A system and method for cutting reinforced concrete based on a combined cutterhead.

Abstract

This invention belongs to the field of reinforced concrete cutting technology, and provides a system and method for cutting reinforced concrete based on a combined cutterhead. The system includes a combined cutterhead and a control unit. The combined cutterhead is a shield abrasive waterjet-mechanical combined cutterhead. The control unit controls the combined cutterhead to perform step-by-step cyclic cutting of the reinforced concrete. In each cutting cycle, the control unit first controls the combined cutterhead to rotate without advancing, using the abrasive waterjet to perform multiple cuts, so that the total cut depth of the reinforced concrete structure reaches a preset depth. Then, the abrasive waterjet is shut off, and the shield cutters, working in conjunction with the abrasive waterjet, perform cutting along the same trajectory. Simultaneously, other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

Description

Technical Field

[0001] This invention belongs to the field of reinforced concrete cutting technology, and particularly relates to a system and method for cutting reinforced concrete based on a combined cutter head. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Tunnel boring machines (TBMs) offer advantages such as high automation, fast tunneling speed, and minimal impact on the surrounding environment. However, with increasing urban building density and widespread underground space development, TBMs face more complex engineering conditions. When encountering existing underground reinforced concrete structures such as pile foundations, diaphragm walls, and reinforced areas at tunnel entrances and exits, traditional mechanical tunneling methods can lead to problems like rebar entanglement on the cutterhead, abnormal cutter damage, and machine jamming, resulting in low safety and slow construction speed. To address the challenge of insufficient TBM tunneling capacity through reinforced concrete, the concept of using abrasive waterjet-assisted cutterhead cutting has been proposed. Related experimental studies have been reported, validating the effectiveness of this method to some extent. Furthermore, a combined abrasive waterjet and mechanical cutterhead design for TBMs has also been published.

[0004] As a composite material, reinforced concrete exhibits significant differences in mechanical properties between the reinforcing steel and the concrete itself. During tunnel boring machine (TBM) excavation, concrete is easily cut and broken; however, reinforcing steel, with its high strength, is difficult to cut. When the concrete encasing and securing the reinforcing steel breaks, the steel is exposed, further increasing the difficulty of cutting and becoming the root cause of engineering problems such as cutter entanglement and auger jamming. Therefore, for TBM abrasive waterjet-mechanical combined cutterheads, effectively cutting the reinforcing steel in reinforced concrete into shorter segments for smooth discharge and to avoid engineering problems is crucial for efficient tunneling over reinforced concrete obstacles.

[0005] In existing technologies, the method of cutting with a combined cutter head, the determination of combined cutting parameters, and the reduction of water jet energy consumption are all key challenges restricting the combined cutter head from fully utilizing the auxiliary effect of abrasive water jets. For example, the extreme diameters (distances from the center of the cutter head) of multiple water nozzles on the combined cutter head vary greatly, and the lateral velocity of the water nozzles differs significantly as the cutter head rotates, resulting in significantly different abrasive water jet cutting capabilities (cutting capability decreases rapidly with increasing linear velocity). If parameters such as the diameter of the water nozzles and the pump pressure are not selected reasonably, it will be difficult to ensure that each water jet has the same auxiliary effect, thus making it difficult to cut the reinforcing steel at some cutting points. Summary of the Invention

[0006] To address at least one of the technical problems existing in the background art, the first aspect of the present invention provides a system for cutting reinforced concrete based on a combined cutterhead, and the second aspect of the present invention provides a method for cutting reinforced concrete based on a combined cutterhead. The present invention can be matched with a shield tunneling abrasive waterjet-mechanical combined cutterhead, coordinating the combined cutting capabilities of multiple abrasive waterjet-mechanical cutters on the combined cutterhead, ensuring efficient cutting of reinforcing bars while considering energy consumption, and promoting the industrial application of combined cutting technology.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a system for cutting reinforced concrete based on a combined cutterhead.

[0009] A system for cutting reinforced concrete based on a combined cutterhead includes: a combined cutterhead and a control unit, wherein the combined cutterhead is a shield tunneling abrasive waterjet-mechanical combined cutterhead, and the control unit is used to control the combined cutterhead to perform step-by-step cyclic cutting of reinforced concrete;

[0010] In each cutting cycle, the control unit first controls the combined cutterhead to not advance but only rotate, and uses the abrasive water jet to make multiple cuts, so that the total depth of the cut in the reinforced concrete structure reaches the preset depth; then controls the abrasive water jet to be turned off, and the shield cutter in cooperation with the abrasive water jet performs cutting along the same trajectory, while other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

[0011] The abrasive waterjet-mechanical cutter step-by-step cyclic cutting refers to the process where, during the combined cutterhead cutting process, the total advance of reinforced concrete tunneling is divided into equal-length tunneling segments, and the cutting process for each segment is called a cutting cycle. Each cutting cycle consists of two steps: In the first step (jet cutting step), the cutterhead rotates without advancing, and the abrasive waterjet performs multiple cuts to achieve a total cut depth of Lj in the reinforced concrete structure; in the second step (mechanical tunneling step), the waterjet is shut off, and the shield cutters, working in conjunction with the waterjet, perform the cutting (same trajectory cutting) to a depth of Lm, ensuring the reinforcing steel is severed in one go. Simultaneously, other shield cutters break through the concrete between the cut points of the reinforcing steel and peel it off. Due to the cyclic cutting, the actual cutting depth of the waterjet in one cutting cycle is Lm. For reinforced concrete structures such as pile foundations, the distribution of reinforcing bars is complex, and encounters with reinforcing bars are frequent in the excavation direction. During abrasive waterjet cutting, the entire cutting target is considered as reinforcing material, with Lj being greater than Lm, and the difference between Lj and Lm being less than the diameter of the reinforcing bar. The water nozzle target distance h is the sum of the structural target distance h1 and the target distance h2 formed during the cutting process, where h2 = Lj - Lm. In the jet cutting step, the disc advance speed S1 is set to 0, and the cutter head rotation speed R1 is set to a low value; generally, the lowest rotation speed can be used.

[0012] In one implementation, the control unit is used to: set different cutting times for abrasive water jets with different installation diameters in a multi-cutting mode, and adjust the cutting depth of these abrasive water jets on the reinforced concrete structure.

[0013] The advantage of the above technical solution is that it can coordinate the cutting performance of multiple waterjet streams on the cutter head, thereby improving cutting efficiency.

[0014] In one implementation method, the cutting depth achieved by using abrasive water jet is greater than the cutting depth of the shield cutter that works in conjunction with the abrasive water jet, and the difference between the two is less than the diameter of the reinforcing bar.

[0015] In one implementation, the target distance of the water nozzle is the sum of the structural target distance and the target distance formed during the cutting process, wherein the target distance formed during the cutting process = the cutting depth of the abrasive water jet - the cutting depth of the shield cutter that cooperates with the abrasive water jet.

[0016] As one implementation method, by acquiring test data of cutting steel bars, and using the depth of the steel bar cut as an evaluation index, the key parameter range for efficient cutting of steel bars by water jet is determined.

[0017] As one implementation method, the key parameters of abrasive waterjet cutting include traverse speed, pump pressure, target distance, nozzle diameter, number of cuts, and abrasive concentration.

[0018] As one implementation method, a model for predicting the depth of steel bar cuts is fitted based on the key parameters of abrasive waterjet cutting;

[0019] Based on the estimated ranges of water nozzle diameter and pump pressure, a model for predicting rebar cut depth is fitted, and the actual cutting depth of the water jet in each cutting cycle is used. The number of cuts for each nozzle under each diameter-pump pressure combination within a cutting cycle is calculated and listed to obtain the diameter-pump pressure-cutting number combination that meets the cutting requirements.

[0020] Among them, the key parameters of abrasive waterjet cutting (lateral velocity v, pump pressure P, target distance h, nozzle diameter d, number of cuts n, abrasive concentration η) are fitted with a prediction formula for the cutting depth Dj of a steel bar with the following structure:

[0021]

[0022] Where k1-k5 are fitting coefficients. The abrasive concentration η also has a significant impact on the cutting performance of the abrasive waterjet. Considering both cutting performance and abrasive dosage, a reasonable value is generally selected and not used as a variable in parameter optimization. Based on equation (1), the energy consumption of each water nozzle in a cutting cycle is calculated:

[0023]

[0024] Where C is an empirical constant, ρ w Let Lm be the density of water, and t be the time it takes for the water jet nozzles on the combined cutter head to cut the rebar once. Since the time t for each water nozzle to cut once is the same, that is, the time it takes for the cutter head to rotate by the same angle; and since Lm and h are constant values ​​after the combined cutter head design is completed and the step-by-step cutting method is established, when comparing the energy consumption of the water nozzles, it is only necessary to use the following formula:

[0025]

[0026] The advantage of the above technical solution is that, when optimizing the water jet parameters, it proposes a basic form of a predictive model for the cutting depth of the reinforcing bar by the key parameter of abrasive water jet, which provides guidance for fitting the cutting performance of abrasive water jet using limited experimental data and becomes an important basis for parameter optimization.

[0027] For the manufactured abrasive waterjet-mechanical combined cutterhead, the target distance of the water nozzles has been determined in the step-by-step cyclic cutting. The cutting lateral velocity of each water nozzle can be calculated based on the designed extreme diameter of the water jet nozzle on the cutterhead and the cutterhead rotation speed. The parameters to be optimized are the water nozzle diameter d, the pump pressure P, and the number of cuts n. According to step (1), the estimated range of the diameter and pump pressure of each water nozzle is listed. The outermost water nozzle on the cutterhead has the largest lateral velocity, which restricts the waterjet cutting efficiency of the cutterhead. The nozzle with the largest diameter and the highest pump pressure in the reasonable range of nozzle parameter values ​​are selected. For nozzles with smaller extreme diameters installed on the inner side of the cutterhead, a larger range of estimated diameter and pump pressure is selected.

[0028] As one implementation method, when there are multiple water nozzles with different diameter-pump pressure-cutting frequency combinations, the combination with the lowest energy consumption is determined based on energy consumption calculations.

[0029] The advantage of the above technical solution is that it improves cutting efficiency while minimizing energy consumption based on the energy consumption calculation of each water nozzle in a cutting cycle.

[0030] The advantage of the above technical solution lies in its ability to solve the problem of inconsistent cutting performance caused by the significant difference in lateral velocity of abrasive waterjet nozzles at different diameters. Because the waterjet nozzles at different diameters have the same rotational angular velocity as the cutterhead rotates, the larger the diameter, the greater the lateral velocity. However, as the lateral velocity increases, the abrasive jet's ability to cut rebar decreases sharply. If waterjet parameters are selected blindly, it is difficult to ensure that the waterjet at different diameters creates the same kerf depth on the rebar, leading to localized rebar that is difficult to cut by the mechanical cutter, becoming a bottleneck restricting the cutterhead's excavation efficiency. Therefore, optimizing parameters to ensure that different waterjet nozzles have the same cutting performance, i.e., the same kerf depth on the rebar during the waterjet cutting step, is key to guaranteeing combined cutting efficiency.

[0031] A second aspect of the present invention provides a method for cutting reinforced concrete based on a combined cutterhead.

[0032] A method for cutting reinforced concrete based on a combined cutterhead, comprising:

[0033] The combined cutter head is controlled to perform step-by-step cyclic cutting of reinforced concrete;

[0034] In each cutting cycle, the combined cutterhead is first controlled to rotate without advancing, and multiple cuts are made using abrasive water jets to make the total cut depth of the reinforced concrete structure reach the preset depth. Then, the abrasive water jets are controlled to shut off, and the shield cutters that work in conjunction with the abrasive water jets perform cuts along the same trajectory. At the same time, other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

[0035] As one implementation method, under multiple cutting methods, different cutting times are set for abrasive water jets with different installation diameters, and the cutting depth of these abrasive water jets on reinforced concrete structures is adjusted.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] (1) This invention proposes a step-by-step cyclic cutting method using abrasive waterjet and mechanical cutter. In the waterjet cutting step, the abrasive waterjet cuts the reinforcing steel multiple times to form a kerf of the required depth, avoiding the problem that the single kerf depth of the jet is insufficient and cannot effectively assist the cutter. At the same time, in the multiple cutting method, different cutting times can be set for waterjet with different installation diameters, adjusting their kerf depth on the reinforcing steel, which becomes a way to coordinate the cutting performance of multiple waterjet on the cutter head. In addition, a method for determining the efficient value range of construction step parameters, cutter head parameters, and abrasive waterjet parameters involved in the step-by-step cyclic cutting is proposed, improving the basic framework of the combined efficient cutting method for reinforced concrete.

[0038] (2) This invention provides a basic form of a prediction model for the cutting depth of steel bars by abrasive waterjet key parameters, which provides guidance for fitting the cutting performance of abrasive waterjet using limited experimental data and becomes an important basis for parameter optimization; at the same time, based on the energy consumption calculation of each water nozzle in a cutting cycle, it improves the cutting efficiency while taking into account the lowest energy consumption.

[0039] (3) Based on the estimated range of key parameters of each water nozzle, the present invention optimizes the nozzle diameter, pump pressure and number of cuts by means of a tiered list. The implementation process is simple. Compared with computer-based intelligent optimization algorithms, it is easier to form standardized parameter optimization tables and guidelines, which is more user-friendly for front-line designers.

[0040] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0042] Figure 1 This is a schematic diagram showing the positional relationship between the shield tunneling abrasive waterjet-mechanical combined cutterhead and the pile foundation;

[0043] Figure 2 This is a schematic diagram of the shield tunneling abrasive waterjet-mechanical combined cutterhead structure.

[0044] Figure 3 This is a side view of the layout of the abrasive waterjet-mechanical combined cutting tool on the combined cutter head;

[0045] Figure 4 This is a schematic diagram of the structure of the abrasive waterjet-mechanical combined cutting tool disclosed in this publication;

[0046] Figure 5 This is a schematic diagram of the step-by-step cyclic cutting process of the combined cutter head disclosed in this publication;

[0047] Figure 6 This is a schematic diagram of a method for efficiently cutting reinforced concrete using a combined cutterhead. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0049] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] In order to solve the problem of poor cutting effect of reinforced concrete in the prior art, this invention urgently needs a method for cutting reinforced concrete that can be matched with the shield tunneling abrasive waterjet-mechanical combined cutterhead, to coordinate the combined cutting capabilities of multiple abrasive waterjet-mechanical cutters on the combined cutterhead, to ensure efficient cutting of reinforcing bars, while also taking energy consumption into account, and to promote the industrial application of combined cutting technology.

[0052] The basic idea behind the combined cutter head design of this invention is as follows:

[0053] (1) With the goal of cutting the steel bars at a fixed point, the length of the steel bar segment is determined according to the discharge capacity of the shield screw conveyor for the steel bar segment, and multiple water jet nozzles are arranged in the radial direction of the cutterhead based on this.

[0054] (2) Each water jet nozzle on the cutter head is equipped with a mechanical cutter to cut along the same trajectory, forming a superposition effect of water jet and mechanical cutter damage;

[0055] (3) The mechanical cutter that works with the water jet is raised to ensure that the concrete fixes the steel bars during the cutting process.

[0056] Example 1

[0057] This embodiment provides a system for cutting reinforced concrete based on a combined cutterhead, which includes: a combined cutterhead and a control unit. The combined cutterhead is a shield abrasive waterjet-mechanical combined cutterhead, and the control unit is used to control the combined cutterhead to perform step-by-step cyclic cutting of reinforced concrete.

[0058] In each cutting cycle, the control unit first controls the combined cutterhead to not advance but only rotate, and uses the abrasive water jet to make multiple cuts, so that the total depth of the cut in the reinforced concrete structure reaches the preset depth; then controls the abrasive water jet to be turned off, and the shield cutter in cooperation with the abrasive water jet performs cutting along the same trajectory, while other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

[0059] Taking a subway line in a certain city as an example:

[0060] The subway line in a certain city is buried deep below the water level and is excavated by a shield machine. During the construction process, it encounters existing bridge pile foundations that cannot be avoided and needs to pass through bored cast-in-place piles with a diameter of 1.0 m. The main reinforcement bars of the pile foundation have a diameter of 22 mm, and the concrete strength is C30. Since it is difficult to effectively cut the steel bars by conventional mechanical cutting, the construction process causes great disturbance to the bridge and has high risks. Therefore, this project uses an abrasive water jet - tool combined cutter head 1 and proposes an efficient method for cutting reinforced concrete to guide the combined tunneling. The relative position of pile foundation 5 and the shield combined cutter head 1 is as Figure 1 shown. The horizontal distance between the center line of the pile foundation and the center of the tunnel is about 1.6 m.

[0061] As Figure 2 shown, the combined cutter head adopts an 8 - rib 2 - panel structure with a diameter of 6124 mm. A total of 65 shell cutters 3 and 5 combined cutters 41 - 45 are arranged. The distances (installation polar radii) of the 5 combined cutters from the center of the cutter head are 1204 mm, 1544 mm, 1884 mm, 2224 mm, and 2274 mm respectively. As Figure 3 shown, the combined cutter integrates the shell cutter 401 and the water jet nozzle 402. The target distance h1 formed by the combined cutter structure for the water nozzle is 取值 as 5 mm, which not only ensures that the shell cutter and the water jet cut along the same trajectory but also reduces the target distance for the water jet to cut the steel bars 71 and concrete 72. At the same time, the shell cutter 401 plays a good protective role for the water jet nozzle. The layout of the combined cutters 41 - 45 on the rib 2 is as Figure 4 shown. In order to cut the steel bars at the water jet cut seam first, the combined cutters are raised to achieve pre - cutting ahead of the shell cutter 3. According to the shield machine instruction manual, the minimum rotation speed of the combined cutter head is 0.1 rpm, the minimum tunneling speed is 1.0 mm / min, and the inner diameter of the screw conveyor supporting the combined cutter head is 910 mm.

[0062] Figure 5 shows the implementation process of the method for the combined cutter head to efficiently cut reinforced concrete, which generally includes two parts, namely step - by - step cyclic cutting and optimization of water jet parameters. The step - by - step cyclic cutting of the combined cutter head means that the total tunneling footage of the reinforced concrete is divided into equal - length tunneling segments Lm, and the cutting process for each tunneling segment is called a cutting cycle, as seen Figure 6 shown.

[0063] It should be noted that the "取值" in the original text seems to be an incorrect or incomplete expression. I translated it as "取值" as it was in the original, but it might need to be corrected to a proper value or description in the original context.The cutting process is divided into two steps in each cutting cycle. In the first step (jet cutting step), the cutter head does not advance but only rotates, and the abrasive water jet makes multiple cuts to achieve a total cut depth of Lj in the reinforced concrete structure. In the first cutting cycle, the actual cutting depth of the water jet is Lj, and in subsequent cycles it is Lm, with Lj being greater than Lm. In the second step (mechanical excavation step), the water jet is turned off, and the shell cutter performs the cutting with a total cutting depth of Lm. The shell cutter of the combined cutter cuts the reinforcing steel first due to its advanced cutting capability, ensuring that the reinforcing steel is cut off in one go, while the other shell cutters mainly break the concrete between the cut points of the reinforcing steel and peel off the already cut reinforcing steel.

[0064] In the jet cutting step, the disk advance speed S1 is set to 0, and the disk rotation speed R1 is set to the minimum speed of 0.1 rpm.

[0065] Since the target distance for efficient cutting of reinforcing bars by abrasive waterjet should not exceed 50mm, the value of Lj should not be greater than 50mm. In this embodiment, the value of Lj is 40mm.

[0066] Because the project is located below the groundwater level, the abrasive waterjet cutting of reinforced concrete is an underwater submerged cutting process. To determine the relevant mechanical and tunneling parameters, a combined cutting test was conducted, first submerging the cut with the abrasive waterjet, and then having the shield cutter cut the reinforced concrete along the cut. Using the cutting of the reinforcing steel as the evaluation index, the test results showed that the optimal range for the advance speed S2 during mechanical tunneling is 1-4 mm / min, and the optimal range for the cutterhead rotation speed R2 is 0.5-2 rpm. In this embodiment, S2 is set to 3 mm / min, and the cutterhead rotation speed R2 is set to 1 rpm. Based on the combined cutting test results, when the reinforcing steel can be cut in this combined process, the target distance h2 (h2 = Lj - Lm) formed during the cutting process should not be less than 10 mm and should not be greater than the diameter of the reinforcing steel. In this embodiment, the value is 10 mm. Therefore, the target distance h of the waterjet in the waterjet cutting step is: h = h1 + h2 = 15 mm, while the construction step parameter Lm = Lj - h2 = 30 mm.

[0067] The optimization process for abrasive waterjet parameters in the jet cutting step is as follows:

[0068] (1) For the key parameters of abrasive waterjet cutting (lateral velocity v, pump pressure P, target distance h, nozzle diameter d, number of cuts n, abrasive concentration η), a submerged cutting test of steel bars was carried out. The cutting depth of the steel bars was used as the evaluation index to obtain the parameter range of efficient cutting of steel bars by abrasive waterjet: lateral velocity not greater than 2m / min, pump pressure 280-380MPa, waterjet nozzle diameter 0.33-0.68mm, target distance not greater than 50mm, abrasive mass concentration not less than 13%, and number of cuts not less than 1 (cutting depth is proportional to the number of cuts).

[0069] Within the parameter range for the efficient cutting of reinforcing bars by abrasive waterjet, a prediction formula for the cutting depth Dj of the reinforcing bar is obtained based on the results of the abrasive waterjet submerging and cutting of the reinforcing bar:

[0070] D j =0.112nv -0.988 h -0.435 P 0.725 d 1.351 (4)

[0071] Taking into account both cutting performance and abrasive dosage, the abrasive concentration η is selected as a constant of 13% and is not included as a variable in parameter optimization. Substituting equation (4) into equation (2) of this invention, the energy consumption of each water nozzle in one cutting cycle is obtained:

[0072] W j =0.112 -1 CtL m v 0.988 h 0.435 d 0.649 P 0.775 (5)

[0073] Where C is an empirical constant, and t is the time it takes for the water jet nozzles on the combined cutter head to cut the rebar once. Since the time t for each water nozzle to cut once is the same, that is, the time it takes for the cutter head to rotate by the same angle; Lm is taken as 30mm and h is taken as 15mm, both of which are constant values, therefore, when comparing the energy consumption of the water nozzles, it is only necessary to follow the following formula:

[0074] W j0 =v 0.988 d 0.649 P 0.775 (6)

[0075] (2) Based on the combined cutter's installation diameter and the cutter head rotation speed in the waterjet cutting step, the transverse velocity of each water nozzle is calculated. Then, within the efficient range of the abrasive waterjet parameters, the diameter and pump pressure prediction range of each water nozzle are listed, as shown in Table 1. The combined cutter 45 has the highest transverse velocity and is the control nozzle affecting the abrasive waterjet cutting efficiency of the cutter head. The nozzle diameter and pump pressure are both selected to be large values, namely 0.68 mm and 380 MPa, respectively.

[0076] Table 1. Estimated range of water nozzle diameter and pump pressure

[0077] serial number Lateral speed m / min Diameter range (mm) Pump pressure range (MPa) 41 0.8 0.33-0.60 280-380 42 1.0 0.40-0.68 280-380 43 1.2 0.50-0.68 280-380 44 1.4 0.50-0.68 280-380 45 1.9 0.68 380

[0078] (3) The water nozzle diameters in Table 1 are divided into 5 levels: 0.33mm, 0.40mm, 0.50mm, 0.60mm and 0.68mm. The pump pressures are divided into 3 levels: 280MPa, 330MPa and 380MPa. Then, according to Equation (1) and the actual cutting depth Lm of the water jet in each cutting cycle, the number of cuts for each nozzle under each diameter-pump pressure combination in one cutting cycle is calculated and listed in Table 2. Among them, the diameter and pump pressure of the outermost joint cutter water nozzle are selected as the maximum values ​​within the estimated range to ensure the overall cutting efficiency of the cutter head. For other water nozzles, the diameter and pump pressure are selected based on the number of cuts of the outermost water nozzle, and the diameter and pump pressure are not greater than the number of cuts to obtain the diameter-pump pressure-number of cuts combination that meets the cutting requirements.

[0079] Table 2 Selection Table for Water Nozzle Diameter-Pump Pressure Combination Parameters

[0080]

[0081]

[0082] (4) For each water nozzle in step (3), there are usually multiple combinations of diameter-pump pressure-cutting times that meet the requirements. For example, for the 44 combined cutter water nozzle, the parameters that meet the requirements are 0.68mm-280MPa-13 times, 0.60mm-330MPa-13 times, 0.68mm-330MPa-11 times, 0.60mm-380MPa-12 times, and 0.68mm-380MPa-10 times. Substituting these parameter combinations into equation (6) for energy consumption calculation, the combination with the lowest energy consumption is finally determined to be 0.68mm-280MPa-13 times. Following the same method, the parameters of high-efficiency, low-energy-consumption water jets are listed in Table 3.

[0083] Table 3 Optimization Results of High-Efficiency Waterjet Cutting Parameters

[0084]

[0085]

[0086] In summary, the step-by-step cyclic cutting method establishes the overall framework for the efficient cutting of reinforced concrete using a combined cutterhead, and provides relevant mechanical and tunneling parameters. The optimized water jet parameters achieve high efficiency and low energy consumption, ensuring the consistency of water jet cutting performance at different diameters and further improving the tunneling performance of the combined cutterhead.

[0087] Example 2

[0088] This embodiment provides a method for cutting reinforced concrete based on a combined cutterhead, which includes:

[0089] The combined cutter head is controlled to perform step-by-step cyclic cutting of reinforced concrete;

[0090] In each cutting cycle, the combined cutterhead is first controlled to rotate without advancing, and multiple cuts are made using abrasive water jets to make the total cut depth of the reinforced concrete structure reach the preset depth. Then, the abrasive water jets are controlled to shut off, and the shield cutters that work in conjunction with the abrasive water jets perform cuts along the same trajectory. At the same time, other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

[0091] In the multiple cutting method, different cutting times are set for abrasive water jets with different installation diameters, and the cutting depth of these abrasive water jets on reinforced concrete structures is adjusted.

[0092] It should be noted that the optimization process of the corresponding control parameters of the combined tool turret is as described in Embodiment 1 above, and will not be repeated here.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for cutting reinforced concrete based on a combined cutterhead, characterized in that, include: The combined cutterhead and control unit are described above. The combined cutterhead is a shield abrasive waterjet-mechanical combined cutterhead, and the control unit is used to control the combined cutterhead to perform step-by-step cyclic cutting of reinforced concrete. In each cutting cycle, the control unit is used to first control the combined cutter head to not advance but only rotate, and use the abrasive water jet to make multiple cuts so that the total depth of the cut in the reinforced concrete structure reaches the preset depth; then control the abrasive water jet to shut off, and the shield cutter that cooperates with the abrasive water jet to perform the same trajectory cutting, while other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar. By acquiring test data on cutting steel bars, and using the depth of the steel bar cut as an evaluation index, the key parameter range for efficient water jet cutting of steel bars was determined. A model for predicting the cut depth of reinforcing bars was fitted based on the key parameters of abrasive waterjet cutting; the formula for the model for predicting the cut depth of reinforcing bars is as follows: ； in, This indicates the predicted depth of the rebar cut. k 1 -k 5 is the fitting coefficient. v The lateral velocity, P For pump pressure, h Target distance, d Nozzle diameter, n The number of cuts; Based on the estimated ranges of water nozzle diameter and pump pressure, a model for predicting rebar cut depth is fitted, and the actual cutting depth of the water jet in each cutting cycle is used. The number of cuts for each nozzle under each diameter-pump pressure combination within a cutting cycle is calculated and listed to obtain the diameter-pump pressure-cutting number combination that meets the cutting requirements.

2. The system for cutting reinforced concrete based on a combined cutterhead as described in claim 1, characterized in that, The control unit is used to: set different cutting times for abrasive water jets with different installation diameters under multiple cutting methods, and adjust the cutting depth of these abrasive water jets on reinforced concrete structures.

3. The system for cutting reinforced concrete based on a combined cutterhead as described in claim 1, characterized in that, The cutting depth achieved by using abrasive waterjet is greater than the cutting depth of the shield cutter that is used in conjunction with abrasive waterjet, and the difference between the two is less than the diameter of the reinforcing bar.

4. The system for cutting reinforced concrete based on a combined cutterhead as described in claim 1, characterized in that, The target distance of the water nozzle is the sum of the structural target distance and the target distance formed during the cutting process, where the target distance formed during the cutting process = the cutting depth of the abrasive water jet - the cutting depth of the shield cutter in conjunction with the abrasive water jet.

5. The system for cutting reinforced concrete based on a combined cutterhead as described in claim 1, characterized in that, Key parameters for abrasive waterjet cutting include traverse speed, pump pressure, target distance, nozzle diameter, number of cuts, and abrasive concentration.

6. The system for cutting reinforced concrete based on a combined cutterhead as described in claim 1, characterized in that, When there are multiple water nozzles with different diameters, pump pressures, and cutting frequency combinations, the combination with the lowest energy consumption is determined based on energy consumption calculations.

7. A method for cutting reinforced concrete based on a combined cutterhead, characterized in that, The system for cutting reinforced concrete based on a combined cutterhead as described in any one of claims 1-6 includes: The combined cutter head is controlled to perform step-by-step cyclic cutting of reinforced concrete; In each cutting cycle, the combined cutterhead is first controlled to rotate without advancing, and multiple cuts are made using abrasive water jets to make the total cut depth of the reinforced concrete structure reach the preset depth. Then, the abrasive water jets are controlled to shut off, and the shield cutters that work in conjunction with the abrasive water jets perform cuts along the same trajectory. At the same time, other shield cutters are used to break the concrete between the rebar breakpoints and peel off the rebar.

8. The method for cutting reinforced concrete based on a combined cutterhead as described in claim 7, characterized in that, In multiple cutting methods, different cutting times are set for abrasive water jets with different installation diameters, and the cutting depth of these abrasive water jets on reinforced concrete structures is adjusted.

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