As the scale of foundation pit projects of subway stations in Shenzhen becomes larger, and the construction constraints become more and more complex, there is an urgent need for intelligent monitoring and safety management of foundation pits. In this study, an integrated intelligent approach for monitoring and management of a deep foundation pit in a subway station was proposed and a case study based on the Waterlands Resort East Station Project of Shenzhen Metro Line 12 was used for validation. The present study first proposed the path of intelligent foundation pit engineering. Based on geotechnical survey and building information modeling, a three-dimensional transparent geological model of foundation pit was constructed. Multi-source sensing technologies were integrated, including micro electromechanical system sensing technology, Brillouin optical frequency domain analysis sensing technology, an unmanned aerial vehicle and machine vision for real-time high-precision wireless monitoring of the foundation pit. Moreover, machine learning models were developed for predicting key parameters of foundation pits. Finally, a digital twin integrated platform was developed for the management of the subway foundation pit in both construction and maintenance phases. This typical case study is expected to improve the construction, maintenance and management level of foundation pits in subway stations.

The interaction mechanism between grouted anchor cables and the surrounding rock mass or soil are complicated and difficult to investigate using conventional monitoring technologies. This study focuses on the in-situ pullout behavior of grouted anchor cables using Brillouin Optical Time-Domain Analysis technique. A series of pullout tests were conducted on anchor cables with five different anchor lengths and three grouting methods. Distributed fiber optic sensors were used to measure the strain distribution of cable bolts from tip to top. The in-situ pullout test results show that both ultimate pullout resistance and ultimate displacement at the ultimate pullout resistance increase with anchor length. The bond strength suffers a slight variation with an increase in anchor length. Both ultimate pullout resistance and the ultimate displacement for Type-B grouting (grouting with reaming) and Type-C grouting (secondary grouting) are larger than those for Type-A grouting (one-time grouting). The shear bond strength of Type-C grouting is greater than that of Type-A grouting. Results from Gaussian functions analysis show that it is feasible to use the function to characterize the axial stress of anchor cables. Furthermore, the overall mobilized percentage η was evaluated. The anchor cables with smaller anchor lengths will result in greater η. The η for the anchor cables of 6 m reaches 92% at the last load, whereas the anchor cables of 18 m were mobilized by only 29% at the last load. The grouting method has a negligible effect on the η, increasing from 22% to 29% in process of the pullout test.

Silicon (Si) has emerged as a promising anode material in the pursuit of higher energy‐density lithium‐ion batteries (LIBs). The large‐scale applications of Si anode, however, are hindered by its significant swelling, severe pulverization, and continuous electrode–electrolyte reaction. Therefore, the development of an efficient approach to mitigate Si particle swelling and minimize interface parasitic reactions has emerged as a prominent research focus in both academia and industry. Here, a facile and scalable strategy is reported for the preparation of a double‐layer coated submicron Si anode, comprising ceramic (silicon oxide) and graphene layers, denoted as Si@SiO_x@G. In this approach, SiO_x is in situ synthesized on the surface of Si and bonded with graphene through hydrogen bond interactions. The prepared Si electrode shows exceptional structural integration and demonstrates outstanding electrochemical stability, with a capacity retention of 92.58% after 540 cycles at 1 A g⁻¹, as well as remarkable rate capability, achieving a specific capacity of 875 mAh g⁻¹ at 2 A g⁻¹. This study presents a straightforward yet pragmatic approach for the widespread implementation of high‐energy‐density silicon‐based batteries.

Graphene-based sensors have drawn significant attention in the field of monitoring due to their excellent mechanical and electrical properties. In this study, an innovative graphene wireless displacement transducer was developed. This displacement transducer consists of two components: a processing unit characterized by the features of low cost, low latency, and low power consumption, and a sensing unit composed of a graphene-based displacement sensor with the advantages of simplification, a large measurement range, and high durability. The structural design of the graphene-based displacement sensor was realized using 3D printing technology. A series of calibration experiments were carried out to evaluate the measurement performance of the displacement transducer. Measurement results of calibration experiments indicate that the measurement sensitivity and static error were 29.6 kΩ/mm and 7.62%, respectively. The maximum measurement range was 0-90 mm. The obtained maximum resistance difference of the graphene sensor is less than 4.5% under the cyclic test, indicating the sensor has excellent stability. The displacement transducer is expected to apply for structural health monitoring of infrastructures such as crack monitoring, relative movement measurement, etc.