Shield muck treatment and discharge method

Abstract

The invention relates to the technical field of muck treatment, in particular to a shield muck treatment and discharge method which comprises the treatment and discharge steps that S1, muck generated by shield tunneling is subjected to centralized recovery treatment, gravel screening equipment is used for screening the recovered muck, gravel is separated out, and the gravel is collected for standby application; s2, taking out a sample from the screened muck, detecting the heavy metal content of the muck and the curing performance of the muck, and preparing a curing agent; and S3, a prepared curing agent is added into the waste soil from which the gravel is separated out, and mixing and stirring are conducted. According to the method, the curing agent is added into the muck, the loose and soft muck is changed into a civil engineering material with certain engineering performance, the shield muck is effectively treated, the treated shield muck is reasonably utilized, the overall resource utilization rate of the muck generated by shield tunneling is greatly increased, the muck is subjected to secondary recycling, and the cost is reduced. And the resource waste of waste soil is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of muck treatment, and specifically relates to a method for treating and discharging shield muck. Background Art

[0003] In actual construction, the methods for treating slurry-containing muck mainly include direct discharge method, solid-liquid separation method, land cultivation treatment method, and chemical solidification method. The direct discharge method is simple to implement, but the price of external transportation treatment has increased sharply, supervision and accountability are strict, and it is difficult to guarantee a compliant disposal outlet. With the improvement of environmental protection requirements, this method is rarely used. The solid-liquid separation method uses physical or chemical means to achieve the purpose of solid-liquid separation, which can reduce transportation and disposal costs. However, the reagent cost, equipment investment, and operation and maintenance costs are relatively high, and the separation effect is limited, with large limitations in use. The land cultivation treatment method is to directly sprinkle the waste slurry-containing muck on the soil and naturally treat it by cultivation. This method is relatively simple and the cost is not high. The disadvantage is that the harmful components and large particle waste residues in the slurry-containing muck may cause environmental pollution and even damage arable land, making it inconvenient to handle and difficult to effectively utilize resources. In view of this, we propose a method for treating and discharging shield muck. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a method for treating and discharging shield muck to solve the above technical problems.

[0005] To achieve the above object, the present invention provides the following technical solution: A method for treating and discharging shield muck, and the treatment and discharge steps are as follows:

[0006] S1. Concentrate and recycle the muck generated by the shield, use a sand and gravel screening device to screen the recycled muck, separate the sand and gravel, and collect the sand and gravel for standby;

[0007] S2. Take a sample of the screened muck, detect the heavy metal content and solidification performance of the muck, and prepare the curing agent;

[0008] S3. Add the prepared curing agent to the muck from which the sand and gravel have been separated, and perform mixing and stirring;

[0009] S4. Collect the stirred muck, conduct a slump test, and after passing the test, transport the muck to a construction site for use as a building material;

[0010] S5. Wash the sand and gravel with clean water, react and precipitate the generated slurry water by adding a flocculant, send the bottom precipitated slurry into a plate and frame filter press for dehydration, and collect and transport the sand and gravel for utilization;

[0011] S6. Use a plate and frame filter press to dehydrate the slurry, quickly drain the water in the slurry to form dry solid particles, collect them, transport them to agricultural planting land, and use them as planting soil.

[0012] Preferably, in step S1, the sand and gravel screening equipment is a thin oil vibrating screen, which is used to screen the recycled shield muck. Small particles pass through the gaps on the thin oil vibrating screen and are transferred to the lower conveyor for transportation. Since the gaps of small particles are small, large particles cannot pass through, resulting in separation. Stratification is carried out according to the particle size, forming an arrangement rule with small particles at the bottom and coarse sand and gravel particles at the top to complete the screening. The sand and gravel are transported to the collection box through the conveyor belt for collection and standby.

[0013] Preferably, in step S2, the detection of heavy metal content in the muck is carried out by spectrometry. The detection is carried out by pre-treating the collected samples. After removing impurities from the samples, 0.25 g of the samples are weighed, aqua regia is added to the samples, and the samples are heated and digested on a temperature-controlled electric hot plate until evaporation to dryness. Dilute nitric acid is used to make the volume up to 30 ml, and the samples are left for detection. Then, 0.2 g of soil samples are weighed, nitric acid, hydrofluoric acid and hydrochloric acid are added, and the samples are digested in a microwave digestion furnace. After cooling, the acid is removed, the volume is made up to 50 mL, and a thiourea solution reducing agent is added to reduce pentavalent arsenic to trivalent arsenic, and the samples are left for detection.

[0014] Preferably, after the pre-treatment of the muck samples is completed, a standard solution with a known concentration is used to carry out the determination under the same determination conditions as the samples, a standard curve is drawn, the treated soil samples are inhaled into the tester, the fluorescence intensity of the samples is recorded, and according to the fluorescence intensity, the corresponding concentration value is found on the standard curve, and the actual content of heavy metals in the soil samples is calculated.

[0015] Preferably, in step S2, the curing agent materials are waterborne epoxy resin, silicone waterproof agent, photoinitiator and cellulose dispersant. Among them, the waterborne epoxy resin is the main agent, and the silicone waterproof agent, photoinitiator and cellulose dispersant are dispersants. The waterborne epoxy resin is prepared by using a ball mill, a colloid mill and a homogenizer to pre-grind solid epoxy resin into micron-sized epoxy resin powder, then adding an emulsifier aqueous solution, and then dispersing the particles in water by mechanical stirring, and gradually adding water under continuous stirring to form an emulsion, thus forming the waterborne epoxy resin.

[0016] Preferably, in step S3, the prepared curing agent is poured into the muck and continuously stirred for 1 h. Water is poured in during the stirring process to increase the reaction degree.

[0017] Preferably, the slump test steps in step S4 are as follows:

[0018] A1. Fill the muck material into the slump cone in three times. After each filling, use a tamper to insert and tamp 25 times evenly from the outside to the center along the barrel wall.

[0019] A2. After ramming, scrape off the excess muck material and level it with a trowel;

[0020] A3. Lift the slump cone vertically and steadily. Manually use a ruler to measure the height difference between the height of the cone and the highest point of the muck material specimen after slumping. This height difference is the slump value of the muck.

[0021] Preferably, in step S5, the sand and gravel are washed by using a spiral sand washer. By putting the sand and gravel into the spiral sand washer, under the action of high-speed centrifugal force, the impurities on the sand and gravel collide with clean water, and the impurities are washed away to complete the cleaning of the outer surface of the sand and gravel, generating clean sand and gravel and muddy water with impurities.

[0022] Preferably, in step S5, the muddy water is put into a flocculation pool for flocculation treatment. Before the flocculation process, a flocculant is poured into the muddy water for precipitation, and the precipitation time is 3 days.

[0023] Preferably, in step S6, the plate and frame filter press separates the solid particles in the muddy water based on the pressure difference and the filtering medium.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] In this application, a curing agent is added to the muck. The physical and mechanical indexes of the soil are changed through the cementitious material, and the loose and weak muck is changed into a civil engineering material with certain engineering properties, effectively treating the shield muck, reasonably utilizing the treated shield muck, greatly improving the overall resource utilization rate of the muck generated by the shield, recycling the muck for the second time, and avoiding the waste of waste soil resources. Description of the Drawings

[0026] Figure 1 It is a flow chart of the treatment and discharge steps of the shield muck of the present invention. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0028] The present invention provides a technical solution: a method for treating and discharging shield muck, and the treatment and discharge steps are as follows:

[0029] S1. Collect and process the muck generated by the shield centrally. Use a sand and gravel screening device to screen the recycled muck, separate the sand and gravel, and collect the sand and gravel for standby;

[0030] S2. Take samples of the screened muck, detect the heavy metal content and solidification performance of the muck, and prepare the solidifying agent.

[0031] S3. Add the prepared solidifying agent to the muck from which sand and gravel have been separated, and perform mixing and stirring.

[0032] S4. Collect the stirred muck, conduct a slump test. After passing the test, transport the muck to the construction site and use it as building materials.

[0033] S5. Wash the sand and gravel with clean water, react and precipitate the generated slurry water by adding a flocculant, send the bottom precipitated slurry into a plate and frame filter press for dehydration, and collect and transport the sand and gravel for utilization.

[0034] S6. Use a plate and frame filter press to dehydrate the slurry, quickly discharge the water in the slurry, form dry solid particles, collect them, and transport them to agricultural planting land for use as planting soil.

[0035] The whole process of this application realizes the resource utilization and environmental protection discharge of muck. A solidifying agent is added to the muck, and the physical and mechanical indexes of the soil are changed through the cementitious material, turning the loose and weak muck into a civil engineering material with certain engineering properties, effectively treating the shield muck, reasonably utilizing the treated shield muck, greatly improving the overall resource utilization rate of the muck generated by the shield, recycling the muck for secondary use, and avoiding the waste of waste soil resources.

[0036] Further, in step S1, the sand and gravel screening equipment is a thin oil vibrating screen, which is used to screen the recycled shield muck. Small particles pass through the gaps on the thin oil vibrating screen and are transferred to the lower conveyor for transportation. Since the gaps of small particles are small, large particles cannot pass through, resulting in separation, and stratification is carried out according to the particle size, forming an arrangement rule with small particles at the bottom and coarse sand and gravel particles on top to complete the screening. The sand and gravel are transported to the collection box through the conveyor belt for collection and standby.

[0037] This application adopts a thin oil vibrating screen. Through its unique vibration mechanism, it can effectively separate small particles from coarse sand and gravel particles in the muck. Small particles can pass through the gaps on the screen, while large particles are left on the screen, thus achieving an efficient screening effect. The screened sand and gravel and other materials have high economic value and can be directly used as building materials in construction projects. This can not only reduce the project cost, but also improve the resource utilization rate and economic benefits.

[0038] Further, in step S2, the heavy metal content of the muck is detected by spectrometry. The detection is carried out by preprocessing the collected samples. After removing impurities from the samples, 0.25 g of the samples is weighed, aqua regia is added to the samples, and the samples are heated and digested on a temperature-controlled electric hot plate until they are evaporated to dryness. Then, they are fixed with dilute nitric acid to 30 ml and left for detection. Another 0.2 g of soil samples is weighed, nitric acid, hydrofluoric acid and hydrochloric acid are added, and the samples are digested in a microwave digestion furnace. After cooling, the acid is removed, and the volume is fixed to 50 mL. A thiourea solution reducing agent is added to reduce pentavalent arsenic to trivalent arsenic, and then it is left for detection.

[0039] In the digestion process of the spectrometry detection in this application, the organic substances and mineral structures in the samples can be destroyed, enabling heavy metal elements to transfer from the solid phase to the liquid phase, which is convenient for subsequent spectrometry detection. The spectrometry can selectively detect specific heavy metal elements in the samples without being interfered by other elements, thus improving the accuracy and reliability of the detection.

[0040] Further, after the pretreatment of the muck samples is completed, a standard solution with a known concentration is used to perform the determination under the same determination conditions as the samples, and a standard curve is plotted. The processed soil samples are aspirated into the tester, the fluorescence intensity of the samples is recorded, and according to the fluorescence intensity, the corresponding concentration value is found on the standard curve, and the actual content of heavy metals in the soil samples is calculated.

[0041] The standard curve in this application is plotted by a series of standard solutions with known concentrations under the same determination conditions. It reflects the quantitative relationship between the fluorescence intensity and the heavy metal concentration. Using this relationship, the fluorescence intensity of the soil samples can be accurately converted into the corresponding heavy metal concentration, thereby improving the accuracy of the detection;

[0042] The following Table 1 is the detection table of the actual content of heavy metals in soil samples

[0043]

[0044] Table 1

[0045] According to the "Technical Specification for Sampling and Sample Preparation of Industrial Solid Wastes" (HJ / T 20-1998), a simple random sampling method is selected to detect the properties of indicators such as pH and heavy metal elements in the subway shield soil, and it is compared with the risk screening values specified in the "Soil Environmental Quality - Risk Control Standards for Soil Pollution of Construction Land (Trial)" (GB36600-2018) and the "Soil Environmental Quality - Risk Standards for Agricultural Land" (GB15618-2018).

[0046] Further, in step S2, the curing agent material is composed of waterborne epoxy resin, silicone waterproofing agent, photoinitiator, and cellulose dispersant. Among them, the waterborne epoxy resin is the main agent, and the silicone waterproofing agent, photoinitiator, and cellulose dispersant are dispersants. The waterborne epoxy resin is prepared by using a ball mill, colloid mill, and homogenizer to pre-grind solid epoxy resin into micron-sized epoxy resin powder, then adding an emulsifier aqueous solution, and then dispersing the particles in water through mechanical stirring. Water is gradually added under continuous stirring to form an emulsion, thus forming the waterborne epoxy resin.

[0047] This application uses waterborne epoxy resin as the main agent and incorporates external admixtures such as silicone waterproofing agent, photoinitiator, and cellulose dispersant to form the organic components of the photoinitiator latent soil curing agent, solving the problems of poor weather resistance and low impact strength of single organic epoxy resin-based curing agents. By using cementitious materials to change the physical and mechanical indexes of soil, the loose and weak muck is transformed into a civil engineering material with certain engineering properties. The waterborne epoxy resin has low viscosity and good fluidity, is easy to construct and coat, and can penetrate the surface of the substrate to form a uniform coating.

[0048] Further, in step S3, the prepared curing agent is poured into the muck and continuously stirred for 1 hour. During the stirring process, water is poured in to increase the reaction degree.

[0049] Through the stirring process, the uniform mixing between the curing agent and the muck is ensured, enabling the curing agent to fully penetrate into all parts of the muck, thereby improving the overall curing effect.

[0050] Further, the slump test steps in step S4 are as follows:

[0051] A1. Fill the muck material into the slump cone in three times. After each filling, use a tamper to insert and tamp evenly from the outside to the center along the barrel wall 25 times.

[0052] A2. After tamping, scrape off the excess muck material and level it with a trowel.

[0053] A3. Lift the slump cone vertically and smoothly, and manually use a ruler to measure the height difference between the height of the cone and the highest point of the muck material specimen after slumping. This is the slump value of the muck.

[0054] The slump test adopts the method specified in the national standard "Standard for Test Methods of Properties of Ordinary Concrete Mixtures" for manually detecting the slump of concrete. This test measures the slump of the backfill mixture in the foundation pit according to this standard. The slump is a basic index for evaluating the workability of fresh concrete containing coarse particles. It is measured using a trumpet-shaped slump cone with a height of 300 mm, a bottom diameter of 200 mm, and an upper diameter of 100 mm. The slump detection process consists of steps of filling the slump cone, inserting and tamping, leveling, lifting the cone, and measuring.

[0055] Furthermore, in step S5, the sand and gravel are cleaned by using a spiral sand washing machine. By putting the sand and gravel into the spiral sand washing machine, the impurities on the sand and gravel collide with clean water under the action of high-speed centrifugal force, and the impurities are washed away to complete the cleaning of the outer surface of the sand and gravel, thereby producing clean sand and gravel and muddy water with impurities;

[0056] Spiral sand washing machine can effectively remove dirt, dust, stone powder impurities on the surface of sand and gravel, and improve the cleanliness of sand and gravel. It is crucial for subsequent construction, road, water conservancy and other engineering applications. Clean sand and gravel can ensure the quality and durability of the project. Spiral sand washing machine adopts advanced energy-saving technology, which can significantly reduce energy consumption compared with traditional cleaning methods.

[0057] Furthermore, in step S5, the muddy water is placed in a flocculation tank for flocculation treatment. Before the flocculation process, a flocculant is poured into the muddy water for precipitation, and the precipitation time is 3 days;

[0058] The 3-day sedimentation time in this application ensures that the flocculant fully contacts and reacts with the suspended particles, colloidal particles, etc. in the mud water to form larger flocs, which facilitates the subsequent separation and removal process and improves the overall treatment efficiency.

[0059] Furthermore, in step S6, the plate and frame filter press separates solid particles from the muddy water based on the pressure difference and the filter medium;

[0060] The plate and frame filter press in the present application can separate solid particles from mud water, improve the recycling rate of mud, and reduce the discharge of waste materials. These solid particles can be further processed or used for other purposes.

[0061] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A shield slag treatment and discharge method, characterized in that: The steps to deal with emissions are: S1. Centrally recycle the slag generated by the shield, use sand and gravel screening equipment to screen the recycled slag, separate the sand and gravel, and collect the sand and gravel for later use; S2. Take out samples of the sieved soil, test the heavy metal content and curing performance of the soil, and prepare a curing agent; S3, adding the prepared curing agent into the slag from which the sand and gravel are separated, and mixing and stirring; S4, collecting the mixed slag and conducting a slump test. After the test is qualified, the slag is transported to the construction site and used as a building material; S5. Use clean water to wash the sand and gravel, add flocculants to the generated mud water for reaction precipitation, send the sedimentation mud at the bottom to the plate and frame filter press for dehydration, and collect and transport the sand and gravel for use; S6. Use a plate and frame filter press to dehydrate the mud, quickly drain the water from the mud, form dry solid particles, collect them, and transport them to agricultural planting sites as planting soil.

2. The shield slag treatment and discharge method according to claim 1 is characterized by: In step S1, the sand and gravel screening equipment is a thin oil vibrating screen, which screens the recovered shield slag. Small particles pass through the gaps on the thin oil vibrating screen and are transferred to the lower conveyor for transportation. Since the gaps between small particles are small, large particles cannot pass through, resulting in separation. The particles are layered according to their size, forming an arrangement rule where small particles are at the bottom and coarse sand and gravel particles are at the top to complete the screening. The sand and gravel are transported to the collection box through a conveyor belt for collection and standby use.

3. The shield slag treatment and discharge method according to claim 1 is characterized in that: In step S2, the heavy metal content of the slag is detected by spectroscopy. The detection is carried out by pre-treating the collected samples. After the pre-treatment, 0.25g of the sample is weighed, aqua regia is added to the sample, and it is heated and digested on a temperature-controlled hot plate, and waited for evaporation. The volume is fixed to 30ml with dilute nitric acid, and it is placed for detection; then 0.2g of the soil sample is weighed, nitric acid, hydrofluoric acid and hydrochloric acid are added, and the solution is digested in a microwave digestion furnace. After cooling, the acid is driven out and the volume is fixed to 50mL. A thiourea solution reducing agent is added to reduce pentavalent arsenic to trivalent arsenic, and the sample is placed for detection.

4. The shield slag treatment and discharge method according to claim 3 is characterized in that: After the pretreatment of the slag soil sample is completed, a standard solution of known concentration is used to measure it under the same measurement conditions as the sample, and a standard curve is drawn. The treated soil sample is sucked into the tester, and the fluorescence intensity of the sample is recorded. According to the fluorescence intensity, the corresponding concentration value is found on the standard curve, and the actual content of heavy metals in the soil sample is calculated.

5. The shield slag treatment and discharge method according to claim 1 is characterized by: In step S2, the curing agent materials are water-based epoxy resin, silicone waterproofing agent, photoinitiator and cellulose dispersant, wherein the water-based epoxy resin is the main agent, and the silicone waterproofing agent, photoinitiator and cellulose dispersant are dispersants; the water-based epoxy resin is prepared by using a ball mill, a colloid mill and a homogenizer to pre-grind the solid epoxy resin into micron-sized epoxy resin powder, then adding an emulsifier aqueous solution, and then dispersing the particles in water by mechanical stirring, and gradually adding water under continuous stirring to form an emulsion to form a water-based epoxy resin.

6. The shield slag treatment and discharge method according to claim 1, characterized in that: In step S3, the prepared curing agent is poured into the slag and stirred continuously for 1 hour. During the stirring process, water is poured into the slag to increase the degree of reaction.

7. The shield slag treatment and discharge method according to claim 1, characterized in that: The slump test steps in step S4 are: A1. Fill the soil material into the slump cone three times. After each filling, use a tamping rod to tamp the cone evenly from the outside to the center along the wall of the cone 25 times. A2. After compaction, scrape off the excess soil material and smooth it with a spatula; A3. Lift the slump cone vertically and steadily, and use a ruler to manually measure the height difference between the cone height and the highest point of the slag material specimen after collapse, which is the slump value of the slag.

8. The shield slag treatment and discharge method according to claim 1, characterized in that: In step S5, the sand and gravel are cleaned by using a spiral sand washing machine. By putting the sand and gravel into the spiral sand washing machine, the impurities on the sand and gravel collide with clean water under the action of high-speed centrifugal force, and the impurities are washed away to complete the cleaning of the outer surface of the sand and gravel, thereby producing clean sand and gravel and muddy water with impurities.

9. The shield slag treatment and discharge method according to claim 1, characterized in that: In step S5, the muddy water is placed in a flocculation tank for flocculation treatment. Before the flocculation process, a flocculant is poured into the muddy water for precipitation, and the precipitation time is 3 days.

10. The shield slag treatment and discharge method according to claim 1, characterized in that: In step S6, the plate and frame filter press separates the solid particles in the mud water based on the pressure difference and the filter medium.

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