In order to monitor the thermal expansion, dynamic effects and vibration of pipelines during thermal function tests in nuclear power plants, displacement sensors need to be installed on high-energy pipes and equipment. The sensor bracket is the most critical structure and bearing unit of the monitoring system, and the feasibility study has always been a hot issue. The temporary support designed and made of C-shaped steel (that is, the domestic alternative product of the famous American pipeline system support brand unistrut steel) is not only structurally firm, but also the support rooting method will not damage the infrastructure of the plant. The mechanical characteristics and functional principles of the temporary support are studied by theoretical analysis and numerical simulation, and the maximum deflection of the support rod under the tensile (compressive) working load and the failure conditions of the support are analyzed. The critical condition and the limit value of the bearing capacity of the temporary support reaching the steady state are obtained, and the above theory combined with numerical simulation is applied to engineering practice.

To achieve coordinated control of multi-speed operation in the spiral concrete batching machine, this paper proposes a trajectory tracking-based coordinated control method. By analyzing the working process of the spiral concrete batching machine, the coordinated relationship between lateral movement and concrete conveying rate is investigated, and a two-degree-of-freedom kinematic model for the batching machine is established. The error model for the trajectory tracking system of the batching machine is developed and discretized to meet the requirements of computer numerical calculation and real-time control. Based on model predictive control theory, a prediction equation for the trajectory tracking system is established. The objective function for the batching machine trajectory tracking is formulated, and the optimal control strategy is derived. Simulation results demonstrate that the trajectory tracking-based control method effectively achieves coordinated control of multi-speed operation in the spiral concrete batching machine.

With the wide application of target detection technology in unmanned construction and other scenarios, traditional target detection algorithms face challenges such as low recognition accuracy, large computational volume, and slow processing speed in complex engineering environments. Based on these challenges, this paper proposes a target detection method based on improved YOLOv8 for engineering scenes, which improves the C2f structure by introducing the star block in YOLOv8, significantly reducing the number of model parameters and computational volume while ensuring the detection accuracy. Based on this, this paper introduces a lightweight shared and detail-enhanced convolutional detection head, which further improves the detail-capturing ability of the detection head and significantly reduces the computational burden. The experimental results show that compared with YOLOv8n on Roboflow-based engineering scene dataset, the mAP@0.5 and mAP@0.5: 0.95 of the improved model improves by 0.3% and 2.0%, while the number of parameters and computational volume decreases by 36.7% and 34.6%, and improves the frames per second (FPS) by 23.3% accordingly, which verifies the superiority of the improved algorithm in terms of lightweight and detection accuracy.

In shield construction, the tunneling attitude of the shield tunnel is an important parameter affecting the quality of the tunneling, which directly affects the track and the quality of the tunnel. Taking an earth pressure balance tunnel boring machine (TBM) as an example, the relationship between the weight of the main machine and the earth pressure and the bearing capacity of the foundation is determined from the theoretical level at the design of the shield machine, which is based on the analysis of the floating and sinking. The influence of the uneven mass distribution on the center of gravity is further analyzed. Finally, through the comprehensive study of the relationship between the force of the host and the thrust of the cylinder under the soil pressure model, the necessary conditions for the control of the driving attitude of the shield machine are determined. The results of this paper have important practical siginificance for improving the design and manufacturing of the shield machine and the construction level of the shield method in China.

In order to solve the problems of insufficient monitoring strength, poor interaction and low digitization degree during the operation of mobile crane, the construction method of digital twin system for real-time monitoring of crane operation status was proposed. A five-dimensional digital twin model is introduced to establish a digital twin framework for virtual and real control of cranes. Build a physical space from the service scene and physical entity; Establish virtual space from virtual model and visual scene and action control. Based on MySQL database, the twin database is constructed by using inherent, collected and virtual information. Virtual and real interaction, dynamic monitoring and visualization are realized in combination with communication protocols. Taking YDC20/30 light and small mobile crane as an example, the feasibility of this method is verified, and a new scheme is provided for comprehensively controlling the service process of the crane.