Large-space pipeline installation method and system based on BIM

Abstract

The invention discloses a BIM-based large-space pipeline installation method and system, and relates to pipeline installation: performing three-dimensional gridding processing on BIM model data, generating a gridding space model, and constructing a pipeline installation space; calculating the load per unit length of the pipeline according to the self weight of the pipeline and the weight of a medium in the pipeline in the physical parameters; a dynamic planning method is adopted for optimization arrangement of the supports and hangers; constructing a state transition equation according to the load per unit length of the pipeline and the structural mechanics continuous beam model; according to the state transition equation, an optimal decision sequence is obtained through reverse recursion solution, backtracking is conducted from the tail end of the pipeline to the starting point, in each decision stage, the position of a supporting point enabling accumulated deflection of all follow-up pipe sections to be minimum is selected, and a globally optimal supporting and hanging bracket arrangement sequence is generated; according to the globally optimal arrangement sequence of the supports and the hangers and the load per unit length of the pipeline, the deflection value of each pipe section is calculated; according to the method, the problem of non-uniform deflection distribution caused by a traditional local optimization method is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pipeline installation, and particularly relates to a large-space pipeline installation method and system based on BIM. BACKGROUND

[0002] With the development of modern buildings towards large-scale and complex, airport terminals, high-speed rail stations, exhibition centers, stadiums and other large-space buildings are increasing. Such buildings have characteristics such as large span, high clearance and complex structure, and the design and installation of their mechanical and electrical pipeline systems face many challenges. The pipeline system in a large-space building usually includes multiple specialties such as water supply and drainage, heating and air conditioning, and fire sprinkler, and the pipeline diameter is large and the conveying distance is long, with a single pipeline length of tens of meters or even hundreds of meters. In the process of large-space pipeline installation, the reasonable arrangement of supports and hangers is the key to ensuring the safe and reliable operation of the pipeline system. The supports and hangers not only bear the weight of the pipeline and the medium, but also consider the thermal expansion and contraction effect caused by temperature changes. Unreasonable arrangement of supports and hangers will cause excessive deflection of the pipeline, affect the pipeline slope and fluid transportation, and even cause safety hazards such as pipeline stress concentration and interface leakage.

[0003] The traditional pipeline support and hanger arrangement method mainly relies on the experience of designers, and uses fixed spacing or recommended values in design manuals for arrangement. This method has the following problems: when using fixed spacing arrangement, the non-uniformity of pipeline load distribution and the influence of structural constraints are not fully considered, which easily leads to deflection of some pipeline sections exceeding the allowable value, affecting the normal use function of the pipeline. Experience arrangement is often too conservative, with excessive support in areas with small deflection and insufficient support in critical parts, resulting in material waste and unreasonable stress. Large-space buildings have large temperature differences, and the thermal expansion and contraction effect of the pipeline is significant. The traditional method is difficult to accurately calculate the influence of temperature deformation on pipeline deflection. The traditional method usually uses local adjustment, which is difficult to optimize the arrangement of supports and hangers from a global perspective, and cannot guarantee the optimality of the overall scheme.

[0004] In recent years, although some scholars have proposed some pipeline support and hanger optimization methods, most of them are limited to simple working conditions or idealized models, and are difficult to handle complex spatial constraints and multi-objective optimization problems in large-space buildings. At the same time, existing methods lack accurate consideration of temperature effects and fail to fully utilize BIM technology to realize design-construction integration.

[0005] Therefore, there is an urgent need for a new method that can consider multiple factors such as load distribution, spatial constraints and temperature effects, and realize global optimization of support and hanger arrangement based on BIM platform, to solve the deflection control problem in large-space long-distance pipeline installation. SUMMARY

[0006] In view of the traditional fixed spacing or experience arrangement, which leads to the local pipe segment deflection exceeding the limit in the installation of large space long distance pipeline, the application provides a large space pipeline installation method and system based on BIM. The pipeline support arrangement problem is converted into a three-dimensional space path optimization problem, and a dynamic programming algorithm is used to solve the globally optimal support point sequence under the condition of meeting the deflection and spacing constraints. In combination with the temperature effect calculation, a pre-provision height compensation curve is generated to avoid the problem of uneven deflection distribution caused by the traditional local optimization method.

[0007] One aspect of the application provides a large space pipeline installation method based on BIM, comprising: obtaining BIM model data of a large space building, the BIM model data comprising: spatial coordinates and size parameters of structural members, and physical parameters of a pipeline to be installed; wherein the structural members comprise: structural beams, columns and walls; the physical parameters comprise: pipeline material, pipe diameter, wall thickness and pipeline medium density; performing three-dimensional gridding processing on the BIM model data to generate a gridded space model, and removing the grid cells occupied by the structural members in the gridded space model to construct a pipeline installation space;

[0008] According to the pipeline self-weight and the pipeline medium weight in the physical parameters, the pipeline unit length load is calculated; in the pipeline installation space, a dynamic programming method is used for support arrangement optimization; according to the pipeline unit length load and the structural mechanics continuous beam model, a state transition equation is constructed, and the transition cost function of the state transition equation comprises the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint;

[0009] According to the state transition equation, the optimal decision sequence is obtained by reverse recursion, starting from the pipeline end to the starting point, and at each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe segments is selected to generate a globally optimal support arrangement sequence; according to the globally optimal support arrangement sequence and the pipeline unit length load, the deflection value of each pipe segment is calculated; the corresponding pre-provision height compensation curve is generated in the BIM model, and the pipeline installation scheme containing the support arrangement position and the pre-provision height is output.

[0010] Further, the pipeline installation space is constructed, comprising: determining the three-dimensional boundary range of the space to be processed based on the building boundary information in the BIM model data, setting the grid cell size parameter, dividing the space to be processed into a three-dimensional grid matrix; traversing each grid cell in the three-dimensional grid matrix, calculating the center point coordinates of each grid cell; converting the spatial coordinates and size parameters of the structural members into bounding box data, judging whether the center point of each grid cell is located in the bounding box of any structural member; according to the judgment result, the grid cells are marked, and the available space geometry is generated; based on the available space set, a three-dimensional connected domain is constructed to generate the data structure of the pipeline installation space.

[0011] In particular, the traditional pipe support and hanger design adopts a fixed spacing arrangement method, which essentially simplifies the complex constraint problem in three-dimensional space to a one-dimensional equidistant distribution problem. Although this simplification is convenient for engineering implementation, it ignores the irregular distribution characteristics of structural members in large space buildings. When encountering obstacles such as beams and columns, the actual support points are forced to deviate from the ideal position, resulting in an increase in the local pipe span and an out-of-limit deflection. In addition, the chain effect caused by this local adjustment can spread throughout the entire pipe system, causing serious unevenness in the deflection distribution.

[0012] The present application discretizes the continuous three-dimensional installation space into a regular grid matrix, fundamentally changing the technical path of support point selection.

[0013] Further, a state transition equation is constructed, including: calculating the pipe unit length load based on physical parameters, the pipe unit length load including the load component generated by the pipe self-weight and the load component generated by the medium weight; extracting a candidate support point position set from the pipe installation space; defining the state variables and state transition rules of dynamic programming; establishing the deflection distribution function between the support points based on the pipe unit length load and the structural mechanics model; constructing the state transition equation containing the deflection constraint and the spacing constraint; initializing the boundary conditions of the dynamic programming solving process;

[0014] In particular, the three-dimensional griding provides a complete solution space for the dynamic programming algorithm. In the traditional method, designers can only adjust the support points based on local information, lacking a global perspective. In the discretized grid space, the system can evaluate all possible paths from the starting point to the ending point of the pipe, and through the state transition equation, find the optimal combination of support points that satisfies the deflection constraint and optimizes the overall performance.

[0015] For example, when the pipe needs to bypass a structural column, the traditional method may simply move the support point forward or backward at that location, causing imbalance in the adjacent spans. The dynamic programming method based on grid space will comprehensively evaluate multiple available grid positions before and after the column and select the scheme that makes the deflection distribution of the multiple spans before and after the column most uniform.

[0016] Further, the deflection distribution function between the support points is established, including: defining the pipe segment between two adjacent support points as a calculation unit, and setting the support point spacing L as the independent variable; based on the total unit length load q of the pipe, the deflection curve equation under the action of gravity load is established where E is the elastic modulus, I is the cross-sectional moment of inertia, w is the deflection function, and x is the position coordinate along the pipe axis; the elastic modulus E and the thermal expansion coefficient a corresponding to the pipe material are extracted from the physical parameters, and the cross-sectional moment of inertia I of the pipe is calculated based on the pipe diameter DN and the wall thickness t According to the design temperature variation range of the pipe installation space, the axial thermal stress σ of the pipe is calculated T= E x alpha x Delta T, where Delta T = T max -T min where T max is the highest design temperature, T min is the lowest design temperature

[0017] Set simply supported boundary conditions w(0) = 0 and w(L) = 0, calculate the gravity deflection component w

[0018]

[0019] According to the axial expansion effect caused by temperature change, calculate the temperature deformation deflection component w

[0020]

[0021] According to the gravity deflection component w g (x) and the temperature deformation deflection component w T (x), calculate the deflection distribution function w(x) = w g (x) + w T (x); for the pipeline simply supported at both ends, temperature change mainly produces axial force, rather than direct deflection.

[0022] According to the deflection distribution function w(x) = w g (x) + w T (x), calculate the comprehensive maximum deflection w max under the action of gravity and temperature deformation; calculate the maximum deflection w of gravity and the maximum deflection w of temperature deformation at x = L / 2; get the comprehensive maximum deflection w max = w g,max + w T,max .

[0023] Build a multi-dimensional query table to support the interval L, pipeline specification parameters (DN, t), material type and temperature change amount Delta T as the index key, store the corresponding deflection distribution function coefficient and maximum deflection value, and generate the deflection calculation lookup table for state transition equation call.

[0024] In particular, in the design of pipeline system in large space building, the traditional method only considers the deflection caused by gravity load. The significant feature of large space building is that the environmental temperature fluctuates greatly and the pipeline span is long. The deformation caused by temperature effect is often in the same order of magnitude as the gravity deflection, and even becomes the dominant factor in some working conditions.

[0025] This application introduces the temperature deformation deflection component. Temperature changes not only cause axial expansion and contraction, but also convert into lateral deformation under constrained conditions, and this deformation has a completely different distribution pattern from the gravity deflection. Therefore, based on the buckling theory of compression bars caused by axial thermal stress, this application uses a sine function to describe the spatial distribution of temperature deformation.

[0026] Furthermore, a state transition equation including deflection constraints and spacing constraints is constructed, which includes: defining the state variable S[i], representing the optimal cumulative cost from the pipeline starting point to the corresponding support point when the i-th point in the candidate support point position set is used as the current support point, where i is the index of the candidate support point in the position set; initializing the candidate support point state S[0]=0 at the pipeline starting point, and initializing the states of all other candidate support points to infinity; for each candidate support point i, traverse all predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance from candidate point k to i does not exceed 1.5 times the maximum allowable support spacing L max ; according to the spatial coordinates of the k-th and i-th support points in the candidate support point position set, calculate the support spacing L = |x i - x k |; according to the support spacing L, retrieve the corresponding comprehensive maximum deflection w max from the deflection calculation lookup table; when L > L max , calculate the spacing overrun penalty term P = M×(L - L max ), where M is the penalty coefficient; when L ≤ L 2 , the penalty term P = 0; calculate the transition cost C(k,i) = w max + λ×P, where λ is the penalty weight coefficient; update the state value S[i] = min{S[i], S[k] + C(k,i)}, and when S[k] + C(k,i) < S[i], record the optimal predecessor path[i] = k at the same time; max Process all candidate support points in sequence until the pipeline end, and finally select the point with the minimum S value among the candidate support points in the pipeline end area as the optimal end support point; starting from the optimal end support point, trace back to the pipeline starting point through the path array to obtain the complete optimal support point sequence.

[0027]

[0028] ​In particular, in the pipeline support optimization problem, the traditional dynamic programming method uses a two-dimensional state variable f[i, j], where i represents the pipeline position and j represents the number of support points used. In order to solve the optimal support point number, the search range of the support point number must be specified in advance. This is like knowing the approximate range of the answer before solving the equation. In addition, this two-dimensional state space leads to a quadratic growth in algorithm complexity. For a 100-meter-long pipeline, if a range of 10-20 support points is considered, the number of states that need to be maintained and calculated exceeds 10,000. Each state also needs to traverse all possible predecessor states, resulting in an exponential explosion in calculation amount. In engineering practice, designers are often forced to narrow the search range or use empirical values, thereby missing the true optimal solution.

[0029] The present application defines a one-dimensional state variable S[i], which represents the optimal cumulative cost from the starting point to the i-th candidate point as a support point. The number of support points is converted from an explicit constraint to an implicit result. The algorithm no longer concerns how many support points are used, but focuses on how to achieve the minimum cumulative cost. The number of support points is no longer an input parameter, but a natural manifestation of the optimization result. When the algorithm evaluates the decision of whether to set a support point at each candidate position, it weighs the cost (construction complexity) and benefit (deflection improvement) of increasing the support point. Only when the benefit is greater than the cost will the support point be selected. For example, when the pipeline passes through a large-span space, the algorithm may automatically increase the support point density to control the deflection; while in the section with good stiffness, the support point is automatically reduced to reduce the construction cost. This adaptive feature cannot be achieved by a two-dimensional state space, because the latter must specify the number of support points for each section in advance.

[0030] Further, generating a globally optimal support and hanger arrangement sequence includes: determining an optimal end support point from the set of candidate support point positions; generating a support point index sequence through path backtracking based on the optimal end support point; extracting spatial position information according to the support point index sequence, calculating spatial relationship parameters of adjacent support points; obtaining deformation characteristic values of each pipe section according to the spatial relationship parameters and pipeline parameters; determining the support type according to the spatial position relationship of the support points; constructing a support and hanger arrangement data structure containing spatial position, support type, deformation characteristics and associated relationship, and outputting a globally optimal support and hanger arrangement sequence.

[0031] Another aspect of the present application also provides a BIM-based large space pipeline installation system, comprising: a data acquisition module, acquiring BIM model data of a large space building, the BIM model data comprising spatial coordinates and size parameters of structural members, and physical parameters of a pipeline to be installed; a space modeling module, performing three-dimensional gridding processing on the BIM model data to generate a gridded space model, and removing grid cells occupied by the structural members in the gridded space model to construct a pipeline installation space; a dynamic programming module, calculating a pipeline unit length load according to the pipeline self-weight and the weight of a medium in the pipeline, and performing optimal arrangement of supports and hangers in the pipeline installation space by using a dynamic programming method, and constructing a state transition equation according to the pipeline unit length load and a structural mechanics continuous beam model, wherein a transition cost function of the state transition equation comprises a maximum deflection value between adjacent support points and a maximum allowable support spacing constraint; a global optimization module, obtaining an optimal decision sequence by reverse recursion solving according to the state transition equation, and starting from a pipeline end to backtrack to a starting point, and selecting, at each decision stage, a support point position that minimizes the cumulative deflection of all subsequent pipe sections to generate a globally optimal support and hanger arrangement sequence; and an installation scheme module, calculating deflection values of the pipe sections according to the globally optimal support and hanger arrangement sequence and the pipeline unit length load, generating corresponding pre-provision height compensation curves in the BIM model, and outputting a pipeline installation scheme comprising support and hanger positions and pre-provision heights.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] The traditional method arranges supports and hangers in a fixed spacing or local adjustment manner, which is easy to fall into local optimization, resulting in uneven phenomena that some pipe sections have too large deflection and other pipe sections have too dense supports. The present application constructs a state transition equation to decompose the complex global optimization problem into a series of interrelated sub-problems, and uses optimal substructure characteristics to ensure that the support point position that minimizes the cumulative deflection of all subsequent pipe sections is selected at each decision stage. This reverse recursion solving process from the pipeline end to the starting point can fully consider the influence of each support point decision on the overall deflection distribution, and avoids the problem that the optimization space in the later period is limited by the decisions in the earlier period.

[0034] Meanwhile, the present application introduces a transition cost function comprising deflection constraints and spacing constraints, and simultaneously considers structural safety and economy in the optimization process. When the support spacing exceeds the allowable value, the introduction of the penalty term ensures the feasibility of the scheme; and the cost evaluation based on accurate deflection calculation ensures the reasonableness of the support point distribution. The deflection control problem in large space long distance pipeline installation is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be further described in the manner of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, the same numbers represent the same structures, in which:

[0036] Figure 1 is an exemplary flowchart of a BIM-based large space piping installation method according to some embodiments of the present application;

[0037] Figure 2 is an exemplary flowchart of constructing a multi-dimensional query table according to some embodiments of the present application;

[0038] Figure 3 is an exemplary flowchart of constructing a state transition equation according to some embodiments of the present application;

[0039] Figure 4 is an exemplary flowchart of calculating a cost function according to some embodiments of the present application;

[0040] Figure 5 is a schematic diagram of constraint processing logic according to some embodiments of the present application;

[0041] Figure 6 is a schematic diagram of generating a sequence of support hanger arrangements according to some embodiments of the present application. DETAILED DESCRIPTION

[0042] The method and system provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0043] As Figure 1As shown, the BIM model data of the large space building is acquired, and the BIM model data includes: spatial coordinates and size parameters of structural members, and physical parameters of the pipeline to be installed; wherein the structural members include: structural beams, columns and walls; the physical parameters include: pipeline material, pipe diameter, wall thickness and pipeline medium density; the BIM model data is subjected to three-dimensional grid processing to generate a grid space model, and the grid units occupied by the structural members are removed in the grid space model to construct a pipeline installation space; according to the pipeline self-weight and the pipeline medium weight in the physical parameters, the pipeline unit length load is calculated; in the pipeline installation space, a dynamic programming method is used for optimal arrangement of the support hanger; according to the pipeline unit length load and the structural mechanics continuous beam model, a state transition equation is constructed, and the transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint; according to the state transition equation, an optimal decision sequence is obtained by reverse recursion, and the pipeline is traced back from the end to the starting point, and at each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe sections is selected to generate a globally optimal support hanger arrangement sequence; according to the globally optimal support hanger arrangement sequence and the pipeline unit length load, the deflection value of each pipe section is calculated; the corresponding pre-provision height compensation curve is generated in the BIM model, and the pipeline installation scheme containing the support hanger position and the pre-provision height is output.

[0044] The BIM model data of the large space building is acquired, and the BIM model data includes: for the structural member data, the system extracts the geometric definition of each member, including: structural beams: starting point coordinates (x1, y1, z1), end point coordinates (x2, y2, z2), cross-sectional width b, cross-sectional height h; columns: bottom center coordinates (x c ,y c ,z c ), height H, cross-sectional size (a x b) or radius r; wall: reference line coordinate sequence [(x1, y1), (x2, y2),..., (x n ,y n )], wall bottom elevation z0, wall top elevation z1, thickness t.

[0045] The pipeline physical parameters are obtained by analyzing the MEP (mechanical and electrical pipeline) system data in the BIM model: pipeline path: center line coordinate sequence P = {p1, p2,..., p n}, wherein p i = (x i ,y i ,z i ); material properties: material code is mapped to a material database to obtain elastic modulus E (such as steel pipe E = 2.06 x 10 5 Mpa), density p (such as steel p = 7850 kg / m 3); geometric parameters: nominal diameter DN (e.g. DN300), wall thickness t (e.g. 10mm), medium density p f (e.g. water p f = 1000kg / m 3 ).

[0046] The BIM model data is processed by three-dimensional gridding to generate a gridded space model, and the grid cells occupied by the structural members are removed in the gridded space model to construct a pipeline installation space.

[0047] The gridding process uses a regular voxelization algorithm to discretize the continuous space into uniform grids:

[0048] Determine the space boundary: Xmin = min (x coordinates of all members and pipes) - safety margin; Xmax = max (x coordinates of all members and pipes) + safety margin; Ymin, Ymax, Zmin, Zmax are the same. Calculate the space size: L x = X max -X min , L y = Y max -Y min , L z = Z max -Z min .

[0049] Convert each structural member to an axis-aligned bounding box (AABB): bounding box of beam: consider the inclination of the beam and calculate the minimum circumscribed cuboid; bounding box of column: Bounding box of wall: calculated by wall contour and thickness. For each grid cell G[i,j,k], perform point-bounding box intersection test, and use three-dimensional flood fill algorithm to start from any available grid cell, analyze 26-neighbor connectivity, and construct a connected available space set. The complex three-dimensional space problem is converted into a discrete grid search problem, providing an efficient data foundation for subsequent dynamic programming optimization. Through gridding representation, collision detection, path search and space query can be quickly performed.

[0050] Extract the density value corresponding to the pipe material from the material database, for example, the density of carbon steel pipe is 7850kg / m 3 . Based on the geometric parameters of the pipe, calculate the cross-sectional area of the pipe A where the outer diameter D is determined by the nominal diameter DN, and the inner diameter d = D-2t. The unit length load generated by the self weight of the pipe is q p = p x A x g, where g is the acceleration of gravity 9.81m / s 2 .

[0051] For full pipe flow medium, its cross-sectional area is The unit length load generated by the medium weight is q f = p f x A f x g. The system automatically matches the density value according to the medium type, such as 1000 kg / m 3 for water, and needs to be determined according to the pressure and temperature table for steam.

[0052] The total unit length load of the pipeline q = q p + q f , which will be used as the basic input parameter for all subsequent mechanical calculations.

[0053] In the three-dimensional gridded pipeline installation space, the system performs spatial sampling along the centerline trajectory of the pipeline. A parametric curve interpolation method is used to represent the pipeline path as P(s), where s is the arc length parameter. The pipeline path is discretized with a fixed step size Δs (such as 0.5 m), and at each sampling point, the system checks the availability of the corresponding grid cell.

[0054] For each sampling point, the system not only checks the grid cell where the point is located, but also verifies whether there is enough installation space within a certain radius range around it. This ensures the actual installability of the support hanger. In this way, a set of candidate support point positions C = {c1, c2,..., c n} is generated, each containing three-dimensional coordinates and cumulative distance information along the pipeline.

[0055] The state variables of dynamic programming are defined, where the state includes the index position of the current support point in the candidate support point position set and the cumulative deflection value from the starting point of the pipeline to the current support point; to prevent excessive single-span deflection from causing deflection out of control.

[0056] According to the total unit length load q of the pipeline, the deflection distribution function of adjacent support points is calculated using the structural mechanics continuous beam model, including: defining the pipeline segment between the adjacent two support points as a calculation unit, and setting the support point spacing L as the independent variable;

[0057] Based on the total unit length load q of the pipeline, the deflection curve equation under the action of gravity load is established where E is the elastic modulus, I is the cross-sectional moment of inertia, w is the deflection function, and x is the position coordinate along the pipeline axis;

[0058] The elastic modulus E and the thermal expansion coefficient a corresponding to the pipeline material are extracted from the physical parameters, and the cross-sectional moment of inertia I of the pipeline is calculated based on the pipe diameter DN and the wall thickness t

[0059] According to the design temperature variation range of the pipeline installation space, the axial thermal stress σ T of the pipeline is calculated, where ΔT = T max - Tmax -T min , where T max is the maximum design temperature, and T min is the minimum design temperature;

[0060] Set the simply supported boundary conditions w(0) = 0 and w(L) = 0, and calculate the gravity deflection component; calculate the gravity deflection component: where w g (x) is the vertical downward deflection of the pipeline at position x caused by the gravity load, in mm; x is the axial position coordinate from the left support point, with a value range of 0≤x≤L, in mm; q is the total unit length load of the pipeline calculated, including the pipeline self weight and medium weight, in N / mm;

[0061] E is the elastic modulus of the pipeline material, determined by the material type: carbon steel pipe: E = 2.06 x 10 5 MPa; stainless steel pipe: E = 1.93 x 10 5 MPa; copper pipe: E = 1.1 x 10 5 MPa; I is the moment of inertia of the pipeline cross section, in mm 4 , where D is the outer diameter of the pipeline, d is the inner diameter of the pipeline, d = D - 2t, t is the wall thickness; L is the axial spacing between adjacent two support points, in mm;

[0062] According to the axial expansion effect caused by temperature change, calculate the temperature deformation deflection component; for a simply supported pipeline at both ends, temperature change mainly produces axial force, rather than direct deflection. where w T (x) is the transverse deflection of the pipeline at position x caused by temperature change, in mm; x is the axial position coordinate from the left support point, with a value range of 0≤x≤L, in mm;

[0063] N T is the axial force produced by temperature change, N T = A x E x a x D T, in N, where: A is the cross-sectional area of the pipeline, in mm 2 ; a is the linear expansion coefficient of the pipeline material, in 1 / ℃: carbon steel pipe: a = 11.7 x 10 -6 / ℃; stainless steel pipe: a = 16.0 x 10 -6 / ℃; copper pipe: a = 16.5 x 10 -6 / ℃; D T is the design temperature change, D T = T max -T min, unit: ℃; e0 is the initial geometric defect amplitude of the pipeline, e0 = L / 1000, indicating one-thousandth of the initial bending, unit: mm; E is the elastic modulus of the pipeline material, unit: MPa; I is the moment of inertia of the pipeline cross section, unit: mm 4 ; L is the axial spacing between two adjacent support points, unit: mm; The thermal stress of the long-distance pipeline may exceed the self-weight stress; The temperature deformation and the gravity deformation are superimposed, affecting the actual deflection.

[0064] According to the gravity deflection component w g (x) and the temperature deformation deflection component w T (x), the deflection distribution function w(x) = w g (x) + w T (x) is calculated;

[0065] The maximum deflection of gravity at x = L / 2 is calculated and the maximum deflection of temperature deformation is calculated

[0066] The comprehensive maximum deflection w max = w g,max + w T,max is obtained;

[0067] As shown in Figure 2 , a multi-dimensional query table is constructed to support the interval L, pipeline specification parameters (DN, t), material type and temperature change amount ΔT as index keys, and the corresponding deflection distribution function coefficients and maximum deflection values are stored to generate a deflection calculation lookup table for state transition equation calling, as shown in Table 1.

[0068] Table 1 Carbon steel pipe CS deflection query table, temperature change 30℃, medium: water, heating hot water system

[0069]

[0070]

[0071] As shown in Figure 3 , a state transition equation is constructed, including: defining a state variable S[i] representing the optimal cumulative cost from the starting point of the pipeline to the i-th point in the candidate support point position set as the current support point, where i is the index of the candidate support point in the position set, and the value range is 0≤i≤N-1, N is the total number of candidate support points; The candidate support point state of the starting point of the pipeline S[0] = 0 is initialized, and the states of all other candidate support points are initialized to infinity;

[0072] For each candidate support point i, traverse all predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance between candidate points k and i does not exceed 1.5×L max, L max is the maximum allowable support spacing, which is determined according to the pipe specification: when DN ≤ 100 mm, L max = 6 m; when 100 mm < DN ≤ 300 mm, L max = 8 m; when DN > 300 mm, L max = 10 m;

[0073] According to the spatial coordinates of the k-th and i-th support points in the set of candidate support point positions, calculate the support point spacing L = |x i - x k |, where x i and x k are the axial coordinates of the i-th and k-th candidate support points respectively; according to the support spacing L, retrieve the corresponding comprehensive maximum deflection w max from the deflection calculation lookup table; when L > L max , calculate the spacing overrun penalty term P = M × (L - L max ), where the penalty coefficient 2 ensures that the penalty term reaches the deflection magnitude when overrun by 10%; when L ≤ L max , the penalty term P = 0;

[0074] Figure 4 As shown, calculate the transfer cost C(k, i) from support point k to support point i = w max + λ × P, where the penalty weight coefficient λ = 1000 to ensure that the spacing constraint is preferentially satisfied; update the state value S[i] = min{S[i], S[k] + C(k, i)}, and when S[k] + C(k, i) < S[i], record the optimal predecessor path[i] = k at the same time; '

[0075] Process all candidate support points in sequence until the end of the pipe, and select the point with the minimum S value among the candidate support points within 0.5 m before and after the end as the optimal end support point; starting from the optimal end support point, trace back reversely through the path array to the starting point of the pipe to obtain the complete optimal support point sequence, and the number of support points in this sequence is automatically determined by the algorithm.

[0076] By simplifying the state definition from two-dimensional f[i][j] to one-dimensional S[i], the dependence on the number of support points j is eliminated, making the number of support points a natural result of the optimization solution, and truly achieving the global optimization of the support hanger layout. In the actual installation of large-space pipes, the optimal number of support points should be the result of the optimization solution rather than a preset parameter. Presetting the number of support hangers: It requires multiple attempts with different numbers of support points, resulting in low computational efficiency; it may miss the true global optimal solution.

[0077] As Figure 5As shown, according to the state transition equation, the optimal decision sequence is obtained by inverse recursion, starting from the end of the pipeline and backtracking to the starting point, at each decision stage, the support point position that minimizes the cumulative deflection of all subsequent pipe sections is selected, generating a globally optimal support arrangement sequence, including:

[0078] From the candidate support point position set, identify the candidate points in the end region of the pipeline, determine the end search range according to the pipe diameter DN: when DN≤200mm, the search range is 1.0m; when 200mm<DN≤500mm, the search range is 1.5m; when DN>500mm, the search range is 2.0m; select the candidate support point whose axial coordinate satisfies the condition xend-search range≤xi≤xend as the end candidate set, wherein xend is the coordinate of the end of the pipeline;

[0079] Select the candidate support point i with the smallest state value S[i] in the end candidate set opt Record its corresponding cumulative generation value S[i opt ] as the optimal end support point;

[0080] Start from the optimal end support point i opt , inverse backtracking through the path array, sequentially obtain path[i opt ], path[path[i opt ]] until backtracking to the starting point of the pipeline path[i]=0, forming an inverse sequence support point index chain;

[0081] Reverse the inverse sequence support point index chain to obtain the ordered support point index sequence [0,i1,i2,.....,i opt ] from the starting point to the end of the pipeline, the sequence length is the total number of support points N opt ;

[0082] According to the support point index sequence, extract the corresponding three-dimensional space coordinates (x, y, z) from the candidate support point position set to generate a three-dimensional position coordinate sequence of the support and hanger;

[0083] Calculate the three-dimensional spatial distance between adjacent support and hangers

[0084] Record each distance value and its ratio to the maximum allowed support spacing L max ;

[0085] For each pipe section, according to its support spacing L i and pipeline specification parameters (DN, t), retrieve the corresponding comprehensive maximum deflection w max value and deflection distribution function coefficient from the deflection calculation lookup table of claim 4;

[0086] Based on the retrieved deflection distribution function coefficients, the position of the deflection extreme point in each pipe segment is calculated and the actual deflection value at this position, including the gravity deflection component and the temperature deformation deflection component.

[0087] According to the z coordinate of each support point and the relative height difference with the adjacent support point, the support type is determined: when the z i coordinate is higher than the average height of the adjacent support points, it is marked as a hanger, otherwise it is marked as a support.

[0088] The support-hanger arrangement data structure is constructed, including: support point three-dimensional coordinate sequence, support type identification, adjacent spacing data, maximum deflection value of each pipe segment and its position, cumulative generation value S[i_opt], and the association index with the structural members in the original BIM model.

[0089] The globally optimal support-hanger arrangement sequence is output for the pre-provision height calculation in S5.

[0090] As Figure 6 shown, according to the globally optimal support-hanger arrangement sequence and the pipe unit length load, the deflection value of each pipe segment is calculated.

[0091] The corresponding pre-provision height compensation curve is generated in the BIM model, and the pipe installation scheme containing the support-hanger position and the pre-provision height is output, including:

[0092] The support point three-dimensional coordinate sequence, adjacent spacing data L i and the maximum deflection value of each pipe segment are extracted from the support-hanger arrangement data structure.

[0093] For each pipe segment in the support-hanger arrangement sequence, according to its support spacing L i , the deflection value of the sampling point is calculated at 1m intervals within the pipe segment according to the deflection distribution function:

[0094] Gravity deflection component:

[0095] Temperature deformation deflection component:

[0096] Comprehensive deflection value: w(x) = w g (x) + w T (x);

[0097] Where q is the total unit length load of the pipe calculated;

[0098] According to the comprehensive deflection value w(x) of each sampling point, the corresponding pre-provision height compensation value h(x) = -w(x) is calculated, and the pre-provision height compensation data sequence of the pipe axis is generated.

[0099] The pre-provision height compensation data sequence is subjected to spatial coordinate transformation with the support and hanger three-dimensional position coordinate sequence to generate a compensated pipeline installation axis coordinate sequence, wherein the z coordinate is adjusted as follows: z new (x) = z original (x) + h(x);

[0100] At each support and hanger position, the actual installation height of the support and hanger is calculated according to the pre-provision height compensation value and support type identification of the point:

[0101] For a hanger: installation height = structural beam bottom elevation - pre-provision height - hanger length

[0102] For a support: installation height = ground elevation + pre-provision height + support height

[0103] The compensated pipeline installation axis coordinate sequence is converted into spline curve data recognizable by the BIM model to generate a geometric expression of the pre-provision height compensation curve;

[0104] A new pipeline object is created in the original BIM model, the pre-provision height compensation curve is taken as the pipeline center line, and a three-dimensional pipeline entity is generated according to the pipe diameter and wall thickness parameters;

[0105] Support and hanger family instances are created at the support and hanger positions, the type attribute, spatial position and installation height parameters of the support and hanger are set, and the constraint relationship between the support and hanger and the pipeline entity is established;

[0106] A pipeline installation scheme data file is generated, containing: support and hanger number, three-dimensional coordinate, type identification, installation height, adjacent spacing, maximum deflection value of each pipe segment, pre-provision height compensation curve parameters, and spatial relationship with structural members;

[0107] The updated BIM model and pipeline installation scheme data file are output for construction and installation.

[0108] The above describes the present application and its embodiments in a schematic manner, which is not restrictive, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. The embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the spirit of the present application, similar structural forms and embodiments can be designed without creative design, which shall fall within the protection scope of the present application. In addition, the word "comprising" does not exclude other elements or steps, and the word "one" before an element does not exclude the inclusion of "multiple" elements. The words "first", "second" and the like are used to indicate names, and do not indicate any specific order.

Claims

1. A BIM-based large space pipe installation method, characterized by, The method comprises the following steps: acquiring BIM model data of a large-space building, the BIM model data comprising spatial coordinates and size parameters of structural members and physical parameters of a pipeline to be installed, wherein the structural members comprise structural beams, columns and walls, and the physical parameters comprise pipeline material, pipeline diameter, wall thickness and medium density in the pipeline; performing three-dimensional meshing processing on the BIM model data to generate a meshed space model, and removing grid cells occupied by the structural members in the meshed space model to construct a pipeline installation space; calculating a pipeline unit length load according to the pipeline self-weight and the medium weight in the pipeline in the physical parameters; optimizing arrangement of supports and hangers in the pipeline installation space by using a dynamic programming method; constructing a state transition equation according to the pipeline unit length load and a structural mechanics continuous beam model, wherein a transition cost function of the state transition equation comprises a maximum deflection value between adjacent support points and a maximum allowable support spacing constraint; obtaining an optimal decision sequence by reverse recursion according to the state transition equation, starting from a pipeline end to trace back to a starting point, and selecting, at each decision stage, a support point position that minimizes the cumulative deflection of all subsequent pipeline segments to generate a globally optimal support and hanger arrangement sequence; calculating deflection values of the pipeline segments according to the globally optimal support and hanger arrangement sequence and the pipeline unit length load; generating a corresponding pre-provision height compensation curve in the BIM model, and outputting a pipeline installation scheme comprising support and hanger positions and pre-provision heights.

2. The BIM-based large-space pipeline installation method according to claim 1, wherein the construction of the pipeline installation space comprises: determining a three-dimensional boundary range of a space to be processed based on building boundary information in the BIM model data, setting a grid cell size parameter, and dividing the space to be processed into a three-dimensional grid matrix; traversing each grid cell in the three-dimensional grid matrix to calculate a center point coordinate of each grid cell; converting the spatial coordinates and size parameters of the structural members into bounding box data, and judging whether the center point of each grid cell is located within a bounding box of any structural member; performing state marking on the grid cells according to the judgment result to generate available space geometry; constructing a three-dimensional connected domain based on the available space set to generate a data structure of the pipeline installation space.

3. The BIM-based large-space pipeline installation method according to claim 1, wherein the construction of the state transition equation comprises: calculating the pipeline unit length load based on the physical parameters, wherein the pipeline unit length load comprises a load component generated by the pipeline self-weight and a load component generated by the medium weight; extracting a candidate support point position set from the pipeline installation space; defining state variables and state transition rules of the dynamic programming; establishing a deflection distribution function between the support points based on the pipeline unit length load and the structural mechanics model; constructing the state transition equation comprising the deflection constraint and the spacing constraint; initializing boundary conditions of the dynamic programming solving process.

4. The BIM-based large-space pipeline installation method according to claim 3, wherein the establishment of the deflection distribution function between the support points comprises: defining a pipeline segment between two adjacent support points as a calculation unit, and setting a support point spacing L as an independent variable. ​ ​ ​ Based on the total unit length load q of the pipeline, the deflection curve equation under the action of gravity load is established Wherein, E is the elastic modulus, I is the section moment of inertia, w is the deflection function, and x is the position coordinate along the pipeline axis. The elastic modulus E and the thermal expansion coefficient a corresponding to the pipe material are extracted from the physical parameters, and the pipe section inertia moment is calculated based on the pipe diameter DN and the wall thickness t According to the design temperature variation range of the pipeline installation space, the axial thermal stress σ of the pipeline is calculated T = E x α x ΔT, wherein ΔT = T max -T min , T max is the highest design temperature, and T min is the lowest design temperature; Set simply supported boundary conditions w(0) = 0 and w(L) = 0, calculate the gravity deflection component; According to the axial expansion effect caused by temperature change, calculate the temperature deformation deflection component; According to the gravity deflection component w g (x) and the temperature deflection component w T (x), the deflection distribution function w(x) = w g (x) + w T (x) is calculated; According to the deflection distribution function w(x) = w g (x) + w T (x), the comprehensive maximum deflection w max under the action of gravity and temperature deformation is calculated. Build a multi-dimensional query table to support the interval L, pipe specification parameters (DN, t), material type and temperature change ΔT as the index key, store the corresponding deflection distribution function coefficient and maximum deflection value, and generate the deflection calculation lookup table for the state transition equation call.

5. The BIM-based large space pipe installation method of claim 4, wherein: Compute gravity deflection components:

6. The BIM-based large space pipe installation method of claim 4, wherein: Computing the temperature deformation deflection component:

7. The BIM-based large space pipe installation method of claim 4, wherein: According to the deflection distribution function w(x) = w g (x) + w T (x), the comprehensive maximum deflection w max under the action of gravity and temperature deformation is calculated, comprising: The maximum deflection of the action of gravity is calculated at x = L / 2 and the maximum deflection of the temperature deformation The overall maximum deflection w is obtained max = w g,max + w T,max .

8. The BIM-based large space pipe installation method of claim 4, wherein: Build a state transition equation containing deflection constraints and interval constraints, including: Define the state variable S[i] to represent the optimal cumulative cost from the pipe starting point to the corresponding support point when the i-th point in the candidate support point position set is taken as the current support point, where i is the index of the candidate support point in the position set; Initialize the candidate support point state S[0] of the pipe starting point to 0, and initialize the states of all other candidate support points to infinity; For each candidate support point i, iterate over all predecessor candidate support points k that satisfy the distance constraint, where k < i and the distance from candidate point k to i is not more than 1.5 times the maximum allowed support spacing L max . According to the spatial coordinates of the kth and ith support points in the candidate support point position set, the support point spacing L = |x i -x k | is calculated. From the support spacing L, the corresponding overall maximum deflection w is retrieved from the deflection calculation lookup table max ; When L>L max When calculating the spacing exceeding the limit, the penalty term P = M × (LL) is used. max ) 2 Where M is the penalty coefficient; when L≤L max At that time, the penalty term P = 0; The transfer cost C(k,i) from support point k to support point i is calculated as w max + λ x P, where λ is a penalty weight coefficient. Update the state value S[i] = min{S[i], S[k] + C(k, i)} when S[k] + C(k, i) < S[i], and record the optimal predecessor path[i] = k at the same time; Process all candidate support points in turn until the pipe end, and finally select the point with the smallest S value in the candidate support points at the pipe end region as the optimal end support point; From the optimal end support point, backtrack to the pipe starting point through the path array to obtain the complete optimal support point sequence.

9. The BIM-based large space pipe installation method of claim 8, wherein: Generate a globally optimal support and hanger arrangement sequence, including: Determine the optimal end support point from the candidate support point position set; Based on the optimal end support point, generate a support point index sequence by path backtracking; According to the spatial relationship parameters of the support points, calculate the deformation characteristic values of each pipe segment; Determine the support type according to the spatial position relationship of the support points; Build a support and hanger arrangement data structure containing spatial position, support type, deformation characteristics and associated relationship, and output the globally optimal support and hanger arrangement sequence. Including:

10. A BIM-based large space piping installation system, characterized by, A data acquisition module acquires BIM model data of a large space building, and the BIM model data includes spatial coordinates and size parameters of structural members, and physical parameters of a pipe to be installed; A space modeling module performs three-dimensional gridding processing on the BIM model data to generate a gridded space model, and removes grid cells occupied by structural members in the gridded space model to build a pipe installation space; ​ The dynamic programming module calculates the pipe unit length load according to the pipe self-weight and the medium weight in the pipe among the physical parameters, adopts the dynamic programming method to optimize the layout of the support hanger in the pipe installation space, and constructs a state transition equation according to the pipe unit length load and a continuous beam model of structural mechanics, wherein the transition cost function of the state transition equation includes the maximum deflection value between adjacent support points and the maximum allowable support spacing constraint. The global optimization module obtains an optimal decision sequence by solving the state transition equation through reverse recursion, starts from the pipe end and backtracks to the starting point, selects the support point position that minimizes the cumulative deflection of all subsequent pipe sections at each decision stage, and generates a globally optimal support hanger layout sequence. The installation scheme module calculates the deflection value of each pipe section according to the globally optimal support hanger layout sequence and the pipe unit length load, generates the corresponding pre-supply height compensation curve in the BIM model, and outputs the pipe installation scheme containing the support hanger position and the pre-supply height.

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