Method for cutting reinforced concrete through hob

Abstract

The invention provides a method for cutting reinforced concrete by using a hob, which comprises the following steps of: evaluating the hob stress of hobs with different geometrical characteristics under different construction parameters when the reinforced concrete is cut by using a cutter load calculation algorithm; the construction parameters comprise the penetration speed, the cutting speed, the rotating speed and the cutting depth; the geometrical characteristics comprise the hob contour radius, the hob edge width and the half edge angle; according to the obtained hob stress evaluation result, construction parameters and geometrical characteristics of the hob are determined; and cutting the reinforced concrete based on the determined construction parameters and the geometrical characteristics of the hob.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering technology, specifically a method for cutting reinforced concrete with a roller cutter. Background Technology

[0002] In modern tunnel engineering and underground space development, the study of cutter loads on shield tunneling cutters cutting reinforced concrete is of great significance for cutter design optimization, construction efficiency improvement, and equipment safety assurance. Existing theoretical models of cutter rock-breaking loads mostly rely on traditional cavity expansion models, which are applicable to the process before the initial step fracture of rock when a wedge cutter penetrates the rock. However, this model only analyzes the penetration process and does not consider the dynamic load characteristics under the action of cutterhead pushing speed and rotation speed.

[0003] Existing research on load calculation for hobbing cutters cutting reinforced concrete mostly focuses on calculating the static load of the hob at a certain penetration depth. It often simplifies the process of a single hob cutting steel bars in a single operation as an instantaneous process, approximating the entire hob motion as uniform linear motion along the cutting direction at a fixed cutting depth. It lacks a load model that can comprehensively reflect the dynamic coupling effect of parameters such as push speed and rotation speed. This results in a large deviation between the calculation results and the actual cutting conditions, making it difficult to provide accurate theoretical support for optimizing the collaborative operation of hob groups, controlling construction parameters, and simulating cutter head cutting. Summary of the Invention

[0004] Purpose of the invention: To address the problem that existing studies on load calculation for hobbing cutter cutting of reinforced concrete have significant discrepancies between the calculated results and actual cutting conditions, making it difficult to provide accurate theoretical support for optimizing hobbing cutter group collaborative operations, controlling construction parameters, and simulating cutter head cutting, this invention proposes a method for hobbing cutter cutting of reinforced concrete. Based on the theoretical model of hobbing cutter rock-breaking load and the model of projectile erosion of concrete, this method enables the calculation of tool load for hobbing cutter cutting of reinforced concrete.

[0005] Technical solution: This invention proposes a method for cutting reinforced concrete with a roller cutter, comprising the following steps:

[0006] The algorithm for calculating tool load is used to evaluate the force on a hob cutter when cutting reinforced concrete under different construction parameters or with different geometric features. The construction parameters include penetration speed and rotation speed. The geometric features include hob cutter cutting width and half-cutting angle.

[0007] Based on the obtained stress assessment results of the cutter, determine the construction parameters and / or the geometric characteristics of the cutter;

[0008] Based on the determined construction parameters and / or the geometry of the cutter, the reinforced concrete is cut.

[0009] The tool load calculation algorithm includes:

[0010] The concrete under the cutting action of the roller cutter is simplified into multiple regions including at least a dense core region. The dense core region is where the stress in all directions of the concrete is equal under the action of the roller cutter, and is radial stress. During the expansion process of the concrete cavity, the stress in the dense core region is derived.

[0011] Based on the stress in the dense core region, the geometric characteristics of the cutter, and the construction parameters, the vertical force of the cutter cutting the reinforced concrete section is calculated.

[0012] Based on the geometric characteristics of the hob, the rolling force on the hob is calculated;

[0013] Specifically, determining the construction parameters and geometric characteristics of the cutter based on the obtained cutter stress assessment results includes:

[0014] For hobbing with different tool geometry characteristics, the stress assessment is carried out to determine the influence of different tool selection on the stress of hobbing in cutting reinforced concrete, and the appropriate tool shape is selected for the corresponding working conditions.

[0015] Based on the vertical force of the cutter cutting the reinforced concrete section and the rolling force on the cutter, the construction parameters and geometric characteristics of the cutter are determined.

[0016] Furthermore, the derivation of the stress in the dense core region during the expansion process of the concrete cavity includes the following specific operations:

[0017] Radial stress and circumferential stress are defined as follows:

[0018] (1)

[0019] (2)

[0020] In the formula: For Young's modulus, Poisson's ratio, For radial displacement, , Represents radial stress and circumferential stress, and r represents the radius of the cavity.

[0021] definition , , ,in, The velocity of the dense core interface is represented by t, and the time of cavity expansion is represented by t. Indicates the elastic wave velocity of concrete;

[0022] The radial stress at the boundary is expressed as:

[0023] (3)

[0024] (5)

[0025] In the formula: For concrete density, For Young's modulus, Poisson's ratio, Indicates the tensile strength of concrete;

[0026] definition , , , This is the design value of the axial compressive strength of concrete. Representing the penetration speed of the hob, we can obtain:

[0027] (6)

[0028] In the formula, N= M= m1 represents the volume factor of the plastic cracked zone, and v1 is the particle velocity at the outer boundary of the plastic cracked zone. It is the integration constant;

[0029] make The Runge-Kutta method is used to apply equation (6) in the interval The radial stress is obtained by solving the problem internally. This refers to the stress in the dense core region.

[0030] Furthermore, the calculation of the vertical force of the cutter cutting the reinforced concrete section based on the stress in the dense core region, the geometric characteristics of the cutter, and construction parameters includes the following specific operations:

[0031] Vertical force of hobbing cutter cutting reinforced concrete section Represented as:

[0032] (7)

[0033] , Calculate using the following formulas respectively:

[0034] (8)

[0035] (9)

[0036] In the formula, For the compressive strength of steel bars, This represents the normal projected area of ​​the contact zone between the cutting cutter and the reinforcing bar. This represents the total normal projected area of ​​the portion penetrated by the hob at the current cutting depth. This indicates the stress in the dense core region.

[0037] Furthermore, the calculation of the vertical force of the cutter cutting the reinforced concrete section based on the stress in the dense core region, the geometric characteristics of the cutter, and construction parameters includes the following specific operations:

[0038] The first stage before the cutter contacts the reinforcing bar is defined as the pure concrete cutting stage, at which time the cutter ring is fully engaged in the concrete layer. When the cutter begins to contact the reinforcing bar, the cutting process enters the second stage, and the cutter begins to cut the reinforcing bar until the cutting area of ​​the reinforcing bar reaches the theoretical maximum value under the current cutting depth. The cutter's movement trajectory begins to gradually move away from the reinforcing bar, entering the third stage of the separation process. The cutting effect of the cutter on the reinforcing bar gradually weakens until it completely separates.

[0039] From the first phase to the second phase:

[0040] (36)

[0041] In the formula, Indicates the compressive strength of the steel reinforcement. This indicates the time between the first and second phases; , This represents half the width of the hobbing cutter's cutting edge. Indicates the half-edge angle. Indicates the radius of the hob profile. Indicates the depth of cut of the hob. Indicates velocity in the horizontal direction; , ;

[0042] From the second phase to the third phase:

[0043] (37)

[0044] In the formula, This indicates the duration of the second to third phases.

[0045] Furthermore, the calculation of the rolling force on the hob based on its geometric features includes the following specific operations:

[0046] The rolling force of the hob is calculated as the product of the shear area of ​​the steel bar or concrete surface being cut and the shear strength of the corresponding material, expressed as:

[0047] (38)

[0048] In the formula: For the shear strength of the steel reinforcement; This represents the shear area of ​​the reinforcing bar acting on the side of the cutter. This refers to the shear strength of the concrete. This represents the shear area of ​​the concrete acting on the side of the cutter.

[0049] Beneficial effects: Compared with the prior art, the present invention has significant advantages, specifically including:

[0050] (1) The method of the present invention addresses the shortcomings of the calculation method of the tool load for cutting reinforced concrete by the hob, clarifies the three-stage characteristics of the hob cutting, and fully considers the whole process of the hob intruding into the reinforced concrete, which is closer to reality than the existing static model.

[0051] (2) This invention fully considers the influence of pushing speed and rotation speed on the cutting force of the cutter, establishes a dynamic load model that associates the properties of concrete soil, the pushing speed of the cutter, rotation speed and other parameters, and quantifies the interaction between parameters into mathematical expressions, providing theoretical support for the optimization of collaborative operation of cutter groups, the control of construction parameters and the simulation of cutter head cutting, and has great application value in the engineering field. Attached Figure Description

[0052] Figure 1 This invention provides a method for calculating the tool load when using a hobbing cutter to cut reinforced concrete.

[0053] Figure 2 A cavity expansion model for concrete cutter using a roller cutter;

[0054] Figure 3 This is a schematic diagram of the hob shape parameters;

[0055] Figure 4 This refers to the process of using a roller cutter to cut reinforced concrete.

[0056] Figure 5 This is a plane rectangular coordinate system under the condition that the hob and the steel bar outline are tangent;

[0057] Figure 6 A simplified diagram of the vertical projected area of ​​the cut area of ​​the reinforcing bar;

[0058] Figure 7 A simplified diagram of the vertical projected area of ​​the cutter intrusion portion;

[0059] Figure 8 This represents the horizontal projection of the concrete shear failure zone. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the following description, in conjunction with the accompanying drawings, will further illustrate the method for calculating the load of a hobbing cutter for cutting reinforced concrete.

[0061] Example 1:

[0062] This invention proposes a method for calculating the load of a hobbing cutter used in cutting reinforced concrete, such as... Figure 1 As shown, it mainly includes:

[0063] Step 1: Using the analysis and derivation results of each response zone during the expansion of the concrete cavity, obtained from the Dilatant-Kinematic equation, the mass conservation equation in spherical coordinates, and the momentum conservation equation, calculate the stress in the compacted core zone of the concrete section cut by the hob cutter. Specific operations include:

[0064] Concrete under the cutting action of a roller cutter is simplified into three regions: a dense core region, an elasto-plastic failure region, and an elastic region. For example... Figure 2 As shown, the cutting force of the hob mainly depends on the stress distribution in these three regions. In the dense core region, the concrete is highly compacted under the action of the hob, and is in an approximately uniform stress state, meaning the stress in all directions is equal; we assume radial stress in this region. In the elastic region, Hooke's law can be used to describe the stress-strain relationship of the concrete. We can assume compressive stress is positive and tensile stress is negative, and calculate the expressions for radial and circumferential stress in spherical coordinates. In the elastoplastic failure region, the yield stress can be calculated using the modified Ottosen yield criterion. At this point, the concrete is in a plastic uniaxial compression state, and the Dilatant-Kinematic equations are used.

[0065] After determining the characteristics of each response zone, this embodiment of the invention uses the analysis and derivation results of each response zone during the expansion of concrete cavity, calculated based on the Dilatant-Kinematic equation, the mass conservation equation in spherical coordinates, and the momentum conservation equation.

[0066] Assume that the radial stress and circumferential stress are expressed as follows:

[0067] (1)

[0068] (2)

[0069] In the formula: For Young's modulus, Poisson's ratio, This represents radial displacement. , The radial and circumferential stresses are represented by r, where r represents the radius of the cavity.

[0070] definition , , ,in, The velocity of the dense core interface is represented by t, and the time of cavity expansion is represented by t. This indicates the elastic wave velocity of concrete.

[0071] The radial stress at the inner boundary of the elastic zone is:

[0072] (3)

[0073] (4)

[0074] (5)

[0075] In the formula: This refers to the density of concrete.

[0076] definition , , , This is the design value of the axial compressive strength of concrete. Representing the penetration speed of the hob, we can obtain:

[0077] (6)

[0078] In the formula, N= M= m1 represents the volume factor of the plastic cracked zone, and v1 is the particle velocity at the outer boundary of the plastic cracked zone. is the integration constant.

[0079] This equation cannot be solved by integration, so the Runge-Kutta method is used to solve equation (6) in the interval... The radial stress in each region is obtained by solving the problem within the inner region. When... At that time, the result This refers to the stress in the dense core region.

[0080] Step 2: Using the two stress components—compressive fracture of the concrete segment and compressive strength failure of the reinforcing steel segment—calculate the area of ​​the cutter's vertical intrusion into the reinforced concrete, and calculate the vertical force of the cutter cutting the reinforced concrete segment. Specific operations include:

[0081] definition The force exerted on the cutter in the normal direction by the contact area between the cutter and the reinforced concrete section is provided by the concrete and the reinforcing steel. Due to the immense pressure, the concrete at the contact point with the cutter locally pulverizes, forming a dense core; the reinforcing steel undergoes strength failure due to compression, at which point it reaches its compressive strength.

[0082] It can be expressed as follows:

[0083] (7)

[0084] , The following formulas can be used to calculate:

[0085] (8)

[0086] (9)

[0087] In the formula, For the compressive strength of steel bars, This represents the normal projected area of ​​the contact zone between the cutting cutter and the reinforcing bar. This refers to the total normal projected area of ​​the portion penetrated by the hob at the current cutting depth. This represents the stress in the dense core region.

[0088] Hob shape parameters are as follows Figure 3 As shown, For the width of the hobbing cutter blade, It is a half-edge angle. Let be the cutting depth of the hob at a certain moment. Since the hob diameter is much larger than the steel bar, the time taken for the hob to cut the steel bar once is very short. Therefore, it is assumed that the hob moves in a straight line during a single cut, and its horizontal velocity is . The vertical velocity is .

[0089] When the cutter completes its passage through the upper concrete layer and reaches the starting position for cutting the reinforcing steel, the cutter begins to contact the steel and initiate effective cutting. From this moment on, the depth of the cutter's cutting into the steel begins. Based on this assumption, the single cutting action of the hob on the reinforcing bar can be systematically divided into three typical stages.

[0090] The first stage before the cutter contacts the reinforcing bar is the pure concrete cutting stage. At this time, the cutter ring acts entirely on the concrete layer, crushing and stripping the concrete. When the cutter outline and the reinforcing bar outline form a geometric tangent relationship, such as... Figure 4 As shown in (a), the hob begins to contact the rebar, and the cutting process then enters the second stage, where the hob begins to cut the rebar. This continues until the rebar cutting area reaches the theoretical maximum value at the current cutting depth. Then, the hob's trajectory gradually moves away from the rebar, entering the third stage of the separation process, as shown in (a). Figure 5 As shown in (c), the cutting action of the hob on the reinforcing bar gradually weakens until it completely disengages.

[0091] Establish a plane rectangular coordinate system based on the state where the profile of the hobbing cutter is tangent to the profile of the reinforcing bar in stage one, such as... Figure 5 As shown, let the center of the rebar outline be... The center of the hob profile , , The line tangent point The radius of the steel bar outline is The hob profile radius is At this time, passing by s, cutting depth is Then the point of tangency B between the hob profile and the cutting baseline The following equations can be derived using geometric relationships:

[0092] (10)

[0093] Solving the equation yields the following relation:

[0094] (11)

[0095] The solution , and Substituting the values, we obtain the coordinates of each point:

[0096]

[0097]

[0098] .

[0099] This marks the end of the first stage and the beginning of the second stage.

[0100] Establish a Cartesian coordinate system based on the state when the center of the stage two hob profile reaches directly above the center of the rebar profile. At this point, the center of the rebar profile... The center of the hob profile , Assume the state transition takes time. At this point, the cutting depth of the hobbing cutter is The following equations can be derived from the motion state of the hob:

[0101] (12)

[0102] Solving the equation yields the following relationship:

[0103] (13)

[0104] The solution , and Substituting the values, we can obtain the coordinates of each point. At this point, the contact area between the cutter and the rebar reaches its maximum. This state marks the end of the second stage and the beginning of the third stage.

[0105] Establish a Cartesian coordinate system by taking the state where the profile of the three-roll cutter is tangent to the profile of the rebar, and set the center of the rebar profile. The center of the hob profile , , The line tangent point The radius of the reinforcing bar is The hob radius is The point of tangency between the hob profile and the cutting baseline Assume that time elapses between the second and third states. At this point, the cutting depth of the hobbing cutter is The following equations can be derived using geometric relationships:

[0106] (14)

[0107] Solving the equation yields the following relationship:

[0108] (15)

[0109] At this point, the hob is about to leave the rebar, completing a full cut; this state marks the end of the third stage. The shaded area enclosed by the curved segments at the top and bottom of the rectangular cross-section can be simplified into two triangles. Therefore, the projected area of ​​the contact zone between the hob and the rebar in the normal direction can be simplified into two isosceles trapezoids with linearly increasing lower base lengths and heights.

[0110] Time from 0 to At that time, the area of ​​the trapezoid increases continuously with the speed of the hob, until it reaches... Figure 6 The state here The length is Figure 6 The length of the common chord of the two circles, at this time Reach the maximum value. Time starts from... arrive As the cutting speed and rotation speed of the cutter increase, the area of ​​the trapezoid decreases continuously until it leaves the reinforcing bar.

[0111] The approximate length of the lower base CD of isosceles trapezoid ABCD is calculated as shown in equation (16).

[0112] (16)

[0113] By combining the expressions for the two circles in a Cartesian coordinate system, the length of their common chord can be obtained.

[0114] (17)

[0115] (18)

[0116] In the formula, .therefore, , .

[0117] 0 to When the area of ​​an isosceles trapezoid ABCD is approximately calculated, the approximate value is as follows:

[0118] (19)

[0119] (20)

[0120] (twenty one)

[0121] The normal projected area of ​​the contact zone between the hob and the rebar for:

[0122] (twenty two)

[0123] (twenty three)

[0124] arrive When the area of ​​an isosceles trapezoid ABCD is approximately calculated, the approximate value is as follows:

[0125] (twenty four)

[0126] (25)

[0127] (26)

[0128] The normal projected area of ​​the contact zone between the hob and the rebar for:

[0129] (27)

[0130] (28)

[0131] In equation (25), let , ,but In equation (30), the substituents are expanded. , have to: .

[0132] Examine the portion of the reinforced concrete penetrated by the hob in a single cut, and observe its vertical projection shape. Simplify the upper and lower parts of the rectangular section from curved segments to straight segments. Therefore, the vertical projection area of ​​the hob's penetration into the reinforced concrete can be simplified into two isosceles trapezoids, such as... Figure 7 As shown.

[0133] (29)

[0134] (30)

[0135] 0 to When the area of ​​isosceles trapezoid EFGH is approximately calculated, the approximate value is as follows:

[0136] (31)

[0137] (32)

[0138] Substituting into equation (9), we get:

[0139] (33)

[0140] In the formula, .

[0141] arrive When the area of ​​isosceles trapezoid EFGH is approximately calculated, the approximate value is as follows:

[0142] (34)

[0143] (35)

[0144] In the formula, .

[0145] Therefore, substituting the loads of the hobbing cutter cutting steel bars and concrete into equation (7) respectively, we can obtain:

[0146] (1) 0 to hour:

[0147] (36)

[0148] (2) arrive hour:

[0149] (37)

[0151] Step 3: The rolling force on the hob is the reaction force acting on the side of the hob caused by the shear failure of the material being cut laterally. The rolling force of the hob is calculated as the product of the shear area of ​​the steel bar or concrete being cut and the shear strength of the corresponding material. Specific operations include:

[0152] The rolling force on the hob is the reaction force acting on the side of the hob caused by the shear failure of the material being cut laterally. The rolling force of the hob is calculated as the product of the shear area of ​​the steel or concrete surface being cut and the shear strength of the corresponding material. The expression for the rolling force of the hob is:

[0153] (38)

[0154] In the formula: For the shear strength of the steel reinforcement; This represents the shear area of ​​the reinforcing bar acting on the side of the cutter. This refers to the shear strength of the concrete. This represents the shear area of ​​the concrete acting on the side of the cutter.

[0155] Due to the hob profile radius Much larger than the radius of the steel bar outline The edge contour line of the cutter intrusion part can be approximated as a straight line, and the point... , , Collinear, such as Figure 7 As shown.

[0156] Figure 7 The area of ​​the shaded region, i.e., the area where the cutter penetrates the reinforced concrete, can be obtained in the following way:

[0157] (39)

[0158] Center of the hob profile in the coordinate system The coordinates are ,exist s after The coordinates are The expression for the hob profile is:

[0159] (40)

[0160] Substitution We can obtain: .

[0161] Coordinates are .

[0162] The expressions for the combined profiles of the hob and the reinforcing bar are given by... , , , , , good points , The coordinates are:

[0163] (41)

[0164] The coordinates of the point are .

[0165] Using the trigonometric function area formula and the sector area calculation formula, the shear areas of the steel bars and concrete acting on the side of the cutter can be obtained as follows:

[0166] (42)

[0167] (43)

[0168] The obtained , Substituting into equation (43), we can obtain the rolling force of the hob. The final result.

[0169] This invention takes into account the properties of concrete and reinforcing steel, quantifies the influence of rotational speed and pushing speed on load, and reveals the dynamic evolution law of load during cutting. It provides theoretical support for the optimization of collaborative operation of roller cutter groups, the control of construction parameters, and cutting simulation, and has great value for promoting the refined development of mechanized construction technology under complex geological conditions.

[0170] The tool load value calculated by this method can predict the force on hobs with different geometric characteristics under different parameters in actual cutting conditions. This provides a force assessment for hobs with different cutter types selected at different cutting speeds and rotational speeds when cutting reinforced concrete, thereby enabling the selection of suitable hob cutter types and construction parameters.

[0171] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method of cutting reinforced concrete with a milling tool, characterized in that: The method comprises the following steps: The tool load calculation algorithm is used to evaluate the force of the cutter under different construction parameters or different geometric characteristics of the cutter when cutting reinforced concrete; the construction parameters include penetration speed and rotation speed; The geometric characteristics include cutter blade width and half blade angle; According to the obtained evaluation results of the force of the cutter, the construction parameters and / or the geometric characteristics of the cutter are determined; Based on the determined construction parameters and / or the geometric characteristics of the cutter, the reinforced concrete is cut; The tool load calculation algorithm comprises: The concrete under the action of the cutter is simplified into a plurality of regions including at least a dense core region, wherein the stress of the dense core region is equal in all directions under the action of the cutter, and is a radial stress; the stress of the dense core region is derived during the expansion process of the concrete cavity; Based on the stress of the dense core region, the geometric characteristics of the cutter and the construction parameters, the vertical force of the cutter when cutting the reinforced concrete section is calculated; Based on the geometric characteristics of the cutter, the rolling force of the cutter is calculated; The determination of the construction parameters and the geometric characteristics of the cutter according to the obtained evaluation results of the force of the cutter comprises: For the force evaluation of cutters with different geometric characteristics, the influence of different cutter selection on the force of the cutter when cutting reinforced concrete is determined, and the appropriate cutter shape for the corresponding working condition is selected; The construction parameters and the geometric characteristics of the cutter are determined according to the vertical force of the cutter when cutting the reinforced concrete section and the rolling force of the cutter.

2. A method of cutting reinforced concrete with a milling tool according to claim 1, characterized in that: The specific operation of deriving the stress of the dense core region during the expansion process of the concrete cavity comprises: The radial stress and the circumferential stress are defined as: （1） （2） wherein: E is the Young's modulus, ν is the Poisson's ratio, u is the radial displacement, , denotes the radial and circumferential stress, and r denotes the cavity location radius; Definitions , , wherein, denotes the dense core interface moving speed, t denotes the time of cavity expansion, denotes the concrete elastic wave speed; The radial stress of the boundary is defined as: （3） （5） wherein: is the density of the concrete, is the Young's modulus, is the Poisson's ratio, denotes the tensile strength of the concrete; Definitions , , , is the design value of the concrete axial compressive strength, is the penetration speed of the roller, which can be obtained as （6） In the formula, N= M= m1 represents the volume factor of the plastic cracked zone, and v1 is the particle velocity at the outer boundary of the plastic cracked zone. It is the integration constant; Let , the Runge-Kutta method is used to solve equation (6) in the interval , and the radial stress obtained is the stress in the dense core region.

3. A method of cutting reinforced concrete with a milling tool according to claim 2, characterized in that: The specific operation of calculating the vertical force of the cutter when cutting the reinforced concrete section based on the stress of the dense core region, the geometric characteristics of the cutter and the construction parameters comprises: Roller cutter cutting vertical force of a segment of reinforced concrete is represented as: （7） , were calculated using the following formulae, respectively: （8） （9） wherein is the compressive strength of the reinforcement, is the normal projection area of the contact region between the cutter and the reinforcement, is the total normal projection area of the part of the cutter that invades at the current depth of cut, denotes the stress in the compact core region.

4. A method of cutting reinforced concrete with a milling tool according to claim 3, characterized in that: The specific operation of calculating the vertical force of the cutter when cutting the reinforced concrete section based on the stress of the dense core region, the geometric characteristics of the cutter and the construction parameters comprises: The first stage before the cutter contacts the steel bar is defined as a pure concrete cutting stage, at which time the cutter ring fully acts on the concrete layer; when the cutter starts to contact the steel bar, the cutting process enters the second stage, the cutter starts to cut the steel bar, and the cutter moves away from the steel bar until the third stage of disengagement, and the cutting effect of the cutter on the steel bar gradually weakens until complete disengagement; From the first stage to the second stage: （36） wherein represents the compressive strength of the reinforcement, represents the time from the first stage to the second stage; , represents half of the blade width of the cutter, represents half of the blade angle, represents the profile radius of the cutter, represents the cutting depth of the cutter, represents the speed in the horizontal direction; , ; From the second stage to the third stage: （37） In the formulae, denotes the duration of the second to third phase.

5. A method of cutting reinforced concrete with a milling tool according to claim 1, characterized in that: The specific operation of calculating the rolling force of the cutter based on the geometric characteristics of the cutter comprises: The calculation method of the rolling force of the cutter is the product of the shear area of the cut surface of the steel bar and the concrete and the shear strength of the corresponding material, which is represented as: （38） wherein: is the shear strength of the steel reinforcement; is the shear area of the steel reinforcement acting on the side of the roller cutter; is the shear strength of the concrete; is the shear area of the concrete acting on the side of the roller cutter.

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