With the global population aging, urban public transportation systems, particularly subway stations, face significant challenges. This paper outlines the basic concepts of age-friendly design for subway stations, analyzes the behavioral characteristics of elderly passengers, and examines their specific needs regarding barrier-free facilities, information signage systems, and station environments. The paper then reviews recent research advancements, including adaptations of facilities for elderly use, integration of smart technologies, and the development of assessment frameworks tailored to age-friendly criteria. Finally, it identifies key challenges in age-friendly renovations, such as insufficient user research, inadequate data analysis, incomplete evaluation systems, a single-scheme verification mechanism and uneven overall development. The paper also outlines future directions in enhancing intelligent systems and evaluation frameworks to better accommodate the needs of elderly passengers and improve their overall travel experience.

With the rapid development of infrastructure such as railways, highways, and water conservancy and hydropower projects in the western region of China, a number of extremely complex geological conditions and highly challenging ultra-deep buried tunnels have emerged. These developments place higher demands on the collection, analysis, and application of tunnel geological information. Geological information transparency technology plays a crucial role in ensuring safety, controlling costs, and optimizing construction progress, serving as key technical support for the smooth execution of ultra-deep buried tunnel projects. This paper systematically reviews the current development status of geological information detection technologies, covering remote sensing survey technology, geophysical exploration technology, and directional drilling technology in the pre-construction phase, as well as advanced geological forecasting technology during construction. The application scope and development directions of various technologies are analyzed. The paper also reviews the research status of multi-source geological information fusion technology and 3D geological modeling technology, detailing their progress and challenges in predicting geological conditions, model building, and applications. Finally, this paper looks ahead to the overall development of geological information transparency technology for tunnels: First, establishing a five-dimensional integrated detection system encompassing "space-air-ground-borehole-tunnel" to improve detection accuracy; second, developing intelligent geological monitoring technologies and equipment; and third, based on multi-source data fusion, constructing 3D geological models and applying virtual reality technology to achieve dynamic geological information visualization, thus enhancing the safety and efficiency of tunnel construction.

Underground Logistics System (ULS), as a subterranean urban infrastructure with public utility attributes, can effectively meet urban emergency demands through highly resilient freight networks. However, the operational mechanisms and performance assessment methods for ULS in complex emergency logistics scenarios remain underdeveloped. This study examines ULS emergency service capacity, focusing on the impacts of the operational environment, network structure, and scheduling. A model measuring efficiency, effectiveness, and fairness is developed. Simulations based on freight demand and surface road damage, using the Xianlin case in Nanjing, compare ULS and surface truck delivery. Results show that: ULS exhibits significant advantages in emergency freight performance, particularly under conditions of surface traffic congestion and narrow emergency response time windows. Furthermore, increasing node logistics redundancy, optimizing end-point delivery modes, and ensuring local freight fairness are identified as key factors in enhancing ULS emergency service capacity. This research advances ULS planning theory and offers new insights for urban emergency management.

Urban underground logistics system is a complex technology and engineering system developed by the cross integration of modern logistics, transportation, vehicle and underground engineering. Based on the concept of the underground logistics system-pipeline-vehicle collaborative design, a set of cargo vehicle design methods for urban underground pipeline logistics is established. Vehicle technology research and design include vehicle scheme research, vehicle structure and new energy function design, vehicle autonomous driving technology design. This paper designs a special cargo vehicle for pipeline logistics, which is a pipe with inner diameter of 3 800 mm and van with exterior dimension length of 5 000 mm, width of 1 500 mm and height of 2 200 mm. The vehicle has automatic driving, high power, long-distance automatic transportation of goods and wireless charging function when the vehicle is driving in the pipeline. The vehicle design adopts the design concept of green, low-carbon, energy saving and integrated application of more new technological innovations. The technical research and design of cargo vehicle conducted in this paper provides a design scheme of cargo vehicle test sample vehicle and a new vehicle design method of underground pipeline logistics for the implementation of commercial urban underground logistics project.

Aiming at the problem of insufficient bearing capacity of tunnel primary support system under unfavorable geology, such as stress concentration zone and broken structural zone, a composite support structure with stud shear connectors arranged at the interface between steel and concrete is proposed. According to the stress characteristics of tunnel support structure, a large eccentric compression test is carried out to explore the failure mode and bearing characteristics of composite support structure, and the bearing capacity of composite structure under different eccentricity conditions is analyzed by numerical simulation. The results show that when there is no stud shear specimen, the separation failure occurs between I-shaped steel and shotcrete. When the stud shear is arranged, the failure mode of steel reinforced concrete structure is concrete cracking and crushing, and the stud shear effectively limits the relative slip between the contact interface of steel and concrete. Compared with the natural bonding condition, the ultimate bearing capacity of the specimens with double-row stud shear connectors increased by 14.79%, and the lateral deflection decreased by 22.94%. The specimens showed better toughness, bearing capacity and bending stiffness. Under the same eccentricity, the arrangement of stud shear connectors can effectively improve the ultimate bearing capacity of the structure, and with the increase of eccentricity, the effect of stud shear connectors on the bearing capacity of the specimen under large eccentric compression is gradually enhanced. The research results can provide theoretical support for the initial support technology of tunnel.

In order to explore the optimization of air environment and ventilation design parameters in China's extra-long tunnels, this study first analyzed the statistical data of pollutant emission from motor vehicles in China, combined with literature research, and found that the concentration of NO_x in China's tunnels was relatively high, and gradually became the most concerned pollutants in tunnel ventilation. In this study, a field study was carried out in the Yanglin extra-long tunnel in Yunnan. The results show that the peak NO₂ concentration exceeds the ventilation design limit by 2.1 times during the test period, and the emission factors of CO, NO₂ and PM of gasoline vehicles are 0.79 g/(km·veh), 0.04 g/(km·veh) and 10.0 mg/(km·veh), respectively. diesel vehicles are 2.18 g/(km·veh), 1.27 g/(km·veh) and 149 mg/(km·veh), respectively. Compared with the pollutant emission values of domestic and foreign tunnel ventilation design standards, it is found that the current standard values in China are too large. According to the measured emission factors, the required air volume is calculated, and the result is more than 50% lower than the required air volume in Guidelines for Design of Ventilation of Highway Tunnel, which is similar to the required air volume in Standard for the Design of Road Tunnels, and the control item of the required air volume is NO₂ concentration. The results of this study can provide reference for the calculation of pollutant emission and air demand in tunnel ventilation design in China.

Subways, as a primary component of urban public transportation, harbor particulate matter within their microenvironments that pose health risks to commuters. To enhance the health of individuals during their subway commutes, a study was conducted to analyze the spatiotemporal heterogeneity of fine particulate matter (PM_2.5) concentrations in the subway microenvironment. The results show that: The PM_2.5 concentration in underground train carriages on weekdays (113.67 μg/m³) is higher than on non-working days (47.62 μg/m³), and the PM_2.5 concentration in underground train carriages is significantly higher than in above-ground and elevated sections (seven times higher) ; lines constructed earlier have higher PM_2.5 concentrations than newly built lines; the PM_2.5 concentration on platforms exhibit a cyclical trend with the arrival and departure of trains; fully enclosed screen doors are more effective than full-height security doors in controlling the accumulation of particles; the PM_2.5 concentration during off-peak hours (75 μg/m³) is lower than during peak hours (102 μg/m³). Furthermore, the study analyzed the potential impact of off-peak travel strategies on the PM_2.5 exposure levels of commuters, the results suggests that off-peak travel could reduce exposure by 25.58% during a single commute. The results of the study provide data support for the prevention.

To solve the problems of waste accumulation and deep and narrow backfilling of foundation pit in the construction process, by adding polycarboxylate superplasticizer (PCE), cement, phosphogypsum (PG) and water glass (WG), the engineering residue is improved into fluid solidified soil for foundation pit backfill. The effects of various admixtures on the fluidity, strength and drying shrinkage of the improved fluid solidified soil were studied through laboratory mobility test, unconfined compressive strength test, drying shrinkage test and microscopic test, and the improvement mechanism was analyzed. The results show that: The flow property of the material can be greatly improved by adding PCE, but the flow rate decreases rapidly with the increase of cement content. PG can make the sample obtain higher strength in the later stage, while water glass can improve the early performance and drying shrinkage property of the sample. With the incorporation of cement, PG and water glass, various hydration products fill the pores in the soil, and the internal structure of the soil becomes more dense. In addition, the feasibility of using fluid solidified soil as backfill for foundation pit is verified by selecting test section for field backfill. This paper can provide reference for improving the performance of fluid solidified soil and the design of mix ratio.

In order to study the dynamic changes and amplitude values of groundwater level in karst mountainous areas, taking the karst mountainous city of Guiyang as an example, selecting daily monitoring data and precipitation data from nine groundwater level dynamic observation points from 2022 to 2023, autocorrelation and cross-correlation analysis are used to analyze the response of groundwater level to precipitation and explore the influence of runoff and drainage conditions and terrain slope on the dynamic changes of groundwater level. The results show that: (1) The groundwater level in the study area is buried at a depth of 1.21 ~ 27.68 m, with an annual variation range of 1.54 ~ 11.99 m, and there are significant differences in the spatiotemporal distribution of groundwater level dynamics; (2) The relevant analysis results indicate that there is a significant lag in the response of groundwater level to precipitation signals in the study area, with an average lag time of 0~4 days, and it gradually increases from the supply area to the discharge area; (3) The terrain slope is an important factor affecting the amplitude of groundwater level variation in karst mountainous areas. The terrain slope in the study area is positively correlated with the amplitude and variation of groundwater level, with linear goodness of fit (R²) of 0.65 and 0.78, respectively; (4) The depth of groundwater level gradually decreases from the recharge area to the discharge area, and the range of water level changes from the runoff area to the recharge area to the discharge area.

A large number of different inclinations of tectonic fracture exist for the Sichuan-Tibet Railway along the tunnel peripheral rock, and often in the high ground temperature and high stress coupling environment. In order to study the influence of fracture inclination on the unloading failure characteristics of hard rock under high temperature and high stress coupling, this paper analyzes the unloading rupture characteristics of granite specimens of a tunnel of Sichuan-Tibet Railway under 50 ℃ real-time temperature field through unloading test by adopting indoor test and numerical simulation method. The results show that: the unloading strength decreases with the increase of fracture inclination angle, when the fracture inclination angle is 0°, the unloading strength of the specimen under the 50 ℃ real-time temperature field is obviously smaller than the unloading strength at room temperature; the fracture specimen under the unloading condition has strong tensile damage characteristics, and the dilatancy phenomenon of the specimen under the 50 ℃ real-time temperature field is more obvious when the fracture inclination angle is 30°; When the fracture inclination angle is 0°, a penetrating fracture through the center of the pre-fracture is generated; under the real-time temperature field of 50 ℃, the larger the fracture inclination angle is, the more dispersed microcracks are developed in the unloading process of the specimen, and the smaller the inclination angle is of the pre-fracture, the earlier the accelerated point of fracture development occurs.