A method for calculating the maximum shear force and rotation angle of underground rigid pipe joints under ground traffic loads

Abstract

The present invention discloses a calculation method for the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic loads. According to the ground traffic load conditions, the load P2 transmitted to the top of the pipe per meter along its longitudinal direction is calculated; when the two side pipes are not connected by the joint, the total vertical displacement #imgabs0# generated by the left pipe segment at the joint and the total vertical displacement #imgabs1# generated by the right pipe segment at the joint are calculated; based on the compression amount #imgabs2# of the rubber gasket at the pipe joint, the maximum shear force #imgabs3# of the pipe joint is calculated; the maximum joint rotation angle #imgabs4# of the pipe is calculated; according to the calculated maximum shear force #imgabs5# of the pipe joint and the maximum joint rotation angle #imgabs6# of the pipe, the safety state of the current pipe joint is judged, which can meet the precise requirements for the bearing capacity and deformation performance of underground pipe joints in practical engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline engineering, and in particular relates to a method for calculating the maximum shear force and rotation angle of an underground rigid pipeline joint under ground traffic load. Background Art

[0002] With the continuous acceleration of urbanization, the construction and maintenance of underground pipeline systems have increasingly become key facilities to ensure the normal operation of cities. In this process, underground pipelines, especially rigid pipelines, are often directly or indirectly affected by ground traffic loads, which may cause deformation, cracks or even damage to pipeline joints, thus affecting the safety and stability of pipelines. At present, although there are certain load calculation standards and methods in underground pipeline design, most methods are only for continuous pipelines. Due to the complexity of the mechanical behavior of rigid pipeline joints under traffic loads, the existing methods can no longer meet the precise requirements for the bearing capacity and deformation performance of underground pipeline joints in actual engineering.

[0003] Rigid pipe joints are often used in situations that require high sealing and structural stability, and are widely used in water supply, drainage, gas and communication pipelines. Compared with flexible joints, rigid joints can provide stronger structural support and are suitable for environments with greater mechanical stress. However, rigid joints are susceptible to stress concentration when dealing with ground traffic loads, especially at the joint interface. Due to the rigid characteristics of the joint itself and the connection method, local stress concentration and deformation are prone to occur, which poses a great challenge to the sealing performance and durability of the joint. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for calculating the maximum shear force and rotation angle of underground rigid pipe joints affected by ground traffic loads in view of the shortcomings of the prior art, so as to meet the precise requirements for the bearing capacity and deformation performance of underground pipe joints in actual engineering.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for calculating the maximum shear force and rotation angle of an underground rigid pipeline joint under ground traffic loads comprises the following steps:

[0007] S1: According to the traffic load on the ground, calculate the load P transferred to the top of the pipeline per meter along its longitudinal direction. 2 ;

[0008] S2: Calculate the total vertical displacement of the left pipe section at the joint when the pipes on both sides are not connected by joints , the total vertical displacement of the right pipe section at the joint ;

[0009] S3: Based on the compression of the rubber gasket at the pipe joint , calculate the maximum shear force of the pipe joint ;

[0010] S4: Calculate the maximum pipe joint angle ;

[0011] S5: Maximum shear force of pipe joints calculated , Maximum pipe joint angle , determine the safety status of the current pipeline joint.

[0012] Specifically, in step S1, the load P 2 It is calculated by the following formula (1), formula (2) and formula (3):

[0013] (1);

[0014] (2);

[0015] (3);

[0016] Where D is the diameter of the buried rigid pipeline, in meters; h is the buried depth, in meters; P 1 is the ground traffic load, unit is kN; the surface area of ​​the ground traffic load is w×l 1 , where w is the length in the direction perpendicular to the pipeline axis, in m, l 1 is the length along the pipeline axis, in meters; θ is the foundation stress diffusion angle.

[0017] Specifically, in step S2, the total vertical displacement of the left pipe section at the joint is It is calculated by the following steps: Calculate the vertical displacement at the center of the left pipe segment when the left and right pipe segments are not connected by a joint. ; Calculate the vertical displacement of the left pipe section at the joint due to rotation: ; Finally, calculate the total vertical displacement of the left pipe section at the joint ;

[0018] Total vertical displacement of the right pipe segment at the joint It is calculated by the following steps: Calculate the vertical displacement at the center of the right pipe segment when the left and right pipe segments are not connected by a joint. ; Calculate the vertical displacement of the right pipe section at the joint due to rotation: ; Finally, calculate the total vertical displacement of the right pipe section at the joint .

[0019] Specifically, the distance from the midpoint of the ground traffic load action area to the pipeline joint is represented by x, and the load P per meter along the longitudinal direction of the pipeline top is transmitted to the pipeline top. 2 The lengths acting on the left and right pipe segments are denoted as x. L and x R , calculated by the following formula (4) and formula (5):

[0020] (4);

[0021] (5);

[0022] The stress transferred from the ground traffic load to the top of the left pipe segment is equivalent to a concentrated force. , which is calculated by the following formula (6):

[0023] (6);

[0024] Will The distance from the center of the left pipe segment is recorded as , calculated using the following formula (7):

[0025] (7);

[0026] In the formula, is the length of the left pipe section, in m;

[0027] The stress transferred from the ground traffic load to the top of the right pipe segment is equivalent to a concentrated force. , calculated using the following formula (8):

[0028] (8);

[0029] Will The distance from the center of the left pipe segment is recorded as , calculated using the following formula (9):

[0030] (9);

[0031] In the formula, is the length of the right pipe section, in m;

[0032] Vertical displacement at the center of the left pipe segment when the left and right pipe segments are not connected by a joint , calculated by the following formula (10):

[0033] (10);

[0034] In the formula, is the spring stiffness of the soil around the left pipeline segment (kN / m 2 ).

[0035] Furthermore, according to the moment balance condition of the left pipeline section, equation (11) can be obtained:

[0036] (11);

[0037] In the formula, is the rotation angle of the left pipe segment (rad);

[0038] This gives formula (12):

[0039] (12);

[0040] The vertical displacement of the left pipe section at the joint due to rotation Calculated by formula (13):

[0041] (13);

[0042] Total vertical displacement of the left pipe segment at the joint , calculated by the following formula (14):

[0043] (14);

[0044] In the formula, is the spring stiffness of the soil around the left pipeline section, in kN / m 2 ; for The distance from the center of the left pipe segment, in meters.

[0045] Furthermore, when the left and right pipe sections are not connected by a joint, the vertical displacement at the center of the right pipe section is , calculated using the following formula (15):

[0046] (15);

[0047] In the formula, is the spring stiffness of the soil around the right pipeline segment (kN / m 2 );

[0048] According to the moment balance condition of the right pipeline section, equation (16) is obtained:

[0049] (16);

[0050] In the formula, is the rotation angle of the right pipe segment;

[0051] This gives formula (17):

[0052] (17);

[0053] The vertical displacement of the right pipe section at the joint due to rotation Calculated by formula (18):

[0054] (18);

[0055] Total vertical displacement of the right pipe segment at the joint Calculated by formula (19):

[0056] (19);

[0057] In the formula, is the spring stiffness of the soil around the right pipe section, in kN / m 2 ; for The distance from the center of the right pipe segment, in meters.

[0058] Furthermore, the vertical relative displacement at the pipe joint It can be calculated using the following formula (20):

[0059] (20);

[0060] When the left and right pipe sections are connected by pipe joints, the vertical relative displacement at the pipe joints is It can be calculated using the following formula (21):

[0061] (twenty one);

[0062] According to the deformation coordination relationship at the pipe joint position, equation (22) can be obtained:

[0063] (twenty two);

[0064] In the formula, is the compression amount of the rubber gasket at the pipe joint, in m, which can be calculated using the following formula (23):

[0065] (twenty three);

[0066] In the formula, is the compression deformation stiffness of the rubber gasket at the pipe joint, in kN / m;

[0067] Substituting equation (21) and equation (23) into equation (22), we get equation (24):

[0068] (twenty four);

[0069] Substituting equation (20) into equation (24), we get The calculation formula (25) is:

[0070] (25);

[0071] When x L = , x R = 0, the shear force at the pipe joint reaches the maximum, and the maximum shear force at the pipe joint is calculated by the following formula (26): :

[0072] (26).

[0073] Furthermore, in step S4, the maximum pipe joint angle is calculated by the following formula (27): :

[0074] (27);

[0075] In the formula, is the angle of rotation of the left pipe segment when the left and right pipe segments are not connected by a joint; is the angle at which the right pipe segment rotates when the left and right pipe segments are not connected by a joint; When the left pipe section and the right pipe section are connected by a pipe joint, the rotation angle of the left pipe section under the action of the joint shear force can be calculated using the following formula (28); When the left pipe section and the right pipe section are connected by a pipe joint, the rotation angle of the right pipe section under the action of the joint shear force can be calculated using the following formula (29);

[0076] (28);

[0077] (29).

[0078] Furthermore, by substituting formula (12), formula (17), formula (28), and formula (29) into formula (27), we can obtain formula (30):

[0079] (30);

[0080] When x L =x R = When the angle at the pipe joint Reaching the maximum shear force at the joint is zero, and by substituting formulas (6) to (9) into formula (30), we can obtain the maximum pipe joint angle. The calculation formula (31) is:

[0081] (31).

[0082] Specifically, in step S5, when the calculated maximum pipe joint angle Less than the allowable value of the joint angle, and the maximum shear force of the pipe joint If it is less than the allowable value of joint shear force, the current pipe joint is in a safe state;

[0083] When the calculated maximum pipe joint angle Greater than the allowable value of the joint angle, or the maximum shear force of the pipe joint If it is greater than the allowable value of the joint shear force, the current pipe joint has failed and needs to be repaired accordingly.

[0084] Beneficial effects:

[0085] The calculation method of the maximum shear force and rotation angle of underground rigid pipe joints under ground traffic loads provided by the present invention can accurately evaluate the maximum shear force and rotation angle of the joints under ground traffic loads, thereby providing a more scientific basis for engineering design and improving the safety and stability of pipe joints. Unlike traditional load calculation methods, the present invention takes into account complex mechanical behaviors, especially stress concentration and deformation at the joints, and can be used to calculate and analyze the maximum shear force and rotation angle of rigid joints with high requirements for sealing and structural stability under ground traffic loads. This method not only provides reliable theoretical support for the design of pipe joints, but also provides a scientific basis for subsequent maintenance, repair and safety assessment, helping to timely discover potential safety hazards, reduce the risk of pipeline failure, and improve the long-term stability and disaster resistance of the pipeline system. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0087] Figure 1 It is a schematic diagram of the pipe joint of the present invention being affected by ground traffic load.

[0088] Figure 2 is the stress P transmitted to the top of the pipeline by the present invention 2 The lengths x acting on the left and right pipe segments respectively L and x RSchematic diagram of .

[0089] Figure 3 It is a schematic diagram of the corner deformation of the pipe joint of the present invention under the influence of ground traffic load. DETAILED DESCRIPTION

[0090] The present invention can be better understood with reference to the following examples.

[0091] The method for calculating the maximum shear force and rotation angle of an underground rigid pipeline joint under ground traffic load of the present invention mainly comprises the following steps:

[0092] S1: According to the traffic load on the ground, calculate the load P transferred to the top of the pipeline per meter along its longitudinal direction. 2 ;

[0093] S2: Calculate the total vertical displacement of the left pipe section at the joint when the pipes on both sides are not connected by joints , the total vertical displacement of the right pipe section at the joint ;

[0094] S3: Based on the compression of the rubber gasket at the pipe joint , calculate the maximum shear force of the pipe joint ;

[0095] S4: Calculate the maximum pipe joint angle ;

[0096] S5: Maximum shear force of pipe joints calculated , Maximum pipe joint angle , determine the safety status of the current pipeline joint.

[0097] Figure 1 The following is a schematic diagram of the effect of ground traffic load on the pipe joint. Assume that the traffic load acting on the ground is P 1 (kN), the effective area is w (m) × l 1 (m), where w is the length in the direction perpendicular to the pipeline axis, l 1 is the length along the pipeline axis, the foundation stress diffusion angle is θ, the pipeline diameter is D (m), the buried depth is h (m), and the lengths of the pipeline section on the left and right of the joint are l L and l R .

[0098] (1) Calculation of maximum pipe joint shear force

[0099] The load P transmitted to the top of the pipe per meter along its longitudinal direction 2 for:

[0100] (1);

[0101] (2);

[0102] (3);

[0103] Where, D is the diameter of the buried rigid pipeline (m); h is the buried depth (m); P 1 is the ground traffic load; the surface area of ​​the ground traffic load is w (m) × l 1 (m), where w is the length in the direction perpendicular to the pipeline axis, l 1 is the length along the pipeline axis; θ is the foundation stress diffusion angle.

[0104] The distance from the midpoint of the ground traffic load action area to the pipe joint is represented by x, such as Figure 2 As shown, the stress P transmitted to the top of the pipe 2 The lengths acting on the left and right pipe segments are denoted as x. L and x R , can be calculated by the following formula:

[0105] (4);

[0106] (5);

[0107] The stress transferred from the ground traffic load to the top of the left pipe segment is equivalent to a concentrated force. ( Figure 3 a), which can be calculated using the following formula:

[0108] (6);

[0109] Will The distance from the center of the left pipe segment is recorded as , can be calculated by the following formula:

[0110] (7);

[0111] In the formula, is the length of the left pipe section, in m;

[0112] The stress transferred from the ground traffic load to the top of the right pipe segment is equivalent to a concentrated force. ( Figure 3 a), which can be calculated using the following formula:

[0113] (8);

[0114] Will The distance from the center of the left pipe segment is recorded as , can be calculated by the following formula:

[0115] (9);

[0116] In the formula, is the length of the right pipe section, in meters.

[0117] When the left and right pipe segments are not connected by a joint ( Figure 3 b) The vertical displacement at the center of the left pipeline section can be calculated using the following formula:

[0118] (10);

[0119] In the formula, is the spring stiffness of the soil around the left pipeline segment (kN / m 2 ).

[0120] According to the moment balance condition of the left pipe section, we can get:

[0121] (11);

[0122] In the formula, is the rotation angle (rad) of the left pipe segment.

[0123] Further, we can get

[0124] (12);

[0125] The vertical displacement of the left pipe section at the joint due to rotation is:

[0126] (13);

[0127] The total vertical displacement of the left pipe section at the joint can be calculated using the following formula:

[0128] (14).

[0129] When the left and right pipe segments are not connected by a joint ( Figure 3 b) The vertical displacement at the center of the right pipeline section can be calculated using the following formula:

[0130] (15);

[0131] In the formula, is the spring stiffness of the soil around the right pipeline segment (kN / m 2 ).

[0132] According to the moment balance condition of the right pipe section, we can get:

[0133] (16);

[0134] In the formula, is the angle (rad) by which the right pipe segment is rotated.

[0135] Further, we can get

[0136] (17);

[0137] The vertical displacement of the right pipe section at the joint due to rotation is:

[0138] (18);

[0139] The total vertical displacement of the right pipe section at the joint is:

[0140] (19);

[0141] In the formula, is the spring stiffness of the soil around the right pipeline segment (kN / m 2 ); for Distance from the center of the right pipe segment (m).

[0142] The vertical relative displacement at the pipe joint can be calculated using the following formula:

[0143] (20);

[0144] After the left and right pipe sections are connected by pipe joints ( Figure 3 c) Under the action of joint shear force, the vertical relative displacement of the pipe joint can be calculated by the following formula:

[0145] (twenty one);

[0146] According to the deformation coordination relationship at the pipe joint position, it can be obtained that:

[0147] (twenty two);

[0148] In the formula, is the compression amount of the rubber gasket at the pipe joint (m), which can be calculated using the following formula:

[0149] (twenty three);

[0150] In the formula, is the compression deformation stiffness of the rubber gasket at the pipe joint (kN / m).

[0151] Substituting formula (21) and (23) into formula (22), we can obtain:

[0152] (twenty four);

[0153] Substituting formula (20) into formula (24), we can obtain:

[0154] (25);

[0155] When x L = , x R =0, the shear force at the pipe joint reaches the maximum, which can be calculated by the following formula:

[0156] (26).

[0157] (2) Calculate the maximum pipe joint angle:

[0158] The pipe joint angle can be calculated by the following formula:

[0159] (27);

[0160] In the formula, is the angle (rad) of rotation of the left pipe segment when the left and right pipe segments are not connected by a joint; is the angle (rad) at which the right pipe segment rotates when the left and right pipe segments are not connected by a joint; is the angle (rad) at which the left pipe section rotates under the shear force of the joint after the left pipe section and the right pipe section are connected by the pipe joint. It can be calculated using formula (28); is the angle (rad) at which the right pipe section rotates under the shear force of the joint after the left pipe section and the right pipe section are connected by the pipe joint. It can be calculated using formula (29):

[0161] (28);

[0162] (29);

[0163] Substituting formula (12), formula (17), formula (28), and formula (29) into formula (27), we can obtain:

[0164] (30);

[0165] When x L =x R = When the angle at the pipe joint Reaching the maximum shear force at the joint is zero, substituting formulas (6) to (9) into formula (30), we can obtain:

[0166] (31).

[0167] Taking an underground rigid pipeline in a certain place as an example, the diameter D of the reinforced concrete pipe is 0.94 m, the buried depth h is 0.61 m, and the compression deformation stiffness of the rubber gasket at the pipeline joint is is 50 kN / m, the length of the left and right pipe sections (l L and l R ) are 3 m, and the spring stiffness of the soil around the left and right pipeline sections (k L and k R ) are both 23500 kN / m 2 , traffic load P acting on the ground 1 is 186.9 kN, and the action area is w (m) × l 1 (m) = 0.51m × 0.25 m, and the foundation stress diffusion angle is 33°.

[0168] (1) Calculation of maximum pipe joint shear force

[0169] According to formula (2), we can get:

[0170]

[0171] According to formula (3), we can get:

[0172]

[0173] According to formula (1), we can get:

[0174]

[0175] According to formula (26), we can get:

[0176] .

[0177] (2) Calculate the maximum pipe joint angle

[0178] According to formula (31), we can get:

[0179] .

[0180] (3) Verification

[0181] According to the existing test method (Moore, ID; García, D. Becerril; Sezen, H.; and Sheldon, T. Structural design of culvert joints [M]. Washington, DC: The National Academies Press, 2012 https: / / doi.org / 10.17226 / 22748.), the rotation angle of the pipe joint is measured. Table 1 shows the comparison between the experimental measured values ​​and the calculated values ​​of the method of the present invention. It can be seen from the table that the error between the calculated values ​​of the method of the present invention and the experimental measured values ​​is less than 10%, indicating that the shear force and rotation angle of the underground rigid pipe joint affected by ground traffic load calculated by this method are reliable and effective.

[0182] Table 1 Comparison of experimental values ​​and calculated values ​​by the method of the present invention

[0183]

[0184] The present invention provides a method and idea for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for calculating the maximum shear force and rotation angle of underground rigid pipe joints under ground traffic loads, characterized in that: The steps include: S1: According to the traffic load on the ground, calculate the load P2 transferred to the top of the pipeline per meter along its longitudinal direction; S2: Calculate the total vertical displacement of the left pipe section at the joint when the pipes on both sides are not connected by joints , the total vertical displacement of the right pipe section at the joint ; S3: Based on the compression of the rubber gasket at the pipe joint , calculate the maximum shear force of the pipe joint ; S4: Calculate the maximum pipe joint angle ; S5: Maximum shear force of pipe joints calculated , Maximum pipe joint angle , determine the safety status of the current pipeline joint; In step S1, the load P2 is calculated by the following equations (1), (2) and (3): （1）； （2）； （3）； Where, D is the diameter of the buried rigid pipeline, in m; h is the buried depth, in m; P1 is the ground traffic load, in kN; the surface traffic load action area is w×l1, where w is the length in the direction perpendicular to the pipeline axis, in m, l1 is the length along the pipeline axis, in m; θ is the foundation stress diffusion angle; In step S2, the total vertical displacement of the left pipe section at the joint It is calculated by the following steps: Calculate the vertical displacement at the center of the left pipe segment when the left and right pipe segments are not connected by a joint. ; Calculate the vertical displacement of the left pipe section at the joint due to rotation: ; Finally, calculate the total vertical displacement of the left pipe section at the joint ; Total vertical displacement of the right pipe segment at the joint It is calculated by the following steps: Calculate the vertical displacement at the center of the right pipe segment when the left and right pipe segments are not connected by a joint. ; Calculate the vertical displacement of the right pipe section at the joint due to rotation: ; Finally, calculate the total vertical displacement of the right pipe section at the joint .

2. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 1 is characterized in that: The distance from the midpoint of the ground traffic load action area to the pipe joint is represented by x, and the load P2 transferred to the top of the pipe along its longitudinal direction for each meter acts on the left and right pipe sections respectively, which is recorded as x. L and x R , calculated by the following formula (4) and formula (5): （4）； （5）； The stress transferred from the ground traffic load to the top of the left pipe segment is equivalent to a concentrated force. , which is calculated by the following formula (6): （6）； Will The distance from the center of the left pipe segment is recorded as , calculated using the following formula (7): （7）； In the formula, is the length of the left pipe section, in m; The stress transferred from the ground traffic load to the top of the right pipe segment is equivalent to a concentrated force. , calculated using the following formula (8): （8）； Will The distance from the center of the left pipe segment is recorded as , calculated using the following formula (9): （9）； In the formula, is the length of the right pipe section, in m; Vertical displacement at the center of the left pipe segment when the left and right pipe segments are not connected by a joint , calculated by the following formula (10): （10）； In the formula, is the spring stiffness of the soil around the left pipeline section, in kN / m 2 .

3. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 2 is characterized in that: According to the moment balance condition of the left pipeline section, equation (11) can be obtained: （11）； In the formula, is the rotation angle of the left pipe section, in rad; This gives formula (12): （12）； The vertical displacement of the left pipe section at the joint due to rotation Calculated by formula (13): （13）； Total vertical displacement of the left pipe segment at the joint , calculated by the following formula (14): （14）； In the formula, is the spring stiffness of the soil around the left pipeline section, in kN / m 2 ; for The distance from the center of the left pipe segment, in meters.

4. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 3 is characterized in that: Vertical displacement at the center of the right pipe segment when the left and right pipe segments are not connected by a joint , calculated using the following formula (15): （15）； In the formula, is the spring stiffness of the soil around the right pipe section, in kN / m 2 ; According to the moment balance condition of the right pipeline section, equation (16) is obtained: （16）； In the formula, is the rotation angle of the right pipe segment; This gives formula (17): （17）； The vertical displacement of the right pipe section at the joint due to rotation Calculated by formula (18): （18）； Total vertical displacement of the right pipe segment at the joint Calculated by formula (19): （19）； In the formula, is the spring stiffness of the soil around the right pipe section, in kN / m 2 ; for The distance from the center of the right pipe segment, in meters.

5. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 4, characterized in that: Vertical relative displacement at pipe joints It can be calculated using the following formula (20): （20）； When the left and right pipe sections are connected by pipe joints, the vertical relative displacement at the pipe joints is It can be calculated using the following formula (21): （21）； According to the deformation coordination relationship at the pipe joint position, equation (22) can be obtained: （22）； In the formula, is the compression amount of the rubber gasket at the pipe joint, in m, which can be calculated using the following formula (23): （23）； In the formula, is the compression deformation stiffness of the rubber gasket at the pipe joint, in kN / m; Substituting equation (21) and equation (23) into equation (22), we get equation (24): （24）； Substituting equation (20) into equation (24), we get The calculation formula (25) is: （25）； When x L = , x R = 0, the shear force at the pipe joint reaches the maximum, and the maximum shear force at the pipe joint is calculated by the following formula (26): : （26）。 6. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 5, characterized in that: In step S4, the maximum pipe joint angle is calculated by the following formula (27): : （27）； In the formula, is the angle of rotation of the left pipe segment when the left and right pipe segments are not connected by a joint; is the angle at which the right pipe segment rotates when the left and right pipe segments are not connected by a joint; When the left pipe section and the right pipe section are connected by a pipe joint, the rotation angle of the left pipe section under the action of the joint shear force can be calculated using the following formula (28); When the left pipe section and the right pipe section are connected by a pipe joint, the rotation angle of the right pipe section under the action of the joint shear force can be calculated using the following formula (29); （28）； （29）。 7. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 6, characterized in that: Substituting formula (12), formula (17), formula (28) and formula (29) into formula (27), we can obtain formula (30): （30）； When x L =x R = When the angle at the pipe joint Reaching the maximum shear force at the joint is zero, and by substituting formulas (6) to (9) into formula (30), we can obtain the maximum pipe joint angle. The calculation formula (31) is: （31）。 8. The method for calculating the maximum shear force and rotation angle of an underground rigid pipe joint under ground traffic load according to claim 1, characterized in that: In step S5, when the calculated maximum pipe joint angle Less than the allowable value of the joint angle, and the maximum shear force of the pipe joint If it is less than the allowable value of joint shear force, the current pipe joint is in a safe state; When the calculated maximum pipe joint angle Greater than the allowable value of the joint angle, or the maximum shear force of the pipe joint If it is greater than the allowable value of the joint shear force, the current pipe joint has failed and needs to be repaired accordingly.

Images