A three-stage concentration circulation treatment system for shield tunneling mud water

Abstract

The present invention discloses a three-stage concentration circulation treatment system for shield slurry. In the treatment system, a slurry making unit is connected to a slurry mixing unit, the slurry outlet of the slurry mixing unit is connected to a slurry balance shield, the slurry discharge port of the slurry balance shield is connected to a secondary screening unit, the secondary screening unit is connected to a slurry storage tank sand flushing unit, the slurry storage tank sand flushing unit is connected to a cyclone unit, the underflow discharge port of the cyclone unit is connected to a vibrating screening and dewatering unit, the screened slurry in the vibrating screening and dewatering unit flows back into the slurry storage tank sand flushing unit, the overflow outlet of the cyclone unit is connected to a sedimentation tank unit, the sedimentation tank unit is connected to the slurry mixing unit, the waste slurry transfer outlet of the slurry mixing unit is connected to a waste slurry treatment unit, and the liquid outlet of the waste slurry treatment unit is respectively connected to the sedimentation tank unit and the three-stage concentration unit. The advantages of the present invention are: a centrifuge and a filter press are used in a coordinated treatment mode; the centrifuge reduces the specific gravity of the circulating slurry as a supplement to the cyclone screening, slows down the change of slurry indicators, and reduces the number of slurry adjustments.

Description

Technical Field

[0001] The invention belongs to the technical field of shield slurry treatment, and in particular relates to a three-stage concentration circulation treatment system for shield slurry. Background Art

[0002] The slurry shield stabilizes the soil in front of it through mud with adjustable pressure as it cuts the soil in front of it. Because the slurry shield is completely sealed during the entire excavation process, its stability to the stratum is better than that of the earth pressure shield. Therefore, the slurry shield is becoming more and more popular due to its better stability and more reliable safety.

[0003] The slurry shield cuts the soil in front with the cutter head. After cutting, the soil is mixed with the mud in the excavation chamber and enters the mud discharge pipeline through the mud door set at the bottom of the shield. The mud discharge pipeline is then transported to the ground mud and water treatment plant, and the mud and water transported to the ground are subjected to multi-stage separation treatment by the mud and water treatment plant.

[0004] When a slurry shield tunnels through clay, silt, highly weathered, or fully weathered strata, the cyclone's separation performance decreases due to the high viscosity and high concentration of fine particles in the slurry. Fine clay particles gradually accumulate in the slurry after treatment with the secondary separation equipment. If not promptly removed, the slurry's specific gravity and viscosity increase, directly reducing the slurry's slag-carrying capacity and the pumping capacity of the circulation system, ultimately reducing the slurry shield's tunneling efficiency.

[0005] The most important thing is to control the density of the incoming slurry so that it remains relatively stable during excavation in a given stratum. This is because it is not necessary to replace the slurry with clean water until the density of the circulating slurry deteriorates, the circulating pump becomes overloaded, or the shield machine becomes unable to push due to excessive torque. This is to prevent the slurry circulation system from overflowing and causing large amounts of slurry to be discarded.

[0006] Based on this, those skilled in the art are in urgent need of a system device capable of performing three-stage concentration cycle treatment. Summary of the Invention

[0007] The purpose of the present invention is to provide a three-stage concentration circulation treatment system for shield mud water based on the above-mentioned shortcomings of the existing technology. The three-stage concentration circulation treatment system performs secondary concentration through a cyclone unit, and realizes three-stage concentration of the slurry through the coordinated work of a filter press and a centrifuge. As a supplement to the cyclone screening, it slows down the changes in mud indicators and reduces the number of mud adjustments.

[0008] The purpose of the present invention is achieved by the following technical solutions:

[0009] A three-stage concentration circulation treatment system for shield slurry, characterized in that the treatment system includes a pulping unit, a pulp mixing unit, a waste pulp treatment unit, a secondary screening unit, a slurry storage tank sand flushing unit, a cyclone unit, a vibrating screening dehydration unit, a sedimentation tank unit, a secondary concentration unit and a three-stage concentration unit, wherein the pulping unit is connected to the pulp mixing unit, the slurry outlet on the pulp mixing unit is connected to the slurry balance shield for mud intake, the mud discharge port of the slurry balance shield is connected to the secondary screening unit, the secondary screening unit is connected to the slurry storage tank sand flushing unit, the cyclone unit, the vibrating screening dehydration unit, the sedimentation tank unit, the secondary concentration unit and the three-stage concentration unit, wherein the pulping unit is connected to the pulp mixing unit, the slurry outlet on the pulp mixing unit is connected to the slurry balance shield for mud intake, the mud discharge port of the slurry balance shield is connected to the secondary screening unit, the secondary screening unit is connected to the slurry storage tank sand flushing unit The sand unit, the slurry storage tank sand flushing unit is connected to the cyclone unit, the bottom flow outlet of the cyclone unit is connected to the vibrating screening dewatering unit, the screened slurry in the vibrating screening dewatering unit flows back to the slurry storage tank sand flushing unit, the overflow outlet of the cyclone unit is connected to the sedimentation tank unit, the sedimentation tank unit is connected to the slurry mixing unit, the waste slurry transfer outlet of the slurry mixing unit is connected to the waste slurry treatment unit, and the liquid outlet of the waste slurry treatment unit is connected to the sedimentation tank unit and the tertiary concentration unit respectively through the secondary concentration unit.

[0010] The pulping unit includes a clear water tank, a new pulp tank and an ash tank. The ash tank feeds materials to the new pulp tank to prepare bentonite slurry. The water outlet of the clear water tank is provided with a clear water pump. The clear water pump pumps the clear water in the clear water tank into the new pulp tank and the pulping unit respectively. The new pulp tank is provided with a pulping stirring device. The pulp outlet of the new pulp tank is provided with a slurry feeding pump and is connected to the pulping unit through the slurry feeding pump.

[0011] The slurry mixing unit includes a slurry mixing pool, a slurry mixing stirring device is provided in the slurry mixing pool, a first pump is provided at the slurry outlet of the slurry mixing pool, and a waste slurry pump is provided at the waste slurry outlet. The first pump is connected to the slurry balance shield, and the waste slurry pump is connected to the waste slurry treatment unit. One of the pipelines of the clean water pump pumps the clean water in the clean water pool into the slurry mixing pool.

[0012] The slurry shield is discharged through a second pump, and a distributor is provided between the second pump and the secondary screening unit; the secondary screening unit includes a bulk separator and a pre-screening device, and the mud discharge pipeline extending from the distributor is bifurcated into a first mud discharge branch pipe and a second mud discharge branch pipe, and a conversion valve is provided at the bifurcation, wherein the first mud discharge branch pipe is connected to the bulk separator, the second mud discharge branch pipe is connected to the pre-screening device, and the liquid outlet end of the bulk separator is connected to the pre-screening device; the conversion valve is adjusted according to the current The stratum being excavated is used to control the mud discharge branch to be switched. If the slurry shield is excavating in a silt layer, the conversion valve is connected to the first mud discharge branch, and the large block separator separates the soil blocks or silt clumps with a block diameter greater than 50 mm and then enters the pre-screening device for secondary screening. The pre-screening device screens out sand and gravel or small mud clumps with a particle size of 3-50 mm; if the slurry shield is excavating in a sand layer or rock layer, the conversion valve is connected to the second mud discharge branch, and the pre-screening screens out sand and gravel or small mud clumps with a particle size of 3-50 mm.

[0013] The slurry tank sand flushing unit includes a slurry tank and a slurry pump, and the slurry tank receives and stores the slurry pre-screened by the secondary screening unit;

[0014] The cyclone unit includes a primary cyclone group and a secondary cyclone group. The primary cyclone group includes a primary slurry inlet pipe, a primary overflow pipe, and a plurality of primary cyclones. The slurry inlet of each primary cyclone is connected in parallel to the primary slurry inlet pipe, and the overflow of each primary cyclone is connected in parallel to the primary overflow pipe. The secondary cyclone group includes a secondary overflow pipe and a plurality of secondary cyclones. The slurry inlet of each secondary cyclone is connected in parallel to the primary overflow pipe, and the overflow of each secondary cyclone is connected in parallel to the secondary overflow pipe.

[0015] The slurry delivery pump pumps the slurry in the slurry storage tank to the first-level slurry inlet pipe and enters the slurry inlet of each first-level cyclone respectively; the underflow discharge port of each first-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit; the overflow port of each first-level cyclone flows the overflow slurry into the slurry inlet of each second-level cyclone through the first-level overflow pipe; the underflow discharge port of each second-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit; the overflow port of each second-level cyclone conveys the overflow slurry to the sedimentation tank unit through the second-level overflow pipe; the vibrating screening and dehydration unit screens out the sand particles of 0.045-3 mm in the underflow slurry, and the screened underflow slurry is sieved into the slurry storage tank.

[0016] The primary cyclone comprises a cyclone housing, a slurry inlet is provided on the side wall of the cyclone housing, and the slurry inlet pipe is tangent to the cyclone housing; the bottom end of the cyclone housing is provided with the underflow outlet, and the underflow outlet is installed with a paddle-type discharger, the paddle-type discharger consisting of two rubber sheets with side edges sealed together, the upper parts of the two rubber sheets forming a circular interface for sealing connection with the underflow outlet, and the lower parts of the two rubber sheets are detachably fitted; a sleeve is coaxially mounted on the upper end of the cyclone housing, the sleeve is connected to the inner cavity of the cyclone housing, the sleeve is provided with an overflow port and an inner cavity pressure regulating device; the circular interface of the paddle-type discharger is sleeved on the outside of the underflow outlet and is tightened by a sleeve to achieve a sealed connection; the inner cavity pressure regulating device comprises a pressure relief valve and a booster pump; a through hole is provided on the bottom edge of the rubber sheet, and a binding rubber band is inserted into the through hole.

[0017] The lower end of the first-level overflow pipe is set at a height lower than the paddle-type discharger on the first-level cyclone; the structure of the second-level cyclone is the same as that of the first-level cyclone; the lower end of the second-level overflow pipe is set at a height lower than the paddle-type discharger on the second-level cyclone.

[0018] The sedimentation tank unit is composed of several sedimentation tanks connected in sequence, and the liquid outlet of the sedimentation tank at the end is connected to the pulp mixing tank; the waste pulp treatment unit includes a waste pulp tank and a waste pulp stirring device arranged in the waste pulp tank, and the waste pulp pump on the pulp mixing tank transfers the waste pulp to the waste pulp tank; the pulp outlet on the waste pulp tank is connected to the secondary concentration unit through a pulp pump, and the secondary concentration unit concentrates the waste pulp into low-density mud and high-concentration mud, wherein the low-density mud is introduced into the sedimentation tank at the starting end, and the high-concentration mud is introduced into the tertiary concentration unit.

[0019] The three-stage concentration unit includes an underflow tank, a filtrate tank, a filter press and a centrifuge. The underflow tank receives the high-concentration mud delivered by the secondary concentration unit. The underflow tank is provided with an underflow stirring device. Two liquid outlets are provided on the underflow tank, one of which is connected to the filter press via a filter press pump, and the other liquid outlet is connected to the centrifuge via a third pump. The filter press filters the clay particles smaller than 0.045 mm in the high-concentration mud into cakes and transports the filtrate water generated by the filtration into the filtrate tank. The centrifuge separates the clay particles smaller than 0.045 mm in the high-concentration mud and transports the separated filtrate water into the filtrate tank; the filtrate water in the filtrate tank is transported into the slurry mixing tank.

[0020] The advantages of the present invention are:

[0021] (1) Use a centrifuge and filter press to coordinate the treatment process; the centrifuge is used in online mode to reduce the specific gravity of the circulating mud, which serves as a supplement to the cyclone screening, slowing down the change of mud indicators, reducing the number of mud adjustments, and saving the cost of pulping; the filter press is used to treat the discharged waste slurry, and the centrifuge is introduced in offline working mode to coordinate the filter press to treat the waste slurry;

[0022] (2) The cyclone is equipped with an inner cavity pressure regulating device on its overflow pipe and a paddle-type discharger on its bottom flow outlet to achieve reasonable adjustment of the bottom flow density and provide suitable slurry for the downstream dewatering screen. Its maximum bottom flow concentration can reach 85%; the inner cavity pressure regulating device changes with the changes in the inlet slurry concentration and inlet pressure, so that the bottom flow concentration is constant and the classification efficiency is improved; the siphon effect makes the outlet pressure lower than that of the ordinary cyclone, and the inlet pressure is low, thereby reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the principle of the three-stage concentration and circulation treatment system for shield tunneling mud water in the present invention;

[0024] Figure 2 Schematic diagram of the structure of the cyclone unit in the present invention;

[0025] Figure 3 Schematic diagram of the structure of the first-stage cyclone in the present invention;

[0026] Figure 4 A partial detailed view of the paddle-type discharger provided at the underflow discharge outlet of the first-stage cyclone in the present invention;

[0027] Figure 5 This is a front view of the paddle-type discharger provided at the underflow outlet of the first-stage cyclone in the present invention. DETAILED DESCRIPTION

[0028] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art:

[0029] like Figure 1-5 , the marks in the figure are: cyclone shell 1, casing 2, slurry inlet 3, overflow port 4, pressure relief valve 5, booster pump 6, paddle-type discharger 7, hoop 8, first-level overflow pipe 9, and binding rubber band 10.

[0030] Example: Figure 1As shown, this embodiment specifically relates to a three-stage concentration circulation treatment system for shield mud and water, which includes a pulping unit, a pulping unit, a waste pulp treatment unit, a secondary screening unit, a pulp storage tank sand washing unit, a cyclone unit, a vibration screening dehydration unit, a sedimentation tank unit, a secondary concentration unit and a tertiary concentration unit; wherein the pulping unit is connected to the pulping unit, the pulp outlet on the pulping unit is connected to the slurry balance shield for mud intake, and the mud discharge port of the slurry balance shield is used to discharge mud and is connected to the slurry balance shield through a distributor. The secondary screening unit is connected to the slurry tank sand flushing unit, the slurry tank sand flushing unit is connected to the cyclone unit, the underflow outlet of the cyclone unit is connected to the vibrating screening and dewatering unit, and the screened slurry in the vibrating screening and dewatering unit flows back to the slurry tank sand flushing unit, the overflow outlet of the cyclone unit is connected to the sedimentation tank unit, the sedimentation tank unit is connected to the slurry mixing unit, the waste slurry transfer outlet of the slurry mixing unit is connected to the waste slurry treatment unit, and the liquid outlet of the waste slurry treatment unit is connected to the sedimentation tank unit and the tertiary concentration unit respectively through the secondary concentration unit.

[0031] like Figure 1 As shown, the pulping unit includes a clear water tank, a new pulp tank and an ash tank, wherein the ash tank stores bentonite raw materials and is used to transport the bentonite raw materials to the new pulp tank, and the clear water tank pumps clear water into the new pulp tank and into the pulp mixing tank of the pulp mixing unit through a clear water pump. A plurality of pulping and stirring equipment are provided in the new pulp tank, and the bentonite and clear water are stirred and mixed by the pulping and stirring equipment to prepare bentonite slurry; a slurry feeding pump is provided at the slurry outlet of the new pulp tank, and the slurry feeding pump is bifurcated into two paths, one of which pumps out the bentonite slurry in the new pulp tank and then transports it back to the new pulp tank for circulating slurrying, and the discharge port of the ash tank is provided in the circulating slurrying pipeline to mix with the bentonite slurry; the other path is connected to the pulp mixing tank to replenish the pulp mixing tank with new slurry, that is, to replenish the newly prepared bentonite slurry into it.

[0032] like Figure 1 As shown, the slurry mixing unit includes a slurry mixing tank, which is equipped with slurry mixing equipment. The slurry outlet of the slurry mixing tank is equipped with a first pump and a waste slurry pump. The first pump is connected to the slurry balance shield to transport the prepared slurry into the slurry balance shield (i.e., mud inlet). The waste slurry pump is connected to the waste slurry treatment unit (waste slurry tank). One of the pipelines of the clean water pump pumps clean water from the clean water tank into the slurry mixing tank. From the perspective of the entire three-stage concentration circulation treatment system, the slurry that has undergone screening and secondary cyclone screening flows into the slurry mixing tank of the slurry mixing unit after multi-stage sedimentation in the sedimentation tank unit. The filtrate water after the tertiary concentration treatment flows into the slurry mixing tank and is mixed with the newly prepared bentonite slurry and clean water to obtain slurry that meets the requirements and is pumped into the slurry balance shield. The mud concentration can be measured by monitoring with a hydrometer.

[0033] like Figure 1As shown, a shield circulation pipeline is provided in the slurry shield for use during the excavation process. The sludge containing mud generated during the excavation process is discharged through the second pump (mud discharge pump) therein. A plurality of mud treatment lines with the same structure are provided on site. The discharged sludge containing mud is distributed through a distributor, and the distributed sludge containing mud enters a secondary screening unit; the secondary screening unit includes a bulk separator and a pre-screening device. The mud discharge pipeline extending from the distributor is bifurcated into a first mud discharge branch pipe and a second mud discharge branch pipe, and a switching valve is provided at the bifurcation between the two. The switching valve is used to control the mud discharge branch pipe to be connected, wherein the first mud discharge branch pipe is connected to the bulk separator, and the second mud discharge branch pipe is connected to the pre-screening device, and the liquid outlet end of the bulk separator is located above the material distribution end of the pre-screening device; the switching valve controls the mud discharge branch pipe to be switched on according to the stratum currently excavated by the slurry shield; specifically:

[0034] If the slurry shield is excavating in a silt layer, the slag-containing slurry will contain large-sized soil blocks and silt clumps. Therefore, the switching valve is connected to the first mud discharge branch pipe. The large-block separator is specifically a scraper device structure. The large-block separator scrapes out soil blocks or silt clumps with a diameter greater than 50mm in the slag-containing slurry. After that, the slurry enters the distribution end of the pre-screening device for secondary screening. The pre-screening device screens out sand and gravel or small mud clumps with a particle size of 3-50mm.

[0035] If the slurry shield is excavating in a sand layer or rock layer, the switching valve is controlled to connect the second mud branch pipe, and the slag-containing mud enters the distribution end of the pre-screening device, which screens out sand and gravel or small mud clumps with a particle size of 3-50mm.

[0036] like Figure 1 As shown, the slurry tank sand flushing unit includes a slurry tank and a slurry pump. The slurry tank receives and stores the slurry pre-screened by the secondary screening unit. The slurry pump is used to pump the slurry in the slurry tank to the cyclone unit for secondary concentration.

[0037] like Figure 1-2As shown, the cyclone unit specifically includes a primary cyclone group and a secondary cyclone group; the primary cyclone group includes a primary slurry inlet pipe, a primary overflow pipe and several primary cyclones, the slurry inlet of each primary cyclone is connected in parallel to the primary slurry inlet pipe, and the overflow of each primary cyclone is connected in parallel to the primary overflow pipe; the secondary cyclone group includes a secondary overflow pipe and several secondary cyclones, the slurry inlet of each secondary cyclone is connected in parallel to the primary overflow pipe, and the overflow of each secondary cyclone is connected in parallel to the secondary overflow pipe. The slurry pump of the slurry storage tank pumps the slurry in the slurry storage tank to the first-level slurry inlet pipe and enters the slurry inlet of each first-level cyclone respectively. The underflow discharge port of each first-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit. The overflow port of each first-level cyclone flows the overflow slurry into the slurry inlet of each second-level cyclone through the first-level overflow pipe; the underflow discharge port of each second-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit, and the overflow port of each second-level cyclone conveys the overflow slurry to the sedimentation tank unit through the second-level overflow pipe; the vibrating screening and dehydration unit screens out the sand particles of 0.045-3mm in the underflow slurry, and the screened underflow slurry passes through the screen and flows back to the slurry storage tank.

[0038] like Figure 1-5 As shown, the structure of the primary cyclone and the secondary cyclone is identical, differing only in some dimensional parameters. This embodiment uses the structure of the primary cyclone as an example for illustration. The primary cyclone comprises a cyclone housing 1, with a slurry inlet 3 defined on its sidewall. A casing 2 is coaxially mounted on the upper end of the cyclone housing 1, equipped with an overflow port 4 and a corresponding internal pressure regulating device. The lower end of the cyclone housing 1 forms an underflow outlet, connected to a paddle-type discharger 7. The combined use of the internal pressure regulating device and the paddle-type discharger 7 allows for reasonable adjustment of the underflow density, providing suitable slurry for the downstream dewatering screen. The cyclone shell 1 is composed of two parts, namely an upper cylindrical shell and a lower conical shell that is wider at the top and narrower at the bottom. The slurry inlet 3 on the cylindrical shell is connected to a first-stage slurry inlet pipe for conveying slurry into the cyclone shell 1. The upper opening of the cyclone shell 1 is open and coaxially arranged with the casing 2 for closure. The casing 2 is provided with an overflow port 4, which is used to connect to the first-stage overflow pipe 9. The lower end of the first-stage overflow pipe 9 should be lower than the height of the paddle-type discharger 7 on the bottom flow outlet so that it can utilize the siphon effect. The inner cavity pressure regulating device provided on the casing 2 is composed of a pressure relief valve 5 and a booster pump 6. The pressure relief valve 5 can reduce the pressure in the cyclone shell 1, while the booster pump 6 can increase the pressure in the cyclone shell 1, that is, the inner cavity pressure regulating device can be adjusted according to the actual pressure value. The paddle-type discharger 7 connected to the bottom flow outlet of the cyclone shell 1 is similar to a paddle from a front view, such as Figure 5As shown. Specifically, it is composed of two rubber sheets, the side edges of which are sealed and connected. The sealing connection can be made by gluing or hot-melt bonding. The upper part is combined to form a circular interface and is fitted onto the bottom flow outlet. At the same time, it is tightened and sealed by a hoop 8. The lower part of the two rubber sheets is not bonded, but is fitted in a detachable manner. That is, when the slurry is discharged, the two rubber sheets are squeezed and opened. When the slurry is not discharged, the two rubber sheets are closed. In order to further improve the fit of the two rubber sheets, a hole for threading a rope is provided on the bottom edge of the rubber sheet, and a binding rubber band 10 is passed through the hole. Under the rebound force of the binding rubber band 10, the lower parts of the two rubber sheets can be tightly fitted and will only open when squeezed by the slurry. The working method of the first-stage cyclone mainly includes the following steps: the first-stage slurry inlet pipe transports the slurry into the cylindrical shell in a horizontal tangential manner through the slurry inlet 3, thereby generating a strong three-dimensional elliptical strong rotational shear turbulent motion. Due to the different sizes of coarse particles and fine particles and liquid in the mud, they are subjected to centrifugal force, centripetal buoyancy, fluid drag, etc., and are subjected to centrifugal sedimentation. The coarse particles in the slurry are discharged through the bottom flow outlet of the cyclone, while most of the fine particles and the liquid they carry are discharged through the first-stage overflow pipe 9, thereby achieving the purpose of separation and classification; It should be noted that since the lower end of the first-stage overflow pipe 9 There is a certain height difference between the outlet and the paddle-type discharger 7, which will produce a siphon phenomenon, and the siphon phenomenon will generate an upward suction force in the cyclone shell 1; the paddle-type discharger 7 can seal the inner cavity of the cyclone shell 1, and under the action of the upward suction force and the action of the coarse-grained mud, the opening amplitude of the two rubber sheets can be controlled to adjust the concentration change of the underflow slurry. In addition, the inner cavity pressure regulating device can actively regulate the inner cavity pressure, allowing a small amount of air to enter the inner cavity of the cyclone shell 1, so that the upward suction force changes, so as to select the optimal underflow concentration and overflow concentration.

[0039] like Figure 1 As shown, the sedimentation tank unit is composed of several sedimentation tanks connected in sequence to perform multi-stage sedimentation. The overflow slurry of the cyclone unit flows into the sedimentation tank at the starting end, and the outlet of the sedimentation tank at the end is connected to the slurry mixing tank to transport the slurry that has completed precipitation into the slurry mixing tank.

[0040] like Figure 1 As shown, the waste slurry processing unit includes a waste slurry pool and several waste slurry stirring devices arranged in the waste slurry pool. The waste slurry pump on the slurry mixing pool transfers the waste slurry to the waste slurry pool; the slurry outlet on the waste slurry pool is connected to the secondary concentration unit through a slurry pump, and the waste slurry output from the waste slurry pool is concentrated and screened by the secondary concentration unit, that is, the waste slurry is separated into low-density mud and high-concentration mud, wherein the low-density mud is introduced into the sedimentation tank at the starting end, and the high-concentration mud is introduced into the tertiary concentration unit.

[0041] like Figure 1 As shown, the three-stage concentration unit includes an underflow tank, a filtrate tank, a filter press and a centrifuge. The underflow tank receives the high-concentration mud delivered by the secondary concentration unit. An underflow stirring device is provided in the underflow tank. Two liquid outlets are provided on the underflow tank, one of which is connected to the filter press through a filter press pump, and the other is connected to the centrifuge through a third pump. The filter press filters the clay particles smaller than 0.045 mm in the high-concentration mud into cakes and transports them out, and the filtrate water produced by the filtration is transported into the filtrate tank. The centrifuge separates the clay particles smaller than 0.045 mm in the high-concentration mud and transports the separated filtrate water into the filtrate tank; the filtrate water in the filtrate tank is transported into the slurry mixing tank.

[0042] The advantages of this embodiment are:

[0043] (1) Use a centrifuge and filter press to coordinate the treatment process; the centrifuge is used in online mode to reduce the specific gravity of the circulating mud, which serves as a supplement to the cyclone screening, slowing down the change of mud indicators, reducing the number of mud adjustments, and saving the cost of pulping; the filter press is used to treat the discharged waste slurry, and the centrifuge is introduced in offline working mode to coordinate the filter press to treat the waste slurry;

[0044] (2) The cyclone is equipped with an inner cavity pressure regulating device on its overflow pipe and a paddle-type discharger on its bottom flow outlet to achieve reasonable adjustment of the bottom flow density and provide suitable slurry for the downstream dewatering screen. Its maximum bottom flow concentration can reach 85%; the inner cavity pressure regulating device changes with the changes in the inlet slurry concentration and inlet pressure, so that the bottom flow concentration is constant and the classification efficiency is improved; the siphon effect makes the outlet pressure lower than that of the ordinary cyclone, and the inlet pressure is low, thereby reducing energy consumption.

Claims

1. A three-stage concentration and circulation treatment system for shield tunneling mud water, characterized in that The processing system includes a pulping unit, a pulp mixing unit, a waste pulp treatment unit, a secondary screening unit, a pulp storage tank sand flushing unit, a cyclone unit, a vibrating screening dewatering unit, a sedimentation tank unit, a secondary concentration unit and a tertiary concentration unit, wherein the pulping unit is connected to the pulp mixing unit, the pulp outlet on the pulp mixing unit is connected to the slurry balance shield to feed mud, the mud discharge port of the slurry balance shield is connected to the secondary screening unit, the secondary screening unit is connected to the pulp storage tank sand flushing unit, the pulp storage tank sand flushing unit is connected to the cyclone unit, the underflow discharge port of the cyclone unit is connected to the vibrating screening dewatering unit, the screened slurry in the vibrating screening dewatering unit flows back to the pulp storage tank sand flushing unit, the overflow outlet of the cyclone unit is connected to the sedimentation tank unit, the sedimentation tank unit is connected to the pulp mixing unit, the waste pulp transfer outlet of the pulp mixing unit is connected to the waste pulp treatment unit, and the liquid outlet of the waste pulp treatment unit is respectively connected to the sedimentation tank unit and the tertiary concentration unit via the secondary concentration unit; The slurry tank sand flushing unit includes a slurry tank and a slurry pump, and the slurry tank receives and stores the slurry pre-screened by the secondary screening unit; The cyclone unit includes a primary cyclone group and a secondary cyclone group. The primary cyclone group includes a primary slurry inlet pipe, a primary overflow pipe, and a plurality of primary cyclones. The slurry inlet of each primary cyclone is connected in parallel to the primary slurry inlet pipe, and the overflow of each primary cyclone is connected in parallel to the primary overflow pipe. The secondary cyclone group includes a secondary overflow pipe and a plurality of secondary cyclones. The slurry inlet of each secondary cyclone is connected in parallel to the primary overflow pipe, and the overflow of each secondary cyclone is connected in parallel to the secondary overflow pipe. The slurry delivery pump pumps the slurry in the slurry storage tank to the first-level slurry inlet pipe and enters the slurry inlet of each first-level cyclone respectively. The underflow outlet of each first-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit. The overflow outlet of each first-level cyclone flows the overflow slurry into the slurry inlet of each second-level cyclone through the first-level overflow pipe; the underflow outlet of each second-level cyclone conveys the underflow slurry to the vibrating screening and dehydration unit. The overflow outlet of each second-level cyclone conveys the overflow slurry to the sedimentation tank unit through the second-level overflow pipe; the vibrating screening and dehydration unit screens out the sand particles of 0.045-3 mm in the underflow slurry, and the screened underflow slurry is sieved into the slurry storage tank; The primary cyclone comprises a cyclone housing, a slurry inlet is provided on the side wall of the cyclone housing, and the slurry inlet pipe is tangent to the cyclone housing; the bottom end of the cyclone housing is provided with the underflow outlet, and the underflow outlet is installed with a paddle-type discharger, the paddle-type discharger consisting of two rubber sheets with side edges sealed together, the upper parts of the two rubber sheets forming a circular interface for sealing connection with the underflow outlet, and the lower parts of the two rubber sheets are detachably fitted; a sleeve is coaxially mounted on the upper end of the cyclone housing, the sleeve is connected to the inner cavity of the cyclone housing, the sleeve is provided with an overflow port and an inner cavity pressure regulating device; the circular interface of the paddle-type discharger is sleeved on the outside of the underflow outlet and is tightened by a sleeve to achieve a sealed connection; the inner cavity pressure regulating device comprises a pressure relief valve and a booster pump; a through hole is provided on the bottom edge of the rubber sheet, and a binding rubber band is inserted into the through hole.

2. A three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 1, characterized in that The pulping unit includes a clear water tank, a new pulp tank and an ash tank. The ash tank feeds materials to the new pulp tank to prepare bentonite slurry. The water outlet of the clear water tank is provided with a clear water pump. The clear water pump pumps the clear water in the clear water tank into the new pulp tank and the pulping unit respectively. The new pulp tank is provided with a pulping stirring device. The pulp outlet of the new pulp tank is provided with a slurry feeding pump and is connected to the pulping unit through the slurry feeding pump.

3. A three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 2, characterized in that The slurry mixing unit includes a slurry mixing pool, a slurry mixing stirring device is provided in the slurry mixing pool, a first pump is provided at the slurry outlet of the slurry mixing pool, and a waste slurry pump is provided at the waste slurry outlet. The first pump is connected to the slurry balance shield, and the waste slurry pump is connected to the waste slurry treatment unit. One of the pipelines of the clean water pump pumps the clean water in the clean water pool into the slurry mixing pool.

4. A three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 3, characterized in that The slurry shield is discharged through a second pump, and a distributor is provided between the second pump and the secondary screening unit; the secondary screening unit includes a bulk separator and a pre-screening device, and the mud discharge pipeline extending from the distributor is bifurcated into a first mud discharge branch pipe and a second mud discharge branch pipe, and a conversion valve is provided at the bifurcation, wherein the first mud discharge branch pipe is connected to the bulk separator, the second mud discharge branch pipe is connected to the pre-screening device, and the liquid outlet end of the bulk separator is connected to the pre-screening device; the conversion valve is adjusted according to the current The stratum being excavated is used to control the mud discharge branch to be switched. If the slurry shield is excavating in a silt layer, the conversion valve is connected to the first mud discharge branch, and the large block separator separates the soil blocks or silt clumps with a block diameter greater than 50 mm and then enters the pre-screening device for secondary screening. The pre-screening device screens out sand and gravel or small mud clumps with a particle size of 3-50 mm; if the slurry shield is excavating in a sand layer or rock layer, the conversion valve is connected to the second mud discharge branch, and the pre-screening screens out sand and gravel or small mud clumps with a particle size of 3-50 mm.

5. The three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 1 is characterized in that The lower end of the first-level overflow pipe is set at a height lower than the paddle-type discharger on the first-level cyclone; the structure of the second-level cyclone is the same as that of the first-level cyclone; the lower end of the second-level overflow pipe is set at a height lower than the paddle-type discharger on the second-level cyclone.

6. A three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 3, characterized in that The sedimentation tank unit is composed of several sedimentation tanks connected in sequence, and the liquid outlet of the sedimentation tank at the end is connected to the pulp mixing tank; the waste pulp treatment unit includes a waste pulp tank and a waste pulp stirring device arranged in the waste pulp tank, and the waste pulp pump on the pulp mixing tank transfers the waste pulp to the waste pulp tank; the pulp outlet on the waste pulp tank is connected to the secondary concentration unit through a pulp pump, and the secondary concentration unit concentrates the waste pulp into low-density mud and high-concentration mud, wherein the low-density mud is introduced into the sedimentation tank at the starting end, and the high-concentration mud is introduced into the tertiary concentration unit.

7. A three-stage concentration and circulation treatment system for shield tunneling mud water according to claim 6, characterized in that The three-stage concentration unit includes an underflow tank, a filtrate tank, a filter press and a centrifuge. The underflow tank receives the high-concentration mud delivered by the secondary concentration unit. The underflow tank is provided with an underflow stirring device. Two liquid outlets are provided on the underflow tank, one of which is connected to the filter press via a filter press pump, and the other liquid outlet is connected to the centrifuge via a third pump. The filter press filters the clay particles smaller than 0.045 mm in the high-concentration mud into cakes and transports the filtrate water generated by the filtration into the filtrate tank. The centrifuge separates the clay particles smaller than 0.045 mm in the high-concentration mud and transports the separated filtrate water into the filtrate tank; the filtrate water in the filtrate tank is transported into the slurry mixing tank.

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