A calculation model for the reaction force of the buried pipeline foundation and its structural calculation method

Abstract

The present invention discloses a calculation model for the reaction force of the buried pipeline foundation and its structural calculation method, which relates to the technical field of calculating the reaction force of the foundation of trench buried structures. The reaction force calculation model is a trapezoidal model, and the construction process of the trapezoidal model is as follows: establish an x-q' coordinate system, in the x-q' coordinate system, take the coordinate origin o as the position of the pipeline vertex, take the horizontal right direction along the pipeline as the positive direction of the x-axis of the horizontal coordinate axis, and take the vertical downward direction along the pipeline as the positive direction of the q'-axis of the vertical coordinate axis to construct the trapezoidal model. The present invention adopts the above-mentioned calculation model for the reaction force of the buried pipeline foundation and its structural calculation method, proposes a calculation model for the reaction force of the foundation, and obtains the calculation formulas for the pipeline deformation and stress under this model. The distribution of the reaction force of the foundation adopts a trapezoidal distribution form. Compared with the traditional method, the calculation model of the reaction force of the foundation has a better coincidence with the finite element and test results, reducing the error.

Description

Technical Field

[0001] The present invention relates to the technical field of calculating the base reaction force of trench-buried structures, and in particular to a calculation model for the base reaction force of buried pipelines and a structural calculation method therefor. Background Art

[0002] As one of the most commonly used water conveyance structures in water diversion projects, buried pipelines are the "lifeline" of water conveyance projects. Among them, buried steel pipelines have the advantages of light self-weight, simple structure, convenient and rapid construction, high water conveyance efficiency, long service life, low maintenance cost, and the ability to restore vegetation, and are particularly suitable for major water diversion projects with long distances, large diameters, high internal pressures, and complex external environments.

[0003] The basis for the force analysis of buried pipelines is to determine the distribution and magnitude of the soil pressure around the pipe. Therefore, in order to accurately characterize the soil pressure around the pipe, scholars at home and abroad have carried out a large amount of research work. The current mainstream pipeline force model is the Spangler model, which assumes that the base reaction force is uniformly distributed along the cushion wrap angle. In view of the large number of simplifications in the assumption of the soil pressure around the pipe in the Spangler model, Fujita Aikatsu conducted experimental research on buried steel pipelines with a diameter of 2.4 m. It is assumed that the base reaction force is divided into a point foundation (2α = 20°), a 90° foundation (dug manually), and a pressed-in 90° foundation (the pipe wall is pressed into the foundation soil), and all are assumed to be parabolic distributions. In addition, in the past, the calculation models of buried flexible pipelines adopted in industries such as electric power and water supply and drainage in China all referred to the Yemeilianov model proposed by Л.Μ.Εмельянοв (Yemeilianov), and its basic assumption is that the base reaction force is uniformly distributed along the pipe diameter.

[0004] In summary, it can be seen that the current distribution assumptions of the base reaction force of buried pipelines are mainly uniform distribution or parabolic distribution, and there are large errors in these assumptions. Therefore, a calculation model for the base reaction force of buried pipelines and a structural calculation method therefor are proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a calculation model for the base reaction force of buried pipelines and a structural calculation method therefor, so as to solve the problem of large errors existing in the prior art.

[0006] To achieve the above object, the present invention provides a calculation model for the base reaction force of buried pipelines. The reaction force calculation model is a trapezoidal model, and the construction process of the trapezoidal model is as follows: establish an x-q' coordinate system, and in the x-q' coordinate system, take the coordinate origin o as the position of the pipeline vertex, take the horizontal right direction along the pipeline as the positive direction of the x-axis of the horizontal coordinate axis, and take the vertical downward direction along the pipeline as the positive direction of the q'-axis of the vertical coordinate axis to construct the trapezoidal model;

[0007] In the trapezoidal model, the change demarcation point of the base reaction force distribution is at the intersection of the sand cushion and the undisturbed soil, specifically: in the soil arc foundation with a central angle of 2α, the demarcation point is Dsinα / 2, and the base reaction force is uniformly distributed within the range of [0, Dsinα / 2], and is linearly distributed within the range of [Dsinα / 2, D / 2], where D is the pipe diameter.

[0008] Preferably, the expression of the trapezoidal model is:

[0009]

[0010] In the formula, q′ v is the maximum value of the base reaction force, a is Dsinα / 2, D is the pipe diameter, and x is the abscissa variable;

[0011] Or,

[0012]

[0013] In the formula, α is half of the central angle of the soil arc foundation;

[0014] Substitute D = 2r and x = rsin(π - θ) = rsinθ into the above formula to obtain the trapezoidal model expression related to θ:

[0015]

[0016] In the formula, θ is the angle from the top of the pipe to the bottom of the pipe in the clockwise direction.

[0017] A calculation method for buried pipeline structures includes the following steps:

[0018] Step S1: Combine the trapezoidal model of the base reaction force with the Spangler pipe surrounding soil pressure model, and only change the base reaction force on the basis of the Spangler model to obtain a pipe surrounding soil pressure model based on the trapezoidal model;

[0019] Step S2: Under the pipe surrounding soil pressure model, calculate the total sum of the base reaction force, and then calculate the internal force of the pipe wall only under the action of the base reaction force according to different θ ranges. By calculating the generalized displacement, obtain the unknown moment x 21 and the unknown axial force x 22 , and superimpose them with the internal force of the pipe wall caused by the external load q′ to obtain the pipe ring internal force;

[0020] Step S3: Add a horizontal outward unit force at the pipe waist, calculate the internal moment of the pipe, and then calculate the horizontal radial displacement caused by the base reaction force at the pipe waist through the internal moment of the pipe, so as to obtain the pipeline horizontal deformation caused by the soil pressure at the top of the pipe and its base reaction force;

[0021] Step S4: According to K under different central angles of the soil arc foundation 1TValues are finally obtained for the pipeline deformation calculation formula, as well as the moment calculation formula and bending stress calculation formula for the pipe ring at the top, waist, and bottom.

[0022] Preferably, the expression for the total base reaction force in step S2 is as follows:

[0023]

[0024] In the formula, r is the pipeline radius.

[0025] Preferably, the expressions for the internal forces of the pipe wall in different θ ranges in step S2 are as follows:

[0026] When 0 ≤ θ ≤ π / 2,

[0027]

[0028] In the formula, M q′ is the moment caused by only the external load q′, N q′ is the axial force caused by only the external load q′, Q q′ is the shear force caused by only the external load q′;

[0029] When π / 2 ≤ θ ≤ π - α,

[0030]

[0031] When π - α ≤ θ ≤ π,

[0032]

[0033] In the formula, A is a constant related to α, B is a constant related to α, and C is a constant related to α. The calculation formulas are as follows:

[0034]

[0035] Preferably, the unknown moment x 21 unknown axial force x 22 has the following expressions:

[0036]

[0037] In the formula, δ 21 is the generalized displacement that appears in the direction of the unknown moment x 21 when x 21 = 1; δ 22 is the generalized displacement that appears in the direction of the unknown axial force x 22 when x 22 = 1; δ 1q′ is the generalized displacement that appears in the direction of the unknown moment x 21 under the action of the external load q′; δ2q′ Under the action of the external load q′, the unknown axial force is x 22 The generalized displacement occurring in the direction, E is the elastic modulus of the pipeline, I is the moment of inertia of the pipeline cross-section, D1 is a constant related to α, E1 is a constant related to α, F is a constant related to α, G is a constant related to α, and the calculation formula is as follows:

[0038]

[0039]

[0040] Preferably, in the step S2, the expression of the internal force of the pipe ring is as follows:

[0041]

[0042] In the formula, M2 represents the bending moment under the combined action of the unknown bending moment x 21 , the unknown axial force x 22 and the external load q′, N2 represents the axial force under the combined action of the unknown bending moment x 21 , the unknown axial force x 22 and the external load q′, Q2 represents the shear force under the combined action of the unknown bending moment x 21 , the unknown axial force x 22 and the external load q′, M 21 represents the bending moment under the action of only the unknown bending moment x 21 , N 21 represents the axial force under the action of only the unknown bending moment x 21 , Q 21 represents the shear force under the action of only the unknown bending moment x 21 , M 22 represents the bending moment under the action of only the unknown axial force x 22 , N 22 represents the axial force under the action of only the unknown axial force x 22 , Q 22 represents the shear force under the action of only the unknown axial force x 22 .

[0043] Preferably, the horizontal deformation 2Δ' of the pipeline caused by the soil pressure on the top of the pipe and the base reaction force in the step S3 1h has the following expression:

[0044]

[0045] In the formula, 2Δ 1h is the horizontal deformation under the action of only the soil pressure on the top of the pipe, 2Δ 2h is the horizontal deformation caused by the base reaction force at the pipe waist;

[0046] Among them, the vertical deformation coefficient K of the soil pressure 1TThe expression is as follows:

[0047]

[0048] In the formula, H is a constant related to α, and I1 is a constant related to α. The calculation formula is as follows:

[0049]

[0050] Preferably, the calculation formula for pipeline deformation in step S4 is as follows:

[0051]

[0052] The calculation formula for the bending moment of the pipe ring at the top, waist, and bottom is:

[0053]

[0054] The calculation formula for bending stress is:

[0055]

[0056] In the formula, Δ is the vertical / horizontal deformation of the pipeline; D L is the deformation lag coefficient; K 1T is the vertical deformation coefficient of earth pressure, which is related to the value of the central angle 2α of the soil arc foundation; K3 is the pipeline deformation coefficient under the action of lateral soil resistance, which is determined by the central angle 2β of the lateral soil resistance; r is the pipeline radius; E is the pipeline elastic modulus; E′ is the soil reaction modulus; I is the moment of inertia of the pipeline cross-section; W is the resultant force of the soil pressure on the pipe top; t is the pipeline wall thickness.

[0057] Therefore, the present invention adopts the above-mentioned calculation model for the reaction force of the buried pipeline foundation and its structural calculation method, proposes a calculation model for the reaction force of the foundation, and obtains the calculation formulas for pipeline deformation and stress under this model. The distribution of the reaction force of the foundation adopts a trapezoidal distribution form. Compared with the traditional method, the calculation model of the reaction force of the foundation has a better coincidence with the finite element and test results, reducing the error.

[0058] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0059] Figure 1 It is a schematic diagram of the trapezoidal model of the embodiment of the calculation model for the reaction force of the buried pipeline foundation and its structural calculation method of the present invention;

[0060] Figure 2 It is a schematic diagram of the soil pressure model around the pipe of the embodiment of the calculation model for the reaction force of the buried pipeline foundation and its structural calculation method of the present invention;

[0061] Figure 3This is a schematic diagram of the force decomposition of the semi-circular ring of the base reaction force in the embodiment of the calculation model of the base reaction force of the buried pipeline and its structural calculation method of the present invention. Specific embodiments

[0062] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0063] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0064] Embodiment

[0065] Please refer to Figures 1-3 , the present invention provides a calculation model for the base reaction force of a buried pipeline, and the proposed trapezoidal model is as Figure 1 shown. Wherein, D represents the pipe diameter; in the x-q' coordinate system, the coordinate origin o is the position of the pipe vertex, the positive direction of the horizontal axis x is horizontally to the right along the pipeline, and the positive direction of the vertical axis q' is vertically downward along the pipeline. In the trapezoidal model, the change demarcation point of the base reaction force distribution is at the intersection of the sand cushion layer and the undisturbed soil, that is, at the center angle of the soil arc foundation is 2α, and the demarcation point is Dsinα / 2. In the range of [0, Dsinα / 2], it is uniformly distributed, that is, the soil pressure q' = q' v is a constant value, and in the range of [Dsinα / 2, D / 2], it is linearly distributed.

[0066] Since the base reaction force is symmetric about the axis, the right half side of Figure 3 is taken as an example for derivation. The process is as follows.

[0067] When 0 ≤ x ≤ a,

[0068] q'(x) = q′ v (1)

[0069] When a ≤ x ≤ D / 2, in the x1-q′1 coordinate system, assume the linear equation is:

[0070] q′1 = kx1 (2)

[0071] Let \(a = D\sin\frac{\alpha}{2}\), and substitute it into the boundary conditions: \(x_1=\frac{D}{2}-a\), \(q'_1 = -q'\) v . We get \(k=\frac{q'}{a - \frac{D}{2}}\). Therefore, in the \(x_1 - q'_1\) coordinate system, the linear equation is: v / (a - D / 2). So in the \(x_1 - q'_1\) coordinate system, the linear equation is:

[0072]

[0073] After coordinate transformation,

[0074]

[0075] In the \(x - q'\) coordinate system, the linear equation becomes:

[0076]

[0077] Therefore, the formula expression of the trapezoidal model is:

[0078]

[0079] In the formula, \(q'\) v is the maximum value of the base reaction force, \(a = D\sin\frac{\alpha}{2}\), \(D\) is the pipe diameter, and \(x\) is the abscissa variable;

[0080] Or,

[0081]

[0082] In the formula, \(\alpha\) is half of the central angle of the soil arc foundation;

[0083] Substitute \(D = 2r\), \(x = r\sin(\pi-\theta)=r\sin\theta\) into Equation (7), then the trapezoidal model can be transformed into a formula related to \(\theta\):

[0084]

[0085] Among them, \(\theta\) is the angle from the top of the pipe to the bottom of the pipe in the clockwise direction.

[0086] A calculation method for buried pipeline structures includes the following steps:

[0087] Step S1: Combine the trapezoidal model of the base reaction force with the Spangler pipe - surrounding soil pressure model, and only change the base reaction force on the basis of the Spangler model to obtain the pipe - surrounding soil pressure model based on the trapezoidal model;

[0088] Step S2: Under the pipe - surrounding soil pressure model, calculate the total base reaction force, and then calculate the internal force of the pipe wall only under the action of the base reaction force according to different \(\theta\) ranges. By calculating the generalized displacement, obtain the unknown moment \(x\) 21 and the unknown axial force \(x\) 22, superpose it with the internal force of the pipe wall caused by the external load q′ to obtain the internal force of the pipe ring;

[0089] Step S3: Apply a unit horizontal outward force at the pipe waist, calculate the internal moment in the pipe, and then calculate the horizontal radial displacement caused by the base reaction force at the pipe waist through the internal moment in the pipe, so as to obtain the horizontal deformation of the pipeline caused by the soil pressure at the pipe top and its base reaction force;

[0090] Step S4: According to the K 1T value under different central angles of the soil arc foundation, finally obtain the pipeline deformation calculation formula, as well as the moment calculation formula and bending stress calculation formula of the pipe ring at the top, waist and bottom.

[0091] The specific steps of the above method are as follows:

[0092] Combining the trapezoidal model of the base reaction force with the Spangler soil pressure model around the pipe, the calculation method of the buried pipeline structure can be deduced. As Figure 2 shown is the soil pressure model around the pipe. In the figure, Δx is the horizontal deformation of the pipeline; 2α is the central angle of the soil arc foundation; 2β is the central angle of the horizontal resistance on the pipe side; q is the soil pressure at the pipe top; q′ v is the maximum value of the base reaction force; q H is the maximum value of the horizontal resistance on the pipe side; E′ is the soil reaction modulus; W is the resultant force of the soil pressure at the pipe top.

[0093] This model only changes the base reaction force on the basis of the Spangler model, and the horizontal resistance on the pipe side and its distribution form remain unchanged. Therefore, for the pipeline deformation and internal force calculation formulas under this model, only the pipeline deformation coefficient K 1T (α) changes, and the formula derivation process is as follows.

[0094] The force decomposition of the semi-circular ring of the base reaction force is as Figure 3 shown. The total base reaction force is:

[0095]

[0096] Then,

[0097]

[0098] When the base reaction force is in the trapezoidal model, the internal force of the pipe wall under only this load is:

[0099] When 0 ≤ θ ≤ π / 2,

[0100]

[0101] In the formula, M q′ represents the moment caused by only the external load q′; N q′Denotes the axial force caused by only the external load q'; Q q′ Denotes the shear force caused by only the external load q'.

[0102] When π / 2 ≤ θ ≤ π - α,

[0103]

[0104] When π - α ≤ θ ≤ π,

[0105]

[0106] Where A is a constant related to α, B is a constant related to α, C is a constant related to α, and the calculation formulas are as follows:

[0107]

[0108] When x 21 and x 22 are unit forces,

[0109]

[0110] At this time, the generalized displacement is:

[0111]

[0112] Where D1 is a constant related to α, E1 is a constant related to α, F is a constant related to α, G is a constant related to α, and the calculation formulas are as follows:

[0113]

[0114] Where δ 21 is the generalized displacement that appears in the direction of the unknown bending moment x 21 = 1; δ 21 is the generalized displacement that appears in the direction of the unknown axial force x 22 = 1; δ 22 is the generalized displacement that appears in the direction of the unknown bending moment x 22 under the action of the external load q'; δ 1q′ is the generalized displacement that appears in the direction of the unknown axial force x 21 under the action of the external load q'; δ 2q′ is the generalized displacement that appears in the direction of the unknown axial force x 22 under the action of the external load q', E is the elastic modulus of the pipeline, and I is the moment of inertia of the pipeline cross-section.

[0115] Then, the unknown forces x 21 and x 22 are:

[0116]

[0117] Substitute x21 , x 22 By superposing the internal forces caused by the external load q′, the internal forces of the pipe ring can be obtained:

[0118]

[0119] In the formula, M2 represents the unknown bending moment x 21 , the unknown axial force x 22 and the bending moment under the combined action of the external load q′, N2 represents the unknown bending moment x 21 , the unknown axial force x 22 and the axial force under the combined action of the external load q′, Q2 represents the unknown bending moment x 21 , the unknown axial force x 22 and the shear force under the combined action of the external load q′, M 21 represents the bending moment under the action of only the unknown bending moment x 21 acting, N 21 represents the bending moment under the action of only the unknown bending moment x 21 acting, Q 21 represents the bending moment under the action of only the unknown bending moment x 21 acting, M 22 represents the bending moment under the action of only the unknown axial force x 22 acting, N 22 represents the bending moment under the action of only the unknown axial force x 22 acting, Q 22 represents the bending moment under the action of only the unknown axial force x 22 acting.

[0120] When 0 ≤ θ ≤ π / 2

[0121]

[0122] When π / 2 ≤ θ ≤ π - α

[0123]

[0124] When π - α ≤ θ ≤ π,

[0125]

[0126] So far, the internal forces of the pipe ring under the action of the base reaction force have been obtained. Next, the deformation of the pipeline under the action of the base reaction force will be calculated. Add a horizontal outward unit force F at the pipe waist. At this time, the internal bending moment in the pipe is:

[0127]

[0128] Then the horizontal radial displacement △ 2h caused by the base reaction force at the pipe waist is:

[0129]

[0130] In the formula, H is a constant related to α, and I1 is a constant related to α. The calculation formulas are as follows:

[0131]

[0132] Then, the horizontal deformation 2△′ of the pipeline caused by the soil pressure on the top of the pipe and its base reaction force 1h is:

[0133]

[0134] In the formula, 2Δ 1h is the horizontal deformation under the action of only the soil pressure on the top of the pipe, 2Δ 2h is the horizontal deformation caused by the base reaction force at the waist of the pipe, and Δ 2h is the horizontal radial displacement caused by the base reaction force at the waist of the pipe.

[0135] Among them, the vertical deformation coefficient K of the soil pressure 1T has the following expression:

[0136]

[0137] For the convenience of engineering application, the K 1T (α) values from 0° to 180° are listed in Table 1.

[0138] Table 1 K 1T (α) values under different central angles of the soil arc foundation in the trapezoidal distribution model of the base reaction force

[0139]

[0140] Therefore, the calculation formula for the pipeline deformation (the change in the vertical or horizontal diameter of the pipeline) can be finally obtained as:

[0141]

[0142] The calculation formulas for the bending moments at the top, waist, and bottom of the pipe ring are:

[0143]

[0144] The calculation formula for the bending stress is:

[0145]

[0146] In the formula, Δ is the vertical / horizontal deformation of the pipeline; D L is the deformation lag coefficient; K 1Tis the vertical deformation coefficient of earth pressure, which is related to the value of the central angle 2α of the soil arc foundation; K3(β) is the pipeline deformation coefficient under the action of the lateral soil resistance, which is determined by the central angle 2β of the lateral soil resistance; r is the pipeline radius; E is the elastic modulus of the pipeline; E′ is the modulus of subgrade reaction of the soil; I is the moment of inertia of the pipeline cross-section; W is the resultant force of the earth pressure on the pipe crown, and t is the pipeline wall thickness.

[0147] Therefore, the present invention adopts the above-mentioned calculation model of the subgrade reaction of buried pipelines and its structural calculation method, proposes a calculation model of the subgrade reaction, and obtains the calculation formulas for pipeline deformation and stress under this model. The distribution of the subgrade reaction adopts a trapezoidal distribution form. Compared with the traditional method, the calculation model of the subgrade reaction has a better coincidence with the finite element and test results, reducing the error.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A structural calculation method based on the calculation model of the reaction force of the buried pipeline foundation, characterized in that, The reaction force calculation model is a trapezoidal model, and the construction process of the trapezoidal model is as follows: Establish a coordinate system. In the coordinate system, with the origin of coordinates as the vertex position of the pipeline, and with the horizontal right direction along the pipeline as the positive direction of the horizontal coordinate axis and the vertical downward direction along the pipeline as the positive direction of the vertical coordinate axis to construct the trapezoidal model; In the trapezoidal model, the change demarcation point of the base reaction force distribution is at the intersection of the sand cushion and the undisturbed soil, specifically: when the central angle of the soil arc foundation is , the demarcation point is , and the base reaction force is uniformly distributed within , is linearly distributed, where D is the pipe diameter. The expression of the trapezoidal model is as follows: ； In the formula, is the maximum value of the base reaction force, is , is the pipe diameter, is the abscissa variable; Or, ； In the formula, is half of the central angle of the soil arc foundation; Substitute 、 into the above formula to obtain a trapezoidal model expression related to : ； In the formula, is the angle from the top of the pipe to the bottom of the pipe in the clockwise direction.

2. The structural calculation method of the trapezoidal model according to claim 1, characterized in that It includes the following steps: Step S1: Combine the trapezoidal model of the base reaction force with the Spangler model of the soil pressure around the pipe. On the basis of the Spangler model, only change the base reaction force to obtain the soil pressure model around the pipe based on the trapezoidal model; Step S2: Under the model of soil pressure around the pipe, calculate the total base reaction force, and then calculate the internal force of the pipe wall under the action of only the base reaction force according to different θ ranges. By calculating the generalized displacement, obtain the unknown bending moment and the unknown axial force . Superimpose them with the internal force of the pipe wall caused by the external load to obtain the internal force of the pipe ring; Step S3: Add a horizontal outward unit force at the pipe waist, calculate the internal moment in the pipe, and then calculate the horizontal radial displacement caused by the base reaction force at the pipe waist through the internal moment in the pipe, so as to obtain the horizontal deformation of the pipeline caused by the soil pressure at the pipe top and its base reaction force; Step S4. According to the values under different central angles of the soil arc foundation, the pipeline deformation calculation formula, as well as the bending moment calculation formula and bending stress calculation formula of the pipe ring at the top, waist and bottom are finally obtained.

3. The structural calculation method based on the buried pipeline foundation reaction force calculation model according to claim 2, characterized in that The expression of the total base reaction force in step S2 is as follows: ； In the formula, is the pipe radius.

4. A structural calculation method based on the reaction force calculation model of the buried pipeline foundation according to claim 2, characterized in that, The different ones in step S2 The expressions of the internal force of the pipe wall in different ranges are as follows: When then ； In the formula, is the bending moment caused by only the external load, is the axial force caused by only the external load, is the shear force caused by only the external load; ​​​ When then ； When then ； where A is a constant related to and B is a constant related to and C is a constant related to . The calculation formula is as follows: ； ； 。 5. The structural calculation method based on the buried pipeline foundation reaction force calculation model according to claim 2, characterized in that, The unknown bending moment in step S2 unknown axial force The expressions are as follows: ； In the formula, is the generalized displacement that appears in the direction of the unknown bending moment under the action of ; is the generalized displacement that appears in the direction of the unknown axial force under the action of ; is the generalized displacement that appears in the direction of the unknown bending moment under the action of the external load ; is the generalized displacement that appears in the direction of the unknown axial force under the action of the external load . is the elastic modulus of the pipeline, is the moment of inertia of the pipeline cross-section, D1 is a constant related to , E1 is a constant related to , F is a constant related to , G is a constant related to . The calculation formula is as follows: ； ； ； 。 6. The structural calculation method based on the buried pipeline foundation reaction force calculation model according to claim 2, wherein, In step S2, the expression of the internal force of the pipe ring is as follows: ； In the formula, represents the unknown bending moment , the unknown axial force and the bending moment under the combined action of the external load . N 2 represents the unknown bending moment , the unknown axial force and the axial force under the combined action of the external load . represents the unknown bending moment , the unknown axial force and the shear force under the combined action of the external load . represents the bending moment under the action of only the unknown bending moment . N 21 represents the axial force under the action of only the unknown bending moment . represents the shear force under the action of only the unknown bending moment . represents the bending moment under the action of only the unknown axial force . N 22 represents the axial force under the action of only the unknown axial force . represents the shear force under the action of only the unknown axial force .

7. A structural calculation method based on the buried pipeline foundation reaction force calculation model according to claim 2, characterized in that The horizontal deformation 2 of the pipeline caused by the soil pressure on the pipe crown and the reaction force at the base in step S3 has the following expression: ； In the formula, is the horizontal deformation under the action of the soil pressure only on the top of the pipe, is the horizontal deformation caused by the base reaction force at the waist of the pipe; Among them, the vertical deformation coefficient of earth pressure has the following expression: ； where H is a constant related to and is a constant related to The calculation formula is as follows: ； 。 8. A structural calculation method based on the subgrade reaction force calculation model of buried pipelines according to claim 2, characterized in that, The calculation formula of the pipeline deformation in step S4 is as follows: ； The calculation formula of the internal moment of the pipe ring at the top, waist and bottom is: ； The calculation formula of the bending stress is: ； In the formula, is the vertical / horizontal deformation of the pipeline; is the deformation lag coefficient; is the vertical deformation coefficient of the earth pressure, which is related to the value of the central angle of the soil arc foundation; is the pipeline deformation coefficient under the action of the lateral horizontal resistance of the pipeline, which is determined by the central angle of the lateral horizontal resistance of the pipeline; is the pipeline radius; E is the elastic modulus of the pipeline; is the modulus of subgrade reaction; is the moment of inertia of the pipeline cross-section; is the resultant force of the earth pressure on the top of the pipeline; is the pipeline wall thickness.

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