The stability of foundation pit slopes is a key concern during the construction of foundation pits. The deformation and instability of slopes will pose a major threat to the safety of foundation pits construction. Based on the foundation pit project of Shenzhen Dapeng People’s Hospital, this study uses DJI phantom 4 RTK drone to collect oblique photography data of the foundation pit in different periods, reconstructs high-precision 3D virtual models through the Bentley ContextCapture software and generates the Digital Surface Model (DSM) data. The model quality report shows that the accuracy of the three-dimensional model is better than 5 cm, up to about 1 cm. Spatial analysis of DSM data in different periods using ArcGIS can obtain the deformation of the foundation pit slopes. This method can also be used for the calculation of earthwork excavation of the foundation pit, which can effectively reduce the field workload of traditional earthwork surveys.

The mechanical performance of precast RC structures relies on the connections, especially the connections of steel bars, between precast RC members. Grouted sleeve splices and grouted spiral-confined overlap connections are widely used in engineering practice in China. Both of these two connection splices require on-site grouting. The process is concealed and invisible, leading to difficult on-site inspection. The unseen defects cause a challenge for detection and repair, which may impair the reliability of precast RC members’ behavior. This paper presents an RC member assembly connection with visible on-site construction quality-monitoring. The proposed confined headed-bar connection (CHBC) consists of two overlapping headed bars and confinement stirrup. With CHBC, the potential construction defects are diminished, and subsequently the construction quality as well as the reliability is upgraded. Experimental investigation on 18 CHBC specimens was carried out; the main parameters considered were overlap length and bar-head size. The failure modes, bearing capacity, stirrup strain development and bond versus slip response are studied. Working mechanism of CHBC is investigated in terms of bond behavior force and concrete compression force at head experimentally and numerically; distributive relationship of these two forces is revealed. The results show that for Φ12 reinforcement, a 90 mm overlap length under test parameters is adequate to reach headed bar ultimate strength in CHBC. Finally, a CHBC-bearing capacity prediction method is suggested based on the superposition method and strut-and-tie model theory.

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The BIM (Building Information Modeling) operation and maintenance management system of the nuclear power plant has been developed to cope with the security risks in the operation and maintenance process of nuclear power plant, the difficulty in querying the operation and maintenance status, the low work efficiency and the difficulty in statistical analysis of various large-scale operation and maintenance data. Practice has shown that the BIM operation and maintenance management system enhances the safety of the plant; on the other hand, the convenience of the results information query improves the professionalization, refinement and systematization of the nuclear power plant safety and operation management; in that way, the safety management efficiency of nuclear power plants will be comprehensively improved.