Su H.,Beijing Jiaotong University |
Su H.,Shandong University of Science and Technology |
Li X.,China University of Mining and Technology |
Wang C.,Beijing Urban Construction Design & Development Group Co. Ltd
Tiedao Xuebao/Journal of the China Railway Society | Year: 2016
Targeting the metro station to be built with prefabricated concrete structure, a new type of joint was proposed which is based on the tongue and groove connection with bond slurry to strengthen the reliability and the anti-deformability. An axial force and moment destructive experiment was conducted on the single tongue and groove type joints with two different lengths. By means of the analysis of the surface crack, surface concrete strain and internal reinforcement stress, the flexural capacity of the joint was determined, which was divided into five stages. Combined with the joint opening, the maximum safety bearing value in design was put forward from the prospective of water resistance and structure stress. Finally, by analyzing the maximum eccentricity of the safety stage, the flexural capacity of joints within a certain range of axial force under different working conditions was defined. © 2016, Editorial Office of Journal of the China Railway Society. All right reserved.
Cheng X.-H.,Beijing Urban Construction Design & Development Group Co. |
Pang Z.-Y.,Beijing Urban Construction Design & Development Group Co. |
Zeng D.-Y.,China Communications Construction Company Ltd. |
Zeng D.-G.,Beijing Urban Construction Design & Development Group Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2016
To discriminate and measure the whole stability of unlined shallow earth tunnel in theory, considering the effect of oblique slip surface beside tunnel body, a theoretical solution of ultimate surcharge is deduced by adopting the limit equilibrium method during the occurrence of the tunnel overall instability, and then the solution is examined using the typical loading tests. It is found that the solution of ultimate surcharge formulation is close to the test results. On the basis, the ratio of sliding resistance to sliding force is defined as the whole stability safety factor, and its influencing aspects are analyzed. It is shown that the stability safety factor increases along with the increment of the cohesive force and the internal friction angle, and the effect of cohesive force on the safety factor is significant, but the effect of internal friction angle is less potent. The stability safety factor decreases with the increment of the span, the depth-span ratio, and the surcharge of earth tunnel, but the surcharge has less effect on the stability safety factor when it is larger. With the increment of the height-span ratio, the stability safety factor decreases as the cohesive force is low, but it increases firstly and then decreases as the cohesive force is high. Finally, the whole stability safety factor is verified by typical loading experiments, demonstrating that the calculation error is within the engineering allowance. © 2016, Academia Sinica. All right reserved.
Hu S.-M.,Beijing Urban Construction Design & Development Group Co.
Tiedao Xuebao/Journal of the China Railway Society | Year: 2015
With regional tunnel in Xi'an metro as the project background, by means of theoretical analysis, site experiment and finite element numerical calculation, the safety for support parameters was evaluated based on convergence-confinement method. The results showed that: (1) The characteristic curve of the loess stratum can be divided into straight line and curve segments. Yield first occurred at sidewall surrounding the tunnel and plastic slip wedge gradually formed extending to the vaults and arch bottom; (2) All the components in the composite support structure were in parallel to bear the pressure of surrounding rock; (3) The mechanical properties of supporting structure in a plastic state were deteriorated sharply. As plastic yield was not allowed in the supporting structure during the construction and operation, this paper proposed the method of defining the safety factor of supporting structure from the perspective of allowed displacement; (4) The maximum reaction force that the supporting structure provided during the field test was greater than the stress of the equilibrium point between surrounding rock and supporting characteristic curve, showing that current supporting parameters met the safety requirements; (5) The safety evaluation method for supporting structure was proposed from the perspective of the permissible displacements. Through the finite element calculation results, the corresponding strata and support characteristic curves were drawn to obtain corresponding safety factors. The calculation showed that the minimum safety factor of the tunnel support structure was 1.14 at the sidewall, which should receive attention during design and construction. ©, 2015, Science Press. All right reserved.
Zhu B.,University of Science and Technology of China |
Kou W.,Beijing Urban Construction Design & Development Group Co. Ltd |
Li H.,University of Science and Technology of China |
Li G.,University of Science and Technology of China
Open Construction and Building Technology Journal | Year: 2016
A new type of prefabricated arch culvert is consisted of precast arch pieces and cast-in-place concrete bases. The shape of precast arch pieces is confirmed by catenary theory. In the case of simulating placement in layers of embankment, internal forces of arch piece structure are statically analyzed by using finite element method. The results indicate that under the designed filling height, arch pieces mainly suffer from stress and only very little bending moment and shear force acted on them. The prefabricated arch culverts have reasonable structure stress and simple installation process, which can substantially save materials and shorten project duration of culverts with obvious economic benefits, and should be promoted and applied in mine highway engineering. © Zhu et al.
Hu S.,Beijing Urban Construction Design & Development Group Co.
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2016
Cavern-pile stations of Beijing 6th line metro were taken as project background in this paper, the ground surface settlement prediction was performed by site measured data of mined metro station in Beijing area. Firstly, the ground surface settlement regularity was analyzed by Cam-clay model. Then, the settlement control of cavern-pile station was performed in every construction sequence based on deformation distribution method. The results show as follows: The stratum loss ratio V1 of cavern-pile station is less than 1%, and the settlement trough width parameter K ranges between 0.65~0.8. The proportion of ground surface settlement is approximately 80% induced by pilot excavation (construction sequence (1)) and arch support in second lining stage(construction sequence (3)), thus construction sequence (1) and (3) are vital to the control of ground surface settlement. The measured value of ground surface settlement basically agrees with the calculated, and the maximum value appears above station center line. © 2016, Editorial Department of Journal of Beijing Jiaotong University. All right reserved.
Xu B.-C.,China University of Petroleum - Beijing |
Zhang Y.-D.,Beijing Urban Construction Design & Development Group Co.
International Journal of Systems Science | Year: 2014
Disorder and peak noises or large disturbances can deteriorate the identification effects of Hammerstein non-linear models when using the least-square (LS) method. The least absolute deviation technique can be used to resolve this problem; however, its absolute value cannot meet the need of differentiability required by most algorithms. To improve robustness and resolve the non-differentiable problem, an approximate least absolute deviation (ALAD) objective function is established by introducing a deterministic function that exhibits the characteristics of absolute value under certain situations. A new identification method for Hammerstein models based on ALAD is thus developed in this paper. The basic idea of this method is to apply the stochastic approximation theory in the process of deriving the recursive equations. After identifying the parameter matrix of the Hammerstein model via the new algorithm, the product terms in the matrix are separated by calculating the average values. Finally, algorithm convergence is proven by applying the ordinary differential equation method. The proposed algorithm has a better robustness as compared to other LS methods, particularly when abnormal points exist in the measured data. Furthermore, the proposed algorithm is easier to apply and converges faster. The simulation results demonstrate the efficacy of the proposed algorithm. © 2014 Taylor & Francis
Yin J.,Beijing Jiaotong University |
Yin J.,University of Wisconsin - Madison |
Zhao W.,Beijing Urban Construction Design & Development Group Co.
Engineering Applications of Artificial Intelligence | Year: 2016
With the rapid development of high-speed railways (HSRs) throughout the world, the fault diagnosis systems of vehicle on-board equipments (VOBEs) for high speed trains have received increasing attention. Since the faults of VOBEs in HSRs are usually uncertain and complex, the current fault diagnosis methods are mainly based on manual judgement in real-world operations, which is generally inefficient and insecurity with the big rail traffic data. In this paper, we propose an automated diagnosis network of VOBE for high-speed train via a deep learning approach. First, we propose a mathematical model to formulate the fault diagnosis problem in HSRs, involving the definition of fault evidence vectors and reason vectors by analyzing the real-world fault data that are collected in Wuhan-Guangzhou high speed railway. Then, a deep belief network (DBN) and its training procedures are developed on the basis of Restricted Boltzmann Machine (RBM). Finally, the proposed diagnosis network is trained and validated with real-world data. Furthermore, we compare the DBN-based fault diagnosis network with k-nearest neighbor (KNN) and ANN-BP (artificial neural network with back propagations). The results indicate that, the developed DBN outperforms both KNN and ANN-BP, and improves the accuracy of fault diagnosis for VOBEs to 90–95% in HSRs. © 2016 Elsevier Ltd
PubMed | Beijing Urban Construction Design & Development Group Co. and Beijing Forestry University
Type: Journal Article | Journal: Water science and technology : a journal of the International Association on Water Pollution Research | Year: 2016
Significant concerns have been raised over the presence of antibiotics including sulfadimethoxine (SDMO) in aquatic environments. This study investigated the removal capability and mechanism involved in the removal of SDMO by hydrous ferric oxides (HFO). Results showed that SDMO removal was highly pH and ionic strength dependent. The pseudo-first-order model fitted well the kinetic results, and the value of the calculated activation energy for SDMO adsorption onto HFO was 8.6 kJ mol(-1). Adsorption isotherms at varied temperatures were well described by the Langmuir model. Thermodynamic parameters (change in enthalpy > 0, change in entropy > 0, and change in Gibbs free energy < 0) calculated from the temperature-dependent sorption data revealed spontaneous and endothermic process. The exchange of the surface hydroxyl groups of HFO and the negative anions of SDMO(-) and the electrostatic interaction between the positively charged surface of HFO and the deprotonated imino (-N(-)-) accounted for the uptake of SDMO by HFO.
Hua F.,Beijing Jiaotong University |
Hua F.,Beijing Urban Construction Design & Development Group Co.
Modern Tunnelling Technology | Year: 2015
With respect to mined metro tunnelling in mixed ground, a combined phreatic water and fissure water media analysis model is established based on the continuous porous media model for a phreatic aquifier, a formula and specific parementer values used to predict fissure water inflow are derived in light of the dynamics of groundwater, and the application method for the above formula for predicting water inflow at the grouting-reinforced section of metro tunnels is put forward. Using the Qingdao metro tunnel as an example, the water inflow is predicted by the analytical method and the numerical analysis method, respectively, and is compared with the measured values at the site. Analysis results show that the estimation error is lower for the analytical method. In addition, the effects of different tunnel shapes on water inflow are analyzed and it is concluded that the section type has little effect on the water inflow. Thus, the derived analytic formula has high applicability for predicting water inflow in mined metro tunnels in combined rock and soil strata. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.
Li Z.,Beijing Jiaotong University |
Wang C.,Beijing Urban Construction & Design Development Group Co. |
Su H.,Beijing Jiaotong University |
Shi S.,Beijing Jiaotong University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015
The application of prefabricated structure in metro station has an advantage of shorting the construction period, increasing efficiency and improving engineering quality. At present, an open cut metro station has been constructed by using the prefabricated structure. The segment joint is the weakness part in the integral structure, and its mechanical properties determine the deformation and bearing capacity of the prefabricated structure to a great extent. In this paper, taking the joint of the prefabricated metro station as the research object. The joint mechanical properties are studied by the full-scale loading test. The evolution law of concrete structure crack and joint seam deformation for tenon groove joints of the prefabricated metro station are discussed in detail. The experiment research result has an important application value for the design of metro station structure joint and calculation of prefabricated structure being used in the open cut metro engineering. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved.