust the transportation flow rate and pressure of the mud. For example, when the flow rate is insufficient, increase the pump speed; conversely, decrease the speed. 4. Valve adjustment: Adjusting the flow direction and flow rate distribution of the mud by controlling the valve opening degree on the pipeline to ensure that each working area receives appropriate mud supply. 5. Pressure balance control: Maintaining the pressure balance in the pipeline to prevent pipeline damage or unsmooth mud transportation caused by excessive or too low pressure. 6. Feedback and correction: Continuously receiving new monitoring data and correcting and optimizing the control signals according to the actual operating conditions to achieve precise and stable control of the mud pipeline. 7. Fault monitoring and protection: Real-time monitoring of the operating status of the system. Once a fault is detected, such as pump overload, pipeline blockage, etc., take protection measures in a timely manner, stop the operation of relevant equipment and issue an alarm. It consists of a control electrical box and the electrical equipment circuits of each system. The circuits of each system are connected to the main control electrical box, and electrical appliances, circuit breakers, relays, contactors, etc. required for each system are installed in the electrical box. Monitoring system: 1. Flow monitoring: Measuring the flow rate of mud, muck, etc. in the circulation system using a flowmeter. 2. Pressure monitoring: Monitoring the pressure at different positions in the circulation pipeline through pressure sensors, including inlet pressure, outlet pressure, local pressure, etc. 3. Concentration monitoring: Measuring the concentration of solid particles in the circulation using a concentration meter to understand the transportation situation of the muck. 4. Temperature monitoring: Monitoring the temperature of key parts in the circulation system to prevent overheating. 5. Speed monitoring: The rotation speed of the circulation pump, etc. 6. Image monitoring: Using a camera to collect real-time images of key parts of the experimental platform to visually observe the phenomena during the experimental process. 7. Data acquisition and transmission: Transmitting the data collected by various sensors to the data processing center in real time. 8. Data processing and analysis: Processing, calculating, and analyzing the collected data to generate relevant charts and reports to provide data support for experimental research. 9. Alarm system: When the monitored parameters exceed the set safety range or normal range, an alarm signal is issued to remind the operator to take measures. 10. Control system interface: Connecting to the control system of the experimental platform to realize the interaction of monitoring data and control instructions, so as to adjust and control the experimental platform according to the monitoring results. Through this set of monitoring systems, the operating characteristics and laws of the shield circulation system can be understood more deeply, providing a scientific basis for the improvement and optimization of shield tunneling construction technology. Geological particle feeding and control system: 1. Particle storage container: Used to store geological particles to be fed, and the size and capacity of the container are designed according to specific requirements. 2. Conveyor mechanism transports the particles from the storage container to the feeding port. 3. Feeding port: Controls the position and direction of particle feeding.Control system: It includes sensors, controllers, and actuators, and is used to monitor and control the speed, quantity, and timing of the delivery. Meanwhile, tracer particles are delivered to a specific area to track the path and speed of the muddy water movement. According to the specific geological conditions and the properties of the particles, the accuracy and effectiveness of the delivery are ensured. The geological particle delivery system is a system device for accurately delivering particles in a specific geological and engineering application environment.

[0045] Embodiment 2

[0046] As Figure 2 shown, the reduced-scale experimental equipment for slurry balance shield circulation under simulated large-diameter shield working conditions in this embodiment includes an experimental chamber 1, a simulated cutterhead stirring system 2, and a circulation system 3. The structures of the experimental chamber 1 and the simulated cutterhead stirring system 2 are the same as those in Embodiment 1, and the difference lies in the circulation system 3.

[0047] Specifically, the circulation system 3 includes a slurry discharge pipeline assembly 30, a slurry inlet pipeline assembly 31, and a slurry treatment unit 32. The structures of the slurry inlet pipeline assembly 31 and the slurry treatment unit 32 are the same as those in Embodiment 1. Compared with Embodiment 1, the slurry discharge pipeline assembly 30 is replaced by a screw feeder.

[0048] In this example, the feeding end of the screw feeder is inserted into the confluence port from the side wall of the air cushion chamber 1b, and the discharging end forms a transfer chamber 34. The transfer chamber 34 is connected to the slurry discharge pipeline p. Specifically, the slurry can be precipitated in the transfer chamber 34, and the slurry is sent into the slurry screening device 320 by means of the slurry discharge pipeline p and pumping. After the experiment is completed, the transfer chamber 34 can be cleaned of particles. In short, once the direct discharge method in Embodiment 1 cannot meet the simulation experiment under the current working conditions, the short-screw spiral feeding method can be used for discharging to meet the needs of different working conditions.

[0049] Embodiment 3

[0050] As Figure 3 shown, the reduced-scale experimental equipment for slurry balance shield circulation under simulated large-diameter shield working conditions in this embodiment includes an experimental chamber 1, a simulated cutterhead stirring system 2, and a circulation system 3. The structures of the experimental chamber 1 and the simulated cutterhead stirring system 2 are the same as those in Embodiment 1, and the difference lies in the circulation system 3.

[0051] Specifically, the circulation system 3 includes a slurry discharge pipeline assembly 30, a slurry inlet pipeline assembly 31, a slurry treatment unit 32, and a screw feeder 33. The structures of the slurry discharge pipeline assembly 30, the slurry inlet pipeline assembly 31, and the slurry treatment unit 32 are the same as those in Embodiment 1. Compared with Embodiment 1, the circulation system 3 is additionally provided with a screw feeder 33 (briefly, the screw feeder 33 and the slurry discharge pipeline assembly 30 are arranged side by side in the scheme, that is, the two implementation modes are arranged simultaneously, and the experiment can be carried out in a way of choosing one of them). The specific structure is as follows.

[0052] In this example, the feeding end of the screw feeder 33 is inserted into the confluence port from the side wall of the air cushion bin 1b, and the discharging end forms a transfer bin 34, and the transfer bin 34 is communicated with the slurry discharge pipeline assembly 30. Specifically, the slurry can be precipitated in the transfer bin 34, and the slurry is communicated with the self-discharge pipeline 300 through a pipeline or pumping and then sent to the slurry screening device 320 for screening. After the experiment is completed, the particles in the transfer bin 34 can be cleaned.

[0053] In summary, after adopting the slurry balance shield circulation scale experiment equipment for simulating large-diameter, large-diameter shield, and super-large-diameter shield working conditions, this experimental equipment can simulate the turbulence of the solid-liquid two-phase flow in the slurry pressure chamber with the participation of the cutter head rotation, and generate the transportation characteristics of the limit settling velocity of rock slag and clay produced under different geological conditions in the turbulent environment of the solid-liquid two-phase flow. It can obtain the boundary effect in the rectangular chamber pressure mode, master the law of sedimentation and stagnant discharge inside the slurry chamber. At the same time, through the corresponding visible chamber plates, it can realize the dynamic monitoring of the movement characteristics, sedimentation rate, and pipeline resistance characteristics of rock slag and clay in the slurry pressure chamber, the migration discharge outlet, and the pipeline part in the turbulent flow of the solid-liquid two-phase flow. Therefore, on the one hand, based on the slurry balance shield circulation formed by the simulation experiment, this invention can determine the safe migration speed of particulate matter in the slurry pipeline during the propulsion rate of super-large shields in different geological environments, so as to guide the actual shield, reduce the probability of circulation stagnant discharge, and further reduce the secondary wear of peripheral cutters caused by more accumulated slag at the bottom. At the same time, the model experiment can observe the accumulated slag situation at the bottom through the visualization window, visually observe the accumulated slag at the bottom of the cutter head slurry chamber under different modes, quantitatively calculate and evaluate the accumulated slag ratio, and find a supporting basis for further studying the contribution of the accumulated slag at the bottom to the wear of peripheral cutters; on the other hand, it studies the experimental characteristics of the scale restart state of experimental parameters for different geological conditions such as the decreasing or increasing mode of the diameter and block stage of particulate matter, providing continuous synchronization ability for continuous classification of geological particulate matter and block scale experiments; thirdly, based on the slurry balance circulation boundary experiment platform under the geological environment of equal-condition tunneling, by setting the model selection experiment of the air-cushioned slurry shield machine and the direct-discharge slurry shield machine with a screw conveyor, the migration law of particle-size solids and sticky blocks in the slurry chamber is used to carry out the internal circulation migration of different specific gravity slurries in different geological slurry chambers, forming empirical boundary data of the slurry balance system; fourthly, the circulation system consists of a slurry inlet pipeline and a slurry discharge pipeline. The slurry inlet pipeline is connected to a slurry pump, and the slurry and the fed slag enter the slurry chamber and the air-cushioned chamber through the slurry pump. The slurry discharge pipeline is divided into two types. One type is that the rectangular slurry chamber is connected to the screw conveyor and then connected to the discharge pipeline to the screening system, and the other type is that the rectangular slurry chamber is connected to the direct-discharge pipeline and connected to the main discharge pipeline. That is, this experimental equipment can simulate the turbulence of the solid-liquid two-phase flow in the slurry pressure chamber with the participation of the cutter head rotation, generate the transportation characteristics of the limit settling velocity of rock slag and clay produced under different geological conditions in the turbulent environment of the solid-liquid two-phase flow, obtain the boundary effect in the rectangular chamber pressure mode, master the law of sedimentation and stagnant discharge inside the slurry chamber, and can study the two-phase flow transportation characteristics with two pipeline transportation systems of direct discharge and short screw.By corresponding visual bulkheads, sensors, and flow meters, dynamic monitoring of the movement characteristics, deposition rate, and pipeline resistance characteristics of rock slag and clay in the mud pressure chamber, transportation and discharge outlets, and pipeline parts under the turbulent flow of solid-liquid two-phase flow is realized; secondly, determine the safe transportation speed of particulate matter in the mud pipeline generated by the advancing speed of the super-large shield in different geological environments, and the matching support basis for the use of the two transportation interfaces of direct discharge and short spiral in the shield machine facing different geological conditions. Establish the best pipeline transportation experimental function, and also study the experimental characteristics of the scale-down restart state of experimental parameters on the diameter of particulate matter and the decreasing or increasing mode of the block stage generated in different geological conditions, providing continuous synchronous capabilities for continuous classification of geological particulate matter and block scale-down experiments; fifthly, as the pressure increases with depth, the rotation and agitation of the shield cutter head and the energy consumption of the circulation slag carrying cause the deep-earth and deep-sea shields to operate in cycles. Through the shield circulation experimental chamber, the underground high-pressure space area that cannot be seen or touched by current domestic shield technologies is covered by large-diameter shields in various complex geological conditions. Under the pressure of the muck and mud mixture generated by the shield, the shield circulation experimental chamber is composed of an air-cushion chamber and a mud chamber, with a high-pressure resistance of 6Bar. Through scale-down model design, the application of the current world-leading shield equipment technology is verified experimentally, and the technical difficulties of deep-sea and deep-earth shields are tackled with a complete set of experimental technologies. Study the operation experience models of slurry shields and earth pressure shields, and deeply explore the shield equipment in the case of large-diameter coverage of complex geological environments. During the experiment, different geological and combined geological representative proportion block particulate matters are put into the experimental device, and theoretical and applied technical research on the movement characteristics of shield circulation rock slag particulate matter in the air-cushion type slurry circulation system and the short spiral slurry circulation system is carried out. During the experiment, the switching between the shield air-cushion type slurry circulation system and the short spiral slurry circulation system is carried out for the same geological conditions in two modes for the slurry pressure particle circulation slag-carrying experiment. Through unique design monitoring, observe the turbulent flow effect of the shield core mud chamber and Newton's theory, and under the support of the pressure fusion combination effect, simulate the research blank of the current world's large-diameter shield technology. Compare the energy efficiency of the two slag-carrying modes of the shield equipment, and develop the feasibility support for improving the equipment technology through performance experiments. Facing the different and long-distance complex invisible geological conditions of deep-sea and deep-earth, and due to space limitations, current scientific research scholars and shield equipment design, manufacturing, and production parties only make extended technical solutions for the emerging situations. At present, shield equipment does not have the ability to switch between the air-cushion type slurry circulation system and the short spiral slurry circulation system at the same time. For large-diameter or even large-diameter and super-large-diameter shield equipment encountering complex geological conditions, provide an optional solution for how to safely improve the shield efficiency and save energy, and enhance practicality.

[0054] The above has described the present invention in detail, aiming to enable those skilled in the art to understand the content of the present invention and implement it. However, this should not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A scaled experimental device for slurry balance shield circulation under the condition of simulating large-diameter shield working conditions, characterized in that, It includes: An experimental chamber with a sealed pressure inside the chamber of at least 6 bar, and simulating the mud working conditions formed by large-diameter shield tunneling machines and super-large-diameter shield tunneling machines. The experimental chamber includes a slurry chamber and an air-cushion chamber formed by partitioning with a gate plate extending from the top to the bottom in a front-back layout. A confluence port is formed between the bottom of the gate plate and the bottom wall of the experimental chamber. The slurry chamber and the air-cushion chamber are connected through the confluence port, and visual observation holes are provided on the bottom side walls of the slurry chamber and / or the air-cushion chamber; A simulated cutterhead stirring system located inside the air-cushion chamber and rotating around the front-back direction to form a moving stirring; A circulation system including a slurry discharge pipeline assembly, a slurry inlet pipeline assembly, and a mud treatment unit. The mud treatment unit includes a mud screen and a mud processor. The slurry discharge pipeline assembly is connected to the slurry chamber. The mud screen is used for multi-stage screening of particles in the mud. The mud processor is connected to the mud outlet of the mud screen and separates and screens the mud and water to form mud and water with a specific gravity and viscosity meeting the experimental requirements. The slurry inlet pipeline assembly is connected to the mud outlet of the mud processor and respectively returns to the slurry chamber and the air-cushion chamber based on flow control to constitute a mud balance shield circulation.

2. The slurry balance shield circulation scale experiment device for simulating the working conditions of a large-diameter shield according to claim 1, wherein The experimental chamber is a rectangular pressure chamber.

3. The slurry balance shield circulation scale experiment device under the condition of simulating large-diameter shield working conditions according to claim 2, characterized in that, The gate plate is parallel to the bottom wall, and the distance between them is 1 / 12 to 1 / 8 of the downward extension length of the gate plate.

4. The slurry balance shield circulation scale experiment device for simulating the working conditions of a large-diameter shield as described in claim 1, characterized in that The simulated cutterhead stirring system includes a stirring shaft extending along the front-back direction, stirring paddles installed on the stirring shaft, and a power unit driving the stirring shaft to rotate self.

5. The slurry balance shield circulation scale experiment device under the condition of simulating large-diameter shield working conditions according to claim 4, characterized in that, The stirring paddle includes a stirring ring fixed on the stirring shaft and multiple groups of stirring blades circumferentially distributed around the stirring ring. The stirring ring is concentric with the stirring shaft, and multiple groups of stirring blades are located on the same side of the stirring ring.

6. The slurry balance shield circulation scale experiment device under the condition of simulating large-diameter shield working conditions according to claim 5, characterized in that The bottom of the stirring paddle is close to the bottom wall of the experimental chamber, and the stirring area is partially aligned with the confluence port.

7. The slurry balance shield circulation scale experiment device for simulating the working conditions of a large-diameter shield according to claim 1, characterized in that, The slurry discharge pipeline assembly includes a self-discharge pipeline connected to the slurry chamber. The self-discharge pipeline is aligned with the confluence port and discharges the mud and water mixture to the mud screen based on the pressure of the experimental chamber.

8. The slurry balance shield circulation scale experiment equipment for simulating the working conditions of large-diameter shield tunneling according to claim 1, characterized in that The mud screen includes a feeding screen, a particle size grading and screening assembly, and a discharging hopper. The mud and water mixture discharged from the slurry chamber is separated from solid to liquid from top to bottom.

9. The full - scale experimental equipment for slurry balance shield circulation under the condition of simulating large - diameter shield working conditions according to claim 1, characterized in that, The slurry inlet pipeline assembly includes a main slurry inlet pipe connected to the mud outlet of the mud processor, a slurry inlet pump installed on the main slurry inlet pipe, a first slurry inlet branch pipe and a second slurry inlet branch pipe connected to the main slurry inlet pipe and respectively connected to the slurry chamber and the air-cushion chamber. The connection end of the first slurry inlet branch pipe is located at the top of the slurry chamber; the connection end of the second slurry inlet branch pipe is located on the side wall of the air-cushion chamber and is directly opposite to the simulated cutterhead stirring system.

10. The full - scale experimental equipment for slurry balance shield circulation under the condition of simulating large - diameter shield tunneling according to any one of claims 1 to 9, characterized in that, The circulation system further includes a screw feeder. The feeding end of the screw feeder inserts from the side wall of the air-cushion chamber towards the confluence port, and the discharging end forms a transfer bin, and the transfer bin is connected to the slurry discharge pipeline assembly.

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