CN112780289A

CN112780289A - Dual-mode shield muck treatment system

Info

Publication number: CN112780289A
Application number: CN202011634882.9A
Authority: CN
Inventors: 邓涛; 郭涛; 杜涛; 刘光鑫; 郑军; 高旭东; 杨鹏; 王钰辰
Original assignee: China Railway Engineering Service Co Ltd
Current assignee: China Railway Engineering Service Co Ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-11
Anticipated expiration: 2040-12-31
Also published as: CN112780289B

Abstract

The invention belongs to the technical field of shield muck treatment, and particularly relates to a dual-mode shield muck treatment system, which solves the problem that a shield muck treatment system in the prior art cannot switch muck treatment processes along with the mode of an earth pressure-slurry shield. The invention comprises the following steps: a mud-water separation system: the device is used for carrying out mud-water separation on the muck discharged by the shield tunneling machine; a sand treatment system: the sand washing and dewatering device is used for washing and dewatering the sand separated by the mud-water separation system; a size mixing system: the slurry mixing device is used for mixing water separated by the slurry separation system into slurry required by a slurry shield mode of the shield machine; tail slurry treatment system: the system is used for treating waste liquid generated by the mud-water separation system, the sand treatment system and the size mixing system; and the slurry mixing system is respectively connected with the mud-water separation system and the shield tunneling machine through pipelines. The invention can simultaneously meet the treatment of the muck generated by two shield modes, reduces the equipment cost and the cost, and is suitable for the treatment of the muck of the shield.

Description

Dual-mode shield muck treatment system

Technical Field

The invention belongs to the technical field of shield muck treatment, and particularly relates to a dual-mode shield muck treatment system.

Background

At present, the construction of underground space in China is as hot as possible, and the shield construction method is widely adopted due to the advantages of good construction safety, high tunneling efficiency, low tunneling cost, wide applicable stratum, small influence on ground traffic and facilities, no influence of weather conditions on construction and the like.

In the process of the earth pressure shield tunneling, due to the reasons of stratum water content, slag soil improvement in the tunneling process and the like, the output slag soil has more water content and is even in a semi-flowing state. At present, most of shield muck treatment modes are direct outward transportation for yard treatment, and the high water content of the shield muck causes the disadvantages of low transportation efficiency of the direct outward transportation mode, easy spilling and leakage in the transportation process, dust raising and noise generation and the like, thereby greatly affecting the urban environment; the piling of the large amount of high water content shield muck wastes a large amount of national soil resources, occupies large-scale cultivated land, is unstable in piling of the water content muck, is easy to cause geological disasters such as landslide and collapse, and is also one of the main sources of sand dust pollution and surface and underground water pollution. Therefore, local governments and environmental protection departments have strict restriction policies on the discharge of the muck, and normal shield construction is also severely restricted. The shield muck also contains a large amount of inorganic raw materials which can be used for shield grouting and infrastructure construction, and can generate huge economic value through conversion, and the current direct outward transportation and stacking and filling treatment is huge waste of homeland resources. In slurry shield tunneling, part of slurry in the muck is treated and then is injected back to the shield machine for recycling, but the slurry which cannot be recycled faces the same environmental protection transportation problem as the soil pressure balance shield, and meanwhile, inorganic raw materials which can be utilized in the muck of the slurry shield are not considered.

Meanwhile, the existing shield is mostly in an earth pressure-slurry shield double mode, multiple shield tunneling mode switching needs may exist in the same interval, when the shield machine switches modes, single earth pressure or slurry shield muck treatment equipment is difficult to meet the use requirements, equipment needs to be repeatedly input, the equipment cost is increased, the site is rearranged, and the problem is faced by the bottleneck of lack of the site.

The slurry shield is required to firstly ensure the quality of the circulating slurry, and the main parameters are the specific gravity and the viscosity of the slurry, so as to ensure that the circulating slurry can easily convey excavated soil and sand to the ground; can inhibit the spraying of underground water (oil, gas, etc.); the cutting machine has cooling and lubricating functions on the cutting equipment such as a cutter head, a cutter head and the like. The above requirements result in that the original slurry can not be sprayed in large scale in the process, otherwise the slurry can not be recycled.

The earth pressure balance shield does not need to recycle the mud, and the difficult problems of dry underground unearthing, easy conglomeration and high mud content are how to complete the grading solid-liquid separation of coarse sand, fine sand and mud cakes. This requires a powerful spray system and water treatment capacity for the process configuration.

Therefore, an effective process flow is urgently needed, the muck treatment process can be switched along with the mode of the earth pressure-slurry shield, the requirement of shield tunneling under a dual mode is met, meanwhile, the muck is effectively and quickly treated, the reduced transportation, the graded resource utilization and the environmental protection treatment of the muck of the shield are realized, the muck transportation cost of a construction unit is reduced, waste is changed into wealth, available inorganic raw materials and scarce water resources are recycled, the low emission and even zero emission of the muck pollutants of the shield are realized.

Disclosure of Invention

Aiming at the problem that the shield muck treatment system in the prior art cannot switch muck treatment process along with the mode of the earth pressure-slurry shield, the invention provides a dual-mode shield muck treatment system and a dual-mode shield muck treatment method, and aims to: the shield tunneling requirements under two modes of the earth pressure shield and the slurry shield are met, equipment investment is reduced, occupation of a construction site is reduced, and cost is reduced.

The technical scheme adopted by the invention is as follows:

a dual mode shield muck treatment system comprising:

a mud-water separation system: the device is used for carrying out mud-water separation on the muck discharged by the shield tunneling machine;

a sand treatment system: the sand washing and dewatering device is used for washing and dewatering the sand separated by the mud-water separation system;

a size mixing system: the slurry mixing device is used for mixing water separated by the slurry separation system into slurry required by a slurry shield mode of the shield machine;

tail slurry treatment system: the system is used for treating waste liquid generated by the mud-water separation system, the sand treatment system and the size mixing system;

and the slurry mixing system is respectively connected with the mud-water separation system and the shield tunneling machine through pipelines.

After the technical scheme is adopted, when a slurry shield mode is adopted, the slurry mixing system can utilize slurry separated by the slurry-water separation system to prepare slurry required by slurry shield tunneling, when an earth pressure balance shield mode is adopted, a pipeline between the slurry mixing system and the slurry-water separation system and a pipeline between the slurry mixing system and a shield tunneling machine are disconnected, the treatment of residue soil generated by the two shield modes can be met only by one set of equipment, the equipment cost is reduced, the quick switching can be realized, the downtime is reduced, the cost is reduced, sand and water can be treated by the sand treatment system and the tailing treatment system, available inorganic raw materials and scarce water resources are recycled, and the emission of pollutants is reduced.

Preferably, the mud-water separation system comprises a first mud-water separation module and a second mud-water separation module, the first mud-water separation module comprises a first-level vibrating screen, a coarse screening conical tank, a first-level intermediate tank and a coarse sand conveyor, the coarse sand conveyor is arranged below a discharge port of the first-level vibrating screen, the coarse screening conical tank is arranged below the first-level vibrating screen, the second mud-water separation module comprises a first-level swirler, a second-level vibrating screen, a conveyor, a fine sand conical tank and a second-level intermediate tank, a feed inlet of the first-level swirler is communicated with the coarse screening conical tank, a sand discharge port of the first-level swirler is connected with the second-level vibrating screen, a discharge port of the second-level vibrating screen is arranged above the conveyor, the fine sand conical tank is arranged below the second-level vibrating screen, an overflow port of the first-level swirler is communicated with the feed inlet of the first-level intermediate tank, the first-level intermediate tank is respectively connected with, the fine sand cone tank is connected with the secondary cyclone, an overflow port of the secondary cyclone is connected with a feed inlet of the secondary intermediate tank, the conveyor and the coarse sand conveyor are connected with the sand treatment system, and the secondary intermediate tank is respectively connected with the fine sand cone tank and the size mixing system.

After the optimal scheme is adopted, the gravels with different particle sizes can be obtained through two-stage screening, and the mud and the fine sand can be more thoroughly separated through two-stage cyclone, so that the recovery rate of inorganic raw materials is improved.

Preferably, the lower end of the first-stage tundish is provided with a first drainage port and a second drainage port, the first drainage port is located below a feed inlet of the first-stage tundish, a partition plate with an upper opening is arranged inside the first-stage tundish, the first drainage port and the second drainage port are respectively located on two sides of the partition plate, a first float switch is arranged in the coarse screening conical tank and matched with the lower end of the first drainage port, and the second drainage port is communicated with the fine sand conical tank.

When the water level in the coarse screening conical tank is too low, a gap between the first floating ball switch and the first water drainage port is enlarged, so that all overflow liquid in the primary cyclone enters the coarse screening conical tank, the water level in the coarse screening conical tank is raised, the situation that the pump is empty-sucked due to too low water level in the coarse screening conical tank is prevented, and the pump is prevented from being damaged; when the water level in the coarse screening conical tank is too high, the gap between the first floating ball switch and the first water discharge port is completely closed, so that all overflow liquid in the primary cyclone flows into the fine sand conical tank from the second water discharge port, and the overflow of water in the coarse screening conical tank is prevented. By adopting the preferred scheme, the water level in the coarse screening conical tank can be ensured to be always in a reasonable range.

Preferably, the lower end of the secondary intermediate tank is provided with a third water outlet and a fourth water outlet, the third water outlet is positioned below the feed inlet of the secondary intermediate tank, a partition plate with an opening at the upper part is arranged in the secondary intermediate tank, the third water outlet and the fourth water outlet are respectively positioned at two sides of the partition plate, a second float switch is arranged in the fine sand conical tank, the second float switch is matched with the lower end of the third water outlet, and the fourth water outlet is communicated with the size mixing system and the tail pulp treatment system.

When the water level in the fine sand cone tank is too low, a gap between the second floating ball switch and the third water outlet is enlarged, so that all overflow liquid in the secondary cyclone enters the fine sand cone tank, the water level in the fine sand cone tank is raised, the situation that the pump is empty-sucked due to too low water level in the fine sand cone tank is prevented, and the damage of the pump is avoided; when the water level in the fine sand cone tank is too high, the gap between the second floating ball switch and the third water outlet is completely closed, so that all overflow liquid in the secondary cyclone flows into the multistage sedimentation tank from the fourth water outlet, and the overflow of water in the fine sand cone tank is prevented. By adopting the preferred scheme, the water level in the fine sand cone tank can be ensured to be always in a reasonable range.

Preferably, a spraying system is arranged above the first-stage vibrating screen and the second-stage vibrating screen and is connected with the tail slurry treatment system.

Because the dregs water content that adopts the balanced shield mode of soil pressure to produce is lower, easily bonds into a group, adopts this preferred scheme after, and spraying system can spray the dregs on one-level shale shaker and the second grade shale shaker to improve mud-water separation's efficiency, prevent that the screen cloth is plugged up to the dregs.

Preferably, the number of the second mud-water separation modules is several, and the several second mud-water separation modules are connected in parallel.

After the preferable scheme is adopted, the treatment efficiency of mud-water separation can be improved, and the number of the second mud-water separation modules is adjusted according to the treatment capacity of the residue soil.

As preferred, the sand processing system comprises a first sand processing module and a second sand processing module, the first sand processing module comprises a coarse sand crusher, a three-level finished coarse sand dewatering screen, a finished sand conical tank and a three-level swirler, a discharge port of the coarse sand crusher is positioned above the three-level finished coarse sand dewatering screen, the three-level finished coarse sand dewatering screen is positioned above the finished sand conical tank, a sand discharge port of the three-level swirler is positioned above the three-level finished coarse sand dewatering screen, the finished sand conical tank is communicated with a feed port of the three-level swirler, the second sand processing module comprises a four-level swirler, a sand washing machine tail slurry tank, an impeller sand washing machine and a four-level sand washing machine dewatering screen, a sand outlet of the impeller sand washing machine is communicated with the four-level sand washing machine dewatering screen, the four-level sand washing machine dewatering screen is positioned above the sand washing machine tail slurry tank, the sand discharge port of the four-level swirler is positioned above the four-level sand washing machine, the feed inlet and the mill tail slurry groove intercommunication of level four swirler, the overflow mouth of tertiary swirler and the overflow mouth of level four swirler all communicate with tail slurry processing system, impeller sand washer and tertiary finished product coarse sand dewatering screen all communicate with tail slurry processing system.

After the preferred scheme is adopted, the first sand processing module can crush, screen and swirl oversize materials of the primary vibrating screen to prepare coarse sand; the second sand processing module can perform sand washing, screening and rotational flow on oversize products of the secondary vibrating screen to prepare medium and fine sand. Through the operation, the sand and stone can be recycled in a grading way, and the mud content of coarse sand and fine sand can be reduced.

Preferably, the number of the second sand treatment modules is several, and the several second sand treatment modules are connected in parallel.

After the preferable scheme is adopted, the sand treatment efficiency can be improved, and the number of the second sand treatment modules can be adjusted according to the treatment capacity of the residue soil.

Preferably, the slurry mixing system comprises a clean water tank, a multistage sedimentation tank, a slurry mixing tank, a bentonite slurrying machine, a raw slurry tank and a CMC mixing tank, wherein the clean water tank is respectively communicated with the bentonite slurrying machine, the raw slurry tank and the CMC mixing tank through pipelines, a discharge port of the bentonite slurrying machine is respectively communicated with the slurry mixing tank and the raw slurry tank, a discharge port of the CMC mixing tank is respectively communicated with the raw slurry tank and the slurry mixing tank, a discharge port of the raw slurry tank is communicated with the slurry mixing tank, the multistage sedimentation tank is used for precipitating stone powder in slurry discharged by a slurry-water separation system, an overflow port of the multistage sedimentation tank is communicated with the slurry mixing tank, and a discharge port of the slurry mixing tank is respectively communicated with the shield tunneling machine and the tail slurry treatment system.

After the preferable scheme is adopted, the multistage sedimentation tank can carry out multistage sedimentation on the slurry discharged from the secondary intermediate tank, because the impurity content of stone powder and the like in the slurry discharged from the secondary intermediate tank is high, after sedimentation is carried out for a certain time (because the slurry discharge amount of the multistage sedimentation tank is large, the sedimentation time cannot be particularly long), the upper clean slurry with proper concentration is obtained (the clean slurry in the upper clean slurry is low in impurity content), the slurry mixing system utilizes the upper clean slurry to prepare the slurry for slurry shield tunneling, and the slurry is conveyed to the shield tunneling machine by a pipeline, and the redundant slurry in the slurry mixing tank can be conveyed to the overflow tank by the pipeline for storage.

Preferably, tail-stock processing system includes overflow tank, flocculation tank, charge device, pressure filter and filtrating pond, the overflow tank is used for holding the waste liquid that mud-water separation system, sand processing system and size mixing system produced, and the overflow mouth and the flocculation tank intercommunication in overflow tank, charge device is connected with the flocculation tank, the mud discharge mouth and the pressure filter intercommunication of flocculation tank, the delivery port of flocculation tank and the outlet of pressure filter all communicate with the clean water basin, the clean water basin communicates with sand processing system.

After adopting this preferred scheme, the liquid that the overflow tank washed gets into and carries out the flocculation and precipitation in the flocculation jar, charge device adds flocculation reagent to the flocculation jar in, sediment after the flocculation and precipitation gets into and carries out the filter-pressing dehydration in the pressure filter and makes the mud cake, the upper clear liquid in the flocculation jar and the filtrating that the pressure filter produced get into the filtrate pond and store, water accessible pipeline in the filtrate pond carries spraying system to spray the dregs, also can carry sand processing system through the pipeline and wash the coarse sand, also can be used to sand washer centering coarse sand and carry out the sand washing, can also be used to the on-the-spot cleaning operation.

The dual-mode shield muck treatment method is carried out by adopting the dual-mode shield muck treatment system according to the following steps:

step A: treating the shield muck by adopting a slurry shield muck treatment mode or an earth pressure balance shield muck treatment mode;

and B: switching a shield muck treatment mode;

and C: and C, repeating the steps A to B.

After the technical scheme is adopted, the shield muck treatment process can be switched along with the mode of the earth pressure-slurry shield, the muck treatment generated by two shield modes can be met only by one set of equipment, the equipment investment and the site occupation are reduced, and the cost is reduced.

Preferably, the slurry shield muck treatment in the step A specifically comprises the following steps:

a 1: performing mud-water separation on the shield muck to obtain sand and stone and slurry, and performing multi-stage sedimentation on the slurry to precipitate stone powder in the slurry to the bottom to obtain clean slurry on the upper layer;

a 2: crushing, screening and washing the sandstone to obtain coarse sand and medium-fine sand;

a 3: introducing the upper layer clean slurry into a slurry mixing system for preparing slurry for shield tunneling;

a 4: sending slurry for shield tunneling into a shield machine for slurry shield construction;

a 5: storing the wastewater generated in the steps a2 and a3 into an overflow tank, and then performing flocculation precipitation on the wastewater in the overflow tank to obtain a precipitate and a supernatant;

a 6: performing filter pressing and dewatering on the precipitate after the flocculation precipitation to obtain mud cakes and filtrate;

a 7: storing the filtrate and the supernatant into a filtrate tank, and using the liquid in the filtrate tank for sand washing in the step a2 or for on-site cleaning operation.

By adopting the preferable scheme, the slurry shield muck can be recycled, coarse sand, medium and fine sand and water resources in the muck are recycled in a classified manner, the recycled upper layer clean slurry is used for preparing slurry required by shield tunneling, and the recycled water resources are used for sand washing and field flushing operation, so that the water resources are recycled, the mud cakes can be used for making bricks, the waste is changed into valuable, the transportation cost of a construction unit is reduced, and low emission and even zero emission of shield muck pollutants are realized.

Preferably, the step a1 specifically includes the following steps:

a 1.1: performing primary screening on the shield muck to obtain a solid and a first fluid;

a 1.2: carrying out primary rotational flow on the sand-containing slurry to obtain primary overflow liquid and primary sand-containing bottom flow;

a 1.3: screening the first-stage sand-containing underflow to obtain fine sand in the mud and a second fluid; one part of the primary overflow liquid returns to the first fluid, and the other part of the primary overflow liquid is merged with the second fluid;

a 1.4: performing secondary rotational flow on the second fluid to obtain secondary overflow liquid and secondary sand-containing bottom flow;

a 1.5: screening the secondary sand-containing underflow to obtain fine sand in the mud and a second fluid; one part of the secondary overflow liquid returns to the second fluid, and the other part of the secondary overflow liquid is subjected to multi-stage sedimentation.

After the preferable scheme is adopted, the two-stage screening and the two-stage rotational flow of the shield muck are realized, the separation of sand and mud is more thorough, the first-stage overflow liquid and the second-stage overflow liquid partially flow back, the liquid levels of the first fluid and the second fluid can be controlled in a reasonable range, and the damage caused by the air suction of the pump is prevented.

Preferably, the step a2 specifically includes the following steps:

a 2.1: c, crushing, screening and washing the solid obtained in the step a1.1 to obtain coarse sand and a third fluid; washing and screening the mud-containing medium fine sand obtained in the steps a1.3 and a1.5 to obtain medium fine sand and a fourth fluid;

a 2.2: performing three-stage rotational flow on the third fluid to obtain a three-stage overflow liquid and a three-stage sand-containing bottom flow; carrying out four-stage rotational flow on the fourth fluid to obtain four-stage overflow liquid and four-stage sand-containing underflow;

a 2.3: screening the tertiary sand-containing underflow, wherein oversize is coarse sand, and undersize is converged into a third fluid; and (4) screening the four-stage sand-containing underflow, wherein oversize products are medium-fine sand, and undersize products are converged into a fourth fluid.

After the optimal scheme is adopted, the inorganic raw materials in the shield muck are divided into coarse sand and medium-fine sand to be recycled, so that the recycling of the inorganic raw materials is realized, the reduction transportation of the shield muck is realized, and the emission of shield muck pollutants is reduced.

Preferably, the step a3 specifically includes the following steps:

a 3.1: fully mixing clear water and dry bentonite powder to prepare a first mixture, and fully mixing the clear water and a thickening agent to prepare a second mixture;

a 3.2: fully mixing the first mixture, the second mixture and clear water to prepare a third mixture;

a 3.3: and fully mixing the first mixture, the second mixture, the third mixture and the secondary overflow liquid subjected to multistage precipitation to prepare the slurry for shield tunneling.

After the optimal scheme is adopted, the water separated from the shield muck can be used for preparing shield tunneling slurry, so that the cyclic utilization of water resources is realized, the use of clear water is reduced, and the discharge of water in the muck is reduced.

Preferably, the specific steps of step a5 are as follows:

a 5.1: conveying the third-stage overflow liquid, the fourth-stage overflow liquid and unused slurry for shield tunneling to an overflow pool for storage;

a 5.2: and (4) sending the liquid in the overflow tank into a flocculation tank for flocculation and precipitation to obtain a precipitate and a supernatant.

Preferably, the earth pressure balance shield muck treatment in the step a specifically comprises the following steps:

b 1: spraying the shield muck in the shield muck mud-water separation process to obtain sand and stone and slurry;

b 2: crushing, screening and washing the sandstone to obtain coarse sand and medium-fine sand;

b 3: storing the slurry into an overflow tank, and then performing flocculation precipitation on the slurry in the overflow tank to obtain a precipitate and a supernatant;

b 4: performing filter pressing and dewatering on the precipitate after the flocculation precipitation to obtain mud cakes and filtrate;

b 5: the filtrate and supernatant are stored in a filtrate tank and used for spraying operation in step b1 and sand washing operation in step b2 or for on-site cleaning operation.

After the preferable scheme is adopted, the method can be used for treating the earth pressure balance shield muck, the earth pressure balance shield muck has low water content and poor liquidity, mud blocks in the muck can be dispersed through the spraying system, the screening is convenient, the screening efficiency is improved, and the earth pressure balance shield does not need mud, so that water in the muck of the shield is not used for preparing the mud, and is used for spraying, sand washing and field cleaning after being directly treated.

Preferably, the switching of the shield muck treatment mode in the step B specifically includes:

the method comprises the following steps of switching a slurry shield muck treatment mode to an earth pressure balance shield muck treatment mode:

x 1: communicating the filtrate tank with a spraying system;

x 2: closing a pulp mixing system loop;

x 3: disconnecting the pipeline between the mud in the step a1 and the multistage sedimentation tank, and communicating the pipeline between the mud in the step a1 and the overflow tank;

the method comprises the following steps of switching an earth pressure balance shield muck treatment mode to a slurry shield muck treatment mode:

y 1: disconnecting the filtrate tank from the spraying system;

y 2: starting a slurry mixing system loop;

y 3: communicating the slurry in the step a1 with a pipeline between the multistage sedimentation tanks, and disconnecting the pipeline between the slurry in the step a1 and the overflow tank.

After the adoption of the optimal scheme, the switching of the shield muck treatment modes can be completed only by opening and closing the pipeline, the operation is convenient and fast, the treatment of muck generated by a slurry shield and an earth pressure balance shield in two modes is realized, the equipment investment and the occupation of a site are reduced, and the cost is reduced.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. when the slurry shield mode is adopted, the slurry mixing system can utilize slurry separated by the slurry-water separation system to prepare slurry required by slurry shield tunneling, when the earth pressure balance shield mode is adopted, a pipeline between the slurry mixing system and the slurry-water separation system and a pipeline between the slurry mixing system and the shield tunneling machine are disconnected, only one set of equipment is needed to meet the treatment of residue soil generated by the two shield modes, the equipment cost is reduced, the quick switching can be realized, the downtime is reduced, the cost is reduced, sand and water can be treated by the sand treatment system and the tail slurry treatment system, available inorganic raw materials and scarce water resources are recycled, and the emission of pollutants is reduced.

2. Through two-stage screening, can obtain the grit of different particle diameters, through the two-stage whirl, can be with mud and more thorough of fine sand separation, improve the rate of recovery to inorganic raw materials.

3. When the water level in the coarse screening conical tank is too low, a gap between the first floating ball switch and the first water drainage port is enlarged, so that all overflow liquid in the primary cyclone enters the coarse screening conical tank, the water level in the coarse screening conical tank is raised, the situation that the pump is empty-sucked due to too low water level in the coarse screening conical tank is prevented, and the pump is prevented from being damaged; when the water level in the coarse screening conical tank is too high, the gap between the first floating ball switch and the first water discharge port is completely closed, so that all overflow liquid in the primary cyclone flows into the fine sand conical tank from the second water discharge port, and the overflow of water in the coarse screening conical tank is prevented. The water level in the coarse screening conical tank can be ensured to be always in a reasonable range.

4. When the water level in the fine sand cone tank is too low, a gap between the second floating ball switch and the third water outlet is enlarged, so that all overflow liquid in the secondary cyclone enters the fine sand cone tank, the water level in the fine sand cone tank is raised, the situation that the pump is empty-sucked due to too low water level in the fine sand cone tank is prevented, and the damage of the pump is avoided; when the water level in the fine sand cone tank is too high, the gap between the second floating ball switch and the third water outlet is completely closed, so that all overflow liquid in the secondary cyclone flows into the multistage sedimentation tank from the fourth water outlet, and the overflow of water in the fine sand cone tank is prevented. By adopting the preferred scheme, the water level in the fine sand cone tank can be ensured to be always in a reasonable range.

5. The spraying system can spray the dregs on the first-level vibrating screen and the second-level vibrating screen, so that the efficiency of mud-water separation is improved, and the dregs are prevented from plugging the screen.

6. The number of the second mud-water separation modules is several, and the second mud-water separation modules are connected in parallel, so that the mud-water separation treatment efficiency can be improved, and the number of the second mud-water separation modules can be adjusted according to the treatment capacity of the residue soil.

7. The first sand processing module can crush, screen and swirl oversize materials of the primary vibrating screen to prepare coarse sand; the second sand processing module can perform sand washing, screening and rotational flow on oversize products of the secondary vibrating screen to prepare medium and fine sand. Through the operation, the sand and stone can be recycled in a grading way, and the mud content of coarse sand and fine sand can be reduced.

8. The number of the second sand treatment modules is several, and the second sand treatment modules are connected in parallel, so that the sand treatment efficiency can be improved, and the number of the second sand treatment modules can be adjusted according to the treatment capacity of the muck.

9. The multistage sedimentation tank can carry out multistage sedimentation on the slurry discharged from the secondary intermediate tank, the impurity content of stone powder and the like in the slurry is reduced, the upper layer clean slurry with proper concentration (the cleanness means that the impurity content is low) is obtained, the slurry mixing system utilizes the upper layer clean slurry to prepare the slurry for slurry shield tunneling, the slurry is conveyed to the shield tunneling machine by a pipeline, and the redundant slurry in the slurry mixing tank can be conveyed to the overflow tank by the pipeline for storage.

10. Liquid that the overflow tank washed gets into and carries out the flocculation and precipitation in the flocculation jar, charge device adds the flocculation medicament in to the flocculation jar, sediment after the flocculation and precipitation gets into the pressure filter and carries out the filter-pressing dehydration and make the mud cake, the filtrating that supernatant and pressure filter in the flocculation jar produced gets into the filtrate pond and stores, water accessible pipeline in the filtrate pond carries spraying system to spray the dregs, also can carry sand processing system through the pipeline and wash the coarse sand, also can be used for sand washer centering coarse sand to wash the sand, can also be used to the on-the-spot cleaning operation.

11. The shield muck treatment process can be switched along with the mode of the earth pressure-slurry shield, and only one set of equipment is needed to meet the treatment of muck generated by two shield modes, so that the investment of the equipment and the occupation of a field are reduced, and the cost is reduced.

12. The slurry shield muck can be recycled, coarse sand, medium and fine sand and water resources in the muck are recycled in a classified manner, the recycled water is used for preparing slurry required by shield tunneling, washing and on-site flushing operation, the water resources are recycled, the mud cake can be used for making bricks, waste is changed into valuable, the transportation cost of a construction unit is reduced, and low emission and even zero emission of shield muck pollutants are realized.

13. The two-stage screening and the two-stage cyclone of the shield muck enable the separation of sand and mud to be more thorough, and the first-stage overflow liquid and the second-stage overflow liquid partially flow back, so that the liquid levels of the first fluid and the second fluid can be controlled in a reasonable range, and the damage caused by the air suction of a pump is prevented.

14. The inorganic raw materials in the shield muck are divided into coarse sand and medium-fine sand to be recycled, so that the recycling of the inorganic raw materials is realized, the reduction transportation of the shield muck is realized, and the emission of shield muck pollutants is reduced.

15. The water separated from the shield muck is used for preparing shield tunneling slurry, so that the recycling of water resources is realized, the use of clear water is reduced, and the discharge of water in the muck is reduced.

16. The invention can process the muck of the earth pressure balance shield, because the muck of the earth pressure balance shield has lower water content and poor liquidity, the mud blocks in the muck can be dispersed by the spraying system, the screening is convenient, the screening efficiency is improved, and the earth pressure balance shield does not need mud, so the water in the muck of the shield is not used for preparing the mud, and is used for spraying, sand washing and on-site cleaning after being directly processed.

17. The invention can complete the switching of the shield muck treatment modes only by opening and closing the pipeline, is convenient and quick, realizes the treatment of muck generated by a set of equipment in two modes of the slurry shield and the earth pressure balance shield, reduces the equipment investment and the site occupation, and reduces the cost.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic structural diagram of a slurry shield muck treatment mode;

FIG. 2 is a schematic structural diagram of a muck treatment mode of an earth pressure balance shield;

FIG. 3 is a schematic structural view of a first mud-water separation module;

FIG. 4 is a schematic structural view of a second mud-water separation module.

Wherein, 1-a first-stage vibrating screen, 2-a coarse screen conical tank, 3-a first-stage swirler, 4-a first-stage intermediate tank, 401-a first water discharge port, 402-a second water discharge port, 403-a first float switch, 5-a fine sand conical tank, 6-a second-stage swirler, 7-a second-stage vibrating screen, 8-a second-stage intermediate tank, 801-a third water discharge port, 802-a fourth water discharge port, 803-a second float switch, 9-a coarse sand conveyor, 10-a coarse sand crusher, 13-a third-stage finished coarse sand dewatering screen, 14-a finished sand conical tank, 15-a third-stage swirler, 16-a conveyor, 17-a sand washer impeller groove, 18-a sand washer impeller, 19-a fourth-stage sand washer dewatering screen, 20-a sand washer tail slurry groove and 21-a fourth-stage swirler, 22-overflow tank, 23-flocculation tank, 24-dosing device, 25-filter press, 26-filtrate tank, 27-clear water tank, 28-multistage sedimentation tank, 29-size mixing tank, 30-bentonite pulping machine, 31-raw pulp tank, 32-CMC mixing tank and 33-shield machine.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention are usually placed in when used, and are only used for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements that are referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

The present invention will be described in detail with reference to fig. 1 to 4.

A dual mode shield muck treatment system comprising:

In this embodiment, the mud-water separation system includes first mud-water separation module and second mud-water separation module. The first mud-water separation module comprises a first-stage vibrating screen 1, a coarse screening conical tank 2, a first-stage intermediate tank 4 and a coarse sand conveyor 9, wherein the coarse sand conveyor 9 is located below a discharge port of the first-stage vibrating screen 1, and the coarse screening conical tank 2 is located below the first-stage vibrating screen 1. The second mud-water separation module includes one-level swirler 3, second grade swirler 6, second grade shale shaker 7, conveyer 16, fine sand awl jar 5 and second grade pans 8, the feed inlet and the coarse screening awl jar 2 intercommunication of one-level swirler 3, the row's sand mouth and the second grade shale shaker 7 of one-level swirler 3 are connected, the discharge gate of second grade shale shaker 7 is located the top of conveyer 16, fine sand awl jar 5 is located the below of second grade shale shaker 7, the overflow mouth of one-level swirler 3 and the feed inlet intercommunication of one-level pans 4. One-level pans 4 is connected with coarse screening awl jar 2 and fine sand awl jar 5 respectively, fine sand awl jar 5 is connected with second grade swirler 6, second grade swirler 6's overflow mouth is connected with second grade pans 8's feed inlet, conveyer 16 is connected with the sand washing machine among the sand processing system for go on the sand washing operation to the oversize thing of second grade shale shaker 7, coarse sand conveyer 9 is connected with coarse sand breaker 10 among the sand processing system for carry out the breakage with the oversize thing on the one-level shale shaker 1, second grade pans 8 are connected with fine sand awl jar 5 and multistage sedimentation tank 28 among the system of sizing mixing respectively.

In this embodiment, a first drain port 401 and a second drain port 402 are disposed at a lower end of the first-stage tundish 4, the first drain port 401 is located below a feed inlet of the first-stage tundish 4, a partition plate with an upper opening is disposed inside the first-stage tundish 4, and the first drain port 401 and the second drain port 402 are respectively located on two sides of the partition plate. A first float switch 403 is arranged in the coarse screening cone tank 2, the first float switch 403 is matched with the lower end of the first water discharge port 401, and the second water discharge port 402 is communicated with the fine sand cone tank 5. The gap between the first float switch 403 and the lower end of the first drain port 401 is controlled by the water level in the coarse screening cone tank 2, so that the flow rate of the liquid in the primary intermediate tank 4 flowing into the coarse screening cone tank 2 is controlled. When the liquid level of the coarse screening cone tank 2 is too high, the float switch is closed, and the liquid in the primary intermediate tank 4 completely flows into the fine sand cone tank 5 through the second water outlet 402.

In this embodiment, the lower end of the secondary intermediate tank 8 is provided with a third water outlet 801 and a fourth water outlet 802, the third water outlet 801 is located below the feed inlet of the secondary intermediate tank 8, a partition plate with an upper opening is arranged inside the secondary intermediate tank 8, the third water outlet 801 and the fourth water outlet 802 are respectively located on two sides of the partition plate, the fine sand conical tank 5 is provided with a second float switch 803, the second float switch 803 is matched with the lower end of the third water outlet 801, and the fourth water outlet 802 is communicated with the multistage sedimentation tank 28 in the slurry mixing system and the overflow tank 22 in the tail slurry treatment system through pipes. In the slurry shield mode, the fourth water outlet 802 communicates with the pipeline between the multistage settling tanks 28 in the slurry mixing system, and the pipeline between the fourth water outlet 802 and the overflow tank 22 is closed. In the earth pressure balance shield mode, the pipeline between the fourth water outlet 802 and the multistage sedimentation tank 28 in the slurry mixing system is closed, and the pipeline between the fourth water outlet 802 and the overflow tank 22 is communicated.

In this embodiment, a spraying system is arranged above the first-stage vibrating screen 1 and the second-stage vibrating screen 7, and the spraying system is communicated with a filtrate tank 26 in the tail pulp treatment system through a pipeline. In the slurry shield mode, the pipeline between the spraying system and the filtrate tank 26 in the tail slurry treatment system is disconnected, and in the earth pressure balance shield mode, the pipeline between the spraying system and the filtrate tank 26 in the tail slurry treatment system is communicated.

In this embodiment, the number of the second mud-water separation modules is two, and the two second mud-water separation modules are connected in parallel.

In this embodiment, the sand treatment system includes a first sand treatment module and a second sand treatment module. The first sand treatment module comprises a coarse sand crusher 10, a third-level finished coarse sand dewatering screen 13, a finished sand conical tank 14 and a third-level cyclone 15. The discharge port of the coarse sand crusher 10 is positioned above the three-stage finished coarse sand dewatering screen 13, and a spraying system is arranged above the three-stage finished coarse sand dewatering screen 13 and used for spraying the three-stage finished coarse sand dewatering screen 13. The third-level finished coarse sand dewatering screen 13 is positioned above the finished sand conical tank 14, the sand discharge port of the third-level cyclone 15 is positioned above the third-level finished coarse sand dewatering screen 13, and the finished sand conical tank 14 is communicated with the feed inlet of the third-level cyclone 15. The second sand processing module comprises a four-stage cyclone 21, a sand washer tail slurry groove 20, an impeller sand washer and a four-stage sand washer dewatering screen 19. The impeller sand washer comprises a sand washer impeller groove 17 and a sand washer impeller 18 positioned in the sand washer impeller groove, a sand outlet of the sand washer impeller 18 is communicated with a four-stage sand washer dewatering screen 19, and the four-stage sand washer dewatering screen 19 is positioned above a tail slurry groove 20 of the sand washer. The sand discharge port of the four-stage cyclone 21 is positioned above a dewatering screen 19 of the four-stage sand washer, the feed inlet of the four-stage cyclone 21 is communicated with a tail slurry groove 20 of the sand washer, and the overflow port of the three-stage cyclone 15 and the overflow port of the four-stage cyclone 21 are communicated with an overflow tank 22 in a tail slurry treatment system through pipelines. A filtrate tank 26 in the tail pulp treatment system provides water sources for the sand washer impeller trough 17 and a spraying system on the third-stage finished coarse sand dewatering screen 13 through pipelines.

In this embodiment, the number of the second sand treatment modules is two, and the two second sand treatment modules are connected in parallel.

In this embodiment, the slurry mixing system includes a clean water tank 27, a multistage sedimentation tank 28, a slurry mixing tank 29, a bentonite slurrying machine 30, a virgin pulp tank 31, and a CMC mixing tank 32. The clean water basin 27 is respectively communicated with the bentonite slurrying machine 30, the primary slurry tank 31 and the CMC mixing tank 32 through pipelines, the discharge port of the bentonite slurrying machine 30 is respectively communicated with the slurry mixing tank 29 and the primary slurry tank 31, the discharge port of the CMC mixing tank 32 is respectively communicated with the primary slurry tank 31 and the slurry mixing tank 29, and the discharge port of the primary slurry tank 31 is communicated with the slurry mixing tank 29. The multistage sedimentation tank 28 is used for settling impurities such as stone powder in the slurry discharged from the fourth water discharge port 802 to obtain upper layer clean slurry, and an overflow port of the multistage sedimentation tank 28 is communicated with the slurry mixing tank 29. The discharge port of the slurry mixing tank 29 is respectively communicated with the shield machine and the overflow tank 22 in the tail slurry treatment system, and is used for providing slurry required by tunneling for the shield machine or discharging redundant slurry into the overflow tank 22 for treatment.

In this embodiment, the tail pulp treatment system includes an overflow tank 22, a flocculation tank 23, a dosing device 24, a filter press 25, and a filtrate tank 26. Overflow tank 22 is arranged in holding tertiary swirler 15, level four swirler 21 among fourth outlet 802, the sand processing system among the mud-water separation system and the waste liquid of mixing the discharge of slurry tank 29 among the system of sizing mixing, overflow tank 22's overflow mouth and flocculation tank 23 intercommunication, charge device 24 is connected with flocculation tank 23, flocculation tank 23's row mud mouth and pressure filter 25 intercommunication, flocculation tank 23's delivery port and pressure filter 25's outlet all communicate with filtrating pond 26, filtrating pond 26 and the sand washer impeller groove 17 among the sand processing system and the intercommunication of the spraying system on the tertiary finished product coarse sand dewatering screen 13.

step A: processing the shield muck by adopting one of a slurry shield muck processing mode or an earth pressure balance shield muck processing mode;

and B: switching a shield muck treatment mode;

and C: and C, repeating the steps A to B.

In this embodiment, the slurry shield muck treatment in step a specifically includes the following steps:

In this embodiment, the step a1 specifically includes the following steps:

a 1.1: performing primary screening on the shield residual soil to obtain a solid (namely oversize material of a primary vibrating screen 1) and a first fluid (namely fluid in a coarse screening conical tank 2);

a 1.3: screening the first-stage sand-containing underflow to obtain fine sand (namely oversize products of the second-stage vibrating screen 7) in the sludge and a second fluid (namely the fluid in the fine sand conical tank 5); one part of the primary overflow liquid returns to the first fluid, and the other part of the primary overflow liquid is merged with the second fluid;

In this embodiment, the step a2 specifically includes the following steps:

a 2.1: c, crushing, screening and washing the solid obtained in the step a1.1 to obtain coarse sand and a third fluid (namely the fluid in the finished sand cone tank); washing and screening the mud-containing medium and fine sand obtained in the steps a1.3 and a1.5 to obtain medium and fine sand and a fourth fluid (namely the fluid in a tail slurry tank 20 of the sand washing machine);

In this embodiment, the step a3 specifically includes the following steps:

In this embodiment, the specific steps of step a5 are as follows:

In this embodiment, the earth pressure balance shield muck treatment in step a specifically includes the following steps:

In this embodiment, the switching of the shield muck treatment mode in step B specifically includes:

x 1: communicating a filtrate tank 22 with a spraying system on the primary vibrating screen 1 and the secondary vibrating screen 7;

x 2: disconnecting pipelines between the clean water tank 27 and the bentonite slurrying machine 30, between the primary pulp tank 31 and the CMC mixing tank 33, and disconnecting pipelines between the slurry mixing tank 29 and the shield machine 33, and between the slurry mixing tank 29 and the overflow tank 22;

x 3: disconnecting the pipeline between the fourth drain port 802 and the multistage sedimentation tank 28, and connecting the pipeline between the fourth drain port 802 and the overflow tank 22;

y 1: disconnecting the filtrate tank 22 from the spraying systems on the primary vibrating screen 1 and the secondary vibrating screen 7;

y 2: the pipeline is communicated between the clean water tank 27 and the bentonite slurrying machine 30, between the primary pulp tank 31 and the CMC mixing tank 33, and the pipeline is communicated between the slurry mixing tank 29 and the shield machine 33, and between the slurry mixing tank 29 and the overflow tank 22;

y 3: the fourth drain port 802 is connected to the piping between the multistage sedimentation basin 28, and the piping between the fourth drain port 802 and the overflow basin 22 is disconnected.

The above-mentioned embodiments only express the specific embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for those skilled in the art, without departing from the technical idea of the present application, several changes and modifications can be made, which are all within the protection scope of the present application.

Claims

1. A dual mode shield muck treatment system, comprising:

2. The dual-mode shield muck treatment system according to claim 1, wherein: the mud-water separation system comprises a first mud-water separation module and a second mud-water separation module, the first mud-water separation module comprises a first-level vibrating screen (1), a coarse screening conical tank (2), a first-level intermediate tank (4) and a coarse sand conveyor (9), the coarse sand conveyor (9) is positioned below a discharge port of the first-level vibrating screen (1), the coarse screening conical tank (2) is positioned below the first-level vibrating screen (1), the second mud-water separation module comprises a first-level swirler (3), a second-level swirler (6), a second-level vibrating screen (7), a conveyor (16), a fine sand conical tank (5) and a second-level intermediate tank (8), a feed port of the first-level swirler (3) is communicated with the coarse screening conical tank (2), a sand discharge port of the first-level swirler (3) is connected with the second-level vibrating screen (7), a discharge port of the second-level vibrating screen (7) is positioned above the conveyor (16), the fine sand cone tank (5) is located below the secondary vibrating screen (7), an overflow port of the primary cyclone (3) is communicated with a feed inlet of the primary intermediate tank (4), the primary intermediate tank (4) is respectively connected with the coarse screen cone tank (2) and the fine sand cone tank (5), the fine sand cone tank (5) is connected with the secondary cyclone (6), the overflow port of the secondary cyclone (6) is connected with a feed inlet of the secondary intermediate tank (8), the conveyor (16) and the coarse sand conveyor (9) are connected with a sand treatment system, and the secondary intermediate tank (8) is respectively connected with the fine sand cone tank (5) and a size mixing system.

3. The dual-mode shield muck treatment system according to claim 2, wherein: the lower extreme of one-level pans (4) is provided with first outlet (401) and second outlet (402), first outlet (401) is located the below of the feed inlet of one-level pans (4), inside upper portion open-ended baffle that is provided with of one-level pans (4), first outlet (401) and second outlet (402) are located the both sides of baffle respectively, be provided with first float switch (403) in coarse screen awl jar (2), the lower extreme cooperation of first float switch (403) and first outlet (401), second outlet (402) and fine sand awl jar (5) intercommunication.

4. The dual-mode shield muck treatment system according to claim 2, wherein: the lower extreme of second grade pans (8) is provided with third outlet (801) and fourth outlet (802), third outlet (801) are located the below of the feed inlet of second grade pans (8), second grade pans (8) inside is provided with upper portion open-ended baffle, third outlet (801) and fourth outlet (802) are located the both sides of baffle respectively, be provided with second float switch (803) in fine sand awl jar (5), second float switch (803) and the lower extreme cooperation of third outlet (801), fourth outlet (802) and size mixing system and tail thick liquid processing system intercommunication.

5. The dual-mode shield muck treatment system according to claim 2, wherein: and a spraying system is arranged above the first-stage vibrating screen (1) and the second-stage vibrating screen (7), and is connected with the tail slurry treatment system.

6. The dual-mode shield muck treatment system according to claim 2, wherein: the number of the second mud-water separation modules is a plurality, and the second mud-water separation modules are connected in parallel.

7. The dual-mode shield muck treatment system according to claim 1, wherein: the sand processing system comprises a first sand processing module and a second sand processing module, the first sand processing module comprises a coarse sand crusher (10), a three-level finished coarse sand dewatering screen (13), a finished sand conical tank (14) and a three-level swirler (15), a discharge port of the coarse sand crusher (10) is positioned above the three-level finished coarse sand dewatering screen (13), the three-level finished coarse sand dewatering screen (13) is positioned above the finished sand conical tank (14), a sand discharge port of the three-level swirler (15) is positioned above the three-level finished coarse sand dewatering screen (13), the finished sand conical tank (14) is communicated with a feed inlet of the three-level swirler (15), the second sand processing module comprises a four-level swirler (21), a sand washing machine tail slurry tank (20), an impeller sand washing machine and a four-level sand washing machine dewatering screen (19), a sand discharge port of the sand washing machine is communicated with the four-level sand washing machine dewatering screen (19), level four sand washer dewatering screen (19) are located the top of sand washer tailings trough (20), the row's sand mouth of level four swirler (21) is located the top of level four sand washer dewatering screen (19), the feed inlet and the sand washer tailings trough (20) intercommunication of level four swirler (21), the overflow mouth of tertiary swirler (15) and the overflow mouth of level four swirler (21) all communicate with tailings processing system, impeller sand washer and tertiary finished product coarse sand dewatering screen (13) all communicate with tailings processing system.

8. The dual-mode shield muck treatment system according to claim 7, wherein: the number of the second sand treatment modules is several, and the several second sand treatment modules are connected in parallel.

9. The dual-mode shield muck treatment system according to claim 1, wherein: the pulp mixing system comprises a clean water tank (27), a multi-stage sedimentation tank (28), a pulp mixing tank (29), a bentonite pulping machine (30), a primary pulp tank (31) and a CMC mixing tank (32), the clean water tank (27) is respectively communicated with the bentonite slurrying machine (30), the primary pulp tank (31) and the CMC mixing tank (32) through pipelines, the discharge hole of the bentonite pulping machine (30) is respectively communicated with the pulp mixing pool (29) and the primary pulp tank (31), the discharge hole of the CMC mixing tank (32) is respectively communicated with the primary pulp tank (31) and the pulp mixing tank (29), the discharge hole of the raw slurry tank (31) is communicated with the slurry mixing tank (29), the multistage sedimentation tank (28) is used for settling impurities in slurry discharged by the mud-water separation system, the overflow port of the multistage sedimentation tank (28) is communicated with the slurry mixing tank (29), and a discharge hole of the slurry mixing tank (29) is respectively communicated with the shield machine and the tail slurry treatment system.

10. The dual-mode shield muck treatment system according to claim 1, wherein: the tail slurry treatment system comprises an overflow tank (22), a flocculation tank (23), a dosing device (24), a filter press (25) and a filtrate tank (26), wherein the overflow tank (22) is used for containing waste liquid generated by a mud-water separation system, a sand treatment system and a slurry mixing system, an overflow port of the overflow tank (22) is communicated with the flocculation tank (23), the dosing device (24) is connected with the flocculation tank (23), a sludge discharge port of the flocculation tank (23) is communicated with the filter press (25), a water outlet of the flocculation tank (23) and a water outlet of the filter press (25) are communicated with the filtrate tank (26), and the filtrate tank (26) is communicated with the sand treatment system.