Track irregularities have an obvious effect on the running stability and ride quality of maglev trains traveling at high speeds. We developed a measurement principle and data processing method which were applied to the high speed maglev line operating. The method, which includes partial filtering, integration, resampling of signal, and a low pass Butterworth filter, was used to calculate the irregularities of the maglev line. The spectra of the sample space were evaluated. A 7-parameter power spectrum density (PSD) function of line irregularities was fitted, based on the measured data. Analysis of the results showed that the maglev stator plane irregularities were better than conventional railway vertical rail irregularities when the wavelength was 5–100 m, and worse when the wavelength was 1–5 m. The PSD of maglev guidance plane irregularities was similar to that of cross level GRSHL (German railway spectra of high irregularity) when the wavelength was 10–100 m. The irregularities were clearly worse than cross level rail irregularities in a conventional railway when the wavelength was 1–10 m. This suggests that short-wavelength track irregularities of a maglev line caused by deviation and inclination of the stator plane should be minimized by strictly controlling the machining error of functional components during construction and maintenance.

To investigate the displacement and stress distributions for deep circular tunnels with liners in saturated ground, an analytical model is proposed. For a deep tunnel with drainage conditions, plane strain conditions at any cross-section of the tunnel and the elastic regime of the linear elasticity for the remaining liner are assumed, while the ground is assumed to be linearly elastic and perfectly plastic with a failure surface defined by the Mohr-Coulomb criterion. The post-yield behavior of the ground follows the non-associated flow rule defined by the dilation angle. To solve the proposed problem, two procedures are presented. An axisymmetric model for a deep circular tunnel with a steady-state seepage condition is considered, and then a simple closed-form analytical solution is obtained with a common theoretical framework for the boundary conditions of a constant total head along the tunnel circumference. Assuming that certain ground displacements along the tunnel circumference have occurred before the installation of the liner, analytical solutions of stresses and displacements are derived with particular emphasis on the seepage and the stress release effect induced by tunnelling. The proposed analytical model is validated by numerical simulation.

In recent years, local component destruction, collapse failure and the control of long-span cable-stayed bridges under strong multi-support excitations have received increasing attention. In this paper, two kinds of nonlinear finite element (FE) models are established to simulate the seismic responses and failure modes of a multi-span cable-stayed bridge scale model under multi-support excitations. One is the single girder model which is used to simulate the seismic response during four wave excitations. It can be concluded that the FE analysis results of the scale model are a good fit with those from the shaking table tests. The other one is the explicit dynamic FE model which is used to simulate the collapse and failure mechanisms of the scale model during strong earthquakes. The aggressive failure processes of the scale model under two different types of wave excitations were compared to reproduce the mechanisms in which the bearing at the middle tower failed under the El Centro (EC) wave (4.0 m/s²), and we also observed the connection failure of the cables and towers, and the elements failure of the upper beam in the middle tower, which occurred successively under a Jiangxin (JX) wave (4.0 m/s²). This simulation may be referenced as the basis for the collapse failure of a cable-stayed bridge with a large span during a strong earthquake.

The concrete-cored deep cement mixing (DCM) pile is a new kind of composite pile created by inserting a precast core pile into the DCM column socket and has only been used in a few expressway projects to date. In this paper, full scale field tests of composite foundations reinforced by both concrete-cored DCM piles and by conventional DCM columns under embankments were conducted in northeast of Nanjing Surrounding Expressway (NS-N Expressway), China. With the installation of settlement plates, multipoint settlement gauges, inclinometers, piezometers, pressure transducers, and steel stress meters, the results of plate load tests and long-term monitoring, including ultimate bearing capacity, total settlement, settlement along depth, lateral movement, loading sharing ratio, vertical stress of precast core pile, and excess pore pressure were presented. Based on field test results, the reinforcement effects of composite foundations reinforced by concrete-cored DCM piles and conventional DCM columns were compared. The load transfer characteristics of concrete-cored DCM piles under embankments were also discussed. The test results show that the foundation treatment effect of concrete-cored DCM pile is better than that of the conventional DCM column. Compared to the conventional DCM column, the upper load borne by concrete-cored DCM pile is higher, while the excess pore pressure in concrete-cored DCM pile composite foundation is lower than that in conventional DCM column composite foundation. Under embankment, negative friction occurs at the upper section of concrete-cored DCM pile.

Die-less spinning eliminates the dependence upon the mandrel of traditional spinning, but bringing about comparatively poor dimensional accuracy which needs to be improved. In this paper, roller paths in the first pass of die-less spinning, including concave, convex, linear and combined ones are parameterized according to the degree of bending and their effects on dimensional precision (thickness variation and shape deviation) have been studied by using experiments of finite element (FE) analysis. The effects of roller paths on thickness variation, shape deviation, tool forces, and stress and strain variations have been analyzed numerically. The results showed that for concave roller paths, the thickness variation is not very sensitive to the degree of bending, while a low degree of bending of the roller path can result in a low shape deviation. For convex roller paths, a low degree of bending leads to both low thickness reduction and low shape deviation. Further research shows that a combined roller path with convex-concave curve could contribute a low shape deviation, while an inverse combined roller path gives better thickness precision.

A nonlinear cumulative evolution model for corrosion fatigue damage was proposed. Corrosion fatigue damage was considered as a nonlinear cumulative result of stress corrosion damage and fatigue damage. The influences of stress corrosion damage and fatigue damage on corrosion fatigue damage and damage evolution life were studied from a phenomenological point of view. The relevant damage parameters were determined by the experimental results of the LY12CZ aluminum alloy, and the corrosion fatigue life evaluation model based on damage evolution law was established. The corrosion fatigue life predicted by evaluation model agrees well with the experimental result. The damage evolution model in this study can provide a new method for theoretical research and life prediction of corrosion fatigue.

The rapid growth of NO_x emissions in China is mainly due to intensive fossil fuel consumption. In order to control NO_x emissions, a multiyear NO_x emission inventory was established by a bottom-up approach for the period 2000–2010. The results showed that NO_x emissions increased by 2.1 times from 11.81 million tons (Mt) in 2000 to 24.33 Mt in 2010. We found that NO_x emissions had exceeded SO₂ emissions in 2009 by comparison with their emission trends. We also found that the unbalanced NO_x emissions in Eastern China and Western China are mainly due to the different gross regional product and industrial structure. Accounting for 70% of total energy consumption in China, coal is the largest NO_x emission source among all the fossil fuels. In addition, the increased use of diesel and gasoline has spurred the increase of NO_x emissions from the transportation sector. Manufacturing, electricity production, and transportation together composed about 90% of the national NO_x emissions. Meanwhile, energy consumption and NO_x emissions in China are predicted to be 3908.5 Mt standard coal equivalent (SCE) and 19.7 Mt in 2020 with this scenario analysis, respectively. To achieve a desired NO_x reduction target, China should take strict measures to control NO_x emissions, such as improvement in reduction technology, promulgation of new emission standards, and joint control by various Chinese provinces.