Multi-layer drum screen device for screening TBM rock slag and rock breaking efficiency evaluation method

Abstract

The invention relates to the technical field of tunnel construction, in particular to a multi-layer drum screen device for screening TBM rock slag and a rock breaking efficiency evaluation method, by the adoption of the device and the method, a multi-layer nested structure is arranged in a drum screen, automatic screening of rock slag of different sizes can be achieved, and therefore the screening efficiency is improved. The device can be directly placed below a TBM belt conveyor discharging tower and automatically collect and screen rock slag of different particle sizes, the weighing device is arranged at the bottom, the mass of the rock slag of different sizes can be obtained at the same time, and therefore the particle size distribution of the rock slag is obtained, then the multi-fractal theory is applied to the rock slag screening field, and the TBM rock breaking efficiency evaluation result is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a multi-layer shaftless drum screen device for rock slag screening and a rock breaking efficiency evaluation method. Background Art

[0002] During TBM tunnel construction, a large amount of crushed rock slag will be generated. The particle size distribution of TBM rock slag is jointly affected by the surrounding rock geology and TBM operating parameters. As a direct product of rock-machine interaction, rock slag carries a wealth of effective information. The rock slag particle size distribution information can be obtained through appropriate methods, which can be used to evaluate the rock breaking efficiency of TBM. At present, the main methods for extracting the particle size distribution characteristics of rock slag are image processing methods and manual screening methods. The image processing method can quickly obtain the rock slag size distribution information, but the amount of rock slag processed each time is very limited, and it is difficult to accurately obtain its three-dimensional size information after the rock slag is stacked. If the image is collected directly on the slag belt, it will also be affected by multiple factors such as dark light in the tunnel and belt movement. The method of manual screening using a standard square hole sieve is time-consuming and labor-intensive. Because the belt slag discharge method has the characteristics of large volume in a short time and is difficult to stop, the manual screening method cannot complete the slag screening work of the required research section in time.

[0003] Considering that the shape of slag is usually very irregular, it is easy to clog the screening device. The drum screen has the advantages of not being easy to clog and being able to be equipped with an anti-clogging device, but the screening particle size is single or the multi-stage screening is not thorough, resulting in low screening accuracy.

[0004] At present, the rock breaking efficiency of TBM can be evaluated by establishing the relationship between the rock slag particle size distribution information and the rock breaking specific energy. The most commonly used index to describe the rock slag particle size distribution characteristics is the roughness index, but this index is significantly affected by the content of large-sized rock slag. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-layer shaftless drum screen device for rock slag screening and a rock breaking efficiency evaluation method to solve the above-mentioned problems in the prior art.

[0006] The present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a multi-layer drum screen device for TBM slag screening, comprising:

[0008] A supporting device, the supporting device comprising a first supporting frame and a second supporting frame connected to one end of the first supporting frame, the other end of the first supporting frame is provided with a collecting port, and the first supporting frame is used to set a screening device;

[0009] A screening device, comprising a screen fixing frame, a rolling outer cover and a screen unit arranged in the rolling outer cover, wherein the rolling outer cover and the screen unit are both connected to the screen fixing frame, the screen unit is arranged coaxially with the rolling outer cover, and the screen unit comprises a plurality of screens with successively increasing radii but successively decreasing screen apertures;

[0010] A power device, the power device includes a motor and a transmission device, the motor is connected to the screening device through the transmission device, and is used to drive the screening device to rotate.

[0011] Preferably, it also includes spiral bars arranged inside the screen and a cleaning device arranged outside the screen, the cleaning device is provided with an anti-mixing baffle, the anti-mixing baffle is used to prevent the rock debris that has entered the next level of screen from entering the current level of screen again, and the cleaning device is rollingly connected to the outside of the screen without screen holes.

[0012] Preferably, the cleaning device comprises a fixing device, a roller frame, a roller group, an upper limit plate, a lower limit plate, a limit bolt group and bristles, the roller frame is connected to the fixing device, and the roller group is arranged on the roller frame and located between the anti-mixing baffle and the screen;

[0013] An upper limit plate is arranged between the anti-mixing baffle and the lower limit plate, and the plates are connected by a limit bolt group, and the bristles are connected to the upper limit plate and are located below the anti-mixing baffle;

[0014] The fixing device comprises a fan-shaped fixing frame, a horizontal plate, a vertical rod and a plurality of fixing units, wherein the vertical rod is arranged on the second supporting frame, the fan-shaped fixing frame is connected to the vertical rod through the horizontal plate, and the plurality of fixing units are arranged on the fan-shaped fixing frame;

[0015] The fixing unit includes a first fixing plate and a second fixing plate, and the second fixing plate is connected to the roller frame and the first fixing plate through bolts.

[0016] Preferably, the second support frame includes a slide bracket, a collection box and a plurality of slides, the slide bracket is arranged on the collection box, the collection box is divided into a plurality of collection chambers by a plurality of partitions, one end of a plurality of the slides are respectively connected to a plurality of different screens, and the other end is respectively arranged on the top of a plurality of different partitions, and a weight sensing module is arranged in each of the collection chambers.

[0017] Preferably, the first support frame further comprises a support frame and a rolling device, wherein the rolling device is arranged on the upper part of the support frame;

[0018] The rolling device comprises a rotating frame and a plurality of roller groups, wherein the plurality of roller groups are arranged on the left and right sides of the rotating frame and are rotationally connected to the rolling outer cover;

[0019] Preferably, it further comprises a tilting device, and the rolling device is connected to the supporting frame via the tilting device;

[0020] The tilting device includes a limit column, a hydraulic instrument, a main force rod, a secondary force rod and a slider. One end of the limit column is arranged on the support frame, and the other end is rotatably connected to the rotating frame through the limit column. A setting cavity is provided on the support frame. The hydraulic instrument is arranged in the setting cavity, and one end of the hydraulic instrument is rotatably connected to the main force rod. The other end of the main force rod is rotatably connected to the secondary force rod through a slider. One end of the secondary force rod is rotatably connected to the setting cavity. A groove is provided on one side of the rotating frame, and the slider is slidably connected in the groove.

[0021] In a second aspect, the present invention provides a method for evaluating the rock breaking efficiency of a TBM based on multi-fractal theory, comprising the above-mentioned multi-layer drum screen device for TBM slag screening, and further comprising:

[0022] By obtaining the particle size distribution and mass fraction of the slag;

[0023] Extract multi-fractal parameters of rock slag and verify the feasibility of multi-fractal;

[0024] The relationship between the multi-fractal parameters and the rock breaking specific energy and roughness index is obtained to determine the rock breaking efficiency.

[0025] Preferably, the extracting of multiple fractal parameters of the slag includes:

[0026] The screening interval of the device is divided and the coordinates are mapped to the interval [0, 1, 2, 3, 4, 5]. If there is no data point in the divided interval, the interval is discarded; the mapped new coordinates are matrixed;

[0027] Obtain the probability density of rock cuttings particle distribution between each cell and construct a partition function group;

[0028] The calculation results of generalized fractal dimension, singularity index and multifractal spectrum function, point spectrum width and multifractal spectrum symmetry degree are obtained respectively, and the multifractal progress of rock slag particle size distribution is verified;

[0029] The verification result should satisfy that the double logarithmic curve between the partition function and the measurement scale shows a linear relationship.

[0030] Preferably, the obtaining of the relationship between the multi-fractal parameters and the rock breaking specific energy and the roughness index to determine the rock breaking efficiency comprises:

[0031] Obtain the cumulative screening rate of each sieve, and add up the cumulative screening rate of each sieve to obtain the roughness index;

[0032] By recording the TBM operation monitoring data, the TBM excavation parameters corresponding to the day of collecting rock debris are obtained and the rock breaking specific energy is calculated.

[0033] Preferably, the calculation of rock breaking specific energy includes:

[0034]

[0035] Where, SE is the rock breaking specific energy, F v is the average thrust of the TBM, l is the excavation distance of the TBM, M is the average torque of the TBM, θ is the rotation angle of the cutterhead, and R is the radius of the tunnel.

[0036] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0037] By adopting the above-mentioned device and method provided by the present invention, a multi-layer nested structure is set in the drum screen, which can realize the automatic screening of rock slag of different sizes, thereby improving the screening efficiency. The device can be directly placed under the unloading tower of the TBM belt conveyor, automatically collect and screen rock slag of different particle sizes, and a weighing device is set at the bottom to simultaneously obtain the mass of rock slag of different sizes, thereby obtaining the particle size distribution of the rock slag. Secondly, the multi-fractal theory is applied to the field of rock slag screening, so that the evaluation results obtained are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0040] Figure 2 It is the inner screen entrance diagram of the present invention;

[0041] Figure 3 The structure of the cleaning device of the present invention is schematically shown in FIG. Figure 1 ;

[0042] Figure 4 The structure of the cleaning device of the present invention is schematically shown in FIG. Figure 2 ;

[0043] Figure 5 It is a schematic structural diagram of a cross section of the device of the present invention;

[0044] Figure 6 It is a schematic diagram of the structure of the tail fan-shaped fixing frame of the present invention;

[0045] Figure 7 This is a schematic diagram of the structure of the collection box of the present invention;

[0046] Figure 8 This is a schematic diagram of the motor base structure of the present invention;

[0047] Fig. 9 It is a schematic diagram of the method flow of the present invention;

[0048] Fig.10 It is a verification diagram of the multi-fractal behavior of the present invention;

[0049] Fig.11 This is a relationship diagram of the multi-fractal parameters of the present invention, rock breaking specific energy, and roughness index.

[0050] Icons: 1-inner screen, 2-middle screen, 3-outer screen, 4-rolling cover, 41-gear belt, 42-rolling groove, 5-motor, 51-large rotating wheel, 52-belt, 53-roller bracket, 54-roller, 55-main gear, 6-support frame, 61-limiting column, 621-secondary force rod, 622-main rod, 623-slider, 624-hydraulic instrument, 7-rotating frame, 71-roller group, 72-groove, 73-movable column, 74-fixed frame, 81-vertical rod, 82-horizontal plate, 83-fan-shaped fixed frame, 831-first fixed plate, 832-second fixed plate, 9-collecting box, 911-fourth collecting chamber, 912-third collecting chamber, 913-second collecting chamber, 914-first collecting chamber, 921-third chute, 922-second chute, 923-first chute, 96-chute bracket, 94-chute fixing device, 941-cylindrical rod, 10-screen fixing frame, 11-spiral bar, 12-roller frame, 13-roller group, 14-anti-mixing baffle, 15-cleaning device, 151-brush, 152-limit bolt group, 153-lower limit plate, 154-upper limit plate. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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 part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0052] The terms "first, second" and the like in the specification and claims of this application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The naming or numbering of steps in this application does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The named or numbered process steps can be changed in the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0053] Please refer to Figure 1-Figure 8 The multi-layer drum screen device for TBM slag screening provided by the present invention comprises:

[0054] The supporting device includes a first supporting frame and a second supporting frame connected to one end of the first supporting frame, the other end of the first supporting frame is provided with a collecting port, the first supporting frame is used to set a screening device, and the collecting port is used to receive rock debris discharged from the TBM unloading tower.

[0055] A screening device, the screening device comprising a screen fixing frame 10, a rolling outer cover 4 and a screen unit arranged in the rolling outer cover 4, the rolling outer cover 4 and the screen unit are both connected to the screen fixing frame 10, the screen unit is arranged coaxially with the rolling outer cover 4, and the screen unit comprises a plurality of screens with successively increasing radii but successively decreasing screen apertures;

[0056] In this embodiment, three groups of screens are used, namely, inner screen 1, middle screen 2 and outer screen 3. The radius of inner screen 1, middle screen 2 and outer screen 3 increases successively, but the screening holes become smaller and smaller, and the inner screen 1, middle screen 2 and outer screen 3 are coaxially arranged in sequence, and the rolling outer cover 4 is arranged on the outermost side.

[0057] During operation, the inner screen: 1 has the largest screen hole diameter, which is used for the first step of processing rock slag. The largest rock slag in the rock slag is screened, and the rock slag smaller than the screen diameter enters the middle screen 2 for screening again, and the rock slag smaller than the middle screen 2 enters the outer screen 3 for the final screening. The rock slag with a size smaller than the three-layer screen enters the rolling outer cover 4.

[0058] A power device, the power device includes a motor 5 and a transmission device, the motor 5 is connected to the screening device through the transmission device, and is used to drive the screening device to rotate.

[0059] Specifically, a large rotating wheel 51 is installed on the motor 5 and is connected to a roller 54 through a belt 52. A roller 54 bracket 53 is provided on the first support frame for fixing the roller 54. A main tooth 55 is installed at both ends of the roller 54. A gear belt 41 is provided on the outside of the rolling outer cover 4, which is connected to the gear belts 41 at both ends of the rolling outer cover 4 through the gear belt 41.

[0060] By adopting the above-mentioned device and method provided by the present invention, a multi-layer nested structure is set in the drum screen, which can realize the automatic screening of rock slag of different sizes, thereby improving the screening efficiency. The device can be directly placed under the unloading tower of the TBM belt 52 machine, automatically collect and screen rock slag of different particle sizes, and a weighing device is set at the bottom to simultaneously obtain the mass of rock slag of different sizes, thereby obtaining the particle size distribution of the rock slag. Secondly, the multi-fractal theory is applied to the field of rock slag screening, so that the evaluation results obtained are more accurate

[0061] An exemplary embodiment of the present invention further includes a spiral bar 11 arranged inside the screen and a cleaning device 15 arranged outside the screen. The spiral bar 11 is used to push the rock debris to the tail during the rolling process. The cleaning device 15 is provided with an anti-mixing baffle 14. The anti-mixing baffle 14 is used to prevent the rock debris that has entered the next level of the screen from entering the current level of the screen again. The cleaning device 15 is rollingly connected to the outside of the screen where there is no screen hole.

[0062] In this embodiment, the cleaning device 15 includes a fixing device, a roller frame 12, a roller group 13, an upper limit plate 154, a lower limit plate 153, a limit bolt group 152 and bristles 151. The roller frame 12 is connected to the fixing device, and the roller group 13 is arranged on the roller frame 12, between the anti-mixing baffle 14 and the screen, so that the cleaning component is fixed and does not rotate when the screen rolls.

[0063] In this embodiment, there are two roller frames 12, which are respectively arranged at both ends of the anti-mixing baffle 14, and the roller frame 12 at one end is fixedly connected to the fixing device, and the anti-mixing baffle 14 covers the upper part of the screen.

[0064] An upper limit plate 154 is provided between the anti-mixing baffle 14 and the lower limit plate 153, and is connected via a limit bolt group 152. The bristles 151 are connected to the upper limit plate 154 and are located below the anti-mixing baffle 14.

[0065] The cleaning component has a certain ability to move up and down, so that the bristles 151 can move up and down adaptively during the rolling process, and the bristles 151 are located below the anti-mixing baffle 14, thereby extending the service life of the cleaning component.

[0066] The fixing device includes a fan-shaped fixing frame 83, a horizontal plate 82, a vertical rod 81 and a plurality of fixing units, wherein the vertical rod 81 is arranged on the second support frame, the fan-shaped fixing frame 83 is connected to the vertical rod 81 through the horizontal plate 82, and the plurality of fixing units are arranged on the fan-shaped fixing frame 83; the fixing unit includes a first fixing plate 831 and a second fixing plate 832, and the second fixing plate 832 is connected to the roller frame 12 and the first fixing plate 831 through bolts.

[0067] The fixing device is used to improve the structural stability of the cleaning device 15.

[0068] An exemplary embodiment of the present invention, the second support frame includes a slide bracket 96, a collection box 9 and a plurality of slides, the slide bracket 96 is arranged on the collection box 9, the collection box 9 is divided into a plurality of collection chambers by a plurality of partitions, one end of a plurality of the slides are respectively connected to a plurality of different screens, and the other end is respectively arranged on the top of a plurality of different partitions, and a weight sensing module is provided in each of the collection chambers for weighing the mass of the slag in each collection box 9.

[0069] Secondly, a slide slot fixing device 94 is installed on the slide slot bracket 96, and the cylindrical rod 941 can rotate in the slide slot fixing device 94 to be directly connected to the slide slot, and the slide slot can rotate around the cylindrical rod 941 to adapt to the discharge port of the screen.

[0070] In this embodiment, four collection chambers and three chutes are divided. The first collection chamber 914 corresponds to the first chute 923, the second collection chamber 913 corresponds to the second chute 922, the third collection chamber 912 corresponds to the third chute 921, and the fourth collection chamber 911 collects the rock slag in the rolling outer cover 4.

[0071] An exemplary embodiment of the present invention further includes a first support frame including a support frame 6 and a rolling device, wherein the rolling device is disposed on an upper portion of the support frame 6;

[0072] The rolling device includes a rotating frame 7 and a plurality of rollers 54 groups, wherein the plurality of rollers 54 groups are arranged on the left and right sides of the rotating frame 7 , and a rolling groove 42 is arranged outside the rolling cover 4 , and is rotatably connected to the rolling cover 4 through the rolling groove 42 .

[0073] Specifically, the rotating frame 7 includes two cross bars, which are connected by a fixing frame 74 .

[0074] An exemplary embodiment of the present invention further comprises a tilting device, and the rolling device is connected to the supporting frame 6 via the tilting device;

[0075] The tilting device includes a limit column 61, a hydraulic instrument 624, a main rod 622, a secondary rod 621 and a slider 623. One end of the limit column 61 is arranged on the support frame 6, and the other end is rotatably connected to the rotating frame 7 through the limit column 61, and can be specifically connected through a movable column 73. A setting cavity is provided on the support frame 6, and the hydraulic instrument 624 is provided in the setting cavity, one end of which is rotatably connected to the main rod 622, and the other end of the main rod 622 is rotatably connected to the secondary rod 621 through a slider 623. One end of the secondary rod 621 is rotatably connected in the setting cavity, and a groove 72 is provided on one side of the rotating frame 7, and the slider 623 is slidably connected in the groove 72.

[0076] During use, the hydraulic instrument 624 is started to push the main force rod 622 and the auxiliary force rod 621 to rotate upward, and together push the circular slider 623 to move in the slide slot, so that the rolling frame rotates and the inclination angle of the screen body is adjusted to adapt to the terrain and slag screening requirements.

[0077] The motor 5 starts and drives the roller 54 and the main gear 55 to rotate together, so that the screen body rotates and enters the working state. The inner screen: 1 has the largest screen hole diameter, and the rock debris enters the device through the inner screen: 1. The rock debris smaller than the hole diameter enters the middle screen 2. The rock debris larger than the hole diameter moves to the tail of the screen under the action of the spiral bar 11 and gravity, is collected by the chute, and enters the collection box 9 for weighing. The middle screen 2 and the outer screen 3 are rolled with the outer cover 4 in the same way.

[0078] The cleaning device can keep its position fixed when the screen body rotates through the roller frame 12 and roller group 13 connected to it. The upper limit plate 154, the lower limit plate 153 and the limit bolt group 152 inside it allow the brush wheel and the brush to move up and down, reducing the damage of the bristles 151 to the screen and extending the service life of the bristles 151 themselves.

[0079] In addition, wheels can be arranged at the bottom of the device for sliding, and a traction hook can be arranged at the end of the device for pulling and moving.

[0080] refer to Fig. 9 The present invention also provides a TBM rock breaking efficiency evaluation method based on multi-fractal theory, including the above-mentioned multi-layer drum screen device for TBM slag screening, and also includes:

[0081] S101: by obtaining the particle size distribution and mass fraction of the slag;

[0082] S102: extracting multi-fractal parameters of rock slag and verifying the feasibility of multi-fractal;

[0083] S103: Obtain the relationship between the multi-fractal parameters and the rock breaking specific energy and the roughness index to determine the rock breaking efficiency.

[0084] In an exemplary embodiment of the present invention, the extraction of multi-fractal parameters of rock slag includes:

[0085] S201: Divide the screening interval of the device and map the coordinates to the interval [0, 1, 2, 3, 4, 5]. If there is no data point in the divided interval, the interval is discarded; matrix processing is performed on the mapped new coordinates;

[0086] That is, by scaling the x-axis, the following formula can be used to retain the details of the original data to the greatest extent and reduce losses.

[0087]

[0088] Where: X l is the coordinate range of the data column x, N is the total number of scattered points, and ε is the minimum interval for dividing the x-axis. After the division is completed, the vacant part of the y-axis is filled by taking the average of the nearest left and right values.

[0089] S202: Obtain the probability density of the rock cuttings particle distribution between each cell and construct a partition function group;

[0090]

[0091] In the formula, μ i (Q,ε) is the probability of the qth order in the i-th subinterval, μ i (ε) is the probability density of the distribution of rock cuttings particles in each small interval, n(ε) is the total number of divided intervals, and Q is the statistical moment order, which can range from (-∞, +∞).

[0092] S203: respectively obtaining the calculation results of the generalized fractal dimension, the singularity index and the multifractal spectrum function, the width of the point spectrum and the symmetry degree of the multifractal spectrum, and verifying the multifractal progress of the slag particle size distribution;

[0093] The generalized fractal dimension D(q) of the multifractal distribution of rock fragments is calculated in the interval of -10≤q≤10:

[0094]

[0095] Where D(q) is the generalized fractal dimension.

[0096] The singularity index α(q) and the multifractal spectrum function f[α(q)] are calculated in the interval -10≤q≤10:

[0097]

[0098] Where α(q) is the singularity index, f[α(q)] is the multifractal spectrum function, and p i (ε) is the probability mass function.

[0099] The width of the singular point spectrum Δα(q) and the degree of symmetry of the multifractal spectrum Δf[α(q)] are calculated as follows:

[0100] Δα(q)=α(q) max -α(q) min

[0101] Δf[α(q)]=f[α(q) max ]-f[α(q) min ]

[0102] Where α(q) max is the maximum width of the singularity spectrum, α(q) min is the minimum width of the singular point spectrum, f[α(q) max ] is the maximum symmetry degree of the multifractal spectrum, f[α(q) min ] is the minimum symmetry degree of the multifractal spectrum.

[0103] S204: The verification result should satisfy that the double logarithmic curve between the partition function and the measurement scale shows a linear relationship.

[0104] The fitting coefficient R is satisfied in the range of -10≤q≤10. 2 >0.9.

[0105] In an exemplary embodiment of the present invention, the step of obtaining the relationship between the multi-fractal parameter and the rock breaking specific energy and the roughness index to determine the rock breaking efficiency includes:

[0106] Obtain the cumulative screening rate of each sieve, and add up the cumulative screening rate of each sieve to obtain the roughness index;

[0107]

[0108] Where M i is the mass of cuttings larger than the screening size r (kg), M T is the total cuttings mass (kg), N c is the number of screens used and CI is the roughness index of the rock slag.

[0109] By recording the TBM operation monitoring data, the TBM excavation parameters corresponding to the day of collecting rock debris are obtained and the rock breaking specific energy is calculated.

[0110] Specifically, the calculation of rock breaking specific energy includes:

[0111]

[0112] Where, SE is the rock breaking specific energy (MJ / m3), F vis the average thrust of the TBM (kN), l is the excavation distance of the TBM (m), M is the average torque of the TBM (kN·m), θ is the rotation angle of the cutterhead, and R is the radius of the tunnel (m).

[0113] In the present invention, due to the randomness of the size and shape of the slag, the existing multi-layer slag screening machine is often easy to clog and difficult to clean. The drum screen has the advantage of not being easy to clog, but the screening level is single, while the multi-stage drum screen is not easy to clog, but there is a problem of insufficient screening. On the basis of this problem, a multi-layer drum screen for slag screening is proposed to solve the above problems at the same time. The layered design and anti-mixing baffle can fully screen the slag. The elastic cleaning device of each layer can not only solve the problem of slag blocking the sieve hole, but also extend the service life of the cleaning device. The outermost rolling cover can collect the residual slag and play a dust-proof role. Compared with the multi-stage drum screen, the motor speed needs to be continuously adjusted to achieve the ideal screening effect, and there is still insufficient screening and repeated screening. The device only uses one motor and does not need to adjust the speed frequently. The collection device and collection box designed at the tail are used to collect slag at each level and weigh the quality of each level, which is convenient for the subsequent treatment and use of slag.

[0114] The multifractal theory is first applied in the field of rock slag screening. Table 1 shows the mass distribution of rock slag in 11 screening tests. The multifractal parameter table is obtained by using the evaluation method provided by the present invention, and the multifractal behavior is verified. Fig.10 The roughness index (CI) and rock breaking specific energy (SE) are shown in Table 2, and the fitting analysis is performed with the multi-fractal parameters, as shown in Table 2. Fig.11 As shown. The information dimension D(1) is positively correlated with CI and negatively correlated with SE; The index α(0) is negatively correlated with CI and positively correlated with SE. Therefore, the higher the D(1) of the rock slag and the lower the α(0), the smaller the SE and the higher the rock breaking efficiency.

[0115]

[0116] Table 1 Distribution of slag mass fraction

[0117] Group D(1) α(0) CI <![CDATA[SE(MJ / m 3 )]]> 1 0.887 1.104 271 37.54 2 0.874 1.127 269 40.63 3 0.856 1.131 262 42.12 4 0.875 1.117 273 39.57 5 0.886 1.103 277 36.78 6 0.877 1.112 267 38.95 7 0.989 1.010 448 31.23 8 0.972 1.026 402 33.33 9 0.972 1.025 394 33.78 10 0.975 1.025 410 34.09 11 0.987 1.014 416 32.65

[0118] Table 2 Multi-fractal parameters and rock breaking specific energy and roughness index

[0119] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0120] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0121] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-layer drum screen device for TBM slag screening, characterized in that: include: A supporting device, the supporting device comprising a first supporting frame and a second supporting frame connected to one end of the first supporting frame, the other end of the first supporting frame is provided with a collecting port, and the first supporting frame is used to set a screening device; A screening device, comprising a screen fixing frame (10), a rolling outer cover (4), and a screen unit arranged in the rolling outer cover (4), the rolling outer cover (4) and the screen unit are both connected to the screen fixing frame (10), the screen unit and the rolling outer cover (4) are arranged coaxially, and the screen unit comprises a plurality of screens whose radii increase successively but whose screen holes decrease successively; A power device, the power device comprising a motor (5) and a transmission device, the motor (5) being connected to the screening device via the transmission device and being used to drive the screening device to rotate.

2. The multi-layer drum screen device for TBM slag screening according to claim 1 is characterized in that: The invention also comprises a spiral strip (11) arranged inside the screen and a cleaning device (15) arranged outside the screen, wherein the cleaning device (15) is provided with an anti-mixing baffle (14), and the anti-mixing baffle (14) is used to prevent the rock debris that has entered the next-level screen from entering the current-level screen again, and the cleaning device (15) is rollingly connected to the outside of the screen without screen holes.

3. The multi-layer drum screen device for TBM slag screening according to claim 2, characterized in that: The cleaning device (15) comprises a fixing device, a roller frame (12), a roller group (13), an upper limit plate (154), a lower limit plate (153), a limit bolt group (152) and bristles (151); the roller frame (12) is connected to the fixing device; the roller group (13) is arranged on the roller frame (12) and is located between the anti-mixing baffle (14) and the screen; An upper limit plate (154) is arranged between the anti-mixing baffle (14) and the lower limit plate (153), and the two are connected via a limit bolt group (152); the bristles (151) are connected to the upper limit plate (154) and are located below the anti-mixing baffle (14); The fixing device comprises a fan-shaped fixing frame (83), a horizontal plate (82), a vertical rod (81) and a plurality of fixing units, wherein the vertical rod (81) is arranged on the second supporting frame, the fan-shaped fixing frame (83) is connected to the vertical rod (81) through the horizontal plate (82), and the plurality of fixing units are arranged on the fan-shaped fixing frame (83); The fixing unit comprises a first fixing plate (831) and a second fixing plate (832), wherein the second fixing plate (832) is connected to the roller frame (12) and the first fixing plate (831) via bolts.

4. The multi-layer drum screen device for TBM slag screening according to claim 3 is characterized in that: The second support frame comprises a slide bracket (96), a collection box (9) and a plurality of slides, wherein the slide bracket (96) is arranged on the collection box (9), and the collection box (9) is divided into a plurality of collection chambers by a plurality of partitions, one end of the plurality of slides is respectively connected to a plurality of different screens, and the other end is respectively arranged on the top of a plurality of different partitions, and a weight sensing module is arranged in each of the collection chambers.

5. The multi-layer drum screen device for TBM slag screening according to claim 4, characterized in that: The first support frame also includes a support frame (6) and a rolling device, wherein the rolling device is arranged on the upper part of the support frame (6); The rolling device comprises a rotating frame (7) and a plurality of roller (54) groups. The plurality of roller (54) groups are arranged on the left and right sides of the rotating frame (7) and are rotatably connected to the rolling outer cover (4).

6. The multi-layer drum screen device for TBM slag screening according to claim 5, characterized in that: It also includes a tilting device, and the rolling device is connected to the supporting frame (6) via the tilting device; The tilting device comprises a limit column (61), a hydraulic instrument (624), a main force rod (622), a secondary force rod (621) and a slider (623); one end of the limit column (61) is arranged on the support frame (6), and the other end is rotatably connected to the rotating frame (7) through the limit column (61); a setting cavity is provided on the support frame (6); the hydraulic instrument (624) is arranged in the setting cavity, and one end of the hydraulic instrument (624) is rotatably connected to the main force rod (622); the other end of the main force rod (622) is rotatably connected to the secondary force rod (621) through the slider (623); one end of the secondary force rod (621) is rotatably connected to the setting cavity; a groove (72) is provided on one side of the rotating frame (7), and the slider (623) is slidably connected in the groove (72).

7. A rock breaking efficiency evaluation method for TBM slag screening, characterized in that: The multi-layer drum screen device for TBM slag screening according to any one of claims 1 to 6 further comprises: By obtaining the particle size distribution and mass fraction of the slag; Extract multi-fractal parameters of rock slag and verify the feasibility of multi-fractal; The relationship between the multi-fractal parameters and the rock breaking specific energy and roughness index is obtained to determine the rock breaking efficiency.

8. The rock breaking efficiency evaluation method for TBM slag screening according to claim 7, characterized in that: The multi-fractal parameter extraction of rock slag comprises: The screening interval of the device is divided and the coordinates are mapped to the interval [0, 1, 2, 3, 4, 5]. If there is no data point in the divided interval, the interval is discarded; the mapped new coordinates are matrixed; Obtain the probability density of rock cuttings particle distribution between each cell and construct a partition function group; The calculation results of generalized fractal dimension, singularity index and multifractal spectrum function, point spectrum width and multifractal spectrum symmetry degree are obtained respectively, and the multifractal progress of rock slag particle size distribution is verified; The verification result should satisfy that the double logarithmic curve between the partition function and the measurement scale shows a linear relationship.

9. The rock breaking efficiency evaluation method for TBM slag screening according to claim 8, characterized in that: The obtaining of the relationship between the multi-fractal parameters and the rock breaking specific energy and the roughness index to determine the rock breaking efficiency includes: Obtain the cumulative screening rate of each sieve, and add up the cumulative screening rate of each sieve to obtain the roughness index; By recording the TBM operation monitoring data, the TBM excavation parameters corresponding to the day of collecting rock debris are obtained and the rock breaking specific energy is calculated.

10. The rock breaking efficiency evaluation method for TBM slag screening according to claim 9, characterized in that: The calculation of rock breaking specific energy comprises: Where, SE is the rock breaking specific energy, F v is the average thrust of the TBM, l is the excavation distance of the TBM, M is the average torque of the TBM, θ is the rotation angle of the cutterhead, and R is the radius of the tunnel.

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