# Digital Twins' Application for Geotechnical Engineering:
## 2 The Current Situation of Digital Twins in Geotechnical Engineering
[PERSON]'s team [30; 31] proposed the concept of an intelligent tunnel construction system characterized by holographic perception, fusion modeling, intelligent analysis, closed-loop control, and continuous optimization learning based on digital twin technology, and they constructed the intelligent tunnel construction system (iS3), which can be used for integrated intelligent decision-making of data collection, transmission, processing, expression, analysis, and service throughout the lifecycle of the infrastructure. The intelligent construction system (iS3) was used for the support design of the Grand Canyon Tunnel of the Ehan Expressway. It only takes 10 min from the extraction of site information to the automatic feedback of the design plan to the on-site construction personnel, verifying the good applicability of the iS3 system. Figure 4 shows the intelligent tunnel construction system based on information flow. Figure 3: Digital Twin System Architecture of Highway Traffic (reproduced from [PERSON] et al. [29]). [PERSON] et al. [32] carried out the application of \"full-process and full-professional\" BIM technology in the major overhaul project of the western runway at Beijing Capital Airport, and they explored the construction of the \"digital twin\" west runway, which provided a model and data foundation for the future operation of a \"smart airport\". Urumqi Airport has built a digital twin service platform based on GIS + BIM and other technologies. In the whole-lifecycle construction process of airport planning, design, construction, and operation, it meets the needs of multiple entities and units, such as builders and operators, and realizes the concept of \"integration of smart airport construction and operation\" [33]. In the field of transportation and tunnel engineering, the application of digital twin technology covers the whole process, from design and construction to operation and maintenance. Through real-time monitoring, data analytics, and virtual simulation, digital twins can provide intelligent support for transportation systems, reduce costs and risks, improve operational efficiency, and ensure the long-term safety and efficient operation of transportation facilities. In the field of hydraulic engineering:  
Digital twin technology in the field of hydraulic engineering is developing in multiple fields and dimensions, especially in water resources management, flood prediction, irrigation optimization, dam monitoring, etc. In order to achieve high-quality development of water conservancy and meet the requirements of intelligent management, it is necessary to establish a digital hydraulic model based on digital twin technology and construct a smart water resources system with capabilities for real-time monitoring, diagnosis, analysis, decision-making, forecasting, early warning, simulation, and contingency planning. [PERSON] et al. [34] innovatively applied digital twin technology to establish a multi-physical field-coupling monitoring system for the Salakovac concrete gravity dam. By integrating advanced numerical modeling and real-time monitoring data, the accurate evaluation of the structural performance of aging dams was achieved, including the dynamic prediction of key parameters such as temperature field distribution and displacement response, which provides reliable technical support for dam safety monitoring. [PERSON] et al. [5] constructed a digital smart water conservancy application solution for the whole process from model establishment, data transmission, and data analytics to end-point display based on digital twin technology, such as the digital twin of the Gezhouba Hydropower Station. [PERSON] et al. [35] developed a BIM-based full-process information model for hydropower slope construction and implemented it at the Baihetan Hydropower Station. Figure 4: Intelligent tunnel construction system based on information flow (reproduced from [PERSON] et al. [30; 31]). [PERSON] et al.