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.

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.

In order to investigate the plastic yielding mode of surrounding rock caused by the excavation of shallow twin tunnels, the displacement and additional surface force joint controlling the Schwarz alternation method and complex function method are adopted to solve the elastic stress function of surrounding rock of shallow twin circular tunnels through iterative cycles as an example. The expression of plastic stress components of surrounding rock is obtained based on Mohr-Coulomb failure criterion. The elastoplastic solution of the radius of the plastic zone is determined preferentially by using the stress continuity condition at the interface of the elastic-plastic zones around the shallow twin circular tunnels. The analytical solution for the distribution range of the plastic zones around the shallow twin circular tunnels is established, according to the interconversion relationship between polar coordinates and right-angle coordinates. The rationality and applicability of the analytical solution are verified by numerical simulation results and field measurement results of engineering application. The influence of the center spacing of the twin tunnels on the plastic zones around shallow twin circular tunnels are also analyzed. The results show that the analytical solution in this study can be used to solve the problem of predicting the distribution range of the plastic zones around shallow twin tunnels in actual engineering, and meets the requirement of 20% engineering accuracy, fits well with the numerical simulation results, and has a high calculation accuracy. The distribution range of the plastic zones around shallow twin circular tunnels are positively correlated with the center spacing s of the twin tunnels. Based on the distribution pattern of the plastic zone around shallow twin circular tunnels under the influence of this factor, when the plastic zone reaches the critical state of penetration, the reasonableness of the calculation results of the distribution range of the plastic zones is preliminarily judged. It provides theoretical guidance for similar tunnel engineering design calculation and deformation control of surrounding rock.

In order to investigate the impact of pore and fracture structure on the nonlinear deformation characteristics of rocks during the entire stress-strain process, considering the differences in deformation between pores and the matrix, porous rocks are deconstructed into two components: hard springs and soft springs. The Two-part Hooke's Model (TPHM) and statistical damage theory are introduced. Based on the TPHM, the complete stress-strain relationship of rocks is established, and the porosity evolution equation for the entire stress-strain process of rocks is derived. This model overcomes the limitation of the traditional Two-part Hooke's Model, which is unable to represent the plastic deformation of rocks after yielding. It not only accurately characterizes the nonlinear deformation during the pore compaction stage, plastic yielding, stress drop after peak, and residual stress characteristics in the rock compression process, but also effectively represents the porosity variation during the entire stress-strain process of rocks. Extensive experimental data validation has demonstrated that the theoretical curves of this constitutive model align well with the experimental results, with correlation coefficients consistently exceeding 0.9.

With the excavation of tunnels, the surrounding rock is disturbed and damaged, resulting in changes in its geotechnical parameters. To obtain dynamic variation laws of geotechnical parameters accurately, an inversion method for mechanical parameters of tunnel surrounding rock based on updated boundaries particle swarm optimization (UBPSO) algorithm is proposed. Due to the large fluctuation of optimization results with the particle swarm algorithm, an updated boundaries particle swarm algorithm is proposed. By updating the upper and lower limits of search boundaries dynamically, performing reversal and mutation operations on individual historical optimal values, and updating inertia weights adaptively, the updated boundaries particle swarm algorithm achieves high-precision and fast optimization. The stability test of the Ackley function indicates that compared to the particle swarm optimization algorithm, the updated boundaries particle swarm algorithm has the following advantages, fast optimization speed, high accuracy of results, small fluctuation of outcomes, and less sensitivity to getting stuck in local optima. Based on the updated boundaries particle swarm optimization algorithm, a reverse analysis model for mechanical parameters of tunnel surrounding rock using MATLAB-PYTHON-ABAQUS and on-site monitoring data is established. Taking the YK76+470 to YK76+502.5 section of the Tongluoshan tunnel as an example, the model was used to analyze the on-site monitoring data of the tunnel arch settlement. It was found that the elastic modulus of the colluvial soil layer decreased from 0.200 GPa to 0.106 GPa, the internal friction angle dropped from 14° to 12.072°, and the cohesion value fell from 22 kPa to 19.373 kPa.

In order to enhance the prediction accuracy of surrounding rock deformation, enable real-time monitoring of deformation status, prevent deformation failure, and ensure construction safety, a novel underground cavern surrounding rock deformation temporal prediction method based on GRU neural network is proposed to tackle the low training efficiency, slow convergence, and poor generalization of traditional methods, along with the establishment of a corresponding prediction framework. Utilizing monitoring data of surrounding rock deformation from the underground powerhouse on the right bank of the Baihetan Dam, predictions are made and subsequently compared and analyzed with the forecasting results generated by the Long Short-Term Memory (LSTM) neural network algorithm. The results indicate that the GRU neural network model effectively addresses the prediction challenges associated with underground cavern surrounding rock deformation, offering advantages such as simplified structure, relatively fewer parameters, rapid training and convergence rates, and high prediction accuracy. Compared to the predictions derived from the LSTM neural network algorithm, the GRU model demonstrates a reduction in training duration by over 70%, with a corresponding decrease in prediction error of more than 50%. The relative error for cumulative maximum deformation is less than 0.3%, the probability of absolute error less than 0.9 mm is as high as 95%, and the maximum absolute error is only 2.05 mm.

Due to its insufficient cover thickness, the excavation face of shallow-shield tunnels is susceptible to passive instability. Tunnel longitudinal slope lead to sudden changes in cover thickness, making the passive failure mechanism of tunnel faces more complicated. There is an urgent need to explore analytical methods for excavation face stability in shallow-buried longitudinal slope shield tunnels. Based on upper bound analysis, a two-dimensional rotation-translation mechanism is proposed that simultaneously considers tunnel longitudinal slope and local instability at the excavation face. The mechanism is comprised of two rigid translation blocks and one rigid rotation block. The ultimate support pressure and failure mode of passive instability at the excavation face are obtained. Finally, the effects of longitudinal slope δ and partial failure ratio η on ultimate support pressure and failure mode of tunnel faces are analyzed, and the reasonableness of proposed models is verified by combining with engineering cases. The results indicate that: Partial failure range of excavation faces gradually increases with the increase of longitudinal inclination angle δ. As the cover depth ratio C/D increases, partial failure of the excavation face evolves into global failure. The rotation angle θ of the rigid rotating block decreases with the increase of the longitudinal inclination δ, and the longitudinal inclination δ has a significant effect on the rotation angle θ.

The sandy clayey purple soil is susceptible to alterations in particle size distribution due to hydraulic erosion, such as rainfall and fluctuations in reservoir water levels. These changes can affect the soil's strength. To elucidate the strength characteristics of sandy clayey purple soil in the influence of the absence of different particle groups, consolidated drained triaxial shear tests of saturated sandy clayey purple soil with five distinct particle groups were conducted. The fractal dimension was employed to quantify the physical properties of varying particle sizes. The relationship between the strength characteristics of purple soil with different particle groups and the fractal dimension was obtained. The results show that: (1) There is no significant change in the internal friction angle of the soil shear strength index under the missing effect of different grain groups, but the cohesion and fractal dimension show a hyperbolic relationship; the initial tangent modulus of different grain groups is affected by confining pressure and fractal dimension, and there is a quadratic function relationship between parameter n and fractal dimension. Under low confining pressure, the stress-strain relationship of different grain groups is obviously different. With the increase of confining pressure, the stress-strain characteristics tend to be consistent. (2) Based on the Duncan-Chang E-ν model, the nonlinear elastic hyperbolic constitutive model of saturated sandy clayey purple soil under the effect of different particle groups is established by fitting the cohesion-fractal dimension hyperbolic equation, and the validity of the model is verified.

Aiming at the geological characteristics of loess overlying red-bedded mudstone in the Gansu area, two kinds of industrial solid wastes, namely steel slag and mineral powder are adopted to carry out the research on the mechanical properties and the constitutive model of the modified loess-red bedded mudstone mixed fill by compacting and triaxial CU test. The results show that: (1) The maximum dry density of the mixed fill is the largest when the mass ratio of loess: red mudstone is 1 ∶ 3. (2) The shear strength of steel slag is maximum when the mass dosing of steel slag is 7.5%. The larger the mass dosing of mineral powder is, the larger the shear strength is. (3) It is verified that the strain hardening process of soil samples before and after steel slag improvement could be accurately fitted by the Duncan-Zhang model. (4) For the problem that the hyperbolic model promoted by Shen Zhujiang can not fit the strain hardening well, this paper proposes to use the staged fitting method with positive and negative solutions, and it is verified that this method can accurately fit the strain hardening process of the mineral powder amended soil.