Design method of HDPE (High-Density Polyethylene) pipeline shipping track

Abstract

The invention relates to the technical field of HDPE pipeline shipping, in particular to an HDPE pipeline shipping track construction method which comprises the following steps: S1, acquiring calculation parameters of HDPE pipe joints and ballast blocks; s2, calculating the total weight and H draft of the HDPE pipe section; s3, constructing a pipeline model; s4, the pipeline model constructed in the step S3 is used for simulating the working condition that the front end of the HDPE pipe section enters water and the working condition that the tail end of the HDPE pipe section leaves the slope and is subjected to back pressure when the HDPE pipe section runs on rails with different slope ratios under the condition of different tidal water levels; the maximum counter-force N1 of the trolley in the water entering process of the HDPE pipe section and the tail end counter-force N2 of the trolley in the slope leaving process of the HDPE pipe section are obtained; s5, N1 and N2 are compared with the working load N0 of the trolley, if N1 is smaller than or equal to N0 and N2 is smaller than or equal to N0, the slope ratio design of the section of rail passes checking calculation, and the next step is carried out; otherwise, adjusting the slope ratio of the section of track, and repeating the step S4 until the section of track meets the conditions that N1 is smaller than or equal to N0 and N2 is smaller than or equal to N0; and S6, repeating the steps S4-S5 until all the track slope ratios pass the checking calculation. According to the method, reasonable distribution of the track slope ratio is achieved by refining the slope ratio adjustment strategy.

Description

Technical Field

[0001] The invention relates to the technical field of HDPE pipeline transportation, and in particular to a HDPE pipeline transportation track construction method. Background Art

[0002] HDPE pipe (High Density Polyethylene) can be used as the seaside water intake pipe of the seawater cooling system because of its series of excellent properties, such as reliable connection, strong material impact resistance, outstanding crack resistance, aging resistance and corrosion resistance. The installation process of HDPE pipe is complicated and has many steps. First, the welding and assembly of the pipeline are carried out on land to ensure that the connection between the pipeline sections is firm and reliable. After the onshore welding is completed, the assembled pipe sections need to be transported from the land state to the water state, and then further offshore construction can be carried out, including the floating, sinking, positioning and final docking of the pipeline, until the installation of the entire pipeline section is completed.

[0003] At present, the commonly used method for transporting HDPE pipes is to place the HDPE pipes on the transport trolley, and the trolley moves on the transport track to drive the HDPE pipes to move. In this process, it is necessary to ensure the smooth transition of the pipe section to avoid unnecessary damage to the pipe. In order to keep the trolley running smoothly, the design of the HDPE pipe transport track is extremely important. If a track with a single slope ratio or a track design with a slow slope ratio change is adopted, the construction volume of the transport track is huge and the requirements for on-site space are high; if the slope ratio changes too quickly, it is not suitable for HDPE pipes with large diameter (inner diameter exceeding 3m) and overweight (single pipe section length exceeding 5.5m, linear weight exceeding 0.9t / m). When the pipe section composed of large diameter and overweight HDPE pipe sections just enters the water, the buoyancy of the pipe section is less than its own gravity, and the pipe head will fall, and the pressure on the transport trolley near the slope change point will increase sharply. If the slope ratio is not designed properly, it will cause damage to the HDPE pipe and the transport trolley, affecting construction efficiency and increasing construction costs. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that the construction space of the HDPE pipeline shipping track at the seaside is limited. When the slope section adopts a variable slope ratio design, improper slope ratio design may cause damage to the HDPE pipeline and the shipping trolley, affect the construction efficiency, and increase the construction cost. A method for designing a HDPE pipeline shipping track is provided.

[0005] In a first aspect, the present invention provides a method for designing a HDPE pipeline delivery track, comprising the following steps:

[0006] S1. Obtain the calculation parameters of the HDPE pipe section and the calculation parameters of the ballast block;

[0007] S2. Calculate the total weight G of the HDPE pipe segment Z and the draft of the HDPE pipe section H C ;

[0008] S3. Input the material data and cross-sectional data of the HDPE pipe segment and the ballast block into the Midas Civil software to construct a pipeline model;

[0009] S4. Use the pipeline model constructed in S3 to simulate the front water entry condition of the HDPE pipe section and the off-slope back pressure condition of the HDPE pipe section end when the HDPE pipe section is running on tracks with different slope ratios under different tidal water levels;

[0010] Calculate the maximum reaction force N1 of the trolley when the HDPE pipe segment enters the water, and the reaction force N2 of the trolley at the end of the HDPE pipe segment leaving the slope;

[0011] S5. Compare N1 and N2 with the trolley working load N0. If N1≤N0 and N2≤N0, the slope ratio design of this track section passes the verification and proceed to the next step; otherwise, adjust the slope ratio of this track section and repeat S4 until this track section satisfies N1≤N0 and N2≤N0;

[0012] S6. Repeat S4-S5 until all track slope ratios pass verification.

[0013] The HDPE pipeline transportation track design method provided by the present invention obtains the calculation parameters of the HDPE pipe section and the ballast block, uses the Midas Civil software to establish a pipeline model and simulates the operation conditions under different tidal water levels, so as to accurately predict the mechanical performance of the pipeline in the state of the front end entering the water and the end leaving the slope on the ramp. When designing the track, the established pipeline model is used to simulate and calculate different slope ratios, and the slope ratio is repeatedly adjusted until the condition of the trolley working load requirement N0 (that is, N1≤N0 and N2≤N0) is met. The problems of large track construction volume and high space requirements caused by the traditional single slope ratio design can be avoided, and at the same time, the negative impact of too fast slope ratio changes on large-diameter and overweight HDPE pipelines can be effectively avoided, and the risk of the pipe section head falling and the transportation trolley being subjected to a sharp increase in pressure is reduced.

[0014] The HDPE pipeline shipping track design method provided by the present invention is particularly suitable for situations where space is limited at the seaside. A reasonable distribution of track slope ratios is achieved through a detailed slope ratio adjustment strategy, which reduces the construction volume of the shipping track, reduces the demand for construction site space, and improves the flexibility of shipping operations.

[0015] Preferably, the calculation parameters of the HDPE pipe segment in S1 include the length L of the HDPE pipe segment G , the inner diameter R1 of the HDPE pipe segment, the wall thickness T of the HDPE pipe segment G , the linear weight of HDPE pipe section G1, unit t / m.

[0016] Preferably, the calculation parameters of the ballast block in S1 include the width W of the ballast block Y , the height of the ballast block H Y , the minimum distance H between the bottom of the ballast block and the outer wall of the HDPE pipe segment Y2 , the thickness of the ballast block is T Y , the weight of the ballast block is G2.

[0017] By refining and optimizing the calculation parameters of HDPE pipe segments and ballast blocks, the actual stress of pipeline segments on tracks with different slope ratios can be simulated and verified more accurately. Such parameter refinement enables the track design to adapt to various specifications and load conditions of HDPE pipes, and ensures the scientificity and safety of track slope ratio adjustment.

[0018] Preferably, the total weight G of the HDPE pipe section is calculated in S2 Z The method is:

[0019] G Z =N1*G2+G3+L Z *G1+L Z *G4;

[0020] Where N1 is the number of ballast blocks in the HDPE pipe section;

[0021] L Z It is the total length of the HDPE pipe section after the HDPE pipe joints are connected;

[0022] G3 is the weight of the flange joint and flange in the HDPE pipe section;

[0023] G4 is the weight of pore water in the HDPE pipe section, in t / m.

[0024] The calculation method of the total weight of the HDPE pipe section integrates the weight of each component in the HDPE pipe section, which can provide accurate weight data input for track design and slope ratio verification. Z It can help designers determine whether the track and slope ratio meet the load-bearing requirements of the HDPE pipe section, thereby effectively improving the design accuracy.

[0025] Preferably, the draft H of the HDPE pipe section is calculated in S2 C The method is:

[0026] Calculate the outer diameter of the HDPE pipe segment R2 = (R1 / 2 + T G );

[0027] Calculate half of the length of the flooded section L = R2 2 -(R2-H C ) 2 ;

[0028] Calculate half of the central angle of the flooded section α = arccos((R2-H C ) / R2);

[0029] Calculate the HDPE pipe section submerged cross-sectional area S1 = (α / 2π)*R2 2 *3.14-L*(R2-H C );

[0030] Calculate the ballast block submerged cross-sectional area S2 = W Y *(H Y2 +H C )-S1;

[0031] Calculate the buoyancy of the HDPE pipe segment F = (S1*L+S2*T Y *N1)*ρ 海水 ≥G Z ;

[0032] Use trial and error to solve H C .

[0033] The draft depth that meets the buoyancy conditions is solved through trial and error algorithms to ensure that the buoyancy of the pipe section can offset its weight. This method ensures the stability and safety of the HDPE pipeline under different tidal conditions and provides reliable data support for offshore installation operations.

[0034] Preferably, the HDPE pipe segments and ballast blocks in the pipeline model constructed by S3 are both beam elements;

[0035] The material data of the HDPE pipe segment include the elastic modulus E1 of the HDPE pipe segment corresponding to the beam element, and the bulk density Pb1 of the HDPE pipe segment corresponding to the beam element;

[0036] The cross-sectional data of the HDPE pipe segment include the outer diameter D1 and the wall thickness tw1 of the beam element corresponding to the HDPE pipe segment;

[0037] The material data of the ballast block includes the elastic modulus E2 of the beam unit corresponding to the ballast block and the bulk density Pb2 of the beam unit corresponding to the ballast block;

[0038] The cross-sectional data of the ballast block include the outer diameter D2 and the wall thickness tw2 of the beam element corresponding to the ballast block;

[0039] The cross-sectional data of the ballast block is converted according to the moment of inertia of the ballast block, and the bulk density Pb2 of the beam unit corresponding to the ballast block is converted from the area of ​​the annulus.

[0040] The pipeline model simplifies the HDPE pipe sections and ballast blocks into beam units, making the calculation process more efficient and reducing the complexity of the model without affecting the accuracy. The beam unit is an annular solid wall unit, while the actual HDPE pipe section is a hollow structural wall, so that the design reserves sufficient redundancy. Through this simplification, the stress conditions of the pipeline under different tidal water levels and slope ratios can be accurately simulated, ensuring the balance and stability of the pipeline section structure during transportation, and ultimately improving the feasibility and safety of the design scheme.

[0041] Preferably, in the pipeline model constructed by S3, the initial position of the pipeline is horizontal, and a gap unit is set to simulate the distance from the track to the water surface, and the corresponding distance is controlled by the gap of the unit.

[0042] By simulating the distance from the track to the water surface through gap units, it is helpful to effectively control the movement trajectory and force conditions of the pipe section during floating and leaving the slope on the water surface, improve the accuracy of the model, and enable accurate force analysis and reaction force calculation of the delivery track design under different slope ratios and tide conditions, thereby optimizing the design of the delivery track. In addition, the use of gap units can also reduce the complexity of the model and save computing resources when performing calculations and analyses under various working conditions.

[0043] Preferably, in the pipeline model constructed by S3, the bottom ground of the gap unit adopts a compression-only elastic support, and the value of the ground constraint is calculated by converting the settlement of the delivery track.

[0044] By setting up compression-only elastic supports and ground constraints for settlement conversion, the model can more realistically simulate the stress conditions and settlement behavior of the track foundation during transportation. It is more suitable for track design near the seaside and can prevent track damage caused by uneven foundation stress and settlement that may occur during transportation operations.

[0045] Preferably, the pipeline model constructed in S3 is used in S4 to simulate the front end water entry condition of the HDPE pipe section and the off-slope back pressure condition of the end of the HDPE pipe section when the HDPE pipe section is running on tracks with different slope ratios under the conditions of average spring tide low tide and average sea level water level.

[0046] By simulating various working conditions at different water levels, we can more comprehensively estimate the adaptability of different slope ratio designs for large-diameter, ultra-heavy HDPE pipe sections and improve design accuracy.

[0047] Preferably, when simulating the working conditions of the front end of the HDPE pipe section entering water and the end of the HDPE pipe section leaving the slope under reverse pressure when the HDPE pipe section is running on tracks with different slope ratios in S4, the pipeline calculation adopts a method of advancing by a distance of 0.5 times the length of the ballast block spacing.

[0048] By refining the advancement method with a step length of 0.5 times the ballast block spacing, this design method can cover the working conditions where the ballast blocks are located at the joint corners of tracks with different slopes and the ballast blocks are symmetrically distributed on both sides of the joint corners of tracks with different slopes, effectively improving the slope ratio design accuracy.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. The HDPE pipeline delivery track design method provided by the present invention obtains the calculation parameters of the HDPE pipe section and the ballast block, uses the Midas Civil software to establish a pipeline model and simulates the operation under different tidal water levels, so as to accurately predict the mechanical performance of the front end of the pipeline entering the water and the end leaving the slope on the ramp. When designing the track, the established pipeline model is used to simulate and calculate different slope ratios, and the slope ratio is repeatedly adjusted until the condition of the trolley working load requirement N0 (that is, N1≤N0 and N2≤N0) is met. The problems of large track construction volume and high space requirements caused by the traditional single slope ratio design can be avoided, and the negative impact of too fast slope ratio changes on large-diameter and overweight HDPE pipelines can be effectively avoided, and the risk of the pipe section head falling and the sudden increase in pressure on the delivery trolley is reduced;

[0051] 2. The HDPE pipeline shipping track design method provided by the present invention is particularly suitable for situations where space is limited at the seaside. A reasonable distribution of track slope ratios is achieved through a detailed slope ratio adjustment strategy, which reduces the construction volume of the shipping track, reduces the demand for construction site space, and improves the flexibility of shipping operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the HDPE pipe shipping track;

[0053] Figure 2 This is the end view of the connection between the ballast block and the HDPE pipe joint;

[0054] Figure 3 This is the cross-sectional view of the HDPE pipe section immersed in water;

[0055] Figure 4 This is a screenshot of the HDPE pipe material data in the Midas Civil software;

[0056] Figure 5 This is a screenshot of the HDPE pipe section data in Midas Civil software;

[0057] Figure 6 This is a screenshot of the ballast block cross-section data in the Midas Civil software;

[0058] Figure 7 The pipeline model diagram constructed in the Midas Civil software of Example 2;

[0059] Figure 8 Screenshot of the compression-only elastic bearing parameters in Midas Civil software for Example 2;

[0060] Fig. 9 is a line graph of the buoyancy of the ballast block in Example 2;

[0061] Fig.10 It is a line graph of the buoyancy of the HDPE pipe section in Example 2;

[0062] Fig.11 This is a typical linear screenshot of the pipeline after the HDPE pipe section is transported to a certain length in the Midas Civil software;

[0063] Fig.12 This is a screenshot of the maximum reaction force of the car during the water entry process at +0.4mCD water level in Midas Civil software;

[0064] Fig.13 This is a screenshot of the trolley reaction force at the end of the +0.4mCD water level off-slope process in the Midas Civil software;

[0065] Fig.14 This is a screenshot of the maximum reaction force of the car during the water entry process at +0.78mCD water level in Midas Civil software;

[0066] Fig.15 This is a screenshot of the trolley reaction force at the end of the +0.78mCD water level off-slope process in the Midas Civil software.

[0067] Markings in the figure:

[0068] 1-HDPE pipe section, 2-ballast block. DETAILED DESCRIPTION

[0069] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0070] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0071] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0072] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0073] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0074] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0075] Example 1

[0076] This embodiment provides a method for designing a HDPE pipeline delivery track, which is used to design a seaside HDPE pipeline delivery track. The delivery track of this embodiment can be as follows: Figure 1 As shown, it is divided into a horizontal section on land, a slope section on land, and an underwater downhill section. The track designed by the shipping track design method is used to support loads such as the trolley, ballast block, and HDPE pipe section on the track. In this embodiment, the HDPE pipe section is welded by multiple sections of HDPE pipe segments 1. It can be understood that the design difficulty of the HDPE pipeline shipping track lies in the design of the onshore slope section. If the onshore slope section adopts a fixed slope ratio or the slope ratio is improperly designed, it will lead to the limitation of the narrow space at the seaside, making it difficult to place the shipping track; or the slope ratio of the onshore slope section changes too quickly, resulting in a drastic change in the pressure on the shipping trolley on the track, damaging the shipping trolley and then causing damage to the HDPE pipe section. Therefore, in order to overcome the above problems, the HDPE pipeline shipping track design method of this embodiment includes the following steps:

[0077] S1. Obtain the calculation parameters of the HDPE pipe section 1 and the calculation parameters of the ballast block 2;

[0078] Specifically, Figure 1-Figure 3 As shown, the calculation parameters of the HDPE pipe segment 1 include the length L of the HDPE pipe segment 1 G , unit: m; inner diameter R1 of HDPE pipe segment 1, unit: m; wall thickness T of HDPE pipe segment 1 G , unit: m; linear weight G1 of HDPE pipe section 1, unit: t / m.

[0079] Specifically, Figure 1-Figure 3 As shown, the calculation parameters of the ballast block 2 include the width W of the ballast block 2 Y , unit: m; height H of ballast block 2 Y , unit: m; the minimum distance H between the bottom of the ballast block 2 and the outer wall of the HDPE pipe segment 1 Y2 , unit: m; thickness of ballast block 2 T Y , unit: m; weight G2 of ballast block 2, unit: t.

[0080] By refining and optimizing the calculation parameters of the HDPE pipe segment 1 and the ballast block 2, the actual stress of the pipeline segment on tracks with different slope ratios can be simulated and verified more accurately. Such parameter refinement enables the track design to adapt to various specifications and load conditions of HDPE pipes, and ensures the scientificity and safety of the track slope ratio adjustment.

[0081] S2. Calculate the total weight G of the HDPE pipe segment Z , unit: t; and the draft of the HDPE pipe section H C , unit: m;

[0082] Specifically, Figure 1-Figure 3 As shown, the total weight of the HDPE pipe section G Z The calculation method is:

[0083] G Z =N1*G2+G3+L Z *G1+L Z *G4;

[0084] Where N1 is the number of ballast blocks 2 in the HDPE pipe section;

[0085] L Z The total length of the HDPE pipe section after the HDPE pipe section 1 is connected, unit: m;

[0086] G3 is the weight of the flange joint and flange in the HDPE pipe section, unit: t;

[0087] G4 is the weight of pore water in the HDPE pipe section, in t / m.

[0088] The calculation method of the total weight of the HDPE pipe section integrates the weight of each component in the HDPE pipe section, which can provide accurate weight data input for track design and slope ratio verification. Z It can help designers determine whether the track and slope ratio meet the load-bearing requirements of the HDPE pipe section, thereby effectively improving the design accuracy.

[0089] Specifically, Figure 1-Figure 3 As shown, the draft depth H of the HDPE pipe section C The calculation method is:

[0090] Calculate the outer diameter R2 of HDPE pipe section 1, unit: m, R2 = (R1 / 2 + T G );

[0091] Calculate half of the length of the flooded section, L, in m, L = R2 2 -(R2-H C ) 2 ;

[0092] Calculate half of the central angle of the submerged section, α = arccos((R2-H C ) / R2);

[0093] Calculate the HDPE pipe section submerged cross-sectional area S1, unit: m 2 , S1=(α / 2π)*R2 2 *3.14-L*(R2-H C );

[0094] Calculate the ballast block submerged cross-sectional area S2, unit: m2 , S2=W Y *(H Y2 +H C )-S1;

[0095] Calculate the buoyancy F of the HDPE pipe section, unit: t, F = (S1*L+S2*T Y *N1)*ρ 海水 ≥G Z ;

[0096] Use trial and error to solve H C , unit: m.

[0097] The draft depth that meets the buoyancy conditions is solved through trial and error algorithms to ensure that the buoyancy of the pipe section can offset its weight. This method ensures the stability and safety of the HDPE pipeline under different tidal conditions and provides reliable data support for offshore installation operations.

[0098] S3. Input material data and cross-sectional data of the HDPE pipe segment 1 and the ballast block 2 into the Midas Civil software to construct a pipeline model;

[0099] Specifically, when constructing the pipeline model using Midas Civil software, beam elements are used for both HDPE pipe segment 1 and ballast block 2;

[0100] The material data of HDPE pipe segment 1 includes the elastic modulus E1 of the beam element corresponding to HDPE pipe segment 1, unit: MPa, and the bulk density Pb1 of the beam element corresponding to HDPE pipe segment 1, unit: kN / m 3 ;

[0101] The cross-sectional data of HDPE pipe segment 1 includes the outer diameter D1 and the wall thickness tw1 of the beam element corresponding to HDPE pipe segment 1;

[0102] The material data of the ballast block 2 includes the elastic modulus E2 of the beam unit corresponding to the ballast block 2 and the bulk density Pb2 of the beam unit corresponding to the ballast block 2;

[0103] The cross-sectional data of the ballast block 2 includes the outer diameter D2 and the wall thickness tw2 of the beam unit corresponding to the ballast block 2;

[0104] The cross-sectional data of the ballast block 2 is converted according to the moment of inertia of the ballast block 2, and the bulk density Pb2 of the beam unit corresponding to the ballast block 2 is converted according to the area of ​​the annulus.

[0105] In the pipeline model, HDPE pipe section 1 and ballast block 2 are simplified into beam units, making the calculation process more efficient and reducing the complexity of the model without affecting the accuracy. The beam unit is an annular solid wall unit, while the actual HDPE pipe section 1 is a hollow structural wall, so that the design reserves sufficient redundancy. Through this simplification, the stress conditions of the pipeline under different tidal water levels and slope ratios can be accurately simulated, ensuring the balance and stability of the pipeline section structure during transportation, and ultimately improving the feasibility and safety of the design scheme.

[0106] Furthermore, when constructing the pipeline model, the initial position of the HDPE pipe section is horizontal, and a gap unit is set to simulate the distance from the track to the water surface. The corresponding distance is controlled by the gap of the unit. The ground at the bottom of the gap unit adopts a compression-only elastic support, and the value of the ground constraint is converted by the settlement of the delivery track.

[0107] By simulating the distance from the track to the water surface through gap units, it is helpful to effectively control the movement trajectory and force conditions of the pipe section during floating and leaving the slope on the water surface, improve the accuracy of the model, and enable accurate force analysis and reaction force calculation of the delivery track design under different slope ratios and tide conditions, thereby optimizing the design of the delivery track. In addition, the use of gap units can also reduce the complexity of the model and save computing resources when performing calculations and analyses under various working conditions.

[0108] By setting up compression-only elastic supports and ground constraints for settlement conversion, the model can more realistically simulate the stress conditions and settlement behavior of the track foundation during transportation. It is more suitable for track design near the seaside and can prevent track damage caused by uneven foundation stress and settlement that may occur during transportation operations.

[0109] S4. Use the pipeline model constructed in S3 to simulate the front water entry condition of the HDPE pipe section and the off-slope back pressure condition of the HDPE pipe section end when the HDPE pipe section is running on tracks with different slope ratios under different tidal water levels;

[0110] Specifically, the pipeline model built using S3 simulates the front-end water entry conditions of the HDPE pipe section and the back pressure conditions of the HDPE pipe section off the slope when the HDPE pipe section is running on tracks with different slope ratios under the conditions of average spring tide low tide and average sea level water level. Simulating multiple working conditions at different water levels can more comprehensively estimate the adaptability of different slope ratio designs for large-diameter and super-heavy HDPE pipe sections and improve design accuracy.

[0111] Calculate the maximum reaction force N1 of the trolley when the HDPE pipe segment enters the water, and the reaction force N2 of the trolley at the end of the HDPE pipe segment leaving the slope;

[0112] Specifically, when simulating the working conditions of the front end of the HDPE pipe section entering water and the back pressure of the end of the HDPE pipe section leaving the slope when running on tracks with different slope ratios, the pipeline calculation adopts the method of advancing by 0.5 times the spacing length of the ballast block 2. By using the refined advancement method with a step length of 0.5 times the spacing length of the ballast block 2, this design method can cover the working conditions where the ballast block 2 is located at the splicing angle of tracks with different slopes and the ballast block 2 is symmetrically distributed on both sides of the splicing angle of tracks with different slopes, effectively improving the slope ratio design accuracy.

[0113] S5. Compare N1 and N2 with the trolley working load N0. If N1≤N0 and N2≤N0, the slope ratio design of this track section passes the verification and proceed to the next step; otherwise, adjust the slope ratio of this track section and repeat S4 until this track section satisfies N1≤N0 and N2≤N0;

[0114] S6. Repeat S4-S5 until all track slope ratios pass verification.

[0115] The HDPE pipeline delivery track design method provided in this embodiment obtains the calculation parameters of the HDPE pipe section 1 and the ballast block 2, uses the Midas Civil software to establish a pipeline model and simulates the operation conditions under different tidal water levels, so as to accurately predict the mechanical performance of the pipeline in the state of the front end entering the water and the end leaving the slope on the ramp. When designing the track, the established pipeline model is used to simulate and calculate different slope ratios, and the slope ratio is repeatedly adjusted until the condition of the trolley working load requirement N0 (that is, N1≤N0 and N2≤N0) is met. The problems of large track construction volume and high space requirements caused by the traditional single slope ratio design can be avoided, and the negative impact of too fast slope ratio changes on large-diameter and overweight HDPE pipelines can be effectively avoided, and the risk of the pipe section head falling and the transportation trolley being subjected to a sharp increase in pressure is reduced.

[0116] The HDPE pipe shipping track design method provided in this embodiment is particularly suitable for situations where space is limited at the seaside. A reasonable distribution of track slope ratios is achieved through a detailed slope ratio adjustment strategy, which reduces the construction volume of the shipping track, reduces the demand for construction site space, and improves the flexibility of shipping operations.

[0117] Example 2

[0118] This embodiment takes the delivery track of the HDPE water intake pipeline of a seawater cooling system in a coastal area as an example, and uses the HDPE pipeline delivery track design method provided in Example 1 for design. In this embodiment, the conventional working load of the trolley N0=600kN.

[0119] In this embodiment, when designing the delivery track, the heaviest HDPE pipe section is used for design, and the total weight G of the HDPE pipe section is calculated. Z and the draft of the HDPE pipe section H C .

[0120] In this embodiment, the length L of the HDPE pipe segment 1 G =5.85m; inner diameter R1 of HDPE pipe section 1 =3.23m; wall thickness T of HDPE pipe section 1 G =0.144m; the linear weight of HDPE pipe section 1 G1 = 0.935t / m.

[0121] Width W of ballast block 2 Y =4.41m; height H of ballast block 2 Y =4.41m; the minimum distance H between the bottom of the ballast block 2 and the outer wall of the HDPE pipe segment 1 Y2 =0.495m; the thickness of the ballast block 2 is T Y =1.055m; the weight of a single ballast block 2 is G2 = 19.54t. A ballast block 2 is installed at the joint of each HDPE pipe section 1, and a shipping trolley is placed under each ballast block 2 to facilitate the shipping of the pipe section.

[0122] The overall installation length L of the HDPE pipe section in this embodiment Z The length of the pipe is 504.45m, including 86 ballast blocks, 85 standard HDPE pipe sections, 2 sets of flange pipe sections and flanges (one set weighs 5.2t), and the weight of the pore water in the HDPE pipe section is 0.253t / m, then:

[0123] The total weight G of the HDPE pipe section in this embodiment is calculated as Z =N1*G2+G3+L Z *G1+L Z *G4=86*19.45+10.4+0.935*501.45+0.253*501.45=2281.42t.

[0124] The outer diameter R2 of the HDPE pipe segment 1 in this embodiment is calculated to be (R1 / 2+T G )=3.23 / 2+0.144=1.76m;

[0125] Half of the length of the flooded section L = R2 2 -(R2-H C ) 2 =1.76 2 -(1.76-H C ) 2 ;

[0126] Half of the central angle of the immersed section α = arccos((R2-H C ) / R2)=arccos((1.76-H C ) / 1.76);

[0127] Calculate the HDPE pipe section submerged cross-sectional area S1 = (α / 2π)*R2 2 *3.14-L*(R2-H C )=(α / 2π)*1.76 2 *3.14-L*(1.76-H C );

[0128] Calculate the ballast block submerged cross-sectional area S2 = W Y *(H Y2 +H C )-S1=4.41*(0.495+H C )-S1;

[0129] Calculate the buoyancy of the HDPE pipe segment F = (S1*L+S2*T Y *N1)*ρ 海水 =((S1*501.45+S2*1.055*86)*1.025)≥2281.42t;

[0130] So H C It is in the interval (0, 1.76) and the trial algorithm is used to solve H C =1.425m, F=2281t. Therefore, the draft of the HDPE pipe section is 1.425m.

[0131] In this embodiment, since the spacing between the ballast blocks in the onshore part is smaller and the number of trolleys is large, the pressure on the corresponding trolleys is relatively small. Therefore, the data of the HDPE pipe segment 1 and the ballast block 2 in the water section are input into the Midas Civil software for subsequent simulation.

[0132] Specifically, Figure 4 , Figure 5 As shown, in this embodiment, the HDPE pipe segment 1 is a PE100 pipe, and the elastic modulus E1 corresponding to 25 degrees Celsius and a load exposure time of 0.1 hours is 675MPa. The material of the ballast block 2 in this embodiment is C35 / 45 concrete. Since the pipeline beam unit is an annular solid wall unit and the actual HDPE pipeline is a hollow structural wall, the bulk density of the HDPE pipe segment 1 adopts a converted value, Pb1 = 6.11kN / m 3 , the outer diameter D1 of the beam element corresponding to HDPE pipe segment 1 is 3.564m, and the wall thickness tw1 is 0.167m. Figure 6 As shown, in this embodiment, the ballast block 2 uses beam units in the model, and the pipe section model uses annular units. The size of the annular unit is converted according to the moment of inertia of the ballast block 2. The moment of inertia of the outer section of the ballast block 2 is 26.139m 4 , the corresponding circular outer diameter D2 = 4.804m, wall thickness tw2 = 0.62m. The corresponding bulk density Pb2 of ballast block 2 is converted from the area of ​​the ring to 21.44kN / m3 .

[0133] like Figure 7 The pipeline model diagram constructed in this embodiment is shown. In this embodiment, the track is normally settled by 4 mm under the action of the trolley. The total weight of the trolley, the ballast block 2, and the HDPE pipe section 1 is 248.92 kN. Figure 8 As shown, the ground constraint in this embodiment is 248.92 / 4=62.23 kN / mm. Fig. 9 As shown, the buoyancy of the ballast block 2 in this embodiment adopts a multi-segment broken line; Fig.10 As shown, in this embodiment, the buoyancy of the HDPE pipe segment adopts a multi-segment broken line.

[0134] In this embodiment, the average low tide level is +0.4mCD water level, the average sea level is +0.78mCD water level, and the length of a track section in this embodiment (with a fixed slope ratio) is 14.5m, which is about 2.5 times the spacing of the ballast blocks 2. The pipeline calculation adopts the method of advancing at a distance of 0.5 times the spacing of the ballast blocks 2, 2.925m. Fig.11 The typical line shape of the pipeline after a certain length of transportation is shown in Figure 1. Fig.12 , Fig.13 , Fig.14 , Fig.15 As shown by the red arrow and red box, under the condition of the slope ratio of this section of track, when the water level is +0.4mCD, N1=607.1kN, N2=653.5kN; when the water level is +0.78mCD, N1=607.2kN, N2=660.3kN; the calculation results of the slope of this section of track are shown in Table 1.

[0135] Table 1 Calculation results

[0136] +0.4mCD water level +0.78mCD water level <![CDATA[The maximum reaction force N1 of the trolley during the water entry process]]> 607.1kN 607.2kN <![CDATA[The reaction force N2 of the trolley at the end of the slope departure process]]> 653.5kN 660.3kN

[0137] In this embodiment, the maximum reaction force of the trolley during the entry of the HDPE pipe section into the water represents the load that a conventional trolley will experience. According to the current slope design, the buoyancy drives the pressure of the trolley near the entry point to never exceed that of the onshore section. The reaction force of the terminal trolley during the off-slope process represents the maximum load of the terminal trolley caused by the counter pressure of the incompletely floated pipeline on the terminal trolley.

[0138] Through the above calculation, the maximum load of the conventional trolley under the slope ratio of this section of track is 607.2kN, and the maximum load of the end trolley is 660.3kN. However, since the pipeline adopts solid wall structure simulation, the rigidity is relatively large, and the calculation result is relatively conservative. In addition, the conventional working load of the trolley is N0 = 600kN, and the structural design has a 1.5 times coefficient. Therefore, the slope ratio design of this section of track meets the requirements for transportation and use. After verification, the slope ratio verification of the next section of track can be carried out. Figure 1The track slope ratio designed in this embodiment is shown. The slope ratio of the onshore slope section transitions from 1:100 to 1:70, to 1:50, to 1:270, to 1:23, to 1:19, to 1:17, to 1:15.5. The underwater slope section can be designed with a fixed slope ratio of 1:14.5 to facilitate later track construction.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a HDPE pipeline delivery track, characterized in that: The following steps are involved: S1. Obtaining the calculation parameters of the HDPE pipe section (1) and the calculation parameters of the ballast block (2); S2. Calculate the total weight G of the HDPE pipe segment Z and the draft of the HDPE pipe section H C ; S3. The material data and cross-sectional data of the HDPE pipe segment (1) and the ballast block (2) are input into the Midas Civil software to construct a pipeline model; S4. Use the pipeline model constructed in S3 to simulate the front water entry condition of the HDPE pipe section and the off-slope back pressure condition of the HDPE pipe section end when the HDPE pipe section is running on tracks with different slope ratios under different tidal water levels; Calculate the maximum reaction force N1 of the trolley when the HDPE pipe segment enters the water, and the reaction force N2 of the trolley at the end of the HDPE pipe segment leaving the slope; S5. Compare N1 and N2 with the trolley working load N0. If N1≤N0 and N2≤N0, the slope ratio design of this track section passes the verification and proceed to the next step; otherwise, adjust the slope ratio of this track section and repeat S4 until this track section satisfies N1≤N0 and N2≤N0; S6. Repeat S4-S5 until all track slope ratios pass verification.

2. A method for designing a HDPE pipeline delivery track according to claim 1, characterized in that: The calculation parameters of the HDPE pipe segment (1) in S1 include the length L of the HDPE pipe segment (1) G , the inner diameter R1 of the HDPE pipe segment (1), the wall thickness T of the HDPE pipe segment (1) G , the linear weight G1 of the HDPE pipe segment (1), unit: t / m.

3. A method for designing a HDPE pipeline delivery track according to claim 2, characterized in that: The calculation parameters of the ballast block (2) in S1 include the width W of the ballast block (2) Y , the height H of the ballast block (2) Y , the minimum distance H between the bottom of the ballast block (2) and the outer wall of the HDPE pipe segment (1) Y2 , the thickness T of the ballast block (2) Y , the weight G2 of the ballast block (2).

4. A method for designing a HDPE pipeline delivery track according to claim 3, characterized in that: Calculate the total weight G of the HDPE pipe segment in S2 Z The method is: G Z =N1*G2+G3+L Z *G1+L Z *G4; Where N1 is the number of ballast blocks (2) in the HDPE pipe section; L Z is the total length of the HDPE pipe section after the HDPE pipe segment (1) is connected; G3 is the weight of the flange joint and flange in the HDPE pipe section; G4 is the weight of pore water in the HDPE pipe section, in t / m.

5. A method for designing a HDPE pipeline delivery track according to claim 4, characterized in that: Calculate the draft H of the HDPE pipe section in S2 C The method is: Calculate the outer diameter of the HDPE pipe segment (1): R2 = (R1 / 2 + T G ); Calculate half of the length of the flooded section L = R2 2 -(R2-H C ) 2 ; Calculate half of the central angle of the submerged section α = arccos((R2-H C ) / R2); Calculate the HDPE pipe section submerged cross-sectional area S1 = (α / 2π)*R2 2 *3.14-L*(R2-H C ); Calculate the ballast block submerged cross-sectional area S2 = W Y *(H Y2 +H C )-S1; Calculate the buoyancy of the HDPE pipe segment F = (S1*L+S2*T Y *N1)*ρ 海水 ≥G Z ; Use trial and error to solve H C .

6. A method for designing a HDPE pipeline delivery track according to claim 1, characterized in that: In the pipeline model constructed by S3, beam elements are used for both the HDPE pipe segment (1) and the ballast block (2); The material data of the HDPE pipe segment (1) include the elastic modulus E1 of the HDPE pipe segment (1) corresponding to the beam element, and the bulk density Pb1 of the HDPE pipe segment (1) corresponding to the beam element; The cross-sectional data of the HDPE pipe segment (1) include the outer diameter D1 and the wall thickness tw1 of the beam element corresponding to the HDPE pipe segment (1); The material data of the ballast block (2) includes the elastic modulus E2 of the beam unit corresponding to the ballast block (2) and the bulk density Pb2 of the beam unit corresponding to the ballast block (2); The cross-sectional data of the ballast block (2) include the outer diameter D2 and the wall thickness tw2 of the beam unit corresponding to the ballast block (2); The cross-sectional data of the ballast block (2) is converted according to the moment of inertia of the ballast block (2), and the bulk density Pb2 of the beam unit corresponding to the ballast block (2) is converted according to the area of ​​the circular ring.

7. A method for designing a HDPE pipeline delivery track according to claim 1, characterized in that: In the pipeline model constructed by S3, the initial position of the pipeline is horizontal, and gap units are set to simulate the distance from the track to the water surface. The corresponding distance is controlled by the gap of the unit.

8. A method for designing a HDPE pipeline delivery track according to claim 8, characterized in that: In the pipeline model constructed by S3, the ground at the bottom of the gap unit adopts compression-only elastic bearings, and the value of the ground constraint is converted by the settlement of the delivery track.

9. A method for designing a HDPE pipeline delivery track according to claim 1, characterized in that: The pipeline model constructed in S3 is used in S4 to simulate the front-end water entry condition of the HDPE pipe section and the off-slope back pressure condition of the end of the HDPE pipe section when the HDPE pipe section is running on tracks with different slope ratios under the conditions of average spring tide low tide and average sea level water level.

10. A method for designing a HDPE pipeline delivery track according to claim 9, characterized in that: In S4, when simulating the front end water entry and the back pressure of the end of the HDPE pipe section off the slope when the HDPE pipe section is running on tracks with different slope ratios, the pipeline calculation adopts the method of advancing by a distance of 0.5 times the spacing length of the ballast block (2).

Images