Mechanical construction temporary construction road automatic planning method and system based on three-dimensional GIS platform

Abstract

The application provides a kind of mechanized construction temporary construction road automatic planning method and system based on three-dimensional GIS platform, relating to construction road intelligent planning technical field.The method first obtains basic geographic data, sensitive area data and alignment parameter;Then the planning area is discretized, and a cost grid model is constructed based on factors such as terrain slope and curvature.In the path analysis stage, a heuristic graph search algorithm with segment path mask is used, and a discrete drivability check based on mechanical kinematics characteristics and a road sweep volume collision check are performed when the neighborhood is expanded, and the expansion edges that do not pass the check are pruned to generate a candidate path set.Finally, the candidate paths are optimized again through cross-section level earthwork quantity calculation and three-dimensional safety clearance check, and three-dimensional model rendering and simulation are performed.The application effectively solves the problems of low efficiency and lack of global optimality in traditional planning, and realizes accurate engineering quantity calculation and effective pre-control of construction risk.

Description

Technical Field

[0001] This invention relates to the field of intelligent planning technology for construction roads, and more specifically, to an automatic planning method and system for temporary construction roads in mechanized construction based on a 3D GIS platform. Background Technology

[0002] Temporary construction roads in mechanized construction are crucial channels connecting external transportation to the construction site in large-scale infrastructure projects, undertaking the transportation of large machinery and equipment such as crawler cranes, concrete pump trucks, and large transport vehicles, as well as construction materials. In complex terrain conditions such as mountainous and hilly areas, the planning quality of temporary construction roads directly affects construction efficiency, project costs, and construction safety. Traditional methods for planning temporary construction roads mainly rely on manual site surveys and two-dimensional drawing designs.

[0003] Traditional methods suffer from low planning efficiency. Designers need to conduct on-site surveys with surveying equipment, manually measuring parameters such as terrain elevation, slope, and obstacle distribution, and then drawing routes on two-dimensional topographic maps. This method cannot quickly process large areas of complex terrain data and fails to meet the rapid response requirements of modern engineering construction. Furthermore, manual route selection often only optimizes local routes within a small area, failing to comprehensively consider multiple factors such as terrain undulations, cut and fill volumes, and avoidance of sensitive areas on a macro scale. This frequently results in short route selections requiring extensive excavation and filling, or gentle routes with excessively long detours, making it difficult to achieve a scientific balance between the shortest path and minimum construction cost. In addition, large-scale mechanized construction has strict requirements for parameters such as longitudinal slope, cross slope, and turning radius. Traditional manual planning struggles to accurately calculate whether the road section slope meets the climbing capacity of machinery, leading to frequent situations where equipment cannot pass and rework is required during construction.

[0004] In terms of project cost and environmental compliance, traditional methods rely on empirical formulas to estimate earthwork excavation volumes, resulting in significant calculation errors. This leads to insufficient material preparation or waste during construction, making precise cost control difficult. With increasingly stringent protection requirements for sensitive areas such as ecological red lines, permanent basic farmland, and water source protection areas, manual planning, lacking precise spatial overlay analysis capabilities, can easily inadvertently encroach on sensitive areas, putting projects at risk of suspension for rectification or legal proceedings. Furthermore, traditional two-dimensional drawings cannot intuitively represent the three-dimensional layout of roads on real terrain. Construction workers struggle to understand the relationship between roads and the terrain, and the lack of three-dimensional dynamic simulation capabilities for construction machinery movement prevents the early detection of potential safety hazards.

[0005] In recent years, although 3D GIS technology and intelligent algorithms have been applied to engineering route selection, significant shortcomings remain in the automatic planning of temporary construction roads. Existing technologies lack automatic planning methods that comprehensively consider multiple objective factors such as machinery traffic parameters, cut and fill costs, and environmental constraints, and path search algorithms are not deeply coupled with 3D terrain analysis. More importantly, automatic route selection results are mostly single paths, lacking a secondary optimization and scheme comparison mechanism based on precise cut and fill calculations and 3D safety clearances across multiple geometrically feasible paths. Therefore, a technical solution is needed that can perform multi-objective constrained automatic planning, accurately calculate engineering quantities, and provide visual simulations within a 3D GIS environment. Summary of the Invention

[0006] The present invention aims to solve at least one of the aforementioned technical problems existing in the prior art.

[0007] Therefore, the first aspect of the present invention provides an automatic planning method for temporary construction roads in mechanized construction based on a three-dimensional GIS platform.

[0008] The second aspect of the present invention provides an automatic planning system for temporary construction roads in mechanized construction based on a three-dimensional GIS platform.

[0009] This invention provides an automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform, comprising: Acquire basic geographic data, sensitive area data, and route selection parameters for the planning area. The route selection parameters include at least the minimum turning radius of large machinery, the full width of the road design, and the safety clearance threshold. The planning area is discretized into a grid. Based on the terrain slope, curvature, undulation and the sensitive area data, the comprehensive passage cost value of each grid cell is calculated to construct a cost grid model. Based on the entry point and the end point, a heuristic graph search algorithm with introduced segment path mask is executed on the cost grid model. When expanding the neighboring nodes of the current node, the discrete drivability criterion is checked on the expanded edge based on the minimum turning radius, and a three-dimensional spatial collision check is performed on the road sweep body generated based on the full width of the road design. Expanded edges that fail the check are pruned, thereby generating a candidate path set containing multiple feasible paths. Each feasible path in the candidate path set is discretized, and the difference profile between the road surface design elevation and the natural ground at each station is calculated to obtain the earthwork volume. Based on the safety clearance threshold, a three-dimensional safety clearance check is performed on the continuous pile segment. The target construction temporary road path is determined according to the comparison results including earthwork volume and safety penalty. The target temporary construction road path is converted into a three-dimensional spatial line object, a three-dimensional road model is generated along the road centerline, and then fused and rendered in a three-dimensional GIS platform.

[0010] The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to the above-described technical solution of the present invention may also have the following additional technical features: In the above technical solution, the method for calculating the comprehensive toll cost value includes:

[0011] in, This represents the overall passage cost value of the grid cell (i,j). Variable weighting coefficients representing slope; Variable weighting coefficients representing curvature; The variable weighting coefficient represents the fluctuation degree; w_s represents the variable weighting coefficient for sensitive area avoidance. Represents the slope characteristic function; Represents the curvature characteristic function; Represents the variability characteristic function; Represents the sensitive area avoidance feature function; The slope characteristic function is expressed as:

[0012] in, This indicates a preset angle threshold; Indicates the maximum slope; Indicates slope; The curvature characteristic function is expressed as:

[0013] Among them, curvature The calculation is based on the directional change between adjacent grid cells, and the formula is as follows:

[0014] in, This represents the change in direction angle between two adjacent path segments; The grid cell side length; The undulation characteristic function is expressed as:

[0015] in, Indicates the degree of fluctuation;

[0016] in, This represents the maximum elevation value within a grid cell; This represents the minimum elevation within a grid cell; The sensitive region avoidance feature function is configured to assign infinite cost to the grid cells located within the sensitive region.

[0017] In the above technical solution, the heuristic graph search algorithm that introduces segment path masks includes: Based on the mask order, candidate endpoint grid points are determined in the neighborhood of the central grid point. The connectivity between the two points is normalized as a set of line segments pointing from the local origin to integer offsets, wherein the integer offsets are within the range determined by the mask order and are coprime, so as to increase the number of optional discrete directions in the search process and weaken the direction quantization effect.

[0018] In the above technical solution, the evaluation function of the heuristic graph search algorithm is expressed as:

[0019] in, This represents the estimated total cost to reach the target point from the starting point through node n; This represents the actual cost from the starting point to node n; This represents the estimated cost from node n to the target node; The method for calculating the estimated cost includes:

[0020] in, Represents the minimum possible cost per unit distance; This represents the Euclidean distance from node n to the endpoint goal.

[0021] In the above technical solution, the actual cost The calculation process includes: The instantaneous cost function for a path of unit length is defined as follows:

[0022] Where C represents the cost per unit length, i.e., the instantaneous cost function; This represents the variable weighting coefficient for instantaneous slope; Indicates the instantaneous curvature variable weighting coefficient; Indicates the variable weight coefficients for connectivity; This represents the variable weight coefficient of the avoidance constraint; This represents the instantaneous slope characteristic function; Represents the instantaneous curvature characteristic function; Represents the connectivity characteristic function; Represents the characteristic function of the avoidance constraint; The cost of moving between adjacent nodes i and j is calculated as follows:

[0023] in, This represents the cost of movement between adjacent nodes; This represents the distance from node i to node j, for horizontal or vertical movement. For diagonal movement L represents the side length of the grid cell; The movement cost is accumulated along the path to obtain the actual cost from the starting point to node n, expressed as:

[0024] Where C_{k-1,k} represents the movement cost between two adjacent nodes on the path; k is the node number index.

[0025] In the above technical solution, the formula for calculating the instantaneous slope characteristic function is:

[0026] in, This represents the slope angle between two points, and , d represents the elevation difference between two points; d represents the horizontal distance between two points. The formula for calculating the instantaneous curvature characteristic function is:

[0027] in, Indicates the change in direction angle between two adjacent path segments; The connectivity feature function The value is 0 when the node is located on an existing road, and 1 when the node is located in a non-road area; The avoidance constraint characteristic function The value is positive infinity when the node is inside the sensitive area, and 0 when the node is outside the sensitive area.

[0028] In the above technical solution, the discrete drivability criterion verification includes: Obtain the vertex sequence of the polyline composed of adjacent nodes at the end of the path, and calculate the equivalent turning radius at the current extended node using the three-point circle method. If the equivalent turning radius is less than the minimum turning radius, the extended edge is pruned directly.

[0029] In the above technical solution, the three-dimensional spatial collision verification includes: Using the current extended edge as the tangent, offset the road area polygon strip in the horizontal plane according to the full width of the road design, and intersect the polygon strip with the terrain along the elevation direction to generate the road sweep body; The Boolean intersection test is performed between the road sweep body and the three-dimensional envelope of the sensitive area and the existing structure buffer body. If the volume intersection is not empty, the extended edge is determined to be invalid.

[0030] In the above technical solution, determining the target temporary construction road route based on the comparison results including earthwork volume and safety penalties includes: Configure longitudinal slope design lines and standard cross sections for each feasible path, obtain the difference between the design elevation and the natural ground at each station, and obtain the total excavation and total fill volumes for each feasible path through numerical integration. A three-dimensional buffer envelope is generated by combining the road centerline with the width and slope opening. The minimum clearance between the buffer envelope and the tower crane slewing envelope, the edge of the foundation pit and the overhead line corridor is calculated. If the minimum clearance is less than the safe clearance threshold, a safety penalty is applied. Based on the total excavation volume, total filling volume, and safety penalty items, a comprehensive evaluation index is constructed to compare and select the target temporary construction road path from the candidate path set.

[0031] This invention provides an automatic planning system for temporary construction roads in mechanized construction based on a 3D GIS platform, applicable to the method described in any of the above technical solutions. The system includes: The data input module is used to acquire basic geographic data, sensitive area data, and route selection parameters for the planning area. The cost map building module is used to build a cost raster model and calculate the comprehensive passage cost value of the raster cells; The path search module is used to execute a heuristic graph search algorithm that introduces segment path masks, and to perform discrete drivability criterion verification and road sweep collision verification during neighborhood expansion to generate a candidate path set. The secondary optimization module is used to perform cross-sectional-level earthwork volume calculation and three-dimensional safety clearance verification on the candidate path set to determine the target temporary construction road path. The 3D rendering module is used to generate 3D road models and integrate them with the GIS scene for display.

[0032] In summary, due to the adoption of the above-mentioned technical features, the beneficial effects of the present invention are: The beneficial effects of this invention are primarily reflected in the significant improvement in planning efficiency and the global optimality of the solution. Through an automated path planning method based on a 3D GIS platform, the system can complete the optimal path search in a very short time for large areas of complex terrain, greatly reducing the time required for reconnaissance and delineation in traditional manual route selection, thus achieving a leapfrog improvement in planning efficiency. Simultaneously, this invention employs a multi-objective constrained optimization algorithm, comprehensively considering multiple factors such as terrain slope, cut and fill costs, path length, and avoidance of sensitive areas. It can automatically find the globally optimal solution with the lowest overall cost, effectively avoiding the drawbacks of manual route selection easily getting trapped in local optimization, and achieving coordinated optimization of path length and earthwork volume.

[0033] In terms of construction constraint satisfaction and safety pre-control, this invention has strong engineering practicality. The system has a built-in database of large machinery and equipment access parameters, which can automatically and meticulously check the slope, curvature, and width of the planned path segment by segment. This ensures that the planned scheme fully meets the climbing and turning requirements of heavy machinery such as crawler cranes and large transport vehicles, eliminating rework caused by insufficient access conditions from the design stage. In addition, through three-dimensional dynamic simulation technology, the system can simulate the entire process of construction machinery traveling along the planned road, pre-identifying potential safety risks such as blind spots at turns, slope instability hazards, and insufficient sight distance, achieving automatic verification of the safety factor and effective risk pre-control.

[0034] In terms of accuracy in engineering quantity calculations and environmental compliance assurance, this invention provides precise data support. Utilizing a high-precision digital elevation model, the system can automatically and accurately calculate the fill and cut volumes for each road segment, providing a reliable basis for engineering cost control and material procurement. Simultaneously, by automatically loading layers of sensitive areas such as ecological red lines, permanent basic farmland, and water source protection areas, and enforcing avoidance rules or high-cost penalty mechanisms during path search, the system can effectively prevent environmental violations and ensure that the planning scheme meets stringent compliance requirements. The generated planning results are presented as a 3D model, supporting browsing and cross-sectional analysis from any perspective, and can automatically output layout data such as road centerlines, edge lines, and fill / cut boundaries, significantly improving the accuracy of on-site construction positioning.

[0035] Finally, this invention innovatively constructs a multi-scheme comparison and multi-dimensional optimization mechanism. By generating multiple geometrically feasible candidate paths in the first stage and introducing cross-sectional-level fill and cut calculations and three-dimensional safety clearance verification in the second stage, the system can output a recommended set of schemes ranked by multi-dimensional indicators. This two-layer cost system, combining proxy guidance and actuarial correction, avoids the limitations of single-pathfinding results in terms of earthwork economy or lateral safety margin, enabling project managers to make a more scientific and balanced technical trade-off between construction period, cost, and safety risks.

[0036] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating an embodiment of the automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the road path analysis results of an embodiment of the automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the road path avoidance analysis results of an automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a three-dimensional simulation of a road path in an embodiment of the automatic planning method for temporary construction roads in mechanized construction based on a three-dimensional GIS platform according to an embodiment of the present invention. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0040] The following reference Figures 1 to 4 This invention describes an automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform, according to some embodiments of the present invention.

[0041] Some embodiments of this application provide an automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform.

[0042] like Figure 1 As shown, the first embodiment of the present invention proposes an automatic planning method for temporary construction roads in mechanized construction based on a three-dimensional GIS platform, including the following steps S1 to S5.

[0043] S1. Obtain basic geographic data, sensitive area data, and route selection parameters for the planning area. The route selection parameters include at least the minimum turning radius of large machinery, the full width of the road design, and the safety clearance threshold.

[0044] Step S1 is the basic geographic data input and parameter configuration stage. First, the system acquires and inputs basic geographic data and sensitive area data within the planning area to construct a 3D GIS planning basic data platform. The basic geographic data includes, but is not limited to, high-precision digital elevation models (DEMs), digital orthophotos (DOMs), existing road network data, and data on the land area occupied by tower foundations or construction work areas. Sensitive area data covers legally protected layers such as ecological red line data, permanent basic farmland data, water source protection area data, and public welfare forest data. Simultaneously, data such as vegetation cover type and current land use status are input to provide a spatial benchmark for subsequent mandatory avoidance and cost calculation.

[0045] Building upon this foundation, the system further configures a set of parameters to guide automated route selection. These parameters include boundary constraints, specifically curvature factor, connectivity factor, slope factor, and the number of grid cells used to balance computational accuracy and efficiency. Specifically, the slope factor weighs the impact of changes in longitudinal slope on traffic capacity; the curvature factor controls the smoothness of the path and the curvature changes at turns; the connectivity factor controls the tightness of the connection between the planned path and the existing road network; and the number of grid cells controls the resolution of the rasterized discretization of the planning area, balancing computational accuracy and efficiency. Simultaneously, the system sets angle thresholds to limit the directional change angle between adjacent path segments and sets a maximum slope to constrain the upper limit of the road's longitudinal slope, thereby ensuring the safety of large machinery climbing slopes. These parameters collectively constitute a multi-objective constraint set, providing a basis for automatic road route selection.

[0046] Furthermore, to enable the configuration of geometric hard thresholds and economic safety objectives in different zones, this embodiment requires further input of refined parameters related to the mobility of large machinery and engineering construction standards. These parameters include the minimum turning radius R_min of the main machinery, its outer envelope dimensions, and the full design width W of the road, where the full design width W can include widened passing lanes according to stationing rules. Simultaneously, the system configures standard cross-section and slope parameters and sets a three-dimensional safety clearance threshold d_safe between the tower crane's slewing trajectory, the edge of the foundation pit, and overhead lines. For the subsequent second-stage fine calculation, the system also requires input of the spatial locations of spoil heaps and borrowing points for weighted earthwork transport distance, and presets an upper bound K for the number of candidate paths output from the first-stage search and a second-stage fine calculation station spacing Δs, ensuring that the planning scheme closely approximates the traffic and economic requirements of the actual construction scenario.

[0047] After completing the basic geographic data input and parameter configuration, the system enters the interactive setting stage for the avoidance zone and the start and end points of the route. Based on the input basic geographic data and the set road boundary conditions, the system automatically extracts the initial avoidance zone range through multi-criteria discrimination. To further improve the environmental compliance and human intervention capability of the planning scheme, this embodiment supports loading high-precision digital orthophotos into the 3D GIS scene. When the user starts setting the avoidance function, they can select points in the 3D scene with the mouse. The system picks up the intersection point of the ray emitted from the mouse click location and the high-precision terrain model in real time and records the latitude and longitude coordinates of the intersection point. After the user double-clicks to end the selection, the system automatically closes the set of picked latitude and longitude points to generate the avoidance zone range surface data. This interactive delineation method allows users to make precise supplements or corrections based on the automatic extraction according to the actual construction environment or temporary environmental protection requirements.

[0048] After identifying the avoidance area, the system further selects and locates the starting and ending points of the main road. Since temporary construction roads typically need to connect existing main traffic arteries with the target work area, in this embodiment, the system automatically calculates and recommends multiple candidate entry points using the loaded existing road network data and the area occupied by the tower foundation. Users can click the "Main Road Starting Point" button on the interactive interface to directly select the optimal starting point using ray picking technology on the 3D terrain model; the system simultaneously records the latitude, longitude, and elevation information of that point. Similarly, users can click the "Set End Point" button for the construction work area location to complete the endpoint location through 3D scene picking. Through this starting and ending point setting method based on 3D GIS picking technology, the system not only achieves accurate spatial positioning for path planning but also ensures that subsequent path analysis algorithms can accurately calculate slope and workload based on the actual terrain height differences.

[0049] S2. Discretize the planning area into a grid, and calculate the comprehensive passage cost value of each grid cell based on the terrain slope, curvature, undulation and the sensitive area data, and construct a cost grid model.

[0050] Specifically, step S2 is the construction phase of the cost grid model. In some embodiments, step S2 includes: First, the system discretizes the planning area into a regular grid. Let the side length of each grid cell be L, and the number of grid cells in the X and Y directions be M and N respectively. Then, the spatial region corresponding to each grid cell (i,j) is [x_i, x_i+L] × [y_j, y_j+L]. Based on the high-precision digital elevation model input in step S1, terrain feature parameters, including terrain slope, are extracted for each grid cell. Slope aspect The fluctuation degree R(i,j) is used as the basic input variable of the cost function.

[0051] Among them, terrain slope The calculation formula is:

[0052] in, This represents the rate of elevation change of the grid cell in the x-direction; This represents the elevation change rate of the grid cells in the y-direction; specifically, this elevation change rate can be approximated using the finite difference method:

[0053]

[0054] It is understandable that i+1 and i-1 are used here to represent adjacent grid cells in the x-direction; and j+1 and j-1 are used to represent adjacent grid cells in the y-direction.

[0055] Slope The calculation method is as follows:

[0056] undulation The calculation formula is:

[0057] in, This represents the maximum elevation value within a grid cell; This represents the minimum elevation within a grid cell.

[0058] After the feature parameters are extracted, the system combines the sensitive area data and line selection parameters to calculate the comprehensive passage cost value Cost(i,j) for each grid cell. The calculation method for the comprehensive passage cost value includes:

[0059] in, This represents the overall passage cost value of the grid cell (i,j). Variable weighting coefficients representing slope; Variable weighting coefficients representing curvature; The variable weighting coefficient represents the fluctuation degree; w_s represents the variable weighting coefficient for sensitive area avoidance. Represents the slope characteristic function; Represents the curvature characteristic function; Represents the variability characteristic function; This represents the sensitive area avoidance characteristic function; through this variable weight mechanism, the system assigns quantitative indicators reflecting terrain, construction difficulty and environmental constraints to each grid cell, thus constructing a basic planning map in a three-dimensional GIS environment.

[0060] In order to finely control the influence of each factor, the calculation logic of each characteristic function is defined in some embodiments.

[0061] The slope characteristic function is expressed as:

[0062] in, This indicates a preset angle threshold; Indicates the maximum slope; Indicates slope; The curvature characteristic function is expressed as:

[0063] Among them, curvature The calculation is based on the directional change between adjacent grid cells, and the formula is as follows:

[0064] in, This represents the change in direction angle between two adjacent path segments; This is the side length of the grid cell; this parameter guides the algorithm to prioritize areas with gentle terrain.

[0065] The undulation characteristic function is expressed as:

[0066] in, It indicates the degree of undulation; it reflects how fragmented the terrain hinders passage.

[0067]

[0068] in, This represents the maximum elevation value within a grid cell; This represents the minimum elevation within a grid cell; The sensitive area avoidance feature function is configured to assign an infinite cost to the grid cells located in the sensitive area, thereby achieving forced avoidance at the algorithm level.

[0069] S3. Based on the entry point and the end point, execute a heuristic graph search algorithm that introduces a segment path mask on the cost grid model. When expanding the neighboring nodes of the current node, perform discrete drivability criterion verification on the expanded edge based on the minimum turning radius, and perform three-dimensional spatial collision verification based on the full width of the road design to generate a road sweep body. Prune the expanded edges that fail the verification, thereby generating a candidate path set containing multiple feasible paths.

[0070] In some embodiments, the heuristic graph search algorithm that introduces segment path masks includes: Based on the mask order, candidate endpoint grid points are determined in the neighborhood of the central grid point. The connectivity between the two points is normalized as a set of line segments pointing from the local origin to integer offsets, wherein the integer offsets are within the range determined by the mask order and are coprime, so as to increase the number of optional discrete directions in the search process and weaken the direction quantization effect.

[0071] Specifically, based on the entry and exit points determined in step S1, the system executes a heuristic graph search algorithm that introduces segment path masks on the cost grid model constructed in step S2. The evaluation function of this algorithm is:

[0072] in, This represents the estimated total cost to reach the target point from the starting point through node n; This represents the actual cost from the starting point to node n; This represents the estimated cost from node n to the target node; The method for calculating the estimated cost includes:

[0073] in, Represents the minimum possible cost per unit distance; This represents the Euclidean distance from node n to the endpoint goal, calculated as follows:

[0074] in, Let n be the coordinates of node n; The coordinates of the endpoint goal.

[0075] To overcome the common orientation constraints in regular grids during the search process, the system introduces segment path masks to extend implicit adjacency relationships. Based on the mask order k, the system determines a set M_k(p_ij) of candidate endpoint grid points within the r-neighborhood of the central grid point p_ij, standardizing the connectivity between the central grid point and the candidate endpoint grid points as a set of line segments pointing from the local origin to integer offsets. In this set, integer offsets must satisfy coprime relations to increase the number of selectable discrete directions and mitigate orientation quantization effects. Simultaneously, the system elevates the search state from two-dimensional grid points to an orientation state with discrete heading indices, uniformly discretizing the heading angle interval into m parts. This gives the state space both position and orientation information, enabling compatible transitions with heading changes during the path generation stage through extended mask constraints.

[0076] At each expansion step of the neighborhood expansion, the system defines the instantaneous cost function per unit (meter) of path as:

[0077] Where C represents the cost per unit length, i.e., the instantaneous cost function; This represents the variable weighting coefficient for instantaneous slope; Indicates the instantaneous curvature variable weighting coefficient; Indicates the variable weight coefficients for connectivity; This represents the variable weight coefficient of the avoidance constraint; This represents the instantaneous slope characteristic function; Represents the instantaneous curvature characteristic function; Represents the connectivity characteristic function; This represents the characteristic function of the avoidance constraint.

[0078] In one specific embodiment, the formula for calculating the instantaneous slope characteristic function is:

[0079] in, This represents the slope angle between two points, and , d represents the elevation difference between two points; d represents the horizontal distance between two points. The formula for calculating the instantaneous curvature characteristic function is:

[0080] in, Indicates the change in direction angle between two adjacent path segments; The connectivity feature function The value is 0 when the node is located on an existing road, and 1 when the node is located in a non-road area; The avoidance constraint characteristic function The value is positive infinity when the node is inside the sensitive area, and 0 when the node is outside the sensitive area.

[0081] The cost of moving between adjacent nodes i and j is calculated as follows:

[0082] in, This represents the cost of movement between adjacent nodes; This represents the distance from node i to node j, for horizontal or vertical movement. For diagonal movement L represents the side length of the grid cell; The movement cost is accumulated along the path to obtain the actual cost from the starting point to node n, expressed as:

[0083] Where C_{k-1,k} represents the movement cost between two adjacent nodes on the path; k is the node number index.

[0084] While calculating costs, the system performs hard geometric feasibility checks on each edge to be expanded. First, based on the discrete drivability criterion of minimum turning radius, the system obtains a sequence of polyline vertices composed of adjacent nodes at the end of the path, and uses the three-point circle method to calculate the equivalent arc radius R_eq at the current expansion node. If R_eq is less than the minimum turning radius R_min set in step S1, the expansion edge is directly pruned. Second, based on the sweep volume check of road width and lateral land occupation, the system generates a road occupation polygon strip with the current expansion edge as the tangent, according to the full road design width W, and intersects it with the terrain model along the elevation direction to generate a road sweep volume. This sweep volume is then subjected to Boolean intersection checks with the sensitive area's 3D envelope and existing structure buffers. If the volume intersection is not empty, the expansion edge is deemed invalid and pruned.

[0085] In some embodiments, the system performs a cyclical search by maintaining an open list (OpenList) and a closed list (ClosedList) until the target node is found. To obtain a better basis for scheme comparison, after obtaining the cost-optimal path, the system uses a Yen-style k-shortest-circuit algorithm or a mechanism that retains non-repeating paths whose total cost falls within a set interval to obtain a candidate path set Ω={P_1,…,P_K} containing K feasible paths. These paths, while satisfying the upper limit of slope, turning radius, and full-width road space collision constraints, achieve preliminary optimization of terrain conditions and environmental constraints, providing a high-dimensional feasible solution set for subsequent cross-section-level engineering quantity comparison. Figure 2 As shown, the system presents the road planning path generated by the heuristic graph search algorithm in real time within a 3D GIS scene. Starting from the entry point, this path avoids areas with drastic terrain undulations, extending along the corridor with the lowest overall travel cost to the entry point. Its 3D spatial morphology closely matches the surface undulations presented by the digital elevation model, intuitively demonstrating the algorithm's trade-off between global optimality and construction feasibility. Figure 3 As shown, the generated road paths exhibit precise avoidance characteristics when passing through preset sensitive areas or artificially designated avoidance zones. By using avoidance constraints as hard pruning conditions in the graph search process, the system ensures that the entire road surface sweep does not encroach on restricted three-dimensional space, achieving automatic and mandatory avoidance of sensitive areas such as ecological red lines and permanent basic farmland, thus ensuring the environmental compliance of the planning scheme.

[0086] S4. Discretize each feasible path in the candidate path set, calculate the difference profile between the road surface design elevation and the natural ground at each station to obtain the earthwork volume, and perform three-dimensional safety clearance verification on continuous pile segments based on the safety clearance threshold. Determine the target construction temporary road path based on the comparison results including earthwork volume and safety penalty.

[0087] Specifically, step S4 is the secondary optimization and comparison stage focusing on earthwork volume and three-dimensional safety clearance. The system performs cross-sectional volume calculation and three-dimensional safety distance hard verification on the candidate path set generated in step S3, and determines the final target temporary construction road path through a two-layer cost system of "proxy guidance - calculation correction".

[0088] In some embodiments, the system first discretizes each feasible path in the candidate path set according to a station interval Δs. During this process, the system performs actuarial correction logic for the surrogate term, i.e., for the low-dimensional surrogate term introduced in the first-stage graph search to guide the path towards the earthwork equilibrium region. Perform numerical updates, where This represents a rough estimate based on the difference between the design reference elevation and the ground elevation. By introducing precise calculations based on the actual longitudinal slope design line and cross-section in the second stage, the computational bloat caused by directly embedding complex volume calculations into the search step is avoided.

[0089] For the discretized path, the system configures the longitudinal slope design line and standard cross-section according to the temporary road design standards. The standard cross-section includes the road crown, slope gradient, and drainage ditch location. At each station, the system obtains the difference profile between the design elevation and the natural ground level, divides the soil within the road width into strips or prisms, and performs numerical integration to obtain the total excavation volume V_C,k and total fill volume V_F,k of the candidate path. Further, the system incorporates a weighted average of the haulage distance to the spoil disposal site or borrow site to construct the economic item J_E,k of the engineering quantity. Where: Δs represents the secondary precise calculation station spacing; V_C,k represents the total excavation volume of the k-th candidate path; V_F,k represents the total fill volume of the k-th candidate path; J_E,k represents the comprehensive economic item of the engineering quantity.

[0090] While conducting economic evaluation, the system generates a three-dimensional buffer envelope by combining the road centerline with the width W and the slope opening, and performs three-dimensional verification of the safety distance. The system geometrically intersects this three-dimensional buffer envelope with external interference objects such as the tower crane slewing envelope, the edge of the foundation pit, the wedge of the unstable slope, and the overhead line corridor, and calculates the minimum clearance d_min. If the minimum clearance d_min of a continuous pile segment is detected to be less than the safety clearance threshold d_safe set in step S1, the path is marked as unsafe and infeasible, or a safety penalty P_safe,k is applied proportionally based on the excess length. In addition, the system geometrically identifies insufficient sight distance or blind spots in turning by calculating the spatial position of the sight distance triangle and the obstruction on the curve segment, and uses this as an additional penalty. Here, d_min represents the minimum geometric distance between the road surface sweep body and the external object; P_safe,k represents the safety penalty for the k-th candidate path.

[0091] Finally, the system constructs a comprehensive evaluation index J_total,k to rank and compare all candidate paths. The formula for calculating the comprehensive evaluation index is:

[0092] in: This represents the overall evaluation value of the k-th path; , , , L represents the weighting coefficient of each evaluation indicator; L_k represents the horizontal projection length of the path. This represents the smoothness penalty reflecting the rate of curvature change. In practice, the system employs a hierarchical lexicographical optimization method that combines safety hard constraints with the main objective of engineering quantity. It outputs the sorted Top-N schemes and detailed indicators including length, cut and fill volume, maximum longitudinal slope, critical turning radius margin, and minimum safety clearance along the entire line, for manual selection of the target temporary construction road path.

[0093] S5. Convert the target temporary construction road path into a three-dimensional spatial line object, generate a three-dimensional road model along the road centerline, and perform fusion rendering on a three-dimensional GIS platform.

[0094] Step S5 is the 3D model loading, rendering, and construction simulation stage. Specifically, in step S5, the target temporary construction road path determined in step S4 is converted into a 3D spatial line object, and the simulation effect is as follows: Figure 4 As shown, the final generated 3D road model includes a road surface with actual width and cross-sectional parameters, as well as slopes automatically laid out according to the terrain gradient. After being loaded into a 3D GIS scene, this model is deeply integrated with high-precision orthophotos and terrain models. Users can clearly observe the cut and fill morphology of the road in complex mountainous environments, as well as the 3D spatial clearance relationship between the road and surrounding obstacles and existing roads, through interactive functions such as view rotation and zoom. This provides a highly intuitive visual reference for subsequent construction safety pre-control.

[0095] In this process, based on the digital elevation model input in step S1, an elevation value is assigned to each discrete sampling point on the path, thereby forming a three-dimensional road centerline that conforms to the actual terrain features. Subsequently, the system automatically generates a three-dimensional road model along the three-dimensional road centerline. This model is constructed using cross-section layout technology and specifically includes the pavement and slope sections. To ensure the accuracy of construction guidance, the system automatically extracts and outputs construction layout data based on the three-dimensional road model. This construction layout data includes the coordinates of the road centerline, the road edge lines, and the cut-fill boundary lines, thereby assisting on-site personnel in accurate positioning and layout, reducing construction errors.

[0096] The completed 3D road model is then loaded into a 3D GIS scene and integrated with basic geographic data such as the digital elevation model, digital orthophoto, existing road network, and sensitive area layers obtained in step S1. The system assigns realistic material textures to the 3D road model to enhance visualization and provides interactive browsing functions such as view rotation, zoom, and panning, allowing users to view the spatial topological relationship between the temporary road and the surrounding complex terrain and construction work surface from any spatial angle. Furthermore, this embodiment also supports cross-sectional analysis based on the generated 3D road model, intuitively displaying the cut and fill structure of the road at different terrain sections.

[0097] In some embodiments, to further control construction risks, this embodiment introduces a dynamic simulation mechanism in a three-dimensional scene. The system loads a model of the main machinery and simulates its entire passage along the planned three-dimensional road centerline in three-dimensional dynamic simulation, thereby identifying potential safety issues such as blind spots at turns, slope instability hazards, or insufficient sight distance in advance. During the simulation, the system simultaneously performs automatic verification of the safety factor to ensure that the geometric alignment and structural strength of the temporary road meet the actual usage requirements of large machinery. By transforming the static planned path into a three-dimensional engineering model with multi-dimensional attributes, this invention achieves an integrated closed loop from automated route selection to high-precision construction layout and dynamic safety simulation, significantly improving the scientific rigor and safety of temporary construction road planning.

[0098] Other embodiments of the present invention provide an automatic planning system for temporary construction roads in mechanized construction based on a 3D GIS platform, which is applied to the method described in any of the above embodiments. The system includes: a data input module, a cost map construction module, a path search module, a secondary optimization module, and a 3D rendering module.

[0099] The data input module is used to acquire basic geographic data, sensitive area data, and route selection parameters for the planning area; the cost map construction module is used to construct a cost raster model and calculate the comprehensive toll cost value of the raster cells; the path search module is used to execute a heuristic graph search algorithm that introduces a segment path mask, and performs discrete drivability criterion verification and road sweep collision verification during neighborhood expansion to generate a candidate path set; the secondary optimization module is used to perform cross-sectional earthwork volume calculation and three-dimensional safety clearance verification on the candidate path set to determine the target temporary construction road path; the three-dimensional rendering module is used to generate a three-dimensional road model and integrate it with the GIS scene for display.

[0100] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention shall be included within the scope of protection of this invention.

Claims

1. A method for automatically planning temporary construction roads for mechanized construction based on a 3D GIS platform, characterized in that, include: Acquire basic geographic data, sensitive area data, and route selection parameters for the planning area. The route selection parameters include at least the minimum turning radius of large machinery, the full width of the road design, and the safety clearance threshold. The planning area is discretized into a grid. Based on the terrain slope, curvature, undulation and the sensitive area data, the comprehensive passage cost value of each grid cell is calculated to construct a cost grid model. Based on the entry point and the end point, a heuristic graph search algorithm with introduced segment path mask is executed on the cost grid model. When expanding the neighboring nodes of the current node, the discrete drivability criterion is checked on the expanded edge based on the minimum turning radius, and a three-dimensional spatial collision check is performed on the road sweep body generated based on the full width of the road design. Expanded edges that fail the check are pruned, thereby generating a candidate path set containing multiple feasible paths. Each feasible path in the candidate path set is discretized, and the difference profile between the road surface design elevation and the natural ground at each station is calculated to obtain the earthwork volume. Based on the safety clearance threshold, a three-dimensional safety clearance check is performed on the continuous pile segment. The target construction temporary road path is determined according to the comparison results including earthwork volume and safety penalty. The target temporary construction road path is converted into a three-dimensional spatial line object, a three-dimensional road model is generated along the road centerline, and then fused and rendered in a three-dimensional GIS platform. The heuristic graph search algorithm that introduces segment path masks includes: Based on the mask order, candidate endpoint grid points are determined in the neighborhood of the central grid point. The connectivity between two points is normalized as a set of line segments pointing from the local origin to integer offsets, where the integer offsets are within the range determined by the mask order and are coprime, thereby increasing the number of selectable discrete directions in the search process and weakening the direction quantization effect. At the same time, the system elevates the search state from two-dimensional grid points to an orientation state with discrete heading indices, uniformly discretizing the heading angle interval into m parts, so that the state space has dual information of position and orientation, thereby enabling a transition compatible with heading changes through extended mask constraints during the path generation stage.

2. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 1, characterized in that, The method for calculating the comprehensive toll cost includes: in, This represents the overall passage cost value of the grid cell (i,j). Variable weighting coefficients representing slope; Variable weighting coefficients representing curvature; The variable weighting coefficient represents the fluctuation degree; w_s represents the variable weighting coefficient for sensitive area avoidance. Represents the slope characteristic function; Represents the curvature characteristic function; Represents the variability characteristic function; Represents the sensitive area avoidance feature function; The slope characteristic function is expressed as: in, This indicates a preset angle threshold; Indicates the maximum slope; Indicates slope; The curvature characteristic function is expressed as: Among them, curvature The calculation is based on the directional change between adjacent grid cells, and the formula is as follows: in, This represents the change in direction angle between two adjacent path segments; The grid cell side length; The undulation characteristic function is expressed as: in, Indicates the degree of fluctuation; in, This represents the maximum elevation value within a grid cell; This represents the minimum elevation within a grid cell; The sensitive region avoidance feature function is configured to assign infinite cost to the grid cells located within the sensitive region.

3. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 1, characterized in that, The evaluation function of the heuristic graph search algorithm is expressed as: in, This represents the estimated total cost to reach the target point from the starting point through node n; This represents the actual cost from the starting point to node n; This represents the estimated cost from node n to the target node; The method for calculating the estimated cost includes: in, Represents the minimum possible cost per unit distance; This represents the Euclidean distance from node n to the endpoint goal.

4. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 3, characterized in that, The actual cost The calculation process includes: The instantaneous cost function for a path of unit length is defined as follows: Where C represents the cost per unit length, i.e., the instantaneous cost function; This represents the variable weighting coefficient for instantaneous slope; Indicates the instantaneous curvature variable weighting coefficient; Indicates the variable weight coefficients for connectivity; This represents the variable weight coefficient of the avoidance constraint; This represents the instantaneous slope characteristic function; Represents the instantaneous curvature characteristic function; Represents the connectivity characteristic function; Represents the characteristic function of the avoidance constraint; The cost of moving between adjacent nodes i and j is calculated as follows: in, This represents the cost of movement between adjacent nodes; This represents the distance from node i to node j, for horizontal or vertical movement. For diagonal movement L represents the side length of the grid cell; The movement cost is accumulated along the path to obtain the actual cost from the starting point to node n, expressed as: Where C_{k-1,k} represents the movement cost between two adjacent nodes on the path; k is the node number index.

5. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 4, characterized in that, The formula for calculating the instantaneous slope characteristic function is as follows: in, This represents the slope angle between two points, and , d represents the elevation difference between two points; d represents the horizontal distance between two points. The formula for calculating the instantaneous curvature characteristic function is: in, Indicates the change in direction angle between two adjacent path segments; The connectivity feature function The value is 0 when the node is located on an existing road, and 1 when the node is located in a non-road area; The avoidance constraint characteristic function The value is positive infinity when the node is inside the sensitive area, and 0 when the node is outside the sensitive area.

6. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 1, characterized in that, The discrete drivability criterion verification includes: Obtain the vertex sequence of the polyline composed of adjacent nodes at the end of the path, and calculate the equivalent turning radius at the current extended node using the three-point circle method. If the equivalent turning radius is less than the minimum turning radius, the extended edge is pruned directly.

7. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 1, characterized in that, The three-dimensional spatial collision verification includes: Using the current extended edge as the tangent, offset the road area polygon strip in the horizontal plane according to the full width of the road design, and intersect the polygon strip with the terrain along the elevation direction to generate the road sweep body; The Boolean intersection test is performed between the road sweep body and the three-dimensional envelope of the sensitive area and the existing structure buffer body. If the volume intersection is not empty, the extended edge is determined to be invalid.

8. The automatic planning method for temporary construction roads in mechanized construction based on a 3D GIS platform according to claim 1, characterized in that, The determination of the target temporary construction road route based on the comparison results including earthwork volume and safety penalties includes: Configure longitudinal slope design lines and standard cross sections for each feasible path, obtain the difference between the design elevation and the natural ground at each station, and obtain the total excavation and total fill volumes for each feasible path through numerical integration. A three-dimensional buffer envelope is generated by combining the road centerline with the width and slope opening. The minimum clearance between the buffer envelope and the tower crane slewing envelope, the edge of the foundation pit and the overhead line corridor is calculated. If the minimum clearance is less than the safe clearance threshold, a safety penalty is applied. Based on the total excavation volume, total filling volume, and safety penalty items, a comprehensive evaluation index is constructed to compare and select the target temporary construction road path from the candidate path set.

9. An automatic planning system for temporary construction roads in mechanized construction based on a 3D GIS platform, characterized in that, The system, applied to the method of any one of claims 1 to 8, comprises: The data input module is used to acquire basic geographic data, sensitive area data, and route selection parameters for the planning area. The cost map building module is used to build a cost raster model and calculate the comprehensive passage cost value of the raster cells; The path search module is used to execute a heuristic graph search algorithm that introduces segment path masks, and to perform discrete drivability criterion verification and road sweep collision verification during neighborhood expansion to generate a candidate path set. The secondary optimization module is used to perform cross-sectional-level earthwork volume calculation and three-dimensional safety clearance verification on the candidate path set to determine the target temporary construction road path. The 3D rendering module is used to generate 3D road models and integrate them with the GIS scene for display.

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