Fengcheng, China
Fengcheng, China

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Qu Z.-H.,Chang'an University | Qu Z.-H.,Xian Highway Institute | Xie Y.-L.,Chang'an University | Yuan F.-F.,Xuzhou Highway Engineering Group Company | And 2 more authors.
Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering | Year: 2010

The horizontal displacement of geocell flexible retaining wall was analyzed by finite element method, its cut-off point in the middle of the wall was got, and the calculation method of active earth pressure under limit state was put up. The displacement mode above the cut-off point was near translational and the earth pressure of the part was calculated by Coulomb's active earth pressure theory. The displacement under the point was near rotary around the foot of the wall and the earth pressure of the part was calculated by level differential element method. The calculation results were compared with the measured results. Comparison result shows that the distribution shapes and growth trends of earth pressures from the calculation and measurement are basically same along the wall, and the calculated results are a bit smaller than the measured ones. The minimum deviation between the calculation values and measured values is 0.2 kPa, the maximum one is 2.9 kPa, and the average one is 1.2 kPa. Obviously, the calculation method is reliable.

Zheng M.,Chang'an University | Han L.,Chang'an University | Wang F.,Qinghai Airport Co. | Mi H.,Xian Highway Institute | And 2 more authors.
Construction and Building Materials | Year: 2015

The objective of this study is to develop applicable solar heat reflective coating for asphalt pavement. The cooling effects of 10 self devised coats as well as a Japanese paint were compared and evaluated based on laboratory and field tests. Ceramic particles and machine made sands were applied to enhance coat anti skid performance. Results show that scheme 8, 9 and 10 performed better indoor cooling effect than others with a cut in specimen surface temperature by 30°C. While scheme 5 excelled others at outdoor effect by 10°C. In addition, the variation of cooling effect with time between different schemes in field test was similar to that in the laboratory although the outdoor effect of each coat was poorer than the indoor effect. The anti-skid experiment suggested that spreading 160g/m2 of 1.18mm machine made sands contributed to the greatest increase in the British Pendulum Number (BPN). Finally, three optimum schemes were recommended for practical application according to their outdoor cooling effect and impact on driving glare. © 2015 Elsevier Ltd.

Luo Y.-B.,Chang'an University | Chen J.-X.,Chang'an University | Duan X.-L.,Xian Highway Institute
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2012

At a road tunnel construction site, C20 shotcrete samples were made by using the spray large panel. The compressive strength and tensile strength of the samples which experienced different times of freeze-thaw cycles were tested by pressure testing machine to analyze the compressive and tensile strength variation of the shotcrete under freeze-thaw cycles, and the dynamic modulus of elasticity of the samples experiencing different times of freeze-thaw cycles were tested by resonance method and ultrasonic method to analyze the frost resistance durability. Besides, there were descriptions about the appearance of samples experiencing different freeze-thaw cycles. The result indicates that the freeze-thaw has a great influence on the tensile strength and compression strength of shotcrete, the degree of attenuation of tensile strength and compression strength increases gradually with the increasing cycles, the relative dynamic elastic modulus of the shotcrete gradually decreases linearly with increasing cycles, and the relative durability index of C20 shotcrete is 10.1% after 50 freeze-thaw cycles, which is lower than normal C20 concrete, so the frost resistance durability of shotcrete is worse. C20 shotcrete gets heavy spalling after 70 freeze-thaw cycles, which could not meet the freeze resistance demand of engineering.

Zhang Y.Y.,Chinese Research Institute of Highway | Yu C.L.,Xian Highway Institute
Advanced Materials Research | Year: 2013

CFST Arch Bridge under pressure mainly stability is one of the key factors restricting its development. Most of the arch of instability belongs to the second type of instability, and that the non-linear deformation of the structure is nonlinear state, the mechanical properties of the structure also change from elastic state into nonlinear state. In this paper, based on nonlinear and stability theory and using the finite element software ANSYS, parameters of affecting the main arch stability were studied. By analyzing the geometric and material nonlinear factors on the structural stability, the parameters of influence on the stability of the main arch were discussed, including width-span ratio, arch-rib inside inclination, rise-span ratio and arch-axis coefficient. The influence law of these parameters were summarized and will be used to guide the actual project. © (2013) Trans Tech Publications, Switzerland.

Guo P.,Chang'an University | Guo P.,Xian Highway Institute | Qi F.,Xian Highway Institute | Mi H.-C.,Xian Highway Institute
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2010

To study the reasonable forming way, best mixing temperature and performance of warm mix asphalt mixture, using two ways to make specimens which are Marshall method and the superpave gyratory compacter (SGC), this paper analyzed the volume parameters and performance of warm mix asphalt mixture under different temperatures. The result indicates that the superpave gyratory compacter is more suitable to design of the warm mix asphalt mixture, which gross specimen volume density peak corresponds to the best mixing temperature of warm mix asphalt mixture. Under best mixing temperature, the road performance of warm mix asphalt mixture can meet the requirements of technical specifications for construction of highway asphalt pavements on the hot asphalt mixture.

Yu X.,Tongji University | Wu X.,Xian Highway Institute
2nd International Conference on Information Engineering and Computer Science - Proceedings, ICIECS 2010 | Year: 2010

The mechanistic analysis presented in this paper is only a beginning of new approach for understanding the real joint load transfer capability on airport and highway concrete pavements. It gives up the two major assumptions those have been popularly adopted by hundreds of published papers: the load is transferred under a wheel with zero speed and with fixed position. The real load transfer in field is always under wheels with non-zero speed and with varied position at any moment. The objective of this study focuses on quantifying the dynamic effects of a moving wheel while it is crossing a joint on a pavement. The analysis is conducted using a model of two-slab system on Kelvin foundation under a moving wheel with variable speed ν, different pavement damping C s, foundation reaction modulus k and foundation damping C k. The dynamic joint load transfer efficiency is temporarily and empirically defined by the peak strain ratio LTE(S) on the two sides of a joint. The primary findings include: (1) The higher speed of a moving wheel leads to the higher LTE(S);(2) The larger the pavement damping Cs leads to the higher LTE(S);(3) The numerical ratio c(=LTE(S)dynamic/ LTE(S) static) varies in the range 1 to 2 mainly depending on speed ν and damping Cs;(4) The LTE(S)dynamic is not sensitive to foundation reaction modulus k and foundation damping Ck. Further researches are needed for appropriate applications of the new model in practice. ©2010 IEEE.

Xu T.,Beijing University of Technology | Sun X.-D.,Beijing University of Technology | He Y.-L.,Beijing University of Technology | Wang W.-L.,Xian Highway Institute
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2010

Regarded curve sections of mountainous expressway as research object, setting method and procedure of advisory speed limit signs were studied. Speed information data from 8 curves were collected for one year. Speed difference concept was figured out and speed difference threshold was determined by linear model. The value of advisory speed limit was determined through considering operation speed and design speed. Finally, the advanced distance of advisory speed limit sign was determined considering drivers' visual characteristics and operation speed. Results show that when horizontal curve is small than 300 m, advisory speed limit sign should be set on horizontal curve for expressway.

Fang M.,Xidian University | Niu W.,Xidian University | Zhang X.,Xian Highway Institute
Jisuanji Yanjiu yu Fazhan/Computer Research and Development | Year: 2012

The classification methods based on multiple attractor cellular automata can process the classification of two classes, and they are difficult to overcome overfitting problem. There are not yet effective methods for constructing a multiple attractor cellular automata which can process multi-classification and overfitting problem. The pattern space partition in the view of cell space is a kind of uniform partition which is difficult to adapt to the needs of spatial non-uniform partition. By combining the CART algorithm with the multiple attractor cellular automata, a kind of classifier with tree structure is constructed to solve the non-uniform partition problem and overfitting problem. The multiple attractor cellular automata characteristic matrix is defined, and the learning method of classifiers as a node in a tree is studied based on particle swarm optimization algorithm. The multiple attractor cellular automata classifiers built on this approach are able to obtain good classification performance by using less number of bits of pseudo-exhaustive field. The classifier with tree frame of multiple attractor cellular automata reduces the number of empty basin and restrains overfitting problem without lost accurate rate, and shorts the classification time. The feasibility and the effectiveness of the proposed method have been verified by experiments.

Fang M.,Xidian University | Li H.,Xidian University | Zhang X.,Xian Highway Institute
Proceedings - 2012 IEEE/WIC/ACM International Conference on Web Intelligence, WI 2012 | Year: 2012

Since learning action selection strategy is time-consuming due to the reinforcement learning algorithm, a heuristic reinforcement learning algorithm is presented based on the state backtracking reinforcement learning to improve the action selection strategy of the reinforcement learning. The selection strategies of repeated the action are analyzed and compared by state backtracking. A cost function is defined to denote the importance of repetitive actions. A novel heuristic function is given by combing the action-reward with the cost of an action. This algorithm reinforces the important of an action by heuristic function to speed learning and reduces unnecessary explorations by the cost function, so as to steadily improve the learning efficiency. The simulation results of two robot games proves that the algorithm can effectively enhancement the learning rate of Q-learning based on the state backtracking heuristic reinforcement learning method. © 2012 IEEE.

Fang M.,Xidian University | Niu W.,Xidian University | Zhang X.S.,Xian Highway Institute
Proceedings - International Conference on Natural Computation | Year: 2012

The partition of a pattern space as the view of a cell space is a uniform partition, it is difficult to adapt to the needs of spatial non-uniform partition. In this paper, a cellular automaton classifier with a tree structure is constructed by combing with the CART algorithm. The construction method of the characteristic matrix of the multiple attractor cellular automata is studied based on the particle swarm optimization method, and this method can build the nodes of the multiple attractor cellular automata. This kind of classifier can solve the non-uniform partition problem and obtain a good classification performance while using a pseudo-exhaustive field with less bits. The experiment results show that our algorithm is more accurate than those obtained through the multiple attractor cellular automata. © 2012 IEEE.

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