A slurry treatment system and treatment control method for a small slurry mode earth pressure balance shield

Abstract

This invention provides a slurry recovery system and control method for a small-scale slurry-mode earth pressure balance shield tunneling machine. The system includes a homogenization receiving unit, a circulating desanding unit, a detection unit, a slurry storage unit, a quantitative compensation unit, and a reinjection unit. The homogenization receiving unit receives and homogenizes the separated slurry; the circulating desanding unit removes sand from the homogenized slurry; and the detection unit performs performance testing on the desanded slurry. The qualified slurry storage tank in the slurry storage unit stores slurry with a test result indicating level one, while the waste slurry storage tank stores slurry with a test result indicating level three. The quantitative compensation unit adds a quantitative target solution to the homogenization receiving unit when the performance test result indicates level two. The reinjection unit reinjects the slurry from the qualified slurry storage tank into the target injection site. This invention enables refined recycling and reuse of the recovered slurry.

Description

Technical Field

[0001] This invention relates to the field of resource utilization technology for tunnel boring machine (TBM) slurry, and more specifically, to a slurry recovery treatment system and treatment control method for earth pressure balance TBMs operating in a small slurry mode. Background Technology

[0002] Earth pressure balance (EPB) tunnel boring machines (TBMs) typically rely on the plasticity of the modified excavated soil within the soil chamber, the soil chamber pressure, and the soil plug effect formed within the screw conveyor to balance the water and soil pressure at the tunnel face. With the increasing number of underground tunnels in coastal areas, river-sea confluence zones, and areas with high groundwater levels, TBMs are more frequently traversing water-rich sand layers, weathered rock fissure zones, and composite strata with soft upper layers and hard lower layers. When groundwater recharge is rapid, the strata lack fine particles, or the excavated soil is insufficient to form a low-permeability soil plug, the moisture content of the excavated soil discharged by the screw conveyor increases significantly, leading to fluctuations in soil chamber pressure and potential risks of jetting, excavation leakage, and tunnel face instability.

[0003] The small-scale slurry-water earth pressure balance shield tunneling method involves retaining the cutterhead, soil chamber, screw conveyor, and belt conveyor slag removal system. Bentonite slurry is injected into the soil chamber through the existing bentonite system, an upper injection port, or an external air cushion chamber, creating a low-permeability support medium that combines the bentonite slurry with the excavated soil. The existing equipment in the project has a maximum working pressure of approximately 0.30 MPa and a design pressure of approximately 0.50 MPa in the soil chamber; the existing bentonite hose pump has a rated flow rate of approximately 16 m³ / h and a maximum working pressure of approximately 1.60 MPa; and the existing bentonite storage tank has an effective volume of approximately 6 m³. This method enhances the pressure regulation capacity in water-rich strata, but the injected bentonite will enter the screw conveyor discharge along with groundwater, fine particles of the original soil, and residual foaming agent.

[0004] After installing an in-tunnel solid-liquid separation device at the tail end of the screw conveyor, plug pipe, or belt conveyor, the oversize slag and undersize slurry can be separated. This upstream device addresses the issues of slag leakage, wet slag transportation, and preliminary solid-liquid separation within the tunnel. Its endpoint is usually the collection of undersize slurry into pipelines or storage tanks. Undersize slurry may still contain sand, groundwater, foaming agent residue, salt, cement slurry, or grease contaminants. The slurry's density, apparent viscosity, sand content, filtration performance, pH value, and conductivity will also vary with the formation and construction time. Therefore, "liquid has been screened out" does not equate to "reinjectable quality has been achieved."

[0005] Traditional slurry shield tunneling slurry circulation stations handle large-flow, stable circulating slurry within inlet and outlet pipes. These stations are typically located on the ground and utilize vibrating screens, hydrocyclones, thickeners, and slurry conditioning equipment to maintain complete slurry circulation. Small-scale slurry shield tunneling with earth pressure balance (EPB) does not have this same inlet and outlet slurry circulation. Instead, it recovers fluctuating slurry separated from slurry-containing soil, reinjecting it into the shield's existing bentonite pipes, external air cushion chambers, or local injection points within the soil chamber. Simply scaling down a traditional ground-based slurry station and placing it on the shield tunneling trolley presents limitations such as rear support capacity, installation width on the same side of the trolley, maintenance space, batch remixing, and inconsistent interfaces. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a slurry recovery treatment system and treatment control method for earth pressure balance shield tunneling in small slurry mode, so as to realize closed-loop feedback control treatment of slurry recovery in batches, homogenization, fine sand removal, detection and classification, quantitative compensation, qualified isolation and selective reinjection, thereby improving slurry utilization rate and reducing the preparation cost of new slurry such as bentonite during tunneling.

[0007] To address the aforementioned technical problems, embodiments of the present invention provide a slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine, comprising:

[0008] The homogenizing receiving unit is connected to the upstream slurry outlet of the solid-liquid separation system for water-bearing slag in the tunnel boring machine, and is used to receive and homogenize the separated slurry; the homogenizing receiving unit includes at least two receiving tanks arranged in parallel.

[0009] The circulating desanding unit is connected to the homogenizing receiving unit and is used to desand the homogenized slurry and transport the desanded slurry back to the corresponding receiving tank.

[0010] The detection unit is set in the circulation loop between the circulating desanding unit and the homogenizing receiving unit, and is used to perform performance testing on the slurry after desanding.

[0011] The slurry storage unit includes a qualified slurry storage tank and a waste slurry storage tank. Both the qualified slurry storage tank and the waste slurry storage tank are connected to the homogenization receiving unit. The qualified slurry storage tank is used to store slurry with a performance test result indicating level 1, and the waste slurry storage tank is used to store slurry with a performance test result indicating level 3.

[0012] A quantitative compensation unit, connected to the homogenization receiving unit, is used to add a quantitative target solution to the homogenization receiving unit when the performance test result indicates level two; and

[0013] The reinjection unit is connected at one end to the qualified slurry storage tank and at the other end to at least one injection target; it is used to reinject the slurry in the qualified slurry storage tank into the target injection target when both the slurry index and the soil pressure index are met.

[0014] In one embodiment, at least two receiving tanks include a first receiving tank and a second receiving tank, both of which are arranged longitudinally along the tunnel between existing I-beams of the same side trolley, and are arranged side by side; and / or

[0015] The tops of the first receiving tank and the second receiving tank are each equipped with a receiving port, a sand removal return port, a detection return port, and a compensation port. The receiving port is connected to the upstream slurry outlet via a receiving pipe. The sand removal return port is connected to the top overflow port of the circulating sand removal unit via a top overflow pipe. The detection return port is connected to the detection unit via a detection return pipe. The compensation port is connected to the output terminal of the quantitative compensation unit via a compensation return pipe; and / or

[0016] Both the first receiving tank and the second receiving tank are provided with side overflow ports, which are connected to the inlet of the waste slurry storage tank via safety overflow pipes; and / or

[0017] The bottom of the first receiving tank and the bottom of the second receiving tank are provided with a tank body slurry outlet and a sand discharge outlet. The tank body slurry outlets are respectively connected to the side inlet of the circulating sand removal unit, the inlet of the qualified slurry storage tank, and the inlet of the waste slurry storage tank through slurry outlet pipes. The sand discharge outlets are connected to the waste slurry storage tank through sand discharge pipes.

[0018] In one embodiment, the circulating sand removal unit includes,

[0019] A circulation pump, wherein the circulation pump is mounted on the slurry outlet pipe;

[0020] A hydrocyclone is disposed at the discharge end of the circulating pump, and the side inlet of the hydrocyclone is connected to the discharge end of the circulating pump through a main feed pipe. A top overflow port is provided at the top of the hydrocyclone.

[0021] An underflow collection box is located at the bottom of the hydrocyclone and is connected to the underflow port at the bottom of the hydrocyclone.

[0022] In one embodiment, the detection reflux tube includes:

[0023] The first detection return pipe has one end connected to the overflow port at the top of the circulating sand removal unit and the other end connected to the detection return port; and

[0024] The second detection return pipe has one end connected to the overflow port at the top of the circulating sand removal unit, and the other end connected to the detection return port.

[0025] In one embodiment, the detection unit includes;

[0026] The first detection unit, installed on the first detection return pipe, is used to continuously detect the density, temperature, conductivity, pH, and apparent viscosity of the slurry after sand removal; and

[0027] The second detection unit, located on the second detection return pipe, is used to periodically detect the sand content of the desanding slurry and the API filtration loss.

[0028] In one embodiment, the first detection unit includes a detection shut-off valve, a circulating sampling pump, a densitometer, a temperature sensor, a conductivity sensor, a pH sensor, an apparent viscometer, a transparent flow cup, and a detection reflux valve arranged along the first detection reflux pipeline. The detection shut-off valve is located near the top overflow port, and the detection reflux valve is located near the detection reflux port.

[0029] In one embodiment, the second detection unit includes a detection sampling valve, a Marsh funnel interface, a mud hydrometer interface, a sand content detection interface, and an API filtration loss detection interface arranged sequentially along the second detection reflux pipe.

[0030] In one embodiment, the slurry outlet pipe includes:

[0031] The main slurry outlet pipe is connected at one end to the slurry outlet.

[0032] The first slurry outlet branch pipe has one end connected to the other end of the slurry outlet main pipe and the other end connected to the side inlet of the circulating sand removal unit, and a slurry outlet valve is provided on the first slurry outlet branch pipe.

[0033] The second slurry outlet branch pipe has one end connected to the other end of the main slurry outlet pipe and the other end connected to the inlet of the qualified slurry storage tank, and a direct reuse valve is installed on the second slurry outlet branch pipe; and

[0034] The third slurry outlet branch pipe has one end connected to the other end of the main slurry outlet pipe and the other end connected to the inlet of the waste slurry storage tank. The third slurry outlet branch pipe is equipped with a non-reusable valve.

[0035] In one embodiment, the quantitative compensation unit includes:

[0036] The mixer's output is connected to one end of the compensation return pipe;

[0037] The first compensation branch is connected at one end to the input end of the mixer and at the other end to the external first feeding unit;

[0038] The second compensation branch has one end connected to the input terminal of the mixer and the other end connected to the external second feeding unit; and

[0039] The third compensation branch is connected at one end to the input of the mixer and at the other end to the external third feeding unit.

[0040] In one embodiment, the first compensation branch, the second compensation branch, and the third compensation branch are each equipped with a metering pump, a first flow meter, and a compensation check valve.

[0041] In one embodiment, the reinjection unit includes:

[0042] The reinjection pump has its input end connected to the outlet of the qualified slurry storage tank; and

[0043] The main reinjection pipeline is connected at one end to the output end of the reinjection pump, and at the other end to the corresponding target injection object through injection pipeline branches.

[0044] In one embodiment, the reinjection pump input terminal is sequentially provided with a first reinjection shut-off valve, a flexible connection pipeline, an inlet pressure sensor, and a low-pressure protection switch; and / or

[0045] The reinjection main pipeline is sequentially equipped with a pulsation damper, a second flow meter, an outlet pressure sensor, a first reinjection check valve, and a pressure relief return valve; and / or

[0046] An automatic clamp valve, a second back-injection check valve, a second back-injection shut-off valve, a pressure gauge, and a detachable and washable short pipe are sequentially installed on the injection pipeline branch.

[0047] In one embodiment, the slurry storage unit further includes:

[0048] A qualified inlet valve, a homogenizing agitator, a first level gauge, a level switch, a storage sampling valve, and a quality permitting valve are installed on the qualified slurry storage tank; and / or

[0049] The waste slurry storage tank is equipped with a non-reusable inlet valve, a second level gauge, a discharge pump, and an external conveying interface.

[0050] Embodiments of the present invention also provide a treatment and control method for a recycled slurry treatment system of a small slurry mode earth pressure balance shield tunneling machine based on the above embodiments, comprising the following steps:

[0051] Start and control at least two receiving tanks in the homogenizing receiving unit to alternately receive the slurry separated by the solid-liquid separation system of the shield tunnel's water-bearing slag to the preset liquid level position in the corresponding receiving tank, while controlling and locking the corresponding receiving tank to homogenize the recovered slurry.

[0052] Control the opening of the slurry outlet valve and homogenization return valve on the corresponding receiving tank, start and control the circulating desanding unit to desand the homogenized slurry, and at the same time control the circulating desanding unit to transport the desanded slurry back to the corresponding receiving tank;

[0053] The detection unit is started and controlled to perform performance testing on the desanded slurry, and the slurry is classified into different grades based on the performance test results. The performance test results include the relative density of the slurry, the relative viscosity of the slurry, the relative filtrate loss of the slurry, the relative conductivity of the slurry, and the sand content of the slurry.

[0054] When the performance test result indicates that the slurry after sand removal is a Class I slurry, the qualified slurry storage tank in the slurry storage unit is activated and controlled to receive and store the slurry after sand removal in the corresponding receiving tank; when the performance test result indicates that the slurry after sand removal is a Class III slurry, the waste slurry storage tank in the slurry storage unit is activated and controlled to receive and store the slurry after sand removal in the corresponding receiving tank; when the performance test result indicates that the slurry after sand removal is a Class II slurry, the quantitative compensation unit is activated and controlled to add a quantitative amount of target solution to the corresponding receiving tank.

[0055] When both the slurry index and the soil pressure index are met, the reinjection unit is started and controlled to reinject the slurry in the qualified slurry storage tank into the target injection object.

[0056] The above-described solution of the present invention has at least the following beneficial effects:

[0057] (1) In the slurry recovery system of the present invention, the homogeneous receiving unit, the circulating sand removal unit, the first detection unit, the second detection unit and the quantitative compensation unit are concentrated in the existing bearing structure of the same side trolley, without setting up the ground support legs that occupy the transportation route in the middle of the tunnel, thereby avoiding the occupation of the muck truck and material transportation route between the two side trolleys, which is suitable for the limited space behind the shield tunnel.

[0058] (2) In the system of the present invention, at least two receiving tanks of the homogenizing receiving unit alternately receive and lock the batch of fluctuating slurry separated from the slurry-containing slag by the earth pressure balance shield tunnel in the small mud-water mode. This allows the other receiving tank to cooperate with other units to complete homogenization, sand removal, detection and compensation operations while one receiving tank is receiving the slurry. This ensures that the detection value, compensation amount and re-inspection result can correspond one by one, thereby ensuring the accuracy of reinjection. Furthermore, at least two receiving tanks adopt an open structure and eliminate manholes and tank covers, which facilitates cleaning, observation and maintenance within the limited height of the trolley.

[0059] (3) The slurry recycling system of the present invention sets up a detection unit and divides the detected slurry into three flow directions: primary, secondary and tertiary (i.e. direct reuse, blending compensation and non-reusable). The primary slurry enters the qualified slurry storage tank, the secondary slurry remains in the receiving tank of the current batch for quantitative compensation, and must be re-detected and re-classified after compensation. The tertiary slurry enters the waste slurry storage tank which is physically isolated from the qualified slurry storage tank and cannot be directly entered into the reinjection pipeline. This allows slurry with slight deviations to be compensated, and severely contaminated slurry cannot be forcibly reinjected, thus avoiding slurry waste and system pollution, thereby reducing the system's use and maintenance costs.

[0060] It should be understood that the implementation of any embodiment of the present invention does not mean that it will simultaneously possess or achieve multiple or all of the above-mentioned beneficial effects. Attached Figure Description

[0061] Figure 1 This is a schematic diagram showing the overall relationship between the functional units in the recycled slurry treatment system provided in this embodiment of the invention.

[0062] Figure 2 This is a longitudinal installation diagram of two receiving tanks on a unidirectional trolley in a recycled slurry treatment system provided by an optional embodiment of the present invention.

[0063] Figure 3 This is a schematic diagram of the cross-section of the same-side trolley installation and the central transport clearance provided in an optional embodiment of the present invention;

[0064] Figure 4 This is a schematic diagram of the connection between two receiving tanks, a metering cabinet, and interfaces on the same side of the trolley in the recycled slurry treatment system provided in an optional embodiment of the present invention.

[0065] Figure 5 This is a schematic diagram of the internal structure of the receiving tank provided in an optional embodiment of the present invention;

[0066] Figure 6 This is a complete connection diagram of the hydrocyclone feed, hydrocyclone underflow, detection bypass and compensation reflux of the detection unit provided in an optional embodiment of the present invention;

[0067] Figure 7 This is a schematic diagram showing the connection of a qualified slurry storage tank, a new slurry emergency unit, and a reinjection unit according to an optional embodiment of the present invention;

[0068] Figure 8 This is a connection diagram of the circulating sand removal unit in a recycled slurry treatment system provided in an optional embodiment of the present invention;

[0069] Figure 9 This is a schematic diagram of the connection of the first detection unit disposed on the first detection loop according to an optional embodiment of the present invention;

[0070] Figure 10 This is a schematic diagram of the connection of the second detection unit provided on the second detection loop according to an optional embodiment of the present invention;

[0071] Figure 11 This is a schematic diagram of the connection of the quantitative compensation unit in the recycled slurry treatment system provided in an optional embodiment of the present invention.

[0072] Explanation of icon numbers:

[0073] 11. I-beam longitudinal steel beam; 12. Support base frame; 2. Homogenizing receiving unit; 21. First receiving tank; 22. Second receiving tank; 23. First agitator; 24. Second agitator; 25. Support beam; 3. Circulating sand removal unit; 31. Circulating pump; 32. Hydrocyclone; 33. Underflow collection box; 4. First detection unit; 401. Clean water flushing valve; 402. Drain valve; 41. Detection shut-off valve; 42. Circulating sampling pump; 43. Densitometer; 44. Temperature sensor; 45. Conductivity sensor; 46. pH sensor; 47. Apparent viscometer; 48. Transparent flow cup; 49. Detection reflux valve; 5. Second detection unit; 51. Detection sampling valve; 52. Marsh funnel interface; 53. Mud hydrometer interface; 54. Sand content detection interface; 55. API filtration loss detection interface; 6. Diverter valve assembly; 7. Quantitative compensation unit; 71. First compensation branch; 72. Second compensation branch; 73. Third compensation branch; 74. Mixer; 75. Metering pump; 76. First flow meter; 77. Compensation check valve; 81. Qualified slurry storage tank; 82. Waste slurry storage tank; 83. Quality permit valve; 9. Reinjection unit; 91. Reinjection pump; 92. Pulsation damper; 93. Second flow meter; 94. Outlet pressure sensor; 95. First reinjection check valve; 96. Pressure relief reflux valve; 10. New slurry emergency unit. Detailed Implementation

[0074] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0075] In the description of this invention, it should be understood that the terms "comprising / including," "consisting of," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0076] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0077] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0078] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0079] like Figure 1 As shown, an embodiment of the present invention provides a slurry recovery system for a small slurry mode earth pressure balance shield tunnel, which may specifically include a homogenization receiving unit 2, a circulating desanding unit 3, a detection unit, a slurry storage unit, a quantitative compensation unit 7, and a reinjection unit 9.

[0080] The homogenizing receiving unit 2 is connected to the upstream slurry outlet of the solid-liquid separation system for the shield tunnel's water-bearing slag, and is used to receive and homogenize the separated slurry; the homogenizing receiving unit 2 includes at least two receiving tanks arranged in parallel.

[0081] The circulating desanding unit 3 is connected to the homogenizing receiving unit 2, and is used to desand the homogenized slurry and transport the desanded slurry back to the corresponding receiving tank. A testing unit is installed in the circulation loop between the circulating desanding unit 3 and the homogenizing receiving unit 2, and is used to test the performance of the desanded slurry.

[0082] The slurry storage unit includes a qualified slurry storage tank 81 and a waste slurry storage tank 82. Both the qualified slurry storage tank 81 and the waste slurry storage tank 82 are connected to the homogenization receiving unit 2. The qualified slurry storage tank 81 is used to store slurry with a performance test result indicating level 1, and the waste slurry storage tank 82 is used to store slurry with a performance test result indicating level 3. Here, the qualified slurry storage tank 81 and the waste slurry storage tank 82 are physically isolated. Even if there is an operational error upstream, unqualified slurry cannot flow into the qualified slurry storage tank through valves, pipelines, etc., thereby reducing the risk of unqualified slurry accidentally entering the reinjection pump in the reinjection unit.

[0083] The quantitative compensation unit 7 is connected to the homogenization receiving unit 2 and is used to add a quantitative target solution to the homogenization receiving unit 2 when the performance test result indicates level II. One end of the reinjection unit 9 is connected to the qualified slurry storage tank 81, and the other end is connected to at least one injection object; it is used to reinject the slurry in the qualified slurry storage tank 81 into the target injection object when both the slurry index and the soil pressure index are met.

[0084] In this embodiment, at least two receiving tanks in the homogeneous receiving unit 2 are arranged longitudinally along the tunnel between the existing I-beams 11 on the upper and lower parts of the same side trolley. The longitudinal length of the entire processing system is preferably 3200mm, the outer width is preferably 1200mm, and the total height is preferably 2400mm. The lateral projection of the entire processing system must not exceed the inner edge control line of the side trolley. The processing system is not arranged between the two side trolleys, nor are there any ground support legs in the middle transport channel. The passage envelope of the muck truck between the opposite side trolley and the two side trolleys remains unchanged to accommodate the limited space behind the shield tunnel. Before manufacturing each unit in the system, the transport net width and net height should be checked against the maximum outer contour of the muck truck on site, and the inner edge of the trolley, the existing cable tray, and the maintenance channel should also be checked.

[0085] like Figure 2 and Figure 4 As shown, the circulating sand removal unit 3, the detection unit, and the quantitative compensation unit 7 are simultaneously installed on the maintenance end of the same installation side of at least two receiving tanks, preferably in the same detection and metering cabinet. The detection and metering cabinet belongs to a shared installation space, and its cabinet outline does not change the independent functional numbers of the circulating sand removal unit 3, the detection unit, and the quantitative compensation unit 7. Each functional unit is still connected to the external pipeline through an independent interface.

[0086] The testing and metering cabinet adopts a common cabinet and zoned installation layout. The circulating sand removal unit 3 is located in the mechanical processing area, the first testing unit 4 in the testing unit is located in the rapid testing area, the second testing unit 5 in the testing unit is located in the slow verification area, and the quantitative compensation unit 7 is located in the compensation area. The cabinet outline of the testing and metering cabinet only indicates the installation boundaries; the functional zones are only connected at the nodes shown in the diagram. The hydrocyclone underflow, hydrocyclone overflow, testing return flow, and compensation return flow in the circulating sand removal unit 3 do not share a tee and are not interconnected despite being located in the same cabinet.

[0087] The homogenizing receiving unit 2 is equipped with at least two receiving tanks. When processing the slurry after solid-liquid separation from the upstream, the at least two receiving tanks take turns receiving and locking the batch. This transforms the intermittent discharge of slurry from the upstream solid-liquid separation into a continuous process of downstream slurry recovery and treatment. This allows the other receiving tank to cooperate with other units to complete the entire process of homogenization, sand removal, testing, compensation, and reinjection of the recovered slurry while one receiving tank is receiving. This enables the recovery and recycling of the upstream separated slurry. At the same time, it also ensures that the test values, compensation amounts, and retest results of each batch can be matched one by one, thereby guaranteeing the accuracy of the recovered slurry treatment.

[0088] By setting up a detection unit, sand removal can be achieved on the homogenized slurry within an accuracy range of 0.075mm to 0.15mm. Furthermore, the detected slurry can be divided into primary, secondary, and tertiary flow directions by the diversion valve group 6. The primary slurry represents qualified slurry that can be directly reused, the secondary slurry represents qualified slurry that needs to be adjusted and compensated, and the tertiary slurry represents waste slurry that cannot be reused. Quantitative compensation is also performed on the qualified slurry to avoid discarding slightly unqualified slurry, thereby reducing the consumption of new slurry materials such as bentonite.

[0089] When quantitatively compensating the secondary slurry through the quantitative compensation unit 7, it mainly includes density compensation, viscosity compensation, and filtration loss compensation for the secondary slurry. Among them, density compensation adopts the material balance formula, and viscosity and filtration loss compensation adopt the on-site response coefficient and the step limit, thereby ensuring the accuracy of adding quantitative target solution. It should be noted that after quantitative compensation, it is necessary to re-inspect through the detection unit, and then perform grading after the re-inspection.

[0090] When reinjecting qualified grout through reinjection unit 9, reinjection should only be carried out when both the grout index and the soil pressure index are met. This avoids forced grouting when the soil pressure is disordered (such as underpressure or overpressure) and eliminates the engineering risk of surface subsidence caused by instantaneous fluctuations in soil pressure due to abnormal grout density.

[0091] The aforementioned processing system forms a complete closed-loop negative feedback system from the receiving end to the reinjection end: receiving - homogenization - desanding - detection - diversion - compensation - re-inspection - permitted reinjection. This solves the blind spot of traditional shield tunneling slurry, which only processes but does not verify the slurry. Simultaneously, addressing the pain points of large slurry volume, drastic fluctuations, and high sand content in small-scale slurry modes, through fine desanding and grading, the performance of the quantitatively compensated regenerated slurry is consistently superior to that of freshly prepared bentonite slurry. (See also...) Figures 2 to 5 In an optional embodiment of the present invention, at least two receiving tanks include a first receiving tank 21 and a second receiving tank 22. The first receiving tank 21 and the second receiving tank 22 are arranged longitudinally along the tunnel between the existing I-beams 11 of the same side trolley, and are arranged side by side.

[0092] like Figure 2 As shown, the first receiving tank 21 and the second receiving tank 22 can be fixed to the supporting base frame 12 with bolts. Eight rubber-metal vibration damping pads with a rated static load of not less than 12kN are installed between the supporting base frame 12 and the receiving tanks to reduce vibration during the slurry recycling process. Preferably, the supporting base frame 12 is composed of two H200×200×8×12 longitudinal beams and six H150×150×7×10 transverse beams welded together, and the material is Q355B. The supporting base frame 12 is connected to the existing supporting beam of the trolley on the same side by eight sets of M20 bolts with a performance grade of 10.9. Each connection point is equipped with a 10mm thick connecting plate and an 8mm thick triangular stiffening rib.

[0093] Here, both the first receiving tank 21 and the second receiving tank 22 are open-top atmospheric pressure tanks without tank covers or dedicated maintenance manholes. Cleaning, observation, and maintenance are all carried out from the top opening. A first agitator 23 and a second agitator 23 are respectively installed inside the two receiving tanks, and support beams 25 are installed above the top openings of both receiving tanks to support the agitators. During normal operation, a removable splash-proof curtain is installed around the support beams 25 to reduce splashing during agitation. It should be noted that the splash-proof curtain does not constitute a pressure-bearing sealing cover.

[0094] In an optional embodiment of the present invention, the upper part of the first receiving tank 21 and the second receiving tank 22 is preferably a rectangular cylinder with internal dimensions of 1400mm × 900mm × 1650mm, and the lower part is preferably a conical hopper with a height of 550mm and a four-way contraction towards the center. The total height of the tank is preferably 2200mm, the total volume is approximately 2.75m³, and the effective volume is set at 2.40m³. The tank bodies of the first receiving tank 21 and the second receiving tank 22 are preferably welded from Q235B steel plates with a thickness of 6mm, and the inner surface is provided with a wear-resistant and anti-corrosion coating with a thickness of not less than 2mm. Each receiving tank is equipped with a 2.2kW top-entry agitator with an agitator shaft speed of 90r / min, an impeller diameter of 420mm, and the impeller bottom edge 350mm from the lowest point of the conical hopper. The agitator is fixed on a support beam 25 spanning the opening, and the two ends of the beam are connected to the stiffening frame at the upper edge of the tank body; the weight and torque of the agitator are borne by the support beam and not by the splash-proof curtain.

[0095] See Figure 5 The top of the first receiving tank 21 and the top of the second receiving tank 22 are each provided with a receiving port, a desanding return port, a detection return port, and a compensation port. Preferably, the receiving port, the desanding return port, the detection return port, and the compensation port can all be open and connected to the top of the tank body. The receiving port is connected to the upstream slurry outlet through a receiving pipe to receive the slurry separated upstream. The desanding return port is connected to the top overflow port of the circulating desanding unit 3 through a top overflow pipe to receive the slurry after desanding by the circulating desanding unit 3 (preferably, a homogenization return valve is provided on the top overflow pipe to control the return of the desanded slurry to the receiving tank). The detection return port is connected to the detection unit through a detection return pipe to receive the slurry after detection by the detection unit. The compensation port is connected to the output end of the quantitative compensation unit 7 through a compensation return pipe to receive the quantitative target solution provided by the quantitative compensation unit 7. By setting up a receiving port, a sand removal reflux port, a detection reflux port, and a compensation port, the detection reflux, sand removal reflux, and compensation reflux are connected to the receiving tank through independent interfaces, thereby avoiding instantaneous interference of the detection data by the high concentration of the quantitative target solution.

[0096] Preferably, each receiving tank is equipped with a DN100 cam-locking quick-connect fitting at its receiving port, which is connected to the slurry outlet of the upstream separation system via a receiving pipe. Here, the receiving pipe is preferably a DN100 wear-resistant hose with a rated pressure of not less than 0.6 MPa and a minimum bending radius of not less than 600 mm. More preferably, the receiving pipe is equipped with a DN100 manual gate valve (a DN100 pneumatic clamp valve for slurry inlet is located near the receiving port and is in the air-loss closed position, which can cut off the slurry supply from the upstream separation system when the machine stops or the liquid level is too high, and the pneumatic clamp valves of the two receiving tanks are interlocked, allowing only one receiving tank to receive slurry at a time), an electromagnetic flowmeter, a check valve, a sampling port, a pull-out protective filter basket, and pressure sensors located before and after the pull-out protective filter basket.

[0097] The preferred aperture of the pull-out protective filter basket is 5mm. It is used to block bolts, metal pieces, and large particles that may accidentally enter from upstream, and does not perform slag grading. To avoid significant pressure drop during normal slurry flow, the effective flow area of ​​the pull-out protective filter basket should be no less than three times the cross-sectional area of ​​the DN100 pipe. When the pressure difference across the pull-out protective filter basket reaches 0.05MPa and lasts for 10 seconds, the pneumatic clamp valve is closed, upstream conveying stops, and a cleaning prompt is issued. (Continue reading...) Figure 5 Both the bottom of the first receiving tank 21 and the bottom of the second receiving tank 22 are provided with a slurry outlet and a sand discharge outlet. The slurry outlets are connected to the side inlet of the circulating sand removal unit 3, the inlet of the qualified slurry storage tank 81, and the inlet of the waste slurry storage tank 82 via slurry outlet pipes, respectively. The sand discharge outlets are connected to the waste slurry storage tank 82 via sand discharge pipes. Preferably, a slurry pump is provided at the slurry outlet of the tank to extract the slurry from the tank.

[0098] The slurry outlet of the tank is located on the lateral short section at the bottom of the cone, used to send the flowable slurry to the subsequent treatment unit; the sand discharge outlet is located at the absolute lowest point of the cone, used for shutdown evacuation, discharge of sand from the bottom of the tank, and flushing of residual liquid. The slurry outlet of the tank is the normal treatment pipeline, while the sand discharge outlet is the maintenance and non-reusable discharge pipeline, and the two must not be interchanged; the sand discharge pipe is not connected to the circulation pump 31 in the circulating sand removal unit 3, and is not connected to the slurry outlet pipe, so as to separate the sand discharge and slurry discharge functions of the receiving tank, so as to avoid the common engineering problem of high concentration sand particles in the underflow being back-mixed to the overflow end due to shared pipelines, and to ensure that the sand removal efficiency is stably implemented from the design value to the actual operating value.

[0099] Continue reading Figure 5 Preferably, the sides of the first receiving tank 21 and the second receiving tank 22 are provided with continuous 15% first liquid level, 55% second liquid level, 85% third liquid level, and 95% fourth liquid level, as well as level gauges and independent level switches at the corresponding liquid levels; here, the first liquid level switch corresponding to the 15% first liquid level is the liquid level that prevents the circulation pump 31 and the slurry pump in the circulating sand removal unit 3 from starting, the second liquid level switch corresponding to the 55% second liquid level is used to display the batch processing progress, the third liquid level switch corresponding to the 85% third liquid level is the liquid level switching switch for the receiving tank, and the fourth liquid level switch corresponding to the 95% fourth liquid level is the high liquid level that closes the receiving port on the top of the tank and triggers an alarm.

[0100] Continue reading Figure 5Both the first receiving tank 21 and the second receiving tank 22 are equipped with side overflow ports, which are connected to the inlet of the waste slurry storage tank via safety overflow pipes. Preferably, the safety overflow pipe is a DN65 safety overflow pipe, with its elevation higher than the fourth level switch corresponding to the 95% fourth liquid level on the tank body and connected to the waste slurry storage tank. When the slurry inlet valve (located on the receiving pipe) on the receiving tank fails to close in time or the level gauge malfunctions, the slurry first enters the waste slurry storage tank through the safety overflow pipe and must not overflow into the trolley from the open opening.

[0101] In an optional embodiment of the present invention, the slurry outlet pipe may specifically include a main slurry outlet pipe, a first slurry outlet branch pipe, a second slurry outlet branch pipe, and a third slurry outlet branch pipe, each of which is equipped with a pneumatic slurry outlet clamp valve. One end of the main slurry outlet pipe is connected to the slurry outlet port; one end of the first slurry outlet branch pipe is connected to the other end of the main slurry outlet pipe, and the other end is connected to the side inlet of the circulating desanding unit 3. The first slurry outlet branch pipe is equipped with a slurry outlet valve to transport the homogenized slurry to the circulating desanding unit 3 for desanding treatment. The second slurry outlet branch pipe is connected at one end to the other end of the slurry outlet main pipe and at the other end to the inlet of the qualified slurry storage tank 81. A direct reuse valve is installed on the second slurry outlet branch pipe to transport qualified slurry that has been tested and is deemed to be directly reusable to the qualified slurry storage tank 81. The third slurry outlet branch pipe is connected at one end to the other end of the slurry outlet main pipe and at the other end to the inlet of the waste slurry storage tank 82. A non-reusable valve is installed on the third slurry outlet branch pipe to transport waste slurry that has been tested and is deemed to be non-reusable to the waste slurry storage tank 82.

[0102] Here, the direct reuse valve and the non-reusable valve form a diversion valve group 6 of the system. Preferably, the diversion valve group 6 may also include a regulating compensation valve and a safety return valve. The direct reuse valve and the regulating compensation valve are preferably in the power-off closed position, and the non-reusable valve or the safety return valve is preferably in the power-off open safe position. When the slurry index and the soil chamber pressure index are both met, the qualified slurry that can be directly reused enters the qualified slurry storage tank 81 through the direct reuse valve; the qualified slurry that needs to be regulated and compensated enters the quantitative compensation logic through the regulating compensation valve, but the physical slurry is still retained in the receiving tank of the current batch, and the quantitative compensation unit adds the quantitative target solution; the unusable waste slurry enters the waste slurry storage tank 82 through the non-reusable valve; in the event of valve position conflict, sensor failure, or slurry pump abnormality, the safety return valve opens and the slurry pump stops.

[0103] When receiving slurry in the receiving tank, its inlet is closed, the batch is locked, and another tank is switched to receive the slurry once the current receiving tank reaches 85% of its capacity. The locked receiving tank first undergoes homogenization treatment, specifically: stirring for 3 minutes. If the online density difference is still greater than 0.02 g / cm³ within the last 30 seconds, stirring is extended to 5 minutes. Each batch number consists of the tank number, the shield ring number, and the locking time. Once a batch is locked, newly recovered slurry must not enter that tank; the same batch number is used for all records of testing, addition, re-inspection, diversion, and reinjection. Each tank has an effective volume of 2.40 m³. Based on a circulation flow rate of 16 m³ / h, the theoretical evacuation time is approximately 9 minutes, which can cover 3-5 minutes of homogenization, 2-4 minutes of sand removal, and valve switching time.

[0104] During quantitative compensation, the target solution is input into the receiving tank and mixed for at least 3 minutes. After mixing, it is then re-processed through the detection unit. Preferably, a batch of recovered slurry can undergo a maximum of three quantitative compensations. If the slurry still fails to meet the standard for direct reuse after three quantitative compensations, or if the liquid level in the receiving tank reaches 90% after cumulative compensation, the slurry in the current receiving tank is forcibly classified as unreusable waste slurry and transferred to the waste slurry storage tank 82. It should be noted that unreusable waste slurry cannot be manually converted into qualified slurry; it must be resampled and valid test records must be re-established before the classification can be changed.

[0105] See Figure 6 and Figure 8 In an optional embodiment of the present invention, the circulating desanding unit 3 may include a circulating pump 31, a hydrocyclone 32, and an underflow collection box 33. The circulating pump 31 is mounted on the slurry outlet pipe, specifically on the first slurry outlet branch pipe, to input the homogenized slurry into the hydrocyclone 32. Preferably, the rated flow rate of the circulating pump 31 is 16 m³ / h, the head is 25 m, and the inlet pressure of the hydrocyclone 32 is preferably controlled between 0.15 MPa and 0.25 MPa.

[0106] The hydrocyclone 32 is located at the discharge end of the circulating pump 31, and its side inlet is connected to the discharge end of the circulating pump 31 via a feed manifold. A top overflow port is provided at the top of the hydrocyclone 32. Two hydrocyclones 32 can be installed in parallel. The other end of the first discharge branch pipe is connected to the side inlet of the hydrocyclone 32 via the feed manifold. Preferably, the feed manifold is divided into two feed branches to supply slurry to the two parallel four-inch polyurethane hydrocyclones. The first hydrocyclone receives slurry from its left side inlet, and the second hydrocyclone receives slurry from its right side inlet. The two feed branches are arranged in layers on the mounting frame to prevent bends from crossing each other.

[0107] The top overflow ports of the two hydrocyclones 32 are respectively connected to a common top overflow pipe through continuous bends (all bends are long-radius elbows or continuous arc pipes, and the two straight pipe ends are not connected to replace the elbows). Preferably, the top overflow pipe can be a DN65 overflow main pipe. The main path of the top overflow pipe returns directly to the sand removal return port of the current batch receiving tank to form a closed loop (here, the closed loop means that the slurry flows out from the slurry outlet of the current receiving tank, is pressurized by the circulation pump 31 and enters the hydrocyclone 32. The sand removal overflow of the hydrocyclone 32 then returns to the corresponding current receiving tank through the top overflow pipe and the sand removal return port, thus forming a closed loop).

[0108] The bottom underflow ports of the two hydrocyclones 32 are respectively provided with vertically downward underflow pipes. The underflow collection box 33 is located at the bottom of the hydrocyclones 32 and is connected to the bottom underflow ports of the hydrocyclones 32 through the underflow pipes. Preferably, the two underflow pipes can extend directly into the sealed underflow collection box 33 and not share a tee with the top overflow pipe, detection return pipe or compensation return pipe, so as to prevent underflow splashing, back mixing or misconnection.

[0109] Here, the underflow collection tank 33 adopts a closed structure, and its volume is preferably 120L. It is equipped with a high-level switch and a pull-out sand settling box. The bottom of the underflow collection tank 33 is also equipped with an independent underflow discharge port and an underflow discharge pipe, which are connected to the waste slurry storage tank. The underflow collection tank 33 is mainly designed to receive the sand-rich underflow discharged from the two hydrocyclones 32. This underflow contains both removed sand and fine gravel, as well as a small amount of slurry used to carry particles. The sand particles in the sand-rich underflow after settling are periodically removed by the pull-out sand settling box. The liquid in the sand-rich underflow, the flushing wastewater, and the sand-containing slurry that cannot be reused are sent to the waste slurry storage tank 82 through the independent underflow collection tank pipeline.

[0110] In an optional embodiment of the present invention, the detection return pipe may include a first detection return pipe and a second detection return pipe. One end of the first detection return pipe is connected to the top overflow port of the circulating sand removal unit 3, specifically to the top overflow port of one of the hydrocyclones, and the other end of the first detection return pipe is connected to the detection return port; one end of the second detection return pipe is connected to the top overflow port of the circulating sand removal unit, specifically to the top overflow port of another hydrocyclone, and the other end of the second detection return pipe is connected to the detection return port.

[0111] In this embodiment, one end of the first detection return pipe and one end of the second detection return pipe can both be connected to the top overflow pipe at the top overflow port of the hydrocyclone. Preferably, a valved tee can be opened on the top overflow pipe (sampling is not taken from the bottom flow pipe of the hydrocyclone 32 or the inlet of the circulating pump 31, and the valved tee is close to the top overflow port of the hydrocyclone 32). One end of the first detection return pipe and one end of the second detection return pipe are respectively connected to the two ports of the valved tee. The first detection unit 4 and the second detection unit 5 in the detection unit take a small amount of sample from the top overflow pipe for online detection through the first detection circuit and the second detection circuit, respectively. That is, the main slurry after sand removal returns to the corresponding receiving tank, and the detection is completed in an independent bypass (first detection return pipe and second detection return pipe), rather than by the receiving tank itself. This pipeline layout and connection method allows the same batch of slurry to pass through the hydrocyclone multiple times, gradually reducing the sand content. It also ensures that the samples taken for online testing come from the overflow after sand removal, providing a more stable reflection of the reinjectability quality of the current batch. It should be noted that the flow rate of the desanded slurry flowing through the first and second test return pipes is much smaller than the flow rate in the top overflow pipe. The tested slurry also returns to the same receiving tank, eliminating the need for a separate test tank.

[0112] See Figure 9 In an optional embodiment of the present invention, the detection unit may specifically include a first detection unit 4 and a second detection unit 5. The first detection unit 4 is disposed on the first detection return pipe and is used to continuously detect the density, temperature, conductivity, pH, and apparent viscosity of the slurry after sand removal.

[0113] In a specific achievable example, the first detection unit 4 may include a detection shut-off valve 41, a circulating sampling pump 42, a densitometer 43, a temperature sensor 44, a conductivity sensor 45, a pH sensor 46, an apparent viscometer 47, a transparent flow cup 48, and a detection reflux valve 49 arranged along the first detection reflux pipeline. The detection shut-off valve 41 is located near the top overflow port, and the detection reflux valve 49 is located near the detection reflux port.

[0114] In this embodiment, a detection shut-off valve 41, a circulating sampling pump 42, a densitometer 43, a temperature sensor 44, a conductivity sensor 45, a pH sensor 46, an apparent viscometer 47, a transparent flow cup 48, and a detection reflux valve 49 are sequentially connected to the first detection reflux tube, and the sample is returned to the receiving tank of the current batch after the detection is completed.

[0115] In one feasible example of the present invention, the circulation flow rate of the slurry in the first detection reflux pipe can be set to 8 L / min; the range of the densitometer 43 is preferably 0.90 g / cm³ to 1.50 g / cm³, with an accuracy of not less than ±0.005 g / cm³; the range of the temperature sensor 44 is preferably 0℃ to 60℃; the range of the conductivity sensor 45 is preferably 0 mS / cm to 100 mS / cm; the range of the pH sensor 46 is preferably 2 to 12; the apparent viscometer 47 is preferably a differential pressure type, vibration type, or rotation type sensor, and a conversion curve is established based on the field measurement values. Each real-time index (slurry density, temperature, conductivity, pH, apparent viscosity) is collected every 5 seconds, and the median of the valid data for 60 consecutive seconds is taken as the real-time index value for that batch.

[0116] In an optional embodiment of the present invention, a clean water flushing valve 401 and a drain valve 402 are respectively provided at both ends of the first detection return pipe; before switching batch processing of slurry, the sampling valves on the corresponding receiving tank and the corresponding pipeline are closed, the clean water flushing valve 401 is opened to inject clean water, and the drain valve 402 is opened at the same time. Then, the receiving tank, the hydrocyclone 32 and the corresponding pipeline are flushed with clean water (preferably flushed for 20 seconds), and the flushing water enters the waste slurry storage tank 82 through the drain valve 402.

[0117] See Figure 10 The second detection unit 5 is disposed on the second detection return pipe and is used to periodically detect the sand content of the desanding slurry and the API filtration loss. In a specific implementable example, the second detection unit 5 may include a detection sampling valve 51, a Marvin funnel interface 52, a mud hydrometer interface 53, a sand content detection interface 54, and an API filtration loss detection interface 55 arranged sequentially along the second detection return pipe. The Marvin funnel interface 52 is used to connect a Marvin funnel, the mud hydrometer interface 53 is used to connect a mud hydrometer, the sand content detection interface is used to connect a sand content detector, and the API filtration loss detection interface is used to connect an API filtration loss meter.

[0118] Since the sand content and API filtration loss of the slurry need to be tested after the slurry has stabilized (to avoid large fluctuations in test results when tested during the process), the sand content of the slurry is tested once after each new batch is locked, and can be adjusted to once every 30 minutes during stable operation; the API filtration loss is tested once every 2 hours, and immediately retested when the formation segment, groundwater quality, bentonite batch, polymer type or compensation rule changes. Since the API filtration loss test requires a fixed pressure difference and a test duration of 30 minutes, the sand content and API filtration loss of the slurry can be used as periodic quality permits for the slurry, not as real-time online signals for each batch (i.e., real-time indicators).

[0119] After testing, qualified slurry requires automatic retesting of real-time indicators every 30 minutes and manual verification of sand content every 60 minutes. API filtration loss is verified every 2 hours. If qualified slurry remains in the corresponding receiving tank for more than 2 hours, the temperature change exceeds 5°C, or the agitator stops for more than 10 minutes, the quality control unit closes the permissible valve on the reinjection unit until the slurry in the receiving tank passes the retest, ensuring the accuracy of slurry recovery and injection.

[0120] See Figure 6 and Figure 11 In an optional embodiment of the present invention, the quantitative compensation unit 7 may specifically include a mixer 74, a first compensation branch 71, a second compensation branch 72, and a third compensation branch 73. The output end of the mixer 74 is connected to one end of the compensation return pipe; one end of the first compensation branch 71 is connected to the input end of the mixer 74, and the other end is connected to an external first feeding unit; one end of the second compensation branch 72 is connected to the input end of the mixer 74, and the other end is connected to an external second feeding unit; one end of the third compensation branch 73 is connected to the input end of the mixer 74, and the other end is connected to an external third feeding unit.

[0121] In this embodiment, the first compensation branch 71, the second compensation branch 72, and the third compensation branch 73 are three independent source branches provided by the quantitative compensation unit 7. The first feeding unit can be a clean water tank or a clean water main pipe, the second feeding unit can be a bentonite slurry tank, and the third feeding unit can be a polymer maturation tank. The clean water in the first feeding unit is supplied to the mixer 74 via the first compensation branch 72, the bentonite slurry in the bentonite slurry tank is supplied to the mixer 74 via the second compensation branch 72, and the polymer solution in the polymer maturation tank is supplied to the mixer 74 via the third compensation branch 73 to mature the polymer solution. Preferably, each of the first compensation branch 71, the second compensation branch 72, and the third compensation branch 73 is equipped with a metering pump 75, a first flow meter 76, and a compensation check valve 77. After the three compensation branches merge at a clearly defined confluence point, they are mixed evenly by the static mixer 74 and then connected to the independent compensation port of the current batch receiving tank via a compensation return pipe.

[0122] Preferably, the design flow rate of the first compensation branch 71 is 0 m³ / h to 4 m³ / h, the design flow rate of the second compensation branch 72 is 0 m³ / h to 3 m³ / h, and the design flow rate of the third compensation branch 73 is 0 L / h to 200 L / h. The cumulative dosage error of each branch is no greater than ±2%. It should be noted that the polymer should not be added directly to the recovered slurry in dry powder form. It should be prepared in a separate maturation tank, and the maturation time should not be less than 30 minutes. Here, the type of polymer is not limited, and the required polymer can be maturated according to actual needs in practical applications.

[0123] When the slurry in the receiving tank of the current batch is determined to be substandard based on the detection unit's analysis, quantitative compensation is performed based on the current indicators of the recovered slurry obtained from the detection. Specifically:

[0124] When the current density of the recovered slurry is detected to be higher than the target density ρ t Using density ρ w When the density of clean water decreases, the volume of clean water to be added is V. w =V r (ρ r -ρ t ) / (ρ t -ρ w In the formula, V r To determine the volume of slurry in the receiving tank for the current batch, ρ r To determine the current density of the recovered slurry; after determining the volume of clean water to be added, the clean water to be added is transported to the mixer 74 through the first compensation branch 71;

[0125] When the current density of the recovered slurry is detected to be lower than the target density ρ t Using density ρ c When increasing the density of bentonite slurry, the volume of slurry to be added is V. c =V r (ρ t -ρ r ) / (ρ c -ρ t It should be noted that only ρ c >ρ t This formula is valid when the condition is met; otherwise, the control unit will disable the calculation and prompt the user to prepare the concentrated slurry again.

[0126] Since adding water or bentonite concentrate alters the sand content, apparent viscosity, filtration loss, and salt content of the slurry, polymer compensation is required via a third compensation branch 73 in conjunction with either the first compensation branch 71 or the second compensation branch 72. During polymer compensation, the amount of polymer solution to be added can be determined based on the slurry's response coefficient. Simultaneously, the determined amount of polymer solution is input into the mixer 74 via the third compensation branch 73. The mixer 74 then thoroughly mixes the water with the polymer solution, or the bentonite concentrate with the polymer solution, before conveying it to the corresponding receiving tank for subsequent processes (re-entering the detection unit for rapid detection and necessary slow verification, as well as subsequent reinjection or disposal processes).

[0127] It should be noted that if the slurry in the current batch receiving tank is slurry that is not yet qualified, quantitative compensation can be performed a maximum of three times. After three compensations, if the test results of the corresponding slurry still do not meet the requirements for qualified slurry, or if the liquid level in the corresponding receiving tank reaches 90% after cumulative compensation, the slurry in the corresponding receiving tank can be identified as waste slurry and forcibly transferred to waste slurry storage tank 82. Furthermore, waste slurry cannot be directly changed to qualified slurry by manually pressing a button; it must be resampled and a valid test record must be re-established before the classification can be changed.

[0128] See Figure 7 In an optional embodiment of the present invention, the qualified slurry storage tank 81 preferentially reuses the existing 6m³ ​​bentonite tank of the tunnel boring machine, and the qualified slurry storage tank 81 is also equipped with a qualified inlet valve, a homogenizing agitator, a first level gauge, a level switch, a storage sampling valve, and a quality permit valve 83. Here, the qualified inlet valve is only opened when the current batch of slurry is judged to be qualified and the test data is valid.

[0129] The waste slurry storage tank 82 preferably reuses the existing 4m³ wastewater tank of the tunnel boring machine. Preferably, the waste slurry storage tank 82 is equipped with a non-reusable inlet valve, a second level gauge, a discharge pump, and an external conveying interface. Waste slurry, hydrocyclone underflow, underflow collection tank discharge liquid, bottom sediment and flushing water from the receiving tank all enter the waste slurry storage tank 82. Furthermore, there is no automatically openable connecting pipe between the qualified slurry storage tank 81 and the waste slurry storage tank 82 to prevent waste slurry and other waste materials from entering the qualified slurry storage tank 81.

[0130] Continue reading Figure 7 In an optional embodiment of the present invention, the reinjection unit 9 may specifically include a reinjection pump 91 and a main reinjection pipeline. The input end of the reinjection pump 91 is connected to the outlet of the qualified slurry storage tank 81; one end of the main reinjection pipeline is connected to the output end of the reinjection pump 91, and the other end is connected to the corresponding target injection object through injection pipeline branches, and the injection pipeline branches correspond one-to-one with the target injection object. Preferably, the target injection object may include an existing bentonite pipeline, an external air cushion chamber, and an injection port at the top of the soil chamber. Correspondingly, the injection pipeline branches may include an existing bentonite injection pipeline branch, an external air cushion chamber injection pipeline branch, and an injection pipeline branch at the top of the soil chamber injection port.

[0131] In this embodiment, the reinjection pump 91 preferentially reuses an existing bentonite flexible hose pump in the tunnel boring machine with a rated flow rate of 16 m³ / h and a maximum working pressure of 1.60 MPa. The input end of the reinjection pump 91 uses a DN65 pipe to form the main reinjection pipeline. Preferably, the input end of the reinjection pump 91 is sequentially equipped with a first reinjection shut-off valve 93, a flexible connection pipeline, an inlet pressure sensor, and a low-pressure protection switch. (Continue reading...) Figure 7Preferably, the reinjection main pipeline is sequentially equipped with a pulsation damper 92, a second flow meter 93, an outlet pressure sensor 94, a first reinjection check valve 95, and a pressure relief return valve 96. Preferably, the pressure relief return valve is set to 1.20 MPa.

[0132] Preferably, an automatic clamping valve, a second reinjection check valve, a second reinjection shut-off valve, a pressure gauge, and a detachable and washable short pipe are sequentially installed on the injection pipeline branch. The second reinjection shut-off valves on multiple injection pipeline branches are interlocked, and only one injection pipeline branch is allowed to be opened under normal reinjection conditions.

[0133] Here, the switching of injection pipeline branches shall be carried out in the following sequence: "close the second reinjection shut-off valve on the current injection pipeline branch - confirm the closed position - open the second reinjection shut-off valve on the target injection pipeline branch - confirm the open position - start the reinjection pump at low speed". Direct switching of injection pipeline branches under pressure is not allowed. Preferably, during reinjection, existing bentonite injection pipeline branches shall be selected first for normal slag improvement; external air cushion chamber injection pipeline branches shall be selected first when the liquid level is below the lower limit and its pressure allows for grouting; and injection pipeline branches at the upper injection port of the soil chamber shall be selected first when the pressure of the soil chamber continues to drop and rapid grouting is required.

[0134] When the processing system performs automatic reinjection, it is only when both the grout index and the soil pressure index are met that the grout in the qualified grout storage tank 81 is reinjected into the target injection object through the reinjection unit 9. This avoids forced grouting when the soil pressure is disordered (such as underpressure or overpressure), and avoids the engineering risk of surface subsidence caused by instantaneous fluctuations in soil pressure due to abnormal grout density. It also avoids reinjecting qualified grout simply because of a pressure drop, and avoids meaningless grouting to the soil chamber or other branches when there is no need for pressure stabilization.

[0135] Here, the slurry index represents the permissible quality Q of the slurry. q The soil pressure index represents the permissible soil pressure demand Q. p Automatic reinjection requires simultaneous approval of grout quality. q =1 and earthwork pressure requirement permit Q p =1. Slurry quality permitting Q q =1 requires the following conditions to be met simultaneously: the current slurry is a qualified slurry that can be directly reused, the generation time of the indicators detected by the first detection unit 4 does not exceed 10 minutes, the API filtration loss verification is still within the 2-hour validity period, the liquid level in the qualified slurry storage tank is higher than 20%, and the agitator, reinjection pump, and target injection pipeline branch are fault-free (if any of the above conditions fail, Q will be deactivated). q =0).

[0136] Earthwork pressure demand permit Q p =1 must satisfy: target pressure P t Subtract the actual pressure P of the earthwork chamberc The difference is greater than or equal to 0.02 MPa and lasts for 3 seconds, or dP c When / dt≤-0.003MPa / s, the earthwork pressure requirement permit Q p =1; Here, the actual pressure P of the earthwork chamber is... c The pressure is obtained from five soil chamber pressure sensors. In the actual calculation, the measuring points with a difference of more than 0.03 MPa from the median are first removed (automatic reinjection is prohibited when there are fewer than 3 valid measuring points after removal). Then, the median of the remaining valid measuring points is taken as the actual soil chamber pressure Pc used for the final calculation.

[0137] Preferably, during the automatic injection of qualified slurry, the target flow rate within the target injection pipeline branch is... It can be represented as: ;in, The limiting function is defined as follows: when x < a, the value is a; when x > b, the value is b; and when x is between a and b, the value is x. This represents the pressure deviation proportional gain, used to adjust the target pressure. Actual pressure of earthwork The difference between them is converted into additional reinjection flow rate, which can be expressed in m³ / (h·MPa); This indicates the pressure drop rate compensation gain, used to compensate for rapid pressure drops in the earthwork chamber. Increase the reinjection flow rate in advance, which can be expressed in m³ / [h·(MPa / s)].

[0138] In a specific implementation example, the initial extraction traffic Take 3 m³ / h, Take 16 m³ / h, pressure deviation proportional gain The initial value is taken as 30 m³ / (h·MPa), and the pressure drop rate compensation gain is used. The initial value is 60 m³ / [h·(MPa / s)]. Here, the pressure deviation proportional gain is... and pressure drop rate compensation gain It can be updated, but it should not be automatically changed without constraints by the treatment system during a single reinjection. Before the treatment system is put into operation, branch flow tests and pressure response tests can be conducted using clean water or qualified new slurry to establish initial values ​​for the pressure deviation proportional gain and pressure drop rate compensation gain. After the treatment system is put into operation, based on the pressure recovery time, maximum overshoot, and flow fluctuation records of the target injection object during each reinjection, corrections are made according to a controlled step size. For example, if the pressure recovery of the target injection object is too slow and no overshoot occurs, the pressure deviation proportional gain can be adjusted. Increase by approximately 10%; when the pressure of the target injection object shows significant overshoot or cyclical fluctuations, the pressure deviation proportional gain can be increased. Reduce by 10%–20%; if the response to rapid pressure drop is insufficient, the pressure drop rate can be slightly increased to compensate for the gain. When pressure sensor noise causes frequent changes in injection flow, the pressure drop rate is reduced to compensate for the gain. Alternatively, add filtering.

[0139] Preferably, during automatic reinjection control, the automatic injection control cycle is 1 second, and the flow rate change in a single cycle does not exceed 1.6 m³ / h. When the actual pressure of the soil chamber... satisfy: After 5 seconds, grouting is stopped (this indicates that the actual pressure inside the soil chamber has returned to within 0.005 MPa below the target pressure; continuing grouting could easily cause pressure overshoot, therefore grouting is stopped; -0.005 MPa represents the allowable negative deviation of the actual pressure in the soil chamber relative to the target pressure); when the actual pressure in the soil chamber... Immediately stop the pump and open the pressure relief return valve 96 when P is reached. ≥0.08MPa or ≤-0.01MPa / s, while Q q When =0, the processing system isolates the upstream recycled slurry and switches to a new slurry emergency unit (the new slurry emergency unit will be described in detail in the following embodiments).

[0140] See Figure 1 and Figure 7 In an optional embodiment of the present invention, the above-mentioned processing system may further include a control unit and a new slurry emergency unit 10. The control unit may consist of modules such as a data acquisition gateway, a PLC isolation communication module, an independent PLC, a field touchscreen, and a data recording and processing chip. This control unit can communicate with various sensors, electromagnetic valves, and pumps in the processing system to read liquid level, pressure, flow rate, and slurry detection results, and control the switching of at least two receiving tanks, the circulation pump 31, the diversion valve group 6, the metering pump, the reinjection pump 91, and various electromagnetic valves, and save batch processing records to achieve a closed-loop negative feedback loop of receiving, homogenizing, desanding, detecting, diverting, compensating, re-inspecting, and permitting reinjection of the recovered slurry.

[0141] The new slurry emergency unit 10 includes a new slurry pipe and two series-connected shut-off valves, an emergency pneumatic valve, a check valve, and a removable blind flange installed on the new slurry pipe. One end of the new slurry pipe is connected to the new slurry source, and the other end is connected to the input end of the reinjection pump 91. The new slurry pipe and the receiving pipe adopt a double isolation and check structure; only in emergency situations or when the new slurry mode is manually selected, the emergency pneumatic valve in the new slurry emergency unit 10 is controlled and activated to inject the required new slurry from the new slurry source into the injection target. For example, when the target pressure P of the soil chamber... t =0.24MPa, the actual pressure P of the treated earth chamber c=0.15MPa, pressure deviation is 0.09MPa, and the liquid level in the qualified slurry storage tank is below 20%, Q q =0 and reaches the emergency threshold. The control unit closes the slurry outlet pipe and the receiving pipe, and after confirming that the valve is closed, it opens the new slurry emergency unit 10 to replenish the new slurry into the upper injection port of the external air cushion chamber or soil chamber using the existing hose pump. After the pressure is restored, the emergency slurry replenishment stops, and the detection unit is kept in the re-inspection state.

[0142] Embodiments of the present invention also provide a treatment and control method for a slurry recovery system of a small slurry mode earth pressure balance shield tunneling machine based on the above embodiments, which may specifically include the following steps:

[0143] Step 11: Start and control at least two receiving tanks in the homogenizing receiving unit 2 to alternately receive the slurry separated by the solid-liquid separation system of the shield tunneling water-bearing slag to the preset liquid level position in the corresponding receiving tank. At the same time, control and lock the corresponding receiving tank to homogenize the recovered slurry. It should be noted that only one receiving tank is allowed to receive slurry at the same time. After the slurry received in the current receiving tank reaches 85% liquid level, close its receiving port, lock the batch, and switch to another receiving tank. The locked receiving tank is stirred for 3 minutes. If the online density difference detected in the tank is still greater than 0.02 g / cm³ in the last 30 seconds, the stirring is extended to 5 minutes.

[0144] Step 12: Control the opening of the slurry outlet valve and homogenization return valve on the corresponding receiving tank, start and control the circulating desanding unit 3 to desand the homogenized slurry, and at the same time control the circulating desanding unit 3 to transport the desanded slurry back to the corresponding receiving tank; preferably, when desanding, the rated flow rate of the circulating pump 31 in the circulating desanding unit 3 is set to 16m³ / h, the head is set to 25m, the inlet pressure of the hydrocyclone 32 is controlled at 0.15MPa~0.25MPa, and the desanding time is 2min~4min.

[0145] Step 13: Start and control the detection unit to perform performance testing on the desanded slurry, and classify the slurry based on the performance test results; the performance test results include the relative density of the slurry. slurry relative viscosity Relative filtrate loss of slurry slurry relative conductivity and the relative sand content of the slurry ;

[0146] Step 14: When the performance test result indicates that the slurry after sand removal is a first-grade slurry, start and control the qualified slurry storage tank 81 in the slurry storage unit to receive and store the slurry after sand removal in the corresponding receiving tank; when the performance test result indicates that the slurry after sand removal is a third-grade slurry, start and control the waste slurry storage tank 82 in the slurry storage unit to receive and store the slurry after sand removal in the corresponding receiving tank; when the performance test result indicates that the slurry after sand removal is a second-grade slurry, start and control the quantitative compensation unit 7 to add a quantitative target solution to the corresponding receiving tank.

[0147] Step 15: When both the slurry index and the soil pressure index are met, start and control the reinjection unit 9 to reinject the slurry in the qualified slurry storage tank 81 into the target injection object.

[0148] In this embodiment, when performing performance testing on the desanded slurry, the first detection unit 4 continuously detects for 60 seconds at a bypass flow rate of 8 L / min, and obtains the current indicators of the desanded slurry in the receiving tank, specifically including: current density. Current conductivity and current apparent viscosity Simultaneously, the median of the corresponding index within 60 seconds is taken; when the slurry is locked after sand removal in the current receiving tank, the current sand content of the slurry is periodically detected by the second detection unit 5. and the current filter vector ;

[0149] Furthermore, regarding the current density Current conductivity Current apparent viscosity Current sand content and the current filter vector Normalization is performed to obtain the performance test results corresponding to the slurry; preferably, the normalization process is as follows:

[0150]

[0151]

[0152]

[0153]

[0154]

[0155] in, , , , , These represent the reference density, reference conductivity, reference apparent viscosity, reference sand content, and reference filtrate loss of the reference slurry, respectively. Here, the reference slurry is the newly prepared slurry actually used on-site each time a new formation segment is entered or a batch of bentonite or polymer is changed. The corresponding reference performance is obtained from testing at 25°C. Here, performance test results are expressed as relative values ​​to avoid misjudgments caused by absolute differences in values ​​between different bentonite batches, different water sources, and different formations.

[0156] Furthermore, based on the performance test results, the slurry after sand removal in the current receiving tank is classified into different grades, specifically:

[0157] When the relative density of the slurry Within the first preset density range, the relative viscosity of the slurry Within the first preset viscosity range, the relative filtrate loss of the slurry Less than or equal to the first filtration loss threshold, slurry relative conductivity Less than or equal to the first conductivity threshold and the relative sand content of the slurry When the sand content is less than or equal to the first sand content threshold, the sand-removed slurry in the current receiving tank is determined as Grade I slurry (qualified slurry that can be directly reused); in a specific achievable example, the first preset density range can be [0.98, 1.08], the first preset viscosity range can be [0.90, 1.20], the first filtration loss threshold can be 1.5, the first conductivity threshold can be 1.5, and the first sand content threshold can be 2.0%.

[0158] When the relative density of the slurry Within the second preset density range, the relative viscosity of the slurry Within the second viscosity preset range, the relative filtrate loss of the slurry Less than or equal to the second filtration loss threshold, slurry relative conductivity Less than or equal to the second conductivity threshold and the relative sand content of the slurry When the sand content is less than or equal to the second sand content threshold, the slurry after sand removal in the current receiving tank is determined as secondary slurry (slurry to be qualified that needs compensation); in a specific feasible example, the second density preset range can be [0, 90, 1.15], the second viscosity preset range can be [0.70, 1.50], the second filtration loss threshold can be 2.0, the second conductivity threshold can be 3.0, and the second sand content threshold can be 4.0%.

[0159] If any performance test result of the desanded slurry in the current receiving tank exceeds the judgment standard of secondary slurry, the desanded slurry in the current receiving tank will be determined as tertiary slurry (non-reusable waste slurry).

[0160] After determining the slurry level, the diversion valve group 6 can be controlled by the control unit to divert the slurry of the corresponding level. Specifically, the first slurry is diverted to the qualified slurry storage tank 81 for storage. At the same time, when the slurry index and the soil chamber pressure index are both met, the automatic reinjection program is started to reinject the first-level slurry into the target injection object. The third-level slurry is diverted to the waste slurry storage tank 82 for storage, and the quantitative compensation program is started for the second-level slurry.

[0161] Quantitative compensation is then performed based on the current indicators of the recovered slurry obtained from the detection. Specifically:

[0162] When the current density of the recovered slurry is detected to be higher than the target density ρ t Using density ρ w When the density of clean water decreases, the volume of clean water to be added is V. w =V r (ρ r -ρ t ) / (ρ t -ρ w In the formula, V r To determine the volume of slurry in the receiving tank for the current batch, ρ r To determine the current density of the recovered slurry; after determining the volume of clean water to be added, the clean water to be added is transported to the mixer 74 through the first compensation branch 71;

[0163] When the current density of the recovered slurry is detected to be lower than the target density ρ t Using density ρ c When increasing the density of bentonite slurry, the volume of slurry to be added is V. c =V r (ρ t -ρ r ) / (ρ c -ρ t It should be noted that only ρ c >ρ t This formula is valid when the condition is met; otherwise, the control unit will disable the calculation and prompt the user to prepare the concentrated slurry again.

[0164] Since adding water or bentonite concentrate alters the sand content, apparent viscosity, filtration loss, and salt content of the slurry, polymer compensation is required via a third compensation branch 73 in conjunction with either the first compensation branch 71 or the second compensation branch 72. During polymer compensation, the amount of polymer solution to be added can be determined based on the slurry's response coefficient. Simultaneously, the determined amount of polymer solution is input into the mixer 74 via the third compensation branch 73. The mixer 74 then thoroughly mixes the water with the polymer solution, or the bentonite concentrate with the polymer solution, before conveying it to the corresponding receiving tank for subsequent processes (re-entering the detection unit for rapid detection and necessary slow verification, as well as subsequent reinjection or disposal processes). When adding polymer solution to mixer 74 for the first time, the initial actual addition amount is 25% of the calculated amount. After circulating and mixing in mixer 74 for 3 minutes, the amount is measured again. Then, the amount is increased by 10% to 25% of the remaining calculated amount to avoid over-addition at one time. When the conductivity of the slurry in the receiving tank increases significantly after the polymer solution in mixer 74 is added to the receiving tank, the amount is compensated quantitatively with freshly prepared low-salt bentonite slurry and water, and the addition of polymer is not used as the only compensation method.

[0165] It should be noted that if the slurry in the current batch receiving tank is slurry that is not yet qualified, it can be compensated a maximum of three times. After the three compensations are completed, if the test results of the corresponding slurry still cannot meet the qualified slurry quota requirements, or if the liquid level in the corresponding receiving tank reaches 90% after cumulative compensation, the slurry in the corresponding receiving tank can be identified as waste slurry and forcibly transferred to the waste slurry storage tank 82.

[0166] Preferably, the amount of polymer solution added is determined based on the response coefficient of the slurry, which can be specifically expressed as follows:

[0167]

[0168] Where i represents the i-th polymer solution to be added; Represents the calculated dosing volume of the i-th polymer solution; This represents the effective deviation of the target index that needs to be corrected by the i-th polymer solution (for indices that need to be improved, it is calculated as "target value minus current value"; for indices that need to be reduced, it is calculated as "current value minus target value"). When the value is ≤0, it indicates that there is no compensation requirement in the corresponding direction, and the polymer metering branch is not activated; in a specific feasible example, the effective deviation of the target index can be the effective deviation of viscosity and the effective deviation of filtrate loss, wherein the effective deviation of viscosity... and effective deviation of filtration loss They can be represented as: , When the viscosity of the slurry funnel needs to be increased, the target viscosity is adopted. Subtract current viscosity When the slurry filtrate loss needs to be reduced, the current filtrate loss rate should be used. Subtract the target filtration loss This ensures that both types of indicators, once defined according to the prescribed direction, will have positive values ​​indicating the degree of compensation required. This indicates the effective slurry volume in the receiving tank of the currently locked batch; This represents the response coefficient of the slurry after adding a unit amount of polymer solution to a unit volume of slurry. This represents the maximum permissible volume of the i-th polymer solution in a single round or batch, used to prevent overdosing in a single instance.

[0169] Preferably, the response coefficient K i The parameters can be obtained through three-point calibration, either on-site or in the laboratory, and should be recorded according to the formation section, the source of the slurry in the tank, the batch and concentration of the polymer solution. For different types of polymer solutions, corresponding response coefficients K should be established separately. i .

[0170] During three-point calibration, three or four samples of equal volume were taken from the same batch of slurry to be treated. One sample served as a blank control, while the other three samples were added with three known amounts of the same type of polymer solution to be calibrated (low, medium, and high concentrations, respectively). Each sample was stirred at the same intensity and for a 3-minute settling time as in the field. The initial properties of the slurry before adding the polymer solution were measured. Changes in the slurry after adding the polymer solution to be calibrated (Here, the index of the slurry can be the apparent viscosity or density of the slurry.) For the j-th calibration point, first calculate the amount of polymer solution added per unit volume of slurry. and indicator change :

[0171]

[0172]

[0173] in, The mass of the polymer solution to be calibrated added at the j-th calibration point. To calibrate the sample volume; if the index change With the amount added For approximate linearity, the slope can be obtained using least squares through the origin. :

[0174]

[0175] Response coefficient The unit is determined by both the slurry's index and the polymer solution's measurement method. For example, when the slurry's index is apparent viscosity and the polymer solution is measured by the volume of the matured polymer solution, the response coefficient... It can be expressed as "s·m³ / L"; when the slurry index is density and the polymer solution is measured by the volume of bentonite slurry, the response coefficient is... This can be expressed as "(g / cm³)·m³ / L". If the three calibration points do not show monotonically changing or have poor linear correlation, samples should be prepared again, or piecewise response coefficients should be used in the low-dose and high-dose regions respectively. A distorted average value should not be used directly. It should be noted that after changing the polymer solution concentration, the basic formulation of the polymer solution, or the main formation section in the field, the calibrator should be recalibrated or the response coefficients should be updated with the most recent valid batch of slurry from the receiving tank. .

[0176] During automatic re-injection, continuous calculation is performed. and Slurry quality permit Q q With earthwork pressure demand permit Q p When the value is 1, select one of the three reinjection pipeline branches and adjust according to the target flow rate. Control the reinjection unit to perform reinjection.

[0177] In practical applications, the processing system provided by the above embodiments of the present invention, in which each unit is combined according to specific fluid paths, batch switching methods, detection and grading rules, quantitative compensation closed loops, and reinjection interlocking relationships, forms a complete equipment chain of "receiving homogenization—circulating desanding—rapid detection and periodic verification—primary, secondary, and tertiary grading—secondary quantitative compensation—primary slurry storage—selective reinjection according to pressure requirements". The specific process of its continuous operation includes the following steps:

[0178] Step 21: The recovered slurry discharged from the upstream solid-liquid separation system enters the receiving tank of the recovered slurry treatment system, which is currently in the receiving state, through the DN100 wear-resistant hose and the receiving interface of the recovered slurry. The pull-out protective filter basket only intercepts bolts, metal pieces and larger foreign objects that are accidentally mixed in, and does not undertake the formal sand removal and classification function.

[0179] Step 22: When the liquid level in the current receiving tank reaches the set upper limit, such as 85% of the effective volume, the recovered slurry is automatically switched to another receiving tank for continued reception; the receiving tank that has reached the batch level is locked as the current processing tank and homogenized by a stirrer for 3 to 5 minutes. The alternation of the two tanks ensures uninterrupted upstream recovery and also gives each batch of slurry a clear volume and batch number;

[0180] Step 23: The slurry in the current treatment tank enters the circulating pump through the tank outlet, and then is sent to two parallel hydrocyclones in the circulating desanding unit. The hydrocyclones enrich the sand particles in the underflow, and the sand-containing underflow enters the sealed underflow collection box through independent vertical underflow pipes; the slurry after desanding by the hydrocyclones returns to the same treatment tank through the top overflow pipe. This loop forms a closed-loop internal circulation within the tank: "receiving tank - circulating pump - hydrocyclone - original receiving tank";

[0181] Step 24: The first detection unit takes a small amount of representative slurry from the top overflow pipe and tests indicators such as density, temperature, conductivity, pH, and apparent viscosity. The tested slurry is then returned to the current processing tank. The second detection unit provides a standard sampling port and takes slurry from the top overflow pipe for manual or benchtop instrument verification of parameters such as funnel viscosity, density, sand content, and API filtration loss.

[0182] Step 25: The control unit controls the three-stage diversion valve group based on the performance test results of the first and second detection units. Primary slurry meeting the direct use standard enters the qualified slurry storage pipe via the direct reuse valve; secondary slurry requiring compensation remains in the current treatment tank and enters the quantitative compensation logic via the mixing compensation valve; tertiary slurry that is clearly unqualified or exceeds the allowable number of repairs enters the waste slurry storage tank via the non-reusable valve.

[0183] Step 26: For secondary slurry, the quantitative compensation unit adds water or bentonite slurry and matured polymer solution according to the missing indicators. The additives (water, bentonite slurry, or matured polymer solution) are sent back to the current treatment tank through the compensation return pipe after passing through the metering pump, flow meter, check valve, and static mixer; after stirring for 3 minutes, the first and second detection units re-inspect. Slurry that passes the re-inspection is reclassified as primary and enters the qualified slurry storage tank; slurry that is still secondary continues to be compensated in smaller increments, with a maximum of 3 rounds of compensation; if it is still unqualified, it is transferred to the waste slurry storage tank.

[0184] Step 27: The qualified slurry storage tank supplies slurry to the reinjection unit. When the slurry quality meets Q... q =1 and earthwork pressure requirement permits Q p When =1, the control unit selects a target branch from the existing bentonite injection pipeline branch, the external air cushion grout injection pipeline branch, or the injection pipeline branch at the upper injection port of the soil chamber, based on the current construction conditions and the availability of the reinjection pipeline branch. It then controls the corresponding pumps and valves to implement reinjection. If the recovered grout is temporarily unavailable and an emergency pressure drop occurs in the soil chamber, the emergency grout preparation unit will supply grout.

[0185] In this embodiment, the processing system is a continuous processing system based on actual pipelines and mechanical devices, with batch identification and valve-pump interlocking as its operational framework. The receiving tank continuously receives slurry, while the desanding, detection, compensation, and re-inspection of a single receiving tank are performed in a batch-closed loop. The two receiving tanks achieve both continuous receiving and batch processing through state switching. Both receiving tanks in the system adopt an open structure and eliminate manholes and tank covers, facilitating cleaning, observation, and maintenance within the limited height of the trolley. Removable splash-proof curtains reduce splashing without creating a pressurized enclosed space. Furthermore, the slurry outlet of the receiving tank is functionally separated from the lowest point sand discharge outlet. The hydrocyclone underflow, desanding return flow, detection return flow, and compensation return flow are also equipped with separate physical pipelines and interfaces, reducing manufacturing errors and underflow backmixing.

[0186] During the sand removal and testing process, the system combines fine sand removal (0.075mm to 0.15mm), rapid online indicators from the first testing unit, and periodic slow verification from the second testing unit. This protects the pump valves and prevents the 30-minute API filtration loss test from being mistaken for an immediate batch-by-batch online signal. After testing, three flow paths for the slurry are set: primary direct reuse, secondary blending compensation, and tertiary non-reusable. This ensures that slightly deviated slurry is quantitatively compensated, and severely contaminated slurry cannot be forcibly reinjected, thus avoiding slurry waste and contamination. Furthermore, the qualified slurry storage tank for primary slurry and the waste slurry storage tank for tertiary slurry are physically isolated. Swirl underflow, bottom sediment from the receiving tank, and flushing water do not enter the qualified end, reducing the risk of unqualified slurry accidentally entering the reinjection pump. When performing primary grout reinjection, the system automatically reinjects grout only when both the grout quality index and the soil pressure index are met. This avoids forced grouting when soil pressure is erratic (such as under-pressure or over-pressure), and eliminates the engineering risk of surface subsidence caused by instantaneous fluctuations in soil pressure due to abnormal grout density.

[0187] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slurry recovery system for a small-scale slurry-water mode earth pressure balance shield tunneling machine, characterized in that, include: The homogenizing receiving unit is connected to the upstream slurry outlet of the solid-liquid separation system for water-bearing slag in the shield tunnel, and is used to receive and homogenize the separated slurry. The homogeneous receiving unit includes at least two receiving tanks arranged in parallel. The circulating desanding unit is connected to the homogenizing receiving unit and is used to desand the homogenized slurry and transport the desanded slurry back to the corresponding receiving tank. The detection unit is set in the circulation loop between the circulating desanding unit and the homogenizing receiving unit, and is used to perform performance testing on the slurry after desanding. The slurry storage unit includes a qualified slurry storage tank and a waste slurry storage tank. Both the qualified slurry storage tank and the waste slurry storage tank are connected to the homogenization receiving unit. The qualified slurry storage tank is used to store slurry with a performance test result indicating level 1, and the waste slurry storage tank is used to store slurry with a performance test result indicating level 3. A quantitative compensation unit, connected to the homogenization receiving unit, is used to add a quantitative target solution to the homogenization receiving unit when the performance test result indicates a secondary level. as well as The reinjection unit is connected at one end to the qualified slurry storage tank and at the other end to at least one injection target; it is used to reinject the slurry in the qualified slurry storage tank into the target injection target when both the slurry index and the soil pressure index are met.

2. The slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine according to claim 1, characterized in that, At least two receiving tanks, including a first receiving tank and a second receiving tank, are arranged longitudinally along the tunnel between the existing I-beams of the same side trolley, and are arranged side by side; and / or The top of the first receiving tank and the top of the second receiving tank are each provided with a receiving port, a sand removal return port, a detection return port and a compensation port. The receiving port is connected to the upstream slurry outlet through a receiving pipe. The sand removal return port is connected to the top overflow port of the circulating sand removal unit through a top overflow pipe. The detection return port is connected to the detection unit through a detection return pipe. The compensation port is connected to the output end of the quantitative compensation unit through a compensation return pipe. and / or Both the first receiving tank and the second receiving tank are provided with side overflow ports, which are connected to the inlet of the waste slurry storage tank via safety overflow pipes; and / or The bottom of the first receiving tank and the bottom of the second receiving tank are provided with a tank body slurry outlet and a sand discharge outlet. The tank body slurry outlets are respectively connected to the side inlet of the circulating sand removal unit, the inlet of the qualified slurry storage tank, and the inlet of the waste slurry storage tank through slurry outlet pipes. The sand discharge outlets are connected to the waste slurry storage tank through sand discharge pipes.

3. The slurry recovery system for the earth pressure balance shield tunneling machine in the small slurry mode according to claim 2, characterized in that, The circulating sand removal unit includes, A circulation pump, wherein the circulation pump is mounted on the slurry outlet pipe; A hydrocyclone is disposed at the discharge end of the circulating pump, and the side inlet of the hydrocyclone is connected to the discharge end of the circulating pump through a main feed pipe. A top overflow port is provided at the top of the hydrocyclone. An underflow collection box is located at the bottom of the hydrocyclone and is connected to the underflow port at the bottom of the hydrocyclone.

4. The slurry recovery system for the earth pressure balance shield tunneling machine in the small slurry mode according to claim 2, characterized in that, The detection reflux tube includes: The first detection return pipe has one end connected to the overflow port at the top of the circulating sand removal unit and the other end connected to the detection return port; and The second detection return pipe has one end connected to the overflow port at the top of the circulating sand removal unit, and the other end connected to the detection return port.

5. The slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine according to claim 4, characterized in that, The detection unit includes; The first detection unit is installed on the first detection return pipe and is used to continuously detect the density, temperature, conductivity, pH and apparent viscosity of the slurry after sand removal. as well as The second detection unit is installed on the second detection return pipe and is used to periodically detect the sand content of the desanding slurry and the API filtration loss. Preferably, the first detection unit includes a detection shut-off valve, a circulating sampling pump, a densitometer, a temperature sensor, a conductivity sensor, a pH sensor, an apparent viscometer, a transparent flow cup, and a detection reflux valve arranged along the first detection reflux pipeline. The detection shut-off valve is located near the top overflow port, and the detection reflux valve is located near the detection reflux port. Preferably, the second detection unit includes a detection sampling valve, a Marsh funnel interface, a mud hydrometer interface, a sand content detection interface, and an API filtration loss detection interface arranged sequentially along the second detection reflux pipe.

6. The slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine according to claim 2, characterized in that, The slurry outlet pipe includes: The main slurry outlet pipe is connected at one end to the slurry outlet. The first slurry outlet branch pipe has one end connected to the other end of the slurry outlet main pipe and the other end connected to the side inlet of the circulating sand removal unit, and a slurry outlet valve is provided on the first slurry outlet branch pipe. The second slurry outlet branch pipe has one end connected to the other end of the main slurry outlet pipe and the other end connected to the inlet of the qualified slurry storage tank, and a direct reuse valve is installed on the second slurry outlet branch pipe; and The third slurry outlet branch pipe has one end connected to the other end of the main slurry outlet pipe and the other end connected to the inlet of the waste slurry storage tank. The third slurry outlet branch pipe is equipped with a non-reusable valve.

7. The slurry recovery system for a small-scale slurry-mode earth pressure balance shield tunneling machine according to claim 2, characterized in that, The quantitative compensation unit includes: The mixer's output is connected to one end of the compensation return pipe; The first compensation branch is connected at one end to the input end of the mixer and at the other end to the external first feeding unit; The second compensation branch has one end connected to the input terminal of the mixer and the other end connected to the external second feeding unit; and The third compensation branch is connected at one end to the input end of the mixer and at the other end to the external third feeding unit; Preferably, the first compensation branch, the second compensation branch, and the third compensation branch are each equipped with a metering pump, a first flow meter, and a compensation check valve.

8. The slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine according to claim 1, characterized in that, The reinjection unit includes: The reinjection pump has its input end connected to the outlet of the qualified slurry storage tank; and The main reinjection pipeline is connected at one end to the output end of the reinjection pump, and at the other end to the corresponding target injection object through injection pipeline branches.

9. The slurry recovery system for a small-scale slurry mode earth pressure balance shield tunneling machine according to claim 11, characterized in that, The reinjection pump inlet is sequentially equipped with a first reinjection shut-off valve, a flexible connection pipeline, an inlet pressure sensor, and a low-pressure protection switch; and / or The reinjection main pipeline is sequentially equipped with a pulsation damper, a second flow meter, an outlet pressure sensor, a first reinjection check valve, and a pressure relief return valve; and / or An automatic clamp valve, a second back-injection check valve, a second back-injection shut-off valve, a pressure gauge, and a detachable and washable short pipe are sequentially installed on the injection pipeline branch.

10. The slurry recovery system for a small-scale slurry-mode earth pressure balance shield tunneling machine according to claim 1, characterized in that, The slurry storage unit further includes: A qualified inlet valve, a homogenizing agitator, a first level gauge, a level switch, a storage sampling valve, and a quality permitting valve are installed on the qualified slurry storage tank; and / or The waste slurry storage tank is equipped with a non-reusable inlet valve, a second level gauge, a discharge pump, and an external conveying interface.

11. A treatment and control method for a slurry recovery system based on a small slurry mode earth pressure balance shield tunneling machine according to any one of claims 1 to 10, characterized in that, Includes the following steps: Start and control at least two receiving tanks in the homogenizing receiving unit to alternately receive the slurry separated by the solid-liquid separation system of the shield tunnel's water-bearing slag to the preset liquid level position in the corresponding receiving tank, while controlling and locking the corresponding receiving tank to homogenize the recovered slurry. Control the opening of the slurry outlet valve and homogenization return valve on the corresponding receiving tank, start and control the circulating desanding unit to desand the homogenized slurry, and at the same time control the circulating desanding unit to transport the desanded slurry back to the corresponding receiving tank; The detection unit is started and controlled to perform performance testing on the desanded slurry, and the slurry is classified into different grades based on the performance test results. The performance test results include the relative density of the slurry, the relative viscosity of the slurry, the relative filtrate loss of the slurry, the relative conductivity of the slurry, and the sand content of the slurry. When the performance test results indicate that the desanded slurry is a first-grade slurry, the qualified slurry storage tank in the slurry storage unit is started and controlled to receive and store the desanded slurry in the corresponding receiving tank. When the performance test results indicate that the slurry after sand removal is a third-grade slurry, the waste slurry storage tank in the slurry storage unit is started and controlled to receive and store the sand-removed slurry in the corresponding receiving tank. When the performance test results indicate that the slurry after sand removal is a secondary slurry, the quantitative compensation unit is activated and controlled to add a quantitative target solution to the corresponding receiving tank. When both the slurry index and the soil pressure index are met, the reinjection unit is started and controlled to reinject the slurry in the qualified slurry storage tank into the target injection object.

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