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Using geographic information systems (GIS) network analysis technology, this paper studied the impact of new subway projects on the accessibility of an urban transit network. First, the status quo of public transit accessibility in Changsha City was estimated using two improved accessibility models: the cumulative opportunity measurement model and the gravity measurement model. Second, the topological structural information of the public transit network and basic public transit data were collected from mapping software. GIS technology was used to build the public transit network. According to the schedules of different subway lines projected to open in the next few years, the impedance of the GIS network was adjusted. Finally, the public transit accessibilities at different stages were calculated with the improved measurement model. Based on the accessibility calculation results at different sites, the development of public transit in Changsha was analyzed using a cluster analysis method.

This paper studies the subway-induced vibrations on two adjacent masonry structures in Shanghai with focus on the vibration level and frequency. The results show that: (1) the vibration levels of the two masonry structures in three directions are all higher during the peak traffic hours than the off-peak hours and are higher in the daytime than at night. In addition, they are higher at the mid-span of the floor than the wall-floor junctions and staircase. (2) The parameters of the numerical model were calibrated by the measured vibration response. The slab properties, room size, and other factors can affect the vibration response distribution. (3) The vertical vibrations in the rooms with precast slab are greater than those with cast-in-situ slab. The vertical vibrations at the ash seam between the precast slabs are amplified. In addition, the room depth has a small effect on the vibration intensity. The relationship between the room depth and the vibration intensity depends on the relative width and depth of the room. (4) The width of the room has a significant effect on the vertical vibration. The floor corner and surrounding wall constraint conditions greatly affect the vibration intensity.

In this paper, a robust parallel finite-element/genetic-algorithm (FE/GA) procedure is presented for finding the optimal layout of wave barriers in the ground alongside the underground or above-ground railways. The proposed FE/GA procedure is capable of optimizing the topology of the wave barriers by altering the FE model geometry and mesh at each optimization step to cope with the excitations by underground, above-ground, and simultaneous under- and above-ground loadings. The results obtained show that this coupled procedure is effective for the analysis and design of different types of wave barriers subjected to dynamic transient loadings. Three different types of wave barriers are studied including wave impeding blocks (WIBs), jet-grouted columns, and trenches. It is found that the open trenches have the largest mitigation capacity and if they cannot be used, the WIBs perform better than the jet-grouted columns. Although the wave barriers can notably reduce the ground vibrations induced by underground trains, they perform more effectively when the source of vibrations is located at the ground surface.

A time–frequency random approach is proposed in this paper for the prediction of subway train-induced tunnel and ground vibrations. This is a development of the random approach previously proposed by the authors, which takes the discrete track support, singular track defects, etc., into consideration. The proposed approach is developed using a two-step method. First, the pseudo-excitation method (PEM) and the two-dimensional multibody system/finite element method model are effectively combined to derive the track–tunnel pseudo-interaction forces by employing the power spectral density of track irregularity. Second, the random vibrations of the tunnel–soil system are obtained via the PEM in the wavenumber–frequency domain. To improve the computational efficiency, a fast-computing strategy is proposed based on the multipoint synchronous algorithm. Using numerical examples, the proposed time–frequency hybrid modeling process is verified by comparing it with the fully coupled time-dependent three-dimensional approach. Furthermore, the influence of the discrete track support on the random vibrations of the tunnel and ground is discussed by comparing the results predicted by the proposed approach with those predicted by the previously developed approach.

In recent years, with the development of urban rail transit, more and more attention has been paid to the vibration problems caused by its operation. As the main form of urban rail transit’s underground construction, the shield tunnel is the first to bear the brunt. However, the existing researches on the vibration of shield tunnel usually take it as a homogeneous barrel and do not consider the impact of its assembly joints on the vibration propagation. In this paper, to study the influence of the joints caused by the shield tunnel’s assembly forms on the propagation of vibration, two finite element models of shield tunnels with different assembly forms are established. The analysis and comparing results of these models show that the joints caused by segment assembly of shield tunnel have obvious hysteresis and reduction effect on the vibration waves and this ability is obviously related to its location. In addition, the ability to weaken the vibration wave is also related to the frequency of the vibration wave.

Most previous studies have focused on the impact of subways on housing prices instead of rents, while the latter could better measure residential values. Based on a dataset collected from a real estate agency in Beijing, which contains more than 900,000 housing rental transaction records from 2011 to 2020, this paper empirically evaluates the causal effect of subway network expansion on housing rents. It employs a series of progressive difference-in-difference (DID) approaches, to estimate the impact and determine the impact scope. The findings demonstrate that a reduction of the distance to subway stations by 1 km increases the rents by 2.32%; the impact scope is about 1.5 km and the average rent appreciation within the range is 5%. The addition of a line for non-transfer stations raises the rents by 10% for houses 1.5–2 km away from the stations, extending the impact scope. Houses with large areas in upscale and old neighborhoods near the city center are affected less by subways. It also confirms the siphon effect in the rental market, i.e.: rents of houses far away from the new stations fall after the opening of the stations.