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Liu K.,Hefei University of Technology | Huang S.,Hefei University of Technology | Wang F.,Anhui University | Xie H.,Hefei University of Technology | Lu X.,Anhui Expressway Holding Group Ltd
Cold Regions Science and Technology | Year: 2017

The automatically snow-melting system with the electric heating pipes (AS-EHP) is applied in infrastructures (concrete pavement, parking apron, garage entrances and municipal road) in cold regions to mitigate the accumulated snow problem. In order to reduce the energy consumption (EC) and improve the energy utilization rate (EUR) of AS-EHP, the analysis about EC and EUR is investigated. The melting process of AS-EHP is divided into two phases which include preheating the infrastructures and melting. The influence and sensitivity analysis between the inputs (the pipes’ embedded spacing and embedded depth, heating power and wind velocity) and the outputs (EC and EUR) are found and compared in two phases by thermal simulation. The applicability and rationality of the simulation are verified by snow melting experiments. According to the simulation, decreasing embedded spacing and depth in phase 1 and phase 2 could reduce EC and improve EUR. In the two phases, the heating power is suggested to be 100 W/m-140 W/m under the condition that the heating pipe’ embedded spacing is 0.10 m–0.25 m, the depth is 0.06 m–0.12 m, and the wind velocity is 0 m/s–15 m/s. The results and suggestions could be used to efficiently guide the scheme design and operation control of AS-EHP in infrastructures. © 2017 Elsevier B.V.

Lu X.,Anhui Expressway Holding Group Ltd | Zhang S.,Anhui Province Transportation Occupation Technical College | Wu Y.,Indonesian Buton Rock Asphalt Co.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2015

Six different types of AC20 mineral aggregate gradation are provided with distinct Buton rock mixture, and the pavement performance of Buton rock asphalt mixture was conducted by taking AH-70 road asphalt as basis. The results show that rock mineral in raw materials of Buton rock asphalt has a great impact on the mineral aggregate gradation and pavement performance, and appropriate selection of rock mineral mixture can improve comprehensive pavement performance remarkably. The comprehensive pavement performance is close to that of SBS modified asphalt mixture with 0.5%-1.0% mixing content (by mass), but it is limited in improving the water sensibility of asphalt mixture. The relationship between the dynamic stability of Buton rock asphalt mixture and rock mineral content occurs in concave curve characteristics, and the influence of rock mineral content variations on the dynamic stability of asphalt mixture is remarkable. The raw material of Buton rock asphalt cannot be added into the matrix asphalt for carrying out Marshall test to determine the raw material content as SBS modifier. The particularity of Buton rock asphalt material should be considered during the mix design, and its rock mineral should be separated from the pure asphalt, and blended independently, or the mineral aggregate gradation of Buton rock asphalt will have a great impact on the performance of rock asphalt mixture. ©, 2015, Tongji University. All right reserved.

Liu J.-P.,Wuhan University | Cheng F.,Wuhan University | Fan C.-Y.,Anhui Expressway Holding Group Company Ltd | Cao J.,Anhui Expressway Holding Group Company Ltd
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The two-dimensional (2D) numerical simulation of seismic wave fields based on tunnels is a basis for the analysis of propagation laws of seismic waves in the tunnel prediction. All of the current researches, which are designed with observation systems on the sidewalls of tunnels and assume tunnels as homogeneous media with the same elastic parameters of surrounding media, are not in conformity with the actual situations because they cannot involve surface waves. A geological tunnel-based model is established, which is more suitable for the practical tunnels to achieve the 2D numerical simulation of seismic full-wave fields. The results show: (1) using a staggered grid finite-difference (FD) algorithm with a second-order accuracy in time and a fourth-order accuracy in space, we can achieve the 2D numerical simulation of seismic full-wave fields without ignoring the air medium in tunnels; (2) when considering a vertical geological interface, common-source system with shots near the tunnel face is better for obtaining reflection waves than the one with shots on the side walls; (3) with the decrease of the dips of geological interfaces, the energy of reflection waves increases when shots and receivers are on the same side; (4) for the local geological features and interfaces, shear wave shot on the tunnel face, which acquires more energy than pressure wave shot, can help in shear wave imaging.

Wei J.C.,Key Laboratory for Expressway Maintenance Technology | Lu S.D.,Anhui Expressway Holding Group Co. | Li J.,Anhui Expressway Holding Group Co.
Advanced Materials Research | Year: 2014

This study focused on the performance of the Large Stone Permeable Asphalt Mixture (LSPM) with neat asphalt and its feasibility to use as asphalt pavement flexible base. For comparision, LSPM mixtures were designed respectively with neat 60/70-grade asphalt and modified asphalt and the performance of LSPM was studied and compared by volume index test, draindown test, Hamburg Wheel-tracking Test and dynamic modulus test. The results showed that the performance of LSPM with modified asphalt was superior to LSPM with neat asphalt and cellulose fiber, but draindown and rutting performance of LSPM with neat asphalt met requirements of corresponding specification and dynamic modulus of LSPM with neat asphalt had the same characteristic with LSPM with modified asphalt, which proven that LSPM with neat asphalt can use as asphalt pavement flexible base by properly mix design and pavement structure design. © (2014) Trans Tech Publications, Switzerland.

Fang Y.,Beijing Jiaotong University | Fang Y.,Anhui Expressway Holding Group Co. | Liu K.,Beijing Jiaotong University
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2015

A non-linear support vector regression intelligent model which maps the relation between mountain tunnel drill blasting construction parameters, geological conditions and crown subsidence of surrounding rock and loose circle depth is established ultilizing the genetic algorithm and support vector regression coupling algorithm. The model is applied to the construction of Foling long and large highway tunnel. The model is first trained by the field testing data. Then the model is used to optimize the selection of drill blasting parameters with given control indexes such as geological conditions of surrounding rock, vault subsidence value and loose circle depth. The predicted drill blasting parameters are verified by one random selected cross section in Foling tunnel and the model is proved to be correct and feasible. The model can be used to guide the drill blasting construction in Foling tunnel and can provide references for drilling and blasting parameters control optimization in tunnel with similar conditions. ©, 2015, Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University. All right reserved.

Liu K.-Y.,Beijing Jiaotong University | Fang Y.,Beijing Jiaotong University | Fang Y.,Anhui Expressway Holding Group Co. | Liu B.-G.,Beijing Jiaotong University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

Performance of learning machines is the key to determine the effectiveness of intelligent displacement back analysis. The Gaussian process regression (GPR) algorithm is introduced into the field of parameter inversion to make up for the deficiency of the present intelligent inversion method. In addition, a combined kernel function of GPR(CKGPR) obtained by additive single standard isotropy covariance functions is put forward to improve the generalization ability of a single kernel function. At present, the hyper-parameters of GPR are achieved by maximizing likelihood function of training samples based on the conjugate gradient algorithm. The conjugate gradient algorithm is replaced by the genetic algorithm (GA) coded in decimal system to optimize the hyper-parameters of GPR with the combined kernel function, and the corresponding calculation code is programmed in Matlab. From the elasto-plastic parameter inversion results of Beikou tunnel, it can be concluded that the GA-CKGPR algorithm can obviously improve the inversion precision than the standard GA-GPR and GA-SVR algorithms, so it can be utilized in parameter inversion of geotechnical engineering and meanwhile can serve as a reference for similar projects.

Wei J.C.,Key Laboratory for Expressway Maintenance Technology of Ministry of Transport | Li J.,Anhui Expressway Holding Group Co.
Applied Mechanics and Materials | Year: 2013

To study the dynamic modulus characteristic of LSPM mixes, dynamic modulus test was conducted for Large Stone Permeable Asphalt Mixtures (LSPM) with neat asphalt and with modified asphalt and the range of dynamic modulus values for LSPM was determined and the dynamic modulus master curves were developed. The magnitude of the dynamic modulus decreased with an increase in temperature and increased with an increase in the frequency. The phase angle decreased as the frequency increased at low temperature. With temperature increase, there was a transition interval, where the phase angle increased up to frequencies of 0.5 Hz, and then it started to decrease as frequency increased. After the transition interval, the phase angle increased with an increase in frequency. Master curves developed by sigmoidal function showed that LSPM with modified asphalt exhibited higher dynamic modulus values at middle and high frequencies and lower dynamic modulus values at low frequencies. © (2013) Trans Tech Publications, Switzerland.

Guan Q.,Anhui expressway holding group Co.
Applied Mechanics and Materials | Year: 2014

Domestic and foreign road construction for many years of practical experience shows that pavement early damage and between the base and the surface layer of oil related to the quality of construction, the quality of life of the future road surface layer has a major influence [1]. In order for the preparation of high-permeable dialysis oils heavy investment in production, combined with permeable layer of oil in the production of enterprises, taking into account the conditions and existing equipment of enterprises, the paper layer on oil production, put forward the requirements for equipment, processing parameters, control indicators. © (2014) Trans Tech Publications, Switzerland.

Hu G.,Anhui expressway holding group Co.
Applied Mechanics and Materials | Year: 2014

Current specification, does not specify the full construction process. In practice, the majority of construction units according to their own experience, hard to get reliable assurance of construction quality. In the early development of new and the high permeability type layer-penetration oil on the basis of construction of the test section of this article relies on permeable layer, oil on high permeable layer construction process, quality testing, and control indicators complete process was studied, test construction and achieved good results. © (2014) Trans Tech Publications, Switzerland.

The invention discloses a construction method for rooted foundation anchorage, comprising the following steps: The invention also discloses a construction method for a root-type cast in-situ bored pile with anchor roots, comprising the following steps:

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