An integrated system for screening, solidifying and mixing shield slag slurry

Abstract

The present invention discloses an integrated system for screening and solidifying and stirring shield slag slurry, including a support frame, a screening and separation module, a collecting and stirring module and a curing agent adding and homogenizing module; the screening and separation module includes a square hole screen, a transverse vibration motor, a longitudinal vibration motor and one or more spray pipes; the collecting and stirring module includes a collecting box and a horizontal stirring device installed in the collecting box, and the collecting box is located below the square hole screen; the curing agent adding and homogenizing module includes a mud pump, a conveying pipe and a curing agent automatic metering and adding device. The present invention realizes the continuous flow operation of shield slag coarse particles-mud separation, homogenization, and solidifying and stirring. With the help of the turbulent flow formed by the internal spacers of the conveying pipe, the curing agent and the mud are mixed in the conveying pipe, and there is no need to set up a mud homogenizing tank and a solidifying and stirring tank. The equipment occupies a small space and has a high degree of automation, providing equipment support for efficient and environmentally friendly treatment of shield slag.

Description

Technical Field

[0001] The invention relates to the field of shield construction equipment, in particular to a shield slag slurry screening and solidification stirring integrated system. Background Art

[0002] Shield construction is widely used in urban subway construction in my country due to its advantages such as good safety, small ground impact and high construction efficiency. In order to improve the stability of the excavation surface, reduce tool wear and ensure mud discharge, it is usually necessary to use improved materials to improve the shield slag at the heading face and soil bin. The shield slag finally obtained is mostly fluidized and contains a large amount of mud, which increases the difficulty of transportation and backfilling. There are risks such as road traffic safety, environmental pollution and yard landslides, which is a technical problem that needs to be solved urgently.

[0003] In order to achieve effective treatment of slag from a technical level, the existing technology has developed and invented many treatment equipment in conjunction with the treatment process. Patent CN211100741U discloses a shield slag zero-emission treatment system, which provides a set of shield multi-stage screening and cleaning devices. The obtained mud is finally dehydrated and solidified by filter pressing. Patent CN211160702U discloses an earth pressure shield slag screening device. The equipment is arranged from top to bottom as a primary screen, a fine screen, a fine screen and a centrifuge. The main function of the equipment is to achieve efficient screening of slag and dehydration of mud.

[0004] However, the existing technology has an overly complex structure and a single function, and cannot be used for continuous assembly line operation for screening and solidification. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a shield slag slurry screening and solidification mixing integrated system which can realize shield slag coarse particle-mud separation, homogenization, solidification and mixing continuous flow operation, with small equipment footprint and high degree of automation.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: an integrated system for screening and solidifying and stirring shield slag slurry, including a support frame, a screening and separation module, a collection and stirring module and a curing agent adding and homogenizing module;

[0007] The screening and separation module comprises a square hole screen, a transverse vibration motor, a longitudinal vibration motor and one or more spray pipes; the four corners of the square hole screen are respectively connected to the support frame by springs, the transverse vibration motor and the longitudinal vibration motor are respectively fixed to the support frame, and the output shafts of the transverse vibration motor and the longitudinal vibration motor are respectively connected to one side of the wide side and one side of the long side of the square hole screen, and the one or more spray pipes are installed on the support frame and located above the square hole screen;

[0008] The collecting and stirring module comprises a collecting box and a horizontal stirring device installed in the collecting box, wherein the collecting box is installed on the supporting frame and is located below the square hole screen;

[0009] The curing agent addition and homogenization module includes a mud pump, a delivery pipe and an automatic curing agent metering and adding device. The mud inlet of the mud pump is connected to the collection box, the mud outlet of the mud pump is connected to the mud inlet of the delivery pipe, a curing agent addition port is provided at the mud inlet end of the delivery pipe, the curing agent addition port is connected to the automatic curing agent metering and adding device, and a plurality of partitions are installed in the delivery pipe.

[0010] Furthermore, the square hole screen is designed to be inclined 10 to 20 degrees relative to the horizontal plane along the length direction, and the higher end of the square hole screen is the feed end, and the lower end is the discharge end.

[0011] Furthermore, a conical collecting hopper is installed at the bottom of the square hole screen, and the bottom of the conical collecting hopper is located above the center of the collecting box.

[0012] Furthermore, two spray pipes are provided, and the two spray pipes are arranged along the width direction of the square hole screen, and a plurality of spray heads are installed at intervals at the bottom of the two spray pipes.

[0013] Furthermore, two horizontal stirring devices are provided, the bottom wall of the collecting box is composed of two arc-shaped bottom plates, the two horizontal stirring devices are respectively located directly above the two arc-shaped bottom plates, and the two horizontal stirring devices rotate toward the inside of the collecting box when in operation.

[0014] Furthermore, the two arc-shaped bottom plates are both inclined at a slope of 5% relative to the horizontal plane, and the lower ends of the two arc-shaped bottom plates are respectively connected to mud outlet pipes, which are communicated with the mud inlet of the mud pump.

[0015] Furthermore, a plurality of the spacers are fixed on the inner wall of the conveying pipe in an alternating manner along the length direction of the conveying pipe, and the conveying pipe is designed to be inclined at a slope of 5% to 10% relative to the horizontal plane. The lower end of the conveying pipe serves as a mud inlet and is connected to the mud outlet of the mud pump.

[0016] Furthermore, it also includes a temporary storage tank for curing agent, the feed inlet of the automatic metering and adding device for curing agent is connected to the temporary storage tank for curing agent, and the discharge port of the automatic metering and adding device for curing agent is connected to the curing agent addition port.

[0017] Furthermore, it also includes a defoaming agent temporary storage tank and a defoaming agent automatic metering and adding device, the feed port of the defoaming agent automatic metering and adding device is connected to the defoaming agent temporary storage tank, and the discharge port of the defoaming agent automatic metering and adding device is connected to the spray pipe.

[0018] Furthermore, the horizontal stirring device includes a stirring shaft rotatably installed in the collecting box and a stirring blade fixed on the stirring shaft, and a stirring motor for driving the stirring shaft to rotate is installed on the outer wall of the collecting box at a position corresponding to the stirring shaft.

[0019] The present invention also provides a method for preparing synchronous mortar based on the above-mentioned integrated system. The synchronous mortar comprises the following raw materials in parts by weight: 40 to 60 parts of shield slag slurry, 0.02 to 0.07 parts of defoaming agent, 0.5 to 1 parts of viscosity enhancer, 0.03 to 0.05 parts of foam inhibitor, 2 to 6 parts of fast-expanding bentonite, 5 to 15 parts of cement, 5 to 15 parts of fly ash, 10 to 20 parts of medium-fine sand, 0.02 to 0.05 parts of adsorption sacrificial agent, 0.2 to 0.5 parts of early strength agent, and 3 to 10 parts of water. The preparation method comprises the following steps:

[0020] (1) The slag discharged by the shield is evenly mixed in the premixing tank to form the slag to be screened, and then the slag to be screened is transported to the square hole screen of the integrated system for screening. During the screening, the defoamer solution is sprayed evenly in proportion, and the sieve bottom is the shield slag slurry containing the defoamer to be used;

[0021] (2) the shield slag slurry obtained in step (1) is discharged into a collection box of the integrated system and continuously stirred to keep the shield slag slurry in the box uniform and not stratified;

[0022] (3) The shield slag slurry in the collection box is sent to the forced mixing equipment through the curing agent adding homogenization module, and the foam inhibitor, viscosity enhancer and fast-expanding bentonite are added in proportion to obtain the pre-treated slag slurry mixture, and the mixed solution is concentrated and left to stand for no less than 0.5 h;

[0023] (4) Using a forced mixing device, first weigh cement, fly ash, medium-fine sand, adsorption sacrificial agent and early strength agent in proportion, mix and stir for 15 seconds, then add the mixed solution obtained in step (3) and water, and stir for 120 seconds to obtain the synchronous mortar prepared using the shield slag slurry.

[0024] Furthermore, the shield slag slurry is the bottom material of hard rock geological shield slag sieved by a 2.36 mm square hole sieve, and the water content is not less than 50%. When the water content itself is insufficient, water can be added.

[0025] Furthermore, the defoaming agent is a polyether defoaming agent, and the mass concentration of the solution is 0.3% to 0.1%.

[0026] Furthermore, the viscosity enhancer is a mixture of sodium carboxymethyl starch and xanthan gum in a mass ratio of 1:1, the viscosity of a 2% aqueous solution of sodium carboxymethyl starch (25°C) is not less than 500mPa·s, and the viscosity of a 1% aqueous solution of xanthan gum (25°C) is not less than 600mPa·s.

[0027] Furthermore, the antifoaming agent is an alcohol antifoaming agent, and the mass concentration of the solution is 1 / 1000 to 5 / 1000.

[0028] Furthermore, the fast-expanding bentonite is MgO-modified sodium-based bentonite, the content of MgO in the MgO-modified sodium-based bentonite is 0.3%, and the 0.5h viscometer 600r / min reading of the MgO-modified sodium-based bentonite is not less than 30. The preparation method is: sodium-based bentonite and MgO are added to an aqueous solution, stirred to form a suspension, urea solution is added to the suspension, stirred, and then allowed to stand, filtered, ground, and calcined at 450°C for 30 minutes.

[0029] Furthermore, the cement is one of silicate cement, ordinary silicate cement, and slag silicate cement, and the strength grade is not less than 42.5; the fly ash is grade I or II fly ash; and the medium-fine sand is one of river sand and machine-made sand.

[0030] Furthermore, the adsorption sacrificial agent is any one of diphosphonic acid, triphosphonic acid, tetraphosphonic acid and pentaphosphonic acid, or a mixture of two or more of them in any proportion.

[0031] Furthermore, the early strength agent is any one of calcium formate, sodium carbonate and gypsum, or a mixture of two or more of them in any proportion.

[0032] The preparation method of the synchronous mortar of the present invention will focus on solving the technical problems of the negative effects of foaming and setting time of the foaming agent in the earth pressure balance shield slag, assist reasonable technical means to improve the working performance stability and water erosion resistance of the synchronous mortar, and provide a scientific and technological solution for preparing synchronous mortar from earth pressure balance shield slag slurry. The main technical principles are:

[0033] (1) For hard rock geology, the earth pressure balance shield method is used for construction. During the shield process, the cutter head will rub against the soil layer on the face to produce a large amount of continuously graded fine particles. The content of fine particles in the shield slag slurry obtained by screening with a 2.36mm square hole sieve is 50% to 70%. Among them, about 20% of the particles have a particle size below 100 mesh, and the particle fineness is similar to that of fly ash, which can replace part of the fly ash as the filling particles of the synchronous mortar; the remaining coarse particles have a particle size distribution similar to that of medium and fine sand, which can replace medium and fine sand as the accumulation skeleton of the synchronous mortar. The particle size of the shield slag slurry is controlled below 2.36mm to reduce the risk of pipe blockage during the construction of the synchronous mortar.

[0034] (2) The polyether defoamer used in the present invention can effectively eliminate bubbles generated by anionic foaming agents (domestic shield foaming agents are mostly anionic surfactants). The defoamer is evenly sprayed during the shield slag screening process, which can effectively eliminate bubbles generated by slag disturbance and ensure that bubbles generated in the previous process are better eliminated; at the same time, adding an antifoaming agent during the preparation of the mixed liquid can effectively inhibit the generation of mechanical stirring bubbles. By using the defoaming and antifoaming technical means in stages, the content of bubbles in the subsequent use of the shield slag slurry is effectively reduced, and the technical problem that mechanical stirring is prone to bubbles due to the large content of shield slag foaming agent is well solved.

[0035] (3) Anionic surfactant molecules are easily adsorbed on the surface of cement particles, delaying cement hydration, resulting in a long setting time for the synchronous mortar, and reducing the water erosion resistance of the synchronous mortar. The present invention uses the basic principle of competitive adsorption of the adsorbent sacrificial agent on the surface of cement particles to reduce the amount of surfactant adsorbed on the surface of cement particles and reduce the retarding effect of the foaming agent. Furthermore, adding an appropriate amount of early strength component can more accurately control the setting time of the synchronous mortar, so that its working time meets the construction requirements and has good water erosion resistance.

[0036] (4) Fast-expanding bentonite was selected because the actual conditions of the construction site were fully considered. The shield construction site is very small and there is no extra space to configure a large number of expanding tanks. The bentonite is required to have a fast expanding effect to maximize the ready-to-use of the synchronous mortar.

[0037] (5) A composite thickening system of sodium carboxymethyl starch and xanthan gum is used. Firstly, the amount of air entrained during the swelling and thickening process of sodium carboxymethyl starch and xanthan gum is small, which can ensure the density and filling of the synchronous mortar. Secondly, sodium carboxymethyl starch has the function of rapid swelling and stabilizing the system in the early stage, which can quickly and stably homogenize the extremely unstable shield slag slurry system, ensuring the uniformity of the quality of the synchronous mortar and the stability of its working performance. Thirdly, the thickening system obtained after the swelling of xanthan gum has certain thixotropic properties, which makes the synchronous mortar injected into the outer gap of the pipe segment lose its fluidity and inertness quickly, significantly enhancing its water erosion resistance before coagulation and hardening.

[0038] (6) The purpose of mixing the shield slag slurry and the thickener earlier in the preparation of the synchronous mortar is to make the slag slurry system more uniform and ensure the preparation quality of the synchronous mortar; the mixed liquid is left to stand for 0.5 h to achieve full expansion of the bentonite and exert its colloidal effect.

[0039] The beneficial effects of the integrated system of the present invention are embodied in:

[0040] (1) The present invention provides an integrated system for coordinating the slag screening and separation and the mud solidification process, realizing the continuous flow operation of shield slag coarse particles-mud separation, homogenization, solidification and stirring. After the separation, the high-concentration mud is quickly concentrated and homogenized, and then the solidifier is added into the conveying pipeline by an automatic solidifying agent adding device. With the help of the turbulence formed by the partitions inside the pipeline, the solidifying agent and the mud are mixed in the conveying pipeline. Compared with the traditional treatment method, there is no need to set up a mud homogenization tank and a solidification stirring tank, and there is no need to set up a large-scale mud solidifying agent homogenization equipment. The equipment occupies a small space and has a high degree of automation, which overcomes the current constraint of small space in the subway shield construction site and provides equipment support for efficient and environmentally friendly treatment of shield slag.

[0041] (2) The present invention provides equipment support for the slag screening and separation and mud solidification process, which will help promote the popularization and application of the shield slag direct solidification process and promote the efficient resource utilization of shield slag.

[0042] (3) The present invention proposes a device setting form for homogenizing the curing agent and the mud in the pipeline, which solves the problems of traditional mixing and stirring equipment and mechanical dehydration equipment occupying a large space and having high equipment operating costs, effectively reduces the investment in slag treatment equipment and the treatment cost, and helps to achieve economical and environmentally friendly treatment of shield slag.

[0043] The beneficial effects of the preparation method of the synchronous mortar of the present invention are embodied in:

[0044] (1) The foaming and retarding effects of the foaming agent are solved by composite defoaming, foam suppression, and competitive adsorption techniques, so that shield slag slurry can be used as the main component of synchronous mortar. In the same bidding section, the preparation of synchronous mortar on the construction site can consume about 1 / 3 of the volume of shield slag slurry, reducing the dehydration and transportation of slag, providing an effective resource recovery method for the most difficult to handle slurry slag, and achieving significant environmental benefits.

[0045] (2) The shield slag slurry is directly used as the main component of the synchronous mortar. The technical solution provided by the present invention has strong operability, simple equipment, and less required space. Compared with the mechanical dehydration treatment mode, it significantly reduces the cost of shield slag slurry treatment, is economical and reasonable, and has strong scalability.

[0046] (3) The reuse of shield slag slurry reduces the use of medium and fine sand and avoids the exploitation of natural sand and gravel resources.

[0047] (4) The prepared synchronous mortar has the characteristics of moderate setting time, good water erosion resistance, stable working performance and reasonable economic cost, which lays a good foundation for its engineering promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1It is a structural schematic diagram of an embodiment of the present invention.

[0049] Figure 2 It is a schematic structural diagram of a square hole screen and a conical collecting hopper according to an embodiment of the present invention.

[0050] Figure 3 It is a cross-sectional view of a collection box in one embodiment of the present invention.

[0051] Figure 4 It is a cross-sectional view of a delivery pipe in one embodiment of the present invention.

[0052] The markings of the components in the accompanying drawings are:

[0053] 1 support frame;

[0054] 2 screening and separation module, 21 square hole screen, 22 transverse vibration motor, 23 longitudinal vibration motor, 24 spray pipe, 25 spray head, 26 spring, 27 conical receiving hopper, 28 defoaming agent temporary storage tank, 29 defoaming agent automatic metering and adding device;

[0055] 3 collecting and stirring module, 31 collecting box, 32 stirring shaft, 33 stirring blade, 34 stirring motor, 311 arc bottom plate, 312 mud outlet pipe;

[0056] 4 a curing agent adding and homogenizing module, 41 a mud pump, 42 a delivery pipe, 43 a spacer bar, 44 a curing agent adding port, 45 a curing agent temporary storage tank, 46 a curing agent automatic metering and adding device. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0058] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0059] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0060] See also Figures 1 to 4 .

[0061] The shield slag slurry screening and solidification stirring integrated system of the present invention comprises a support frame 1, a screening and separation module 2, a collection and stirring module 3 and a solidifying agent adding and homogenizing module 4;

[0062] The screening and separation module 2 includes a square hole screen 21, a transverse vibration motor 22, a longitudinal vibration motor 23 and one or more spray pipes 24; the four corners of the square hole screen 21 are connected to the support frame 1 through springs 26, the transverse vibration motor 22 and the longitudinal vibration motor 23 are respectively fixed on the support frame 1, and the output shafts of the transverse vibration motor 22 and the longitudinal vibration motor 23 are respectively connected to one side of the wide side and one side of the long side of the square hole screen 21, and one or more spray pipes 24 are installed on the support frame 1 and located above the square hole screen 21;

[0063] The collecting and stirring module 3 includes a collecting box 31 and a horizontal stirring device installed in the collecting box 31. The collecting box 31 is installed on the supporting frame 1 and is located below the square hole screen 21.

[0064] The curing agent addition and homogenization module 4 includes a mud pump 41, a delivery pipe 42 and an automatic curing agent metering and adding device 46. The mud inlet of the mud pump 41 is connected to the collecting box 31, and the mud outlet of the mud pump 41 is connected to the mud inlet of the delivery pipe 42. A curing agent addition port 44 is provided at the mud inlet end of the delivery pipe 42, and the curing agent addition port 44 is connected to the automatic curing agent metering and adding device 46. A plurality of partition bars 43 are installed in the delivery pipe 42.

[0065] When in use, pour the shield slag slurry into the square hole sieve, and the transverse vibration motor and the longitudinal vibration motor drive the square hole sieve to shake alternately from the transverse and longitudinal directions respectively, so that the square hole sieve screens the shield slag slurry to separate the coarse particles from the mud. At the same time, the defoaming agent solution is sprayed into the square hole sieve through the spray pipe to eliminate the foam in the mud. The sieved mud falls directly into the collection box below and is quickly concentrated and homogenized under the stirring action of the horizontal stirring device. Finally, the mud is discharged into the delivery pipe through the mud pump, and the curing agent is added into the delivery pipe through the automatic curing agent metering and adding device. With the help of the turbulence formed by the partitions in the delivery pipe, the curing agent and the mud are mixed in the delivery pipe.

[0066] Of course, the curing agent adding homogenization module can not only be used to add curing agent, but also can be used to add other materials.

[0067] In one embodiment, a curing agent temporary storage tank 45 is further included, and the feed port of the curing agent automatic metering and adding device 46 is connected to the curing agent temporary storage tank 45, and the discharge port of the curing agent automatic metering and adding device 46 is connected to the curing agent adding port 44. With this design, the curing agent can be stored in the curing agent temporary storage tank, which can meet the usage for a certain period of time and has better practicality. In specific implementation, a curing agent adding port can be set at the upper part of the conveying pipe 0.5m away from the mud inlet end to increase the flow distance of the curing agent as much as possible and improve the mixing effect.

[0068] In one embodiment, a plurality of the spacers 43 are fixed on the inner wall of the delivery pipe 42 at intervals and staggered along the length direction of the delivery pipe 42. With this design, the turbulence directions of the curing agent and the mud in the delivery pipe are staggered and changed, and the homogenization effect is better.

[0069] In one embodiment, the delivery pipe 42 is designed to be inclined at a slope of 5% to 10% relative to the horizontal plane, and the lower end of the delivery pipe 42 is connected to the mud outlet of the mud pump 41 as a mud inlet. With this design, the curing agent and mud are transported uphill in the delivery pipe, and have a tendency to move backward under the action of their own gravity, so that the curing agent and mud can be dispersed in more directions, further increasing the turbulence effect.

[0070] Generally, the total length of the conveying pipe is 3m, made of steel pipe, with an inner diameter of 15cm, arranged in a straight line, with the first spacer set 1m away from the mud inlet end, and then four spacers are set up every 0.5m, with a height of 2cm, which can meet the requirements of sufficient mixing of mud and curing agent. Of course, in practice, the above values ​​can also be adjusted as needed.

[0071] In one embodiment, the square hole screen 21 is designed to be inclined 10 to 20 degrees relative to the horizontal plane along the length direction, and the higher end of the square hole screen 21 is the feed end, and the lower end is the discharge end. In this design, the material is screened along the length direction, and the raw materials can be gradually laid on the screen surface, and the screening effect is better.

[0072] In one embodiment, a conical collecting hopper 27 is installed at the bottom of the square hole screen 21, and the bottom of the conical collecting hopper 27 is located above the center of the collecting box 31. The conical collecting hopper is used to discharge the mud into the collecting box to avoid leakage, and has better practicality.

[0073] In general, a 2.36mm square hole screen is selected, and the size of the square hole screen is 2.5m in length and 1.5m in width. The material is screened along the length direction, which can meet the screening of shield slag slurry. The distance between the upper edge plane of the collection box and the lower edge of the conical collecting hopper is 20cm, which can meet the mud discharge requirements. Of course, in practice, the above values ​​can also be adjusted as needed.

[0074] In one embodiment, two spray pipes 24 are provided, and the two spray pipes 24 are arranged along the width direction of the square hole screen 21, and multiple spray heads 25 are installed at intervals at the bottom of the two spray pipes 24. This design can spray the defoaming agent solution into the square hole screen more evenly.

[0075] Preferably, one of the spray pipes 24 is set at 10 cm from the feed end, and the other spray pipe 24 is set at 50 cm from the feed end. In this design, the defoamer can be sprayed into the shield slag slurry twice to ensure that the defoamer and the slurry are mixed evenly.

[0076] In one embodiment, it also includes a defoamer temporary storage tank 28 and a defoamer automatic metering and adding device 29, the feed port of the defoamer automatic metering and adding device 29 is connected to the defoamer temporary storage tank 28, and the discharge port of the defoamer automatic metering and adding device 29 is connected to the spray pipe 24. With this design, the curing agent can be stored in the curing agent temporary storage tank, and then sent to the spray pipe by the defoamer automatic metering and adding device, which can meet the usage for a certain period of time and has better practicality.

[0077] Generally, the vertical distance between the spray pipe 24 and the screen surface of the square hole screen 21 is 15 to 30 cm, which can meet the use requirements.

[0078] In one embodiment, two horizontal stirring devices are provided, the bottom wall of the collection box 31 is composed of two arc-shaped bottom plates 311, the two horizontal stirring devices are respectively located directly above the two arc-shaped bottom plates 311, and the two horizontal stirring devices rotate toward the inside of the collection box 31 during operation. With this design, the two arc-shaped bottom plates form two recessed areas, and the two horizontal stirring devices can not only achieve the mixing of the mud in the two recessed areas during stirring, but also continuously push the mud into each other's area to increase the mixing effect.

[0079] In one embodiment, the horizontal stirring device includes a stirring shaft 32 rotatably mounted in the collection box 31 and a stirring blade 33 fixed on the stirring shaft 32. A stirring motor 34 for driving the stirring shaft 32 to rotate is installed on the outer wall of the collection box 31 at a position corresponding to the stirring shaft 32. This design has a simple structure, is easy to implement, and has a reliable stirring effect.

[0080] Generally, the distance between the lower edge of the stirring blade and the bottom of the arc is 3mm, which can bring up the mud as much as possible and improve the stirring effect.

[0081] In one embodiment, the two arc-shaped bottom plates 311 are both inclined with a slope of 5% relative to the horizontal plane, and the lower ends of the two arc-shaped bottom plates 311 are respectively connected with mud outlet pipes 312, and the mud outlet pipes 312 are connected to the mud inlet of the mud pump 41. This design can guide the mud to be discharged from the mud outlet pipe into the mud pump. Of course, the slope cannot be too high, otherwise the mud will be poured on one side of the collection box, affecting the stirring effect.

[0082] In a specific implementation, the mud pump can be a piston mud pump, the defoaming agent automatic metering and adding device and the curing agent automatic metering and adding device can be metering pumps, and the support frame is designed to be a rectangular frame structure.

[0083] The present invention is a special equipment design for the slag screening and separation and mud solidification process. In view of the small site of the shield construction site and the large daily unearthed volume, the continuous and automated production operation is taken as the basic principle of equipment design, and the technical problems such as equipment miniaturization and streamlined operation are mainly solved. The present invention provides a continuous and streamlined operation integrated device for shield slag coarse particles-mud separation, homogenization, solidification and mixing.

[0084] In order to facilitate understanding of the influence of various raw materials on material properties in the preparation method of synchronous mortar of the present invention, 6 embodiments of the present invention and 5 comparative examples are provided below for effect comparison. The formulas of each embodiment and each comparative example are shown in Table 1. Among them, the embodiment experiment was carried out in a certain section of Guangzhou Metro Line 7. The shield slag slurry was the sieve bottom material of hard rock geological shield slag sieved by a 2.36mm square hole sieve, and the water content was 50%; the defoamer was a polyether defoamer, and the solution mass concentration was 3 parts per thousand; the antifoamer was an alcohol antifoamer, and the solution mass concentration was 1 part per thousand; the viscosity enhancer was a mixture of sodium carboxymethyl starch and xanthan gum in a mass ratio of 1:1, and the viscosity (25°C) of 2% aqueous solution of sodium carboxymethyl starch was 600mP a·s, the viscosity of 1% aqueous solution of xanthan gum (25°C) is 650mPa·s; the fast-expanding bentonite is MgO-modified sodium-based bentonite, the content of MgO in the MgO-modified sodium-based bentonite is 0.3%, and the 0.5h viscometer 600r / min reading of the MgO-modified sodium-based bentonite is not less than 30. The preparation method is: sodium-based bentonite and MgO are added to an aqueous solution, stirred to form a suspension, urea solution is added to the suspension, stirred, then allowed to stand, filtered, ground, and calcined at 450°C for 30min; the cement is ordinary Portland cement with a strength grade of 42.5; the fly ash is grade II; the medium-fine sand is river sand; the adsorption sacrificial agent is triphosphonic acid; the early strength agent is calcium formate;

[0085] The preparation method is the same (in the comparative example, if the raw material is not available, it is not added and the steps are still operated), which is as follows:

[0086] (1) The slag discharged by the shield is mixed evenly in the pre-mixing tank by an excavator to form the slag to be screened, and then the slag to be screened is transported to the square hole screen (2.36mm) of the integrated system by screw conveyor or excavator overturning for screening. During screening, a defoamer solution with a mass concentration of 30,000 to 1000 is sprayed on the surface of the slag in proportion, and the sieve bottom is the shield slag slurry to be used;

[0087] (2) the shield slag slurry obtained in step (1) is discharged into a collection box of the integrated system and continuously stirred to keep the shield slag slurry in the box uniform and not stratified;

[0088] (3) The shield slag slurry in the collection box is sent to the forced mixing equipment through the curing agent adding homogenization module, and the foam inhibitor, viscosity enhancer and fast-expanding bentonite are added in proportion to obtain the pretreated slag slurry mixture, and the mixture is concentrated and left to stand for 0.5 h;

[0089] (4) Using a forced mixing device, first weigh cement, fly ash, medium-fine sand, adsorption sacrificial agent and early strength agent in proportion, mix and stir for 15 seconds, then add the mixed solution obtained in step (3) and water, and stir for 120 seconds to obtain the synchronous mortar prepared using the shield slag slurry.

[0090] Table 1 Composition of Examples and Comparative Examples (Unit: Parts by Weight)

[0091]

[0092] The performance test results of the synchronous mortar prepared from the earth pressure balance shield slag slurry of Examples 1-6 and Comparative Examples 1-5 are shown in Table 2:

[0093] Table 2 Performance test results of embodiments and comparative examples

[0094]

[0095]

[0096] Notes to Table 2: 1. The applicable consistency range of shield synchronous mortar is not more than 140mm; 2. The appropriate initial setting time of shield synchronous mortar is 6 to 12h; 3. The water erosion resistance of synchronous mortar is usually characterized by 30min filtration loss, which should be no more than 15mL; 4. The stone rate of shield synchronous mortar should usually be no less than 95%; 5. The compressive strength of shield synchronous mortar after hardening should usually be no less than 2.5MPa.

[0097] From the above, it can be seen that Examples 1-6 are synchronous mortars obtained by the present invention, and their various properties meet the basic use requirements of synchronous mortars, while some properties of the synchronous mortars in the comparative examples do not meet the basic use requirements. The synchronous mortar provided by this technical solution has been successfully applied in shield construction projects such as Guangzhou Metro Line 7 and Guiyang Metro Line 3.

[0098] It should be understood that the examples and implementation modes described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A shield slag slurry screening and solidification mixing integrated system, characterized by: It comprises a support frame (1), a screening and separation module (2), a collection and stirring module (3) and a curing agent adding and homogenizing module (4); The screening and separation module (2) comprises a square hole screen (21), a transverse vibration motor (22), a longitudinal vibration motor (23) and one or more spray pipes (24); the four corners of the square hole screen (21) are connected to the support frame (1) through springs (26), the transverse vibration motor (22) and the longitudinal vibration motor (23) are respectively fixed to the support frame (1), and the output shafts of the transverse vibration motor (22) and the longitudinal vibration motor (23) are respectively connected to one side of the wide side and one side of the long side of the square hole screen (21), and the one or more spray pipes (24) are installed on the support frame (1) and located above the square hole screen (21); The collecting and stirring module (3) comprises a collecting box (31) and a horizontal stirring device installed in the collecting box (31); the collecting box (31) is installed on the supporting frame (1) and is located below the square hole screen (21); The curing agent adding and homogenizing module (4) comprises a mud pump (41), a delivery pipe (42) and an automatic curing agent metering and adding device (46); the mud inlet of the mud pump (41) is connected to the collecting box (31); the mud outlet of the mud pump (41) is connected to the mud inlet of the delivery pipe (42); a curing agent adding port (44) is provided at the mud inlet end of the delivery pipe (42); the curing agent adding port (44) is connected to the automatic curing agent metering and adding device (46); and a plurality of spacers (43) are installed in the delivery pipe (42); It also includes a curing agent temporary storage tank (45), the feed port of the curing agent automatic metering and adding device (46) is connected to the curing agent temporary storage tank (45), and the discharge port of the curing agent automatic metering and adding device (46) is connected to the curing agent adding port (44); It also comprises a defoaming agent temporary storage tank (28) and a defoaming agent automatic metering and adding device (29), wherein the feed port of the defoaming agent automatic metering and adding device (29) is connected to the defoaming agent temporary storage tank (28), and the discharge port of the defoaming agent automatic metering and adding device (29) is connected to the spray pipe (24).

2. The shield slag slurry screening and solidification mixing integrated system according to claim 1, characterized in that: The square hole screen (21) is designed to be inclined at 10 to 20 degrees relative to the horizontal plane along the length direction, and the higher end of the square hole screen (21) is the feed end, and the lower end is the discharge end.

3. The shield slag slurry screening and solidification mixing integrated system according to claim 1 or 2, characterized in that: Two spray pipes (24) are provided in total. The two spray pipes (24) are arranged along the width direction of the square hole screen (21). A plurality of spray heads (25) are installed at intervals at the bottom of the two spray pipes (24).

4. The shield slag slurry screening and solidification mixing integrated system according to claim 1 or 2, characterized in that: A total of two horizontal stirring devices are provided, the bottom wall of the collection box (31) is composed of two arc-shaped bottom plates (311), the two horizontal stirring devices are respectively located directly above the two arc-shaped bottom plates (311), and the two horizontal stirring devices rotate toward the inside of the collection box (31) when in operation.

5. The shield slag slurry screening and solidification mixing integrated system as claimed in claim 4, characterized in that: The two arc-shaped bottom plates (311) are both inclined at a slope of 5% relative to the horizontal plane. The lower ends of the two arc-shaped bottom plates (311) are respectively connected to mud outlet pipes (312), and the mud outlet pipes (312) are connected to the mud inlet of the mud pump (41).

6. The shield slag slurry screening and solidification mixing integrated system according to claim 1 or 2, characterized in that: A plurality of the spacers (43) are fixed on the inner wall of the delivery pipe (42) at intervals and in an alternating manner along the length direction of the delivery pipe (42). The delivery pipe (42) is designed to be inclined at a slope of 5% to 10% relative to the horizontal plane. The lower end of the delivery pipe (42) serves as a mud inlet and is connected to the mud outlet of the mud pump (41).

7. The shield slag slurry screening and solidification mixing integrated system according to claim 1 or 2, characterized in that: The horizontal stirring device comprises a stirring shaft (32) rotatably mounted in the collection box (31) and a stirring blade (33) fixed on the stirring shaft (32); a stirring motor (34) for driving the stirring shaft (32) to rotate is installed on the outer wall of the collection box (31) at a position corresponding to the stirring shaft (32).

8. A method for preparing synchronous mortar based on the integrated system according to any one of claims 1 to 7, characterized in that: The synchronous mortar comprises the following raw materials by weight: 40-60 parts of shield slag slurry, 0.02-0.07 parts of defoaming agent, 0.5-1 parts of viscosity enhancer, 0.03-0.05 parts of antifoaming agent, 2-6 parts of fast-expanding bentonite, 5-15 parts of cement, 5-15 parts of fly ash, 10-20 parts of medium-fine sand, 0.02-0.05 parts of adsorption sacrificial agent, 0.2-0.5 parts of early strength agent, and 3-10 parts of water. The preparation method comprises the following steps: (1) The slag discharged by the shield is evenly mixed in the premixing tank to form the slag to be screened, and then the slag to be screened is transported to the square hole screen of the integrated system for screening. During the screening, the defoamer solution is sprayed evenly in proportion, and the sieve bottom is the shield slag slurry containing the defoamer to be used; (2) the shield slag slurry obtained in step (1) is discharged into a collection box of the integrated system and continuously stirred to keep the shield slag slurry in the box uniform and not stratified; (3) The shield slag slurry in the collection box is sent to the forced mixing equipment through the curing agent adding homogenization module, and the foam inhibitor, viscosity enhancer and fast-expanding bentonite are added in proportion to obtain the pre-treated slag slurry mixture, and the mixed solution is concentrated and left to stand for no less than 0.5 h; (4) Using a forced mixing device, first weigh cement, fly ash, medium-fine sand, adsorption sacrificial agent and early strength agent in proportion, mix and stir for 15 seconds, then add the mixed solution obtained in step (3) and water, stir for 120 seconds, and obtain a synchronous mortar prepared using shield slag slurry.

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