Keyword

1 Introduction

Whereas traditional dam safety information management systems primarily operate within a two-dimensional framework for managing monitoring instruments, Geographical Information System (GIS) is structured around data as the core, with three-dimensional (3D) visualization as a prominent feature. GIS systems enable positioning and querying of spatial data, with capabilities to collect, manage, analyze, and output various spatial data information [1]. This makes it easier to establish a safety monitoring and management system that integrates dam structure, geology, hydrology and other information, thereby resolving the problems of information islands and data dispersion that currently exist in most dam safety monitoring, and is critical for improving the level of dam safety management [2].

Pioneering research on dam safety monitoring information management systems began in the 1960s in developed countries like the United States, Japan, and Italy, with practical implementation starting in the 1970s. Among them, Italy has developed particularly quickly in this area and is at the international advanced level. Its monitoring information management system enables real-time data collection, review, storage, and transmission, alongside strong online judgment and early warning functions [3].

Despite the fact that research into monitoring information management systems in China began late, it has advanced rapidly, owing to significant attention and support from both the government and businesses [4]. To meet the needs of rapid storage and real-time analysis of a large amount of monitoring data, the development of dam monitoring information management system based on GIS platform has attracted increasing attention. Xiao Zeyun et al. (2010) established the connection between monitoring instrument spatial information and monitoring data based on a GIS platform, and discussed issues like database design, spatial data expression, and the adaptability of monitoring data prediction models [5]. Wang Guowen et al. (2023) constructed a dam-strong earthquake monitoring and analysis system that combines information query, visualization display, and real-time monitoring using WebGIS technology [6].

The research on GIS platform-based dam safety monitoring information management systems is still in its early stages. Monitoring data is primarily analyzed using traditional methods, which underutilize the spatial analysis capabilities inherent in GIS. To address these limitations of GIS platform-based systems, this paper develops a GIS platform-based dam safety monitoring information management system based on previous research, which connects the GIS spatial database to the monitoring database to enable spatial analysis of monitoring data and other functions.

2 Safety Monitoring Information Management System

2.1 System Architecture Design

Fig. 1.
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Architecture of dam safety monitoring information management system based on GIS.

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The primary goal of the dam safety monitoring information management system, built on the GIS platform, is to meet the needs of actual projects while also improving the efficiency of dam safety monitoring system management. Therefore, the design adheres strictly to the principles of practicality, dependability, security, maintainability, advancement, and standardization. Based on the design principles and the Client/Server (C/S) structure, this paper develops the overall architecture of the dam safety monitoring information management system using the GIS platform, as shown in Fig. 1. The system divides main functions of the client program into three modules: information query, data analysis and integration and engineering safety analysis. These modules carry out their functions by accessing data from the system database. The information entry module enters monitoring data either automatically or manually into the monitoring database and GIS database, which are then combined to form the system database.

2.2 System Functional Design

This paper delves deeply into actual projects, including Guandi (gravity dam), Changheba (earth-rock dam), Zilanba (gate dam), Lizhou (arch dam), the dam center of the Yalong river basin hydropower development company, and the dam management center of the Dadu river basin hydropower development company, to investigate the needs of dam safety monitoring managers for the use of monitoring information management systems. According to functional requirements articulated by users, the main functions of the dam safety monitoring information management system based on the GIS platform are divided into information entry, information review and transmission, information query, monitoring data analysis and compilation, engineering safety analysis and system setup and management, as shown in Fig. 2.

Fig. 2.
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Division of functional modules of system.

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3 Key Technology Research

3.1 System Research and Development (R&D) Platform

GIS digitally represents the natural world, enabling the storage and processing of extensive geographic data in different periods, and has powerful comprehensive analysis capabilities of spatial information. The R&D benefits of GIS in dam safety monitoring information management systems are primarily reflected in the following three areas: (1) The GIS 3D simulation and query functions provide technical support for creating a 3D visualization of the hydropower station hub safety monitoring system. (2) GIS can efficiently process massive data, allowing for the rapid location of abnormal dam parts and timely feedback of abnormal data. (3) GIS’s powerful spatial analysis function can perform visual domain analysis, underground seepage analysis, and engineering safety analysis in 3D data models.

The basic idea behind component GIS is to divide the major functional modules of GIS into multiple controls. Each control performs a different function, and controls that perform multiple functions are combined as needed to form an application system. This paper chooses ArcEngine, the most widely used component GIS development tool, as the GIS component for the dam safety monitoring information management system. It not only provides a powerful GIS class library with features such as layer display, 3D simulation, and spatial analysis, but it also increases system development autonomy.

The NET framework consists of the Common Language Runtime (CLR), a hierarchical collection of unified class libraries, and a componentized version of Active Server Pages. Compared to other software development technologies, NET allows for the use of a unified, component-oriented programming model that can well support each component’s properties, events and methods, and developers do not need to understand the internal structure to realize collaboration between different applications and data access services at any time.

3.2 System Architecture

In order to fully utilize high-performance servers and the idle computing power of personal computers, this system uses the C/S architecture. The C/S architecture states that the client program sends the user’s request to the server, which analyzes and processes it before returning the results to the client. The system database is installed on the server. When the client program runs, it performs related tasks by connecting to the server database. The C/S structure usually adopts a hierarchical design, with different levels operating independently of one another, making software upgrades and maintenance easier. The three-layer design structure of data access layer, business logic layer, and interface presentation layer is the most commonly used in current large and medium-sized application software, as shown in Fig. 3.

Fig. 3.
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Schematic diagram of C/S structure and program layering.

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3.3 Links Between GIS Spatial Database and Monitoring Database

The system database consists of two databases: the GIS spatial database and the monitoring database. In order to manage and use these data scientifically and realize the rapid collection, query and analysis of monitoring information by the system, this paper combines the system functions to establish the logical relationship between the GIS spatial database and the monitoring database. That is, the connection between the attribute table in the GIS spatial database and the monitoring database table. The following example shows how to connect the two databases using the system query function.

When using the system, the first thing you see is the 3D visual monitoring system. The data information for the 3D model is entirely derived from the GIS spatial database. When you need to query monitoring data, simply click on the monitoring point to access the data stored in the monitoring database. In order to obtain accurate monitoring data for the corresponding monitoring points, the GIS spatial database table and the monitoring database table are linked using the instrument ID number. Each monitoring point in the system is unique, and it is labeled with an ID based on the type of instrument. For example, for dam appearance deformation monitoring, the displacement meters TP1, TP2, …, TP10 can be assigned ID numbers 1001, 1002, …, 1010, and the instrument number establishes the relationship between the GIS spatial database table and the monitoring database table, as shown in Fig. 4.

Fig. 4.
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Logical relationship between GIS spatial database table and monitoring database table.

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4 Application of the System

4.1 Project Overview

A class II large (2) hydropower station project has an installed capacity of 195MW, and the barrage dam is designed as a first-class building. The primary hydraulic structures include gravel earth-corewall rockfill dams, flood discharge tunnels, drainage holes, water diversion systems, power plants, and so on. There are no comprehensive utilization requirements for flood control, shipping, or water supply.

The main monitoring items of this project include horizontal and vertical displacement of the dam surface, subsidence and horizontal displacement within the dam, foundation subsidence at the dam site, stress within the dam, stress and deformation of the anti-seepage wall, seepage of the dam body and foundation, slope stability on both sides and seepage around the dam, water level, water and air temperature, and earthquakes.

4.2 Application Effect

The dam safety monitoring information management system, built on the GIS platform, is used to realize 3D visualization of the monitoring system. The entire hub model can be arbitrarily scaled, rotated, and moved using the powerful topological relationships of GIS, as shown in Fig. 5, where the red point represents the project’s dam appearance monitoring point.

Fig. 5.
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System scaling, rotation, and movement functions.

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We successfully applied the 3D stability analysis program for slopes developed using the rigid body limit equilibrium method to the project and obtained the most dangerous sliding surface by searching for given initial values. We then investigated the potential locations of the most dangerous sliding surfaces, accounting for changes in the elevation of the wetted surface as the water level in the reservoir fluctuated. By calling the measured values of seepage pressure buried in the dam body, a real-time wettability surface is generated, allowing for the analysis and calculation of the safety factor for dam slope stability while operating. In the downstream dam slope stability calculation diagram on November 28, 2009 (Fig. 6), the blue mesh surface is the most dangerous sliding surface obtained through the search, and the corresponding safety factor is 2.06. In comparison, the water storage safety appraisal report used the 2D simplified Bishop method to calculate dam slope stability under normal water storage conditions, yielding a result of 1.913. It is known from the water storage safety appraisal report that the 3D dam slope stability calculation result is slightly higher than the 2D calculation result. This is mainly because the 3D calculation takes into account the lateral sliding force, and the sliding effect caused by the lateral sliding force is smaller than the sliding effect on the vertical section, so the safety factor will be slightly increased.

Fig. 6.
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The most dangerous sliding surface display.

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5 Conclusion

This paper combines the actual situation of an earth-rock dam project, based on the GIS platform and uses C# as the development language to develop a dam safety monitoring information management system. The main conclusions are as follows:

  1. 1)

    The system divides the database into a GIS spatial database and a monitoring database, allowing for rapid collection and efficient management of spatial monitoring data. By applying GIS 3D visualization to monitoring data query, it successfully avoids the traditional management system that requires clicking on the tree menu to get monitoring data, but instead displays the whole monitoring system in 3D, and users can locate monitoring points through the functions of moving, zooming, rotating, roaming, which greatly improves the management efficiency of the dam monitoring system.

  2. 2)

    The GIS spatial analysis application successfully integrated 3D dam slope stability analysis as the system’s safety analysis function. The stability analysis of the earth-rock dam slope is performed using engineering examples. The calculation results show that the 3D dam slope stability calculation calculations outperform the 2D calculations, which is consistent with the calculation rules. When combined with measured seepage pressure values in the dam body, real-time analysis of the dam slope’s stability is realized, possible dangerous sliding surfaces are identified, and managers are prompted to take engineering measures to reinforce dangerous parts ahead of time to avoid disasters.

  3. 3)

    The 3D visualization of the dam safety monitoring information management system allows users to quickly grasp the operational status of various cascade hydropower stations in the whole basin. This remains the development path for the future dam safety monitoring information management system. The system described in this paper only applies arbitrary operations to points and lines. The ArcGIS Engine library has limitations when it comes to arbitrary surface generation and changes. If the technology can be broken, 3D deformation monitoring of dams, reservoir mountains, and strata can be easily implemented by combining monitoring data.