Ancient city wall daily management and disease management and control system and method based on BIM scene construction

Abstract

The invention belongs to the technical field of cultural relic protection and building information models, and discloses an ancient city wall daily management and disease management and control system and method based on BIM scene construction. An existing disease management and control system has the problems that the urban wall occurrence environment and the repair history are difficult to comprehensively consider, and multi-disease collaborative analysis is lacked. According to the method, non-structural nodes are introduced, environmental factors such as a drainage system, vegetation coverage, underground facilities and an internal space are incorporated into a city wall management system, and collaborative expression of a city wall structure and an occurrence environment is realized on the basis of structural partitioning. According to the system, urban wall block numbers serve as a unified index, monitoring data, disease information and repair records are fused, spatial visualization and information linkage are achieved based on a BIM scene, meanwhile, a threshold value management mechanism is set, when state parameters of non-structural nodes reach a threshold value, a corresponding maintenance protection scheme is triggered, and the maintenance and protection efficiency is improved. And urban wall information management, disease dynamic monitoring and scientific repair decision making are realized.

Description

Technical Field

[0001] This invention relates to the field of cultural relic protection and building information modeling technology, specifically to a system and method for daily management and disease control of ancient city walls based on BIM scene construction. Background Technology

[0002] Ancient city walls, as an important component of my country's immovable cultural relics, carry rich historical and cultural information and are vital material carriers for the continuation and inheritance of Chinese civilization. With the changing times, the strategic function of city walls as military defense facilities and urban spatial constraints has gradually weakened, while their historical, cultural, and scenic value has become increasingly prominent. However, constrained by factors such as their age, changes in the natural environment, and the impact of human activities, many ancient city walls have long been in complex environments, commonly exhibiting varying degrees of damage such as erosion, cracks, deformation, and even partial collapse, posing a serious challenge to the safety and sustainable protection of these cultural relics.

[0003] In existing technologies, the protection of ancient city walls mostly focuses on non-destructive testing and monitoring of single types of damage. For example, damage data is obtained through methods such as crack monitoring, settlement observation, or local structural inspection. Site protection experts then use their experience to assess the development trend of the damage and take corresponding protection or repair measures based on the severity of the damage. While this method can reflect the local damage status of the city wall to some extent, it still has significant limitations overall.

[0004] On the one hand, existing technologies struggle to incorporate the environmental factors surrounding city walls into a unified management and analysis framework. The occurrence and development of city wall defects are often closely related to non-structural environmental factors such as drainage conditions, vegetation growth, underground facilities, and internal cavities. However, in traditional management models, these environmental factors are often recorded in scattered or empirically judged forms, failing to form a systematic connection with the structural information and defect data of the city walls. This results in incomplete analysis of the causes of defects and delayed risk identification.

[0005] On the other hand, there is a lack of effective comprehensive analysis mechanisms between the history of restoration and various types of defects. The restoration methods, materials, and techniques used in different historical periods have a continuous impact on the structural performance of the city walls and the development of subsequent defects. However, relevant information is often stored in a scattered manner, making it difficult to compare and analyze with current defect data. Furthermore, city walls typically exhibit multiple types of defects simultaneously, with complex interrelationships. Existing technologies often employ single-defect, single-index analysis methods, making it difficult to achieve collaborative assessment of multiple defects, thus affecting the accuracy of defect prediction and the reliability of safety and stability evaluation results.

[0006] Furthermore, existing city wall management methods are insufficient in terms of information integration and visualization. Disease data, monitoring information, environmental information, and repair records are mostly managed in scattered text or tabular formats, lacking a direct connection to the physical city wall space. This results in low information retrieval efficiency, making it difficult for managers to grasp the overall condition of the city wall in a timely and comprehensive manner, which is detrimental to daily management and scientific decision-making. In conclusion, there is an urgent need to develop a system that can visually represent the environment in which ancient city walls exist, and can comprehensively statistically manage various attribute information, environmental factors, repair history, and multiple diseases of the city walls. Summary of the Invention

[0007] The purpose of this invention is to provide a system and method for daily management and disease control of ancient city walls based on BIM scenario construction, so as to solve the problem that the above-mentioned background technology is difficult to comprehensively consider the city wall's environment, repair history and multi-disease collaborative analysis, and realize integrated management of city wall information, dynamic monitoring of diseases and scientific decision-making.

[0008] The main design concept of this invention is as follows: This invention takes the segmented management of ancient city walls as its core, and introduces non-structural nodes as key management units connecting the city wall structure and its environment. Based on the segmentation of structural nodes, the city wall is further subdivided by combining non-structural nodes, including drainage systems, vegetation cover, underground facilities, and internal spaces, to achieve a synergistic expression of environmental factors and city wall structure. Through BIM scenarios, the spatial association between structural nodes, non-structural nodes, and disease information of the city wall is constructed, and monitoring data, disease records, and repair history are integrated using the city wall segment number as an index. This enables disease development analysis, risk assessment, and control decisions, forming a disease control system for daily management. At the same time, a threshold management mechanism is introduced to determine thresholds and issue graded early warnings for the status parameters of non-structural nodes and key disease indicators, and to trigger disease monitoring updates and repair and reinforcement treatments in a coordinated manner.

[0009] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, this invention provides a daily management and disease control system for ancient city walls based on BIM scene construction, including: The city wall decomposition module is used to divide the ancient city wall into multiple city wall blocks based on structural nodes and unstructured nodes; The city wall numbering module is used to number the city wall sections, obtain the city wall section numbers, and form a city wall numbering system using the city wall section numbers as indexes; The modeling module is used to model each section of the city wall based on the benchmark system composed of the primary control network and secondary densification points, and assemble them to generate the BIM model of the ancient city wall. The spatial coordinates of monitoring points, unstructured nodes and disease features are embedded into the BIM model. The city wall monitoring module is used to divide and number the on-site monitoring areas, and associate the monitoring area numbers with the city wall block numbers, so as to realize the location and query of monitoring information in the BIM model; The disease monitoring module is used to record the historical development information and current development rate of diseases, and to update the disease markers corresponding to the disease type, location and development level in the BIM model. The database management module is used to store and manage the information of the city wall using the city wall block number as a unified index, and to work in conjunction with the city wall monitoring module and the disease monitoring module to enable the tracing and retrieval of monitoring information, disease information and their historical records based on the city wall block number. The maintenance and reinforcement module, in conjunction with the database management module, is used to conduct safety performance assessments based on potential damage risks, the cumulative development of existing defects, and the current development rate, and to output protection and response strategies. The threshold management module receives real-time status parameters of unstructured nodes, compares them synchronously with the threshold standard for unstructured nodes, and outputs the status judgment result of unstructured nodes to the database management module.

[0010] Furthermore, the specific process of dividing the ancient city wall into blocks by the city wall decomposition module includes: The ancient city wall was structurally divided into nodes, resulting in multiple first-level blocks; The ancient city wall is divided into unstructured nodes, resulting in multiple secondary blocks; By embedding the secondary blocks into the primary blocks, multiple city wall blocks are obtained.

[0011] Furthermore, the first-level blocks include: watchtowers, walls, city gates, barbicans, sheep and horse enclosures, and moat; among which the walls are the wall sections between adjacent watchtowers, and the moat includes the ring park.

[0012] Furthermore, the secondary subdivisions include drainage system nodes, vegetation cover nodes, underground facility nodes, and internal space nodes; Based on the spatial distribution and functional attributes of unstructured nodes, unstructured nodes are associated with each first-level block to obtain the city wall block.

[0013] Furthermore, the specific process of numbering the city wall sections using the city wall numbering module includes: The first-level blocks are numbered: starting from the southwest corner platform, they are numbered clockwise, and a coding rule combining structural type identification and orientation coding is adopted. The wall, enemy platform, city gate and moat are set up with independent numbering groups, and the barbican and sheep and horse city are numbered separately. Based on the primary block numbering, the wall block numbering is carried out using the following method: non-structured identifier - primary block number - non-structured child node - node sequence number.

[0014] Furthermore, the numbering standards for the walls, watchtowers, city gates, moats, barbicans, and sheep and horse enclosures are as follows: The walls and watchtowers are numbered using a structure-location-substructure method, where the location is identified by the orientation, city gate number, and structure number. The moat is coded using a structure-location method, where the location is identified by both the orientation and the city gate number. The city gates are numbered using a structure-substructure method; The barbican and the sheep and horse enclosure are numbered separately based on their structures.

[0015] Furthermore, the disease monitoring module records the characteristics and spatial location of cracks, erosion, or weathering diseases through a local coordinate system, and represents the disease characteristics and spatial location in the BIM model using line markers or area markers. The variation in line width of the line markers or the color intensity of the area markers characterizes the degree of disease development.

[0016] Furthermore, the database management module uses the city wall block number as a unified index to construct a hierarchical information architecture, which includes: The basic information layer for the city wall area is used to store the basic information of the city wall blocks associated with the city wall decomposition module and the city wall numbering module. The basic information of the city wall blocks includes component composition information, material strength information, historical background information and geological structure information. The disease and deterioration information layer is used to store disease and deterioration information linked with the disease monitoring module. The disease and deterioration information includes basic disease information, deterioration trend information, and disease cause correlation information. The monitoring and management information layer is used to store monitoring and management information associated with the city wall monitoring module and the maintenance and reinforcement module. The monitoring and management information includes historical monitoring information, information on responsible personnel, information on the impact of human activities, and maintenance and reinforcement information. The association mapping information layer serves as the connection layer between the storage database, the BIM model, and the city wall monitoring system. It includes number mapping relationships, coordinate association information, and BIM model attribute association information to realize the correspondence between the database information and the spatial location and attribute fields of the corresponding city wall blocks in the BIM model.

[0017] Furthermore, the disease monitoring module and the database management module work together to obtain the status judgment results of unstructured nodes and analyze the types of diseases that abnormal nodes may induce; when the status parameters of unstructured nodes reach the threshold, the maintenance and reinforcement module is triggered to retrieve the maintenance and protection scheme corresponding to the disease type.

[0018] Another objective of this invention is to provide a method for daily management and disease control of ancient city walls based on BIM scene construction, comprising the following steps: S1: Obtain the structural and unstructured node information of the ancient city wall, divide the ancient city wall into multiple first-level blocks based on the structural nodes, and divide it into second-level blocks based on the unstructured nodes. Embed the second-level blocks into the corresponding first-level blocks to form multiple city wall blocks. S2: Number the city wall sections, generate city wall section numbers, and establish a unified city wall numbering system based on the city wall section numbers; S3: Based on the benchmark system composed of the primary control network and secondary densification points, collect spatial coordinate data of each section of the city wall, monitoring points, and disease feature points, and uniformly convert the spatial coordinate data to the local coordinate system; under the local coordinate system, establish BIM models for each section of the city wall and assemble them to generate the overall BIM model of the ancient city wall, and embed the local coordinates of the monitoring points and disease feature points into the BIM model in a coordinate anchoring manner; S4: Divide the actual monitoring area and generate monitoring area number, and associate the monitoring area number with the corresponding city wall block number and its local coordinates; S5: During the monitoring process, collect disease information, record the historical development information and current development rate of the disease, and generate or update disease markers in the BIM model according to the disease type and feature point coordinates, so that the disease markers are bound to the corresponding city wall block number and the associated monitoring area number. S6: Using the city wall block number as a unified index, store the city wall basic information, disease and deterioration information, monitoring and management information, and related mapping information in the database, and realize the linkage between the database and the city wall decomposition module, city wall numbering module, city wall monitoring module, disease monitoring module and repair and reinforcement module, so as to support the traceability, retrieval and statistical analysis of monitoring information and disease information according to the city wall block number; S7: Based on the threshold management module, it receives the real-time status parameters of unstructured nodes and compares them synchronously with the threshold standards for unstructured nodes, outputting the status judgment results of unstructured nodes; it stores the judgment results in the database and associates them with the corresponding wall block information; when the judgment results are abnormal, it links the disease monitoring and repair and reinforcement module to trigger early warning prompts and corresponding disposal measures.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. Compared with the prior art, the present invention introduces non-structural nodes such as drainage system, vegetation cover, underground facilities and internal space into the daily management system of the city wall and establishes a one-to-one correspondence with the city wall blocks to realize the coordinated management of the city wall structure and the environment in which it exists. This effectively makes up for the shortcomings of traditional methods that only focus on structural diseases and ignore environmental factors, and improves the comprehensiveness of disease cause analysis and risk identification. 2. Compared with the prior art, the present invention uses the city wall block numbering as a unified index to link monitoring information, disease data, repair history and management records with the database management module, realize the linkage management between disease monitoring, safety assessment and repair decision-making, avoid information dispersion and duplicate judgment, and significantly improve the efficiency of daily management of ancient city walls and the scientific nature of disease control. 3. Compared with existing technologies, this invention constructs a city wall information model based on BIM scenarios, spatially and visually representing the city wall blocks, unstructured nodes, monitoring areas, and damage information, achieving an intuitive correspondence between data and physical models. Managers can quickly obtain the city wall status and risk distribution through the model, thereby improving decision-making response speed and the ability to manage cultural relics safety.

[0020] 4. The introduction of a threshold management mechanism enables unified judgment and graded early warning of unstructured node status parameters and key disease indicators, reducing missed judgments and misjudgments caused by differences in human experience. When an indicator exceeds the threshold, the system can send the result to the database management module, and trigger targeted maintenance and reinforcement measures through the database management module in conjunction with the disease monitoring module, so as to achieve early identification and early handling of risks and improve the timeliness, traceability and handling efficiency of daily management of the ancient city wall. Attached Figure Description

[0021] Figure 1 This diagram shows the module composition of a BIM-based system for the daily management and disease control of ancient city walls. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] A BIM-based system for the daily management and disease control of ancient city walls includes modules for wall decomposition, wall numbering, wall modeling, wall monitoring, disease monitoring, threshold management, database management, and repair and reinforcement. The system focuses on block-based management of the city walls: firstly, it divides the walls into primary blocks based on structural nodes, and then introduces non-structural nodes such as drainage systems, vegetation cover, underground facilities, and internal spaces to further subdivide and manage these blocks, achieving a collaborative expression of the wall structure and its environment. Subsequently, it collects and uniformly transforms spatial coordinates based on a benchmark system composed of a primary control network and secondary densification points. Each block is then modeled and assembled into a unified BIM model within a local coordinate system, while monitoring points and disease feature points are embedded into the model using coordinate anchoring. The database management module uses the wall block number as a unified index to hierarchically store basic wall information, monitoring and management information, and disease and deterioration information. It binds database fields to BIM model component attributes through association mapping information, allowing users to retrieve all information for a block by clicking on a model component. The threshold management module receives real-time status parameters of unstructured nodes and compares them synchronously with preset thresholds, outputting status judgment results. When an anomaly is determined, the disease monitoring module combines the correlation between unstructured nodes and diseases to conduct disease risk analysis and links with the maintenance and reinforcement module to retrieve corresponding treatment and protection strategies.

[0024] The city wall decomposition module uses structural nodes to divide the city wall into regions for easy location and classification statistics. It mainly decomposes the city wall based on the city gate and the watchtower. The city wall blocks include the watchtower, the wall body (between the watchtowers), the city gate, the barbican, the sheep and horse wall, and the moat (including the ring park).

[0025] The city wall decomposition module uses unstructured nodes (environmentally sensitive points) to divide the city wall into regions. Specifically, environmentally sensitive points include drainage system nodes, vegetation cover nodes, underground facility nodes, and internal space nodes.

[0026] The city wall numbering module is used to number the various parts of the decomposed city wall. Starting from the southwest corner platform, the numbers are assigned in clockwise order using uppercase letters of the structure / direction pinyin. Different numbering groups are used for the wall body, watchtowers, city gates, and moat. The wall body and watchtowers use the "structure-location-substructure" numbering rule. The location is jointly identified by the orientation-city gate number-structure number, for example, X12 ("X" represents the west city wall, "1" represents the section between the southwest corner platform and the first city gate, and "2" represents the corresponding structure number), B21 ("B" represents the north city wall, "2" represents the section between the first and second city gates, and "1" represents the corresponding structure number). Structures such as the barbican and the sheep and horse enclosure are numbered separately. Buildings on the city wall are included in the corresponding numbering group according to their location, using a two-level classification method of city wall block-substructure.

[0027] The city wall numbering module uses the following numbers for enemy watchtowers: JT-XN, DT-X11, DT-X12…DT-X21, DT-X22…, JT-XB, DT-B11, DT-B12…DT-B21, DT-B22…, JT-DB, DT-D11, DT-D12…DT-D21, DT-D22…, JT-DN, DT-N11…DT-N21…. Here, JT represents a corner watchtower, DT represents an enemy watchtower, JT-XN represents the southwest corner watchtower, DT-N11 represents the first enemy watchtower between the south corner watchtower and the first city gate, DT-N22 represents the second enemy watchtower between the first and second city gates on the south wall, and so on. Enemy towers are classified using a two-level system, with DT-N22-DL representing the corresponding enemy tower on that watchtower.

[0028] The city wall numbering module uses the following wall section numbering: QS-X11, ..., QS-B11, ..., QS-D11, ..., QS-N11, ..., where QS represents the wall section, QS-X11 represents the first section of the wall between the western corner platform and the first city gate, and so on. Substructures use a two-level classification system, such as QS-X11-HM (wall slab), QS-X11-YQ (column wall), QS-X11-DQ (crenellated wall), QS-X11-NQ (inner wall), QS-X11-WQ (outer wall), QS-X11-NXT (core soil), and QS-X11-JC (foundation).

[0029] The city wall numbering module uses city gates and corner towers as nodes to number the moat (including the ring park). For example, HCH-X1 represents the section of the moat between the southwest corner tower and the first city gate on the west side of the city wall.

[0030] The city wall numbering module uses the first letter of the name of the city gate as the identifier, such as YXM (Yuxiang Gate), AYM (Anyuan Gate), CYM (Chaoyang Gate), YNM (Yongning Gate), etc. The substructure uses a two-level classification method, such as YNM-MD1 (the first gate opening, which is the gate opening closest to the local coordinate origin).

[0031] The city wall numbering module indicates that the city gate's auxiliary structures are represented by the city gate itself plus the structure name. For example, YNM / YMC represents Yangma City located at Yongning Gate. Substructures use a two-level classification method, such as YNM / YMC-MD (gateway).

[0032] Non-structural nodes link environmental risks with disease risks, thereby closely linking the ancient city wall with its environment and increasing the contribution of the environment to the risk management of the city wall.

[0033] Unstructured nodes, the city wall numbering module, are based on the structural node blocks, and further subdivided into smaller blocks according to the spatial distribution and functional attributes of the unstructured nodes. This ensures that each unstructured node corresponds to a unique sub-block and avoids spatial overlap. Nodes are numbered according to the sequence "Unstructured Identifier - Belonging Structural Block Number - Child Node - Node Sequence Number". Nodes are sorted by their spatial location, with vertical positions sorted from top to bottom and horizontal positions sorted from smallest to largest according to the city wall coordinates. The vertical sorting order precedes the horizontal sorting order.

[0034] Unstructured nodes, the city wall numbering module, adopt the same coding rules as structured nodes. During the data acquisition phase of the modeling module, specialized acquisition tools and parameter recording standards are used to synchronously acquire spatial coordinates and status parameters for the morphological and functional characteristics of unstructured nodes, and bind them with corresponding numbers.

[0035] For unstructured nodes, after data acquisition, the geodetic coordinates are unified to the local coordinate system specified by the system using a coordinate transformation tool to ensure consistency with the BIM model coordinates. During the model building phase of the modeling module, the subdivided blocks of unstructured nodes are modeled separately and embedded into the overall BIM model through coordinate anchoring.

[0036] For unstructured nodes, a new unstructured node-disease association table is added to the database management module. This table associates and stores node status data with disease data, enabling model visualization, data querying, and disease traceability. In the maintenance and reinforcement module, targeted protection strategies are generated based on the node-driven disease early warning results, forming an operational closed loop from node monitoring to disease control.

[0037] Drainage system nodes are divided into structural node blocks, further subdivided according to the composition and vertical distribution of the drainage system, and further subdivided by "drainage hole / drainage ditch - associated wall / embankment - vertical level". The coding format is: Non-structural identifier (PS) - associated block number - sub-node - node sequence number, where the substructure clearly distinguishes the drainage system type, including PK (drainage hole), PG (drainage ditch), and PC (drainage channel). For example: PS-QS-N11-PK-1 (drainage hole number 1 in block QS-N11).

[0038] Drainage system nodes, node parameters include spatial data (three-dimensional coordinates of orifice / ditch opening, depth and cross-sectional dimensions of orifice / ditch) and functional parameters (drainage volume, degree of blockage, water quality pH value, service status: normal / damaged / out of service).

[0039] Drainage system nodes are directly associated with the following types of defects: rammed earth collapsibility, brick wall efflorescence, and wall cracks. For example, when the blockage rate of a node exceeds a threshold according to the PS number, the system correlates this with the growth rate of the corresponding efflorescence area and the correlation between the average drainage volume of all PS nodes in the same area and the number of wall cracks. In the defect monitoring module, through the coding filtering function, such as inputting PS-QS-N11-*, the system automatically calculates the average blockage rate and average drainage volume of all drainage nodes in the area, and calculates the correlation with the growth rate of wall defects in QS-N11, generating a statistical report.

[0040] Vegetation cover nodes are divided into blocks based on structural nodes, according to the coverage area of ​​vegetation (single-plant coverage, patch coverage) and its location relative to the city wall (wall base, seawall, masonry). The encoding format is: Non-structural identifier (ZB) - Block number - Vegetation type - Node number. Vegetation types include QM (trees), GM (shrubs), and CB (herbs), for example: ZB-DT-N11-QM-2 (the second tree node in the DT-N11 block).

[0041] Vegetation cover nodes, with node parameters including spatial coordinates (base, center, and edge coordinates), growth parameters (tree diameter at breast height, crown diameter, root depth, and annual growth rate; shrub diameter and root depth; herbaceous cover area and growth height), and environmental parameters (sunlight duration and soil moisture).

[0042] Vegetation-covered nodes are directly associated with various disease types, including uneven foundation settlement, wall bulging, and brick joint erosion. For example, when the root depth of trees exceeds a threshold according to ZB number, the foundation settlement of the corresponding watchtower can be correlated; and a linear relationship exists between the root growth rate of ZB nodes in a certain area and the wall bulging displacement.

[0043] Underground facility nodes are divided into blocks based on structural nodes, according to the type of underground facility (pipeline, manhole), burial depth (shallow, medium, deep), and horizontal distance from the city wall foundation (near, medium, far). Each facility block is an independent block. The coding format is: Non-structural identifier (DX) - Block number - Facility type - Node number. Equipment types include GX (water supply pipeline), WX (sewage pipeline), and JJ (manhole), for example: DX-YNM-GX-1 (GX represents water supply pipeline).

[0044] The underground facility nodes have parameters including spatial coordinates (pipeline endpoints, manhole opening coordinates, pipeline azimuth, and burial depth) and dynamic parameters (pipeline pressure, leakage, burial depth changes, and manhole structural integrity: intact / damaged / leaking).

[0045] Underground facility nodes are directly associated with various types of defects, including soil softening, foundation erosion, and secondary defects in air-raid shelters. For example, when the leakage of a certain pipeline exceeds a threshold according to the DX number, the decrease in the bearing capacity of the foundation of the YNM city gate is associated with this, as well as the synchronicity between the burial depth change of the DX node of the same pipeline and the settlement rate of the city wall.

[0046] Internal spatial nodes are divided into blocks based on structural nodes and then by spatial size. The encoding format is: Unstructured identifier (KD) - Block number - Node number - Spatial size, where spatial size includes X (small), Z (medium), and D (large).

[0047] For internal space nodes, three types of data bound to the encoding must be recorded synchronously during data acquisition to ensure that the database management module can fully store and retrieve them. Internal space parameters include spatial parameters, morphological parameters, and risk parameters. Spatial parameters include the three-dimensional coordinates of the space's center point, the coordinates of the space's boundaries, and the depth of the space within the city wall (distance from the city wall surface); morphological parameters include the space's length, width, height, volume, cross-sectional shape (circular / rectangular / irregular), and internal filling status (no filling / loose fill / water accumulation); risk parameters include the space's distance from the critical structures of the city wall, the integrity of the surrounding walls, and the cause of the space's formation.

[0048] Table 1. Association between unstructured nodes and diseases

[0049] The modeling module is used to establish a BIM-based city wall information database, drawing each part of the city wall into a BIM model. Each city wall is modeled separately in blocks for detailed simulation of defects.

[0050] In the modeling module and data acquisition phase, a combined data acquisition scheme of "GNSS RTK (real-time dynamic positioning) + total station" was adopted. GNSS RTK was used to obtain large-scale coordinates in open areas; total station was used for local supplementary measurements in obscured areas (such as city gates and the inside of enemy platforms); and handheld laser rangefinders or 3D laser scanners were used to supplement measurements on small components (such as seawall brick joints and crack edges).

[0051] In the modeling module and data acquisition phase, a benchmark system of primary control network and secondary densification points is established. The primary control network consists of 3-5 permanent control points evenly distributed around the perimeter of the city wall. Elevation is determined using second-order leveling, and plane coordinates are obtained using GNSS static surveying. Secondary densification points are set every 50-100m along the city wall itself, and are connected to the primary control points to form a closed traverse network. The control network is re-measured quarterly using a total station to eliminate benchmark offsets caused by temperature and settlement.

[0052] In the modeling module, local coordinates and location attributes must be recorded synchronously during data acquisition. The acquisition points must correspond to the block numbers in the BIM model. For example, when acquiring the coordinates of enemy platform DT-N11, label it "DT-N11-Acquisition Point 1". At least three feature points should be acquired to reduce single-point errors through multi-point fitting. Record the acquisition environment parameters so that abnormal data under interference such as signal strength <30dB and strong winds can be removed during subsequent data processing.

[0053] The modeling module uses a unified coordinate system, with the center point of the bottom of the southwest corner platform (JT-XN) of the ancient city wall as the origin (X=0, Y=0, Z=0). The X-axis is parallel to the direction of the south city wall and points east; the Y-axis is parallel to the direction of the west city wall and points north; the Z-axis is perpendicular to the ground and points upward. This local coordinate system is directly used during BIM modeling to avoid subsequent model coordinate transformation; during on-site data acquisition, a total station is used to convert the geodetic coordinates obtained from GNSS RTK into local coordinates.

[0054] In the modeling module, during the model building phase, models are built independently according to the block division rules of the system's city wall decomposition module, with each block having a set accuracy threshold (1cm). Parametric family library modeling is used, with city brick families drawn at a 1:1 scale to avoid errors caused by scaling. After modeling, each block is compared between the model and the actual site. Feature points of each block are collected using a total station and compared with the coordinates of corresponding points in the model. If the deviation exceeds the threshold, the model is readjusted.

[0055] The modeling module associates coordinates and number attributes during the model building phase. For each block of model components, the center point coordinates and boundary coordinates under the local coordinate system are automatically associated. Through the database management module, the component number, coordinates and attribute information are bound together, and the coordinates can be quickly retrieved by number during subsequent queries.

[0056] The city wall monitoring module is used to divide and number the on-site monitoring area, and associate the city wall monitoring area number with the city wall area number to facilitate location.

[0057] The city wall monitoring module uses the coordinates of monitoring points collected on-site to directly embed the model annotations of the monitored areas.

[0058] The city wall monitoring module uses a hierarchical coding format based on the existing city wall numbering system, consisting of monitoring identifier - city wall block type - city wall location / number - monitoring sequence number.

[0059] In the city wall monitoring module, a new monitoring-city wall mapping table has been added to the system database management module, with the following structure: Table 2 Monitoring-City Wall Mapping Table

[0060] In the city wall monitoring module, the local coordinates of monitoring points are directly embedded into the BIM model through coordinate anchoring in the modeling module, and the numbers are linked and labeled. Clicking on any city wall block will automatically display the numbers of all monitoring areas under that block; clicking on any monitoring number will automatically highlight the corresponding city wall block and its associated attributes.

[0061] The database management module is used to quickly find various information attributes of the city wall area by the city wall area number, including basic information, disease and deterioration information, monitoring and management information, and association mapping information.

[0062] The database management module is directly linked to the basic information of the city wall area, the city wall decomposition module, and the numbering module. It is the basic index layer for database management and needs to be bound to the city wall block number, including component composition information, material strength information, historical background information, and hydrogeological information.

[0063] The database management module, which links disease and deterioration information with the disease monitoring module, serves as the data support layer for disease statistics and trend prediction. It needs to be stored in categories and numbers according to the city wall, including basic disease information, deterioration trend information, and disease cause correlation information.

[0064] The database management module, which links the monitoring and management information with the city wall monitoring module and the maintenance and reinforcement module, serves as the operational execution layer for daily management and emergency response. It includes historical monitoring information, information on responsible personnel, information on the impact of human activities, and maintenance and reinforcement information.

[0065] The database management module, with its association mapping information, serves as the connecting layer between the database, BIM model, and monitoring system. It ensures precise correspondence between data and spatial location, as well as model components, including number mapping relationships, coordinate association information, and BIM model attribute associations. By binding information in the database to the corresponding attribute fields of components in the BIM model, clicking on a BIM model component allows access to all information in the database.

[0066] The disease monitoring module is used to monitor the development of diseases in the city wall and record and analyze them in detail, including the historical development of the diseases and the current development rate.

[0067] The disease monitoring module records the corresponding characteristics of diseases such as cracks and erosion, as well as the three-dimensional coordinates of characteristic points, through a local coordinate system. It generates the disease in the BIM model using lines or planes marked with different colors. The thickness of the lines or the gradient of the plane color depth represents the degree of disease development.

[0068] The disease monitoring module marks different types of diseases separately by component layer in the BIM model. Through the "layer display / hide" function of the BIM model, the independent viewing and overlay comparison of diseases at different levels can be realized, avoiding confusion of disease markings at multiple levels.

[0069] The disease monitoring module adds floating information labels to the disease markers (such as crack lines and weathering patches) in the BIM model. The label content is designed in the disease attributes of the database management module, including basic information of each block (disease type, corresponding wall number, discovery time, latest monitoring time), core parameters of the disease, associated data (associated monitoring number), and influencing factors.

[0070] The disease monitoring module establishes an automatic synchronization trigger rule between the database and the model. When the disease data of a certain numbered area in the database is updated, the system automatically triggers the BIM model marker update and records the update time synchronously.

[0071] Database-model automatic synchronization trigger rules: Step 1: Update the database defect data based on the unified spatial foundation and coding system of the database and BIM model.

[0072] Step 2: Develop a database change push interface. When the database listener detects an update to the defect data, it calls the BIM platform's API to send an update command.

[0073] Step 3: Based on the BIM model interaction interface, automatically update the type, location, and severity of defects in the model.

[0074] The disease monitoring module establishes a numbered guided record entry template. When staff enter disease data, they only need to select the city wall block number - substructure number - monitoring number. The system automatically retrieves the BIM component coordinates and basic attributes corresponding to that number. Staff only need to add core information such as disease type and parameters, and the system can automatically generate a mark at the corresponding location on the model.

[0075] The disease monitoring module adds a number-disease joint filtering function to the BIM model view. It allows filtering by dimensions such as wall number, disease type, monitoring time, and risk level. The system automatically highlights disease markers that meet the criteria.

[0076] The disease monitoring module enables comprehensive and accurate management and prediction of diseases affecting the city wall. Monitoring content includes the cumulative development status and current development rate of diseases. Specific diseases include: cracks, deformation, surface weathering, biological diseases, and human-caused damage.

[0077] The disease monitoring module classifies cracks into wall cracks, paved wall cracks, and rammed earth cracks based on their location. Crack directions can be classified as horizontal, vertical, or oblique (considering the angle with the horizontal direction). Crack monitoring content includes: location, length, width, depth, and direction.

[0078] The disease monitoring module monitors deformation including: uneven foundation settlement, paving settlement, sidewall bulging, voids between surface brickwork and internal rammed earth, and rammed earth subsidence deformation.

[0079] The disease monitoring module categorizes surface weathering into brick wall weathering and soil-lined stone surface weathering and peeling, based on the different developmental locations. Brick wall weathering includes efflorescence, erosion, and efflorescence. Surface weathering monitoring content includes the depth, location, area, and area percentage of both single and combined weathering.

[0080] The disease monitoring module categorizes biological diseases into animal-induced damage, plant-induced damage, and microbial damage based on the type of organism. The monitoring content for biological diseases includes: location, organism type, volume (area), and depth.

[0081] The disease monitoring module mainly monitors air-raid shelters for human-caused damage. The monitoring content of air-raid shelters includes: whether there is lining and the type of lining, the cross-sectional shape and size, location, sealing status, and secondary diseases.

[0082] In the disease monitoring module, changes in water, air-raid shelters, and seawall loads are the main factors leading to the development of city wall diseases and reduced stability. Therefore, during rainy and snowy weather, the focus should be on monitoring rainfall infiltration and changes in groundwater levels. Areas with changes in air-raid shelter and seawall loads should be the key areas for disease monitoring.

[0083] The disease monitoring module includes eight indicators for the safety early warning of the city wall: cumulative settlement of the foundation, cumulative settlement of the sea slab, width of sea slab cracks, width of wall cracks, change in side wall bulging displacement, foundation settlement rate, sea slab settlement rate, and change rate of side wall bulging displacement.

[0084] The maintenance and reinforcement module is used to record and analyze the city wall's repair status in detail, including repair history, current repair progress, safety performance assessment, and protection and response strategies.

[0085] The safety performance assessment of the repair and reinforcement module should be based primarily on the potential risk of damage to the city wall, the cumulative development of existing defects, and the current development rate.

[0086] The repair and reinforcement module should assess the safety performance of the city wall based on existing defects, considering both the foundation and the wall itself. The foundation assessment should verify the bearing capacity under uneven settlement, while the wall assessment should include cracks, deformation, surface weathering, and air-raid shelters. Specific assessment methods and safety levels should follow existing city wall safety performance assessment methods.

[0087] The repair and reinforcement module provides corresponding protection and response strategies for different types of defects. For safe areas and areas with minor defects, daily inspections and regular maintenance are carried out. For relatively safe areas but with significant defect development, on-site inspections should be strengthened, and regular monitoring and maintenance should be carried out. For more dangerous areas, monitoring should be intensified, and multiple methods should be used to investigate the defects and identify their causes. Once an increasing trend in the rate of defect development is observed, an emergency plan should be immediately formulated and rescue reinforcement measures should be taken.

[0088] The maintenance and reinforcement module includes six protection strategies: maintenance and local repair, air-raid shelters, loose rammed earth, insufficient foundation bearing capacity, insufficient stability, and drainage. These strategies are specified in detail based on the guidelines for cultural relic work and experience from similar projects.

[0089] Referring to the specifications for cultural relic protection projects, civil engineering monitoring standards, and similar cases of ancient city wall protection, suggested values ​​and setting bases are proposed for different types of thresholds, including: Unstructured node thresholds are used to determine whether node functions are abnormal, and thus correlate them with disease risk.

[0090] After the real-time collected node status parameters are input into the disease monitoring module (the system includes seven modules; the decomposition, numbering, modeling, and database modules can be summarized as the backend; the monitoring, surveillance, and maintenance modules are the frontend, interacting with staff): ① The threshold standards of the unstructured node threshold management unit are synchronously compared, and the threshold management unit outputs the judgment result. The database management module receives the threshold judgment result from the threshold management unit and stores it in association with the corresponding disease data block. ② The disease monitoring module analyzes the types of diseases that may be induced by the node anomaly in conjunction with the "Unstructured Node and Disease Association Table." When the unstructured node threshold is abnormal, the maintenance and reinforcement module retrieves the corresponding maintenance and protection plan.

[0091] Table 3 Unstructured Node Threshold Table

[0092] The disease development threshold is used to determine whether a disease has entered the repair stage. It is set in conjunction with the severity of the disease type (cracks, settlement, weathering, etc.) and is linked to the city wall safety early warning indicators. Key areas include city gates and watchtowers. Table 4 Disease Development Threshold Table

[0093] Threshold setting instructions: Due to the structural importance and high load-bearing pressure of key areas (city gates, watchtowers, and corner towers), the threshold needs to be 20%-30% stricter than that of ordinary walls. The threshold should be recalibrated and measured every quarter through the control network. If special circumstances occur in the area where the city wall is located (such as continuous rainfall or underground engineering construction), the threshold needs to be temporarily lowered by 20%-50%. The threshold for non-structural nodes is related to the threshold for defects. For example, when the drainage hole blockage rate is >30%, the monitoring frequency of the wall crack width needs to be increased.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0095] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A daily management and disease control system for ancient city walls based on BIM scene construction, characterized in that, include: The city wall decomposition module is used to divide the ancient city wall into multiple city wall blocks based on structural nodes and unstructured nodes; The city wall numbering module is used to number the city wall sections, obtain the city wall section numbers, and form a city wall numbering system using the city wall section numbers as indexes; The modeling module is used to model each section of the city wall based on the benchmark system composed of the primary control network and secondary densification points, and assemble them to generate the BIM model of the ancient city wall. The spatial coordinates of monitoring points, unstructured nodes and disease features are embedded into the BIM model. The city wall monitoring module is used to divide and number the on-site monitoring areas, and associate the monitoring area numbers with the city wall block numbers, so as to realize the location and query of monitoring information in the BIM model; The disease monitoring module is used to record the historical development information and current development rate of diseases, and to update the disease markers corresponding to the disease type, location and development level in the BIM model. The database management module is used to store and manage the information of the city wall using the city wall block number as a unified index, and to work in conjunction with the city wall monitoring module and the disease monitoring module to enable the tracing and retrieval of monitoring information, disease information and their historical records based on the city wall block number. The maintenance and reinforcement module, in conjunction with the database management module, is used to conduct safety performance assessments based on potential damage risks, the cumulative development of existing defects, and the current development rate, and to output protection and response strategies. The threshold management module receives real-time status parameters of unstructured nodes, compares these parameters synchronously with unstructured node threshold standards, and outputs the unstructured node status determination results to the database management module.

2. The daily management and disease control system for ancient city walls based on BIM scene construction according to claim 1, characterized in that, The specific process of dividing the ancient city wall into blocks by the city wall decomposition module includes: The ancient city wall was structurally divided into nodes, resulting in multiple first-level blocks; The ancient city wall is divided into unstructured nodes, resulting in multiple secondary blocks; By embedding the secondary blocks into the primary blocks, multiple city wall blocks are obtained.

3. The daily management and disease control system for ancient city walls based on BIM scene construction according to claim 2, characterized in that, The primary blocks include: watchtowers, walls, city gates, barbicans, sheep and horse enclosures, and the moat; the walls are the sections of walls between adjacent watchtowers, and the moat includes the ring park.

4. The daily management and disease control system for ancient city walls based on BIM scene construction according to claim 3, characterized in that, The secondary blocks include drainage system nodes, vegetation cover nodes, underground facility nodes, and internal space nodes; Based on the spatial distribution and functional attributes of unstructured nodes, unstructured nodes are associated with each first-level block to obtain the city wall block.

5. A daily management and disease control system for ancient city walls based on BIM scene construction according to claim 4, characterized in that, The specific process of numbering the city wall sections using the city wall numbering module includes: The first-level blocks are numbered: starting from the southwest corner platform, they are numbered clockwise, and a coding rule combining structural type identification and orientation coding is adopted. The wall, enemy platform, city gate and moat are set up with independent numbering groups, and the barbican and sheep and horse city are numbered separately. Based on the primary block numbering, the wall block numbering is carried out using the following method: non-structured identifier - primary block number - non-structured child node - node sequence number.

6. The daily management and disease control system for ancient city walls based on BIM scene construction according to claim 5, characterized in that, The following are the standards for numbering the walls, watchtowers, city gates, moats, barbicans, and sheep and horse enclosures: The walls and watchtowers are numbered using a structure-location-substructure method, where the location is identified by the orientation, city gate number, and structure number. The moat is coded using a structure-location method, where the location is identified by both the orientation and the city gate number. The city gates are numbered using a structure-substructure method; The barbican and the sheep and horse enclosure are numbered separately based on their structures.

7. A daily management and disease control system for ancient city walls based on BIM scene construction according to claim 1, characterized in that, The disease monitoring module records the characteristics and spatial location of cracks, erosion or weathering diseases through a local coordinate system, and represents the disease characteristics and spatial location in the BIM model using line markers or area markers. The changes in the line width of the line markers or the color depth of the area markers represent the degree of disease development.

8. The daily management and disease control system for ancient city walls based on BIM scene construction according to claim 1, characterized in that, The database management module uses the city wall block number as a unified index to construct a hierarchical information architecture, which includes: The basic information layer for the city wall area is used to store the basic information of the city wall blocks associated with the city wall decomposition module and the city wall numbering module. The basic information of the city wall blocks includes component composition information, material strength information, historical background information and geological structure information. The disease and deterioration information layer is used to store disease and deterioration information linked with the disease monitoring module. The disease and deterioration information includes basic disease information, deterioration trend information, and disease cause correlation information. The monitoring and management information layer is used to store monitoring and management information associated with the city wall monitoring module and the maintenance and reinforcement module. The monitoring and management information includes historical monitoring information, information on responsible personnel, information on the impact of human activities, and maintenance and reinforcement information. The association mapping information layer serves as the connection layer between the storage database, the BIM model, and the city wall monitoring system. It includes number mapping relationships, coordinate association information, and BIM model attribute association information to realize the correspondence between the database information and the spatial location and attribute fields of the corresponding city wall blocks in the BIM model.

9. A daily management and disease control system for ancient city walls based on BIM scene construction according to claim 1, characterized in that, The disease monitoring module and the database management module work together to obtain the status judgment results of unstructured nodes and analyze the types of diseases that abnormal nodes may induce. When the status parameters of unstructured nodes reach the threshold, the maintenance and reinforcement module is triggered to retrieve the maintenance and protection scheme corresponding to the disease type.

10. A method for daily management and disease control of ancient city walls based on BIM scene construction, characterized in that, Includes the following steps: S1: Obtain the structural and unstructured node information of the ancient city wall, divide the ancient city wall into multiple first-level blocks based on the structural nodes, and divide it into second-level blocks based on the unstructured nodes. Embed the second-level blocks into the corresponding first-level blocks to form multiple city wall blocks. S2: Number the city wall sections, generate city wall section numbers, and establish a unified city wall numbering system based on the city wall section numbers; S3: Based on the benchmark system composed of the primary control network and secondary densification points, collect spatial coordinate data of the city wall blocks, monitoring points, and disease feature points, and uniformly convert the spatial coordinate data to the local coordinate system; under the local coordinate system, establish BIM models for each city wall block and assemble them to generate the overall BIM model of the ancient city wall, and embed the local coordinates of the monitoring points and disease feature points into the BIM model in a coordinate anchoring manner; S4: Divide the actual monitoring area and generate monitoring area number, and associate the monitoring area number with the corresponding city wall block number and its local coordinates; S5: During the monitoring process, collect disease information, record the historical development information and current development rate of the disease, and generate or update disease markers in the BIM model according to the disease type and feature point coordinates, so that the disease markers are bound to the corresponding city wall block number and the associated monitoring area number. S6: Using the city wall block number as a unified index, store the city wall basic information, disease and deterioration information, monitoring and management information, and related mapping information in the database, and realize the linkage between the database and the city wall decomposition module, city wall numbering module, city wall monitoring module, disease monitoring module and repair and reinforcement module, so as to support the traceability, retrieval and statistical analysis of monitoring information and disease information according to the city wall block number; S7: Receive the real-time status parameters of unstructured nodes, compare them synchronously with the threshold standard for unstructured nodes, and output the status judgment result of unstructured nodes. The judgment results are stored in the database and associated with the corresponding city wall block information. When the judgment results are abnormal, the disease monitoring and repair and reinforcement module is linked to trigger early warning prompts and corresponding disposal measures.

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