Deng H.,Chinese Research Institute of Highway |
Zhou Q.,China Civil Engineering Construction Corporation
Modern Tunnelling Technology | Year: 2013
In light of the current reality of road tunnel construction, the sub-classification index system, which takes rock hardness and integrity as a basic index and groundwater status and occurrence of main weak structural surface as a correction factor during tunnel construction, is established by summarizing the indexes of a variety of surrounding rock classification methods at home and abroad. A sub-classification model was also set up based on quantification theory. The sample test demonstrated that this model is highly accurate and rational. Combined with programming techniques and database technology, a computer-aided sub-classification system of surrounding rock was finally developed, which basically realized automatic and intelligent management of the sub-classification.
Guo Y.L.,Chinese Research Institute of Highway
Applied Mechanics and Materials | Year: 2014
Cable corrosion is a serious problem in cable-stayed bridge. The paper analyzes the reason of cable corrosion and introduces the method of damage monitoring and detection. © (2014) Trans Tech Publications, Switzerland.
Cheng Q.,Chinese Research Institute of Highway
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011
The highly seismic region of Wenchuan earthquake locates in the Longmeng mountainous area, due to the landform condition of deep valleys, the earthquake induced a large numbers of landslide and collapse disasters. The disasters caused serious damage to the roads along the river valley. After the earthquake, site investigation on earthquake-induced landslide and collapse had been conducted along the highway with a total length about 6056 km. According to geologic tectonics and seismic intensity, the studied area is divided into different sections. In this paper, the seismic landslide and collapse characteristics of each section is summarized and their relationship with the tectonic position, seismic intensity and lithology, the density and average scale of the geological hazards are calculated. According the density and the scale, the whole area is divided into five subareas, i. e. the strongest-developed area, the stronger-developed area, the strong-developed area, the medium-developed area and the less-developed area. The development rules of the earthquake-induced landslide and collapse are shown as follows: (1) Three deep fault zones controlled the distribution of hazards. The Dujiangyan-Zhuyuanba section of the front fault is the clear boundary of less-developed area of the footwall and medium- and strong-developed areas of the hanging wall;but there is not clear boundary at the NE direction of Zhuyuanba. There are significant differences on the two sides of the central fault from Yingxiu to Donghekou. The two strongest-developed areas are all on the hanging wall and strictly limited by the back fault and lithologic boundary;but the boundaries is not clear at the NE direction of Dongkehou. The Maoxian-Wenchuan fault, which is one of the back fault, is the clear boundary of the strongest-developed area and stronger-developed area. The Qingchuan-Pingwu fault, which is one of the back fault, shows a clear effect of hanging wall at the Qingchuan to Shazhou section. (2) There are significant differences among different lithologies. The hazards with the highest density and average largest scale occur in intrusive rocks and hard sedimentary rocks like limestone and dolomite, while those with the lowest density and smallest scale occur in phyllite. Sandy slate and petroclastic rock are in the middle level. (3) There are significant differences among different landforms. The steeper and greater the relative altitude of salley slope is, more developed the disasters are. The positions of steep slope and hard rock are the high incidence area of seismic landslide and collapse;and the failure position of slopes mainly distribute on the upside of slopes, near the point of gradient change. (4) The statistical results of 399 geological sections show the slope gradients of collapse are larger than 40°. (5) Under dynamic conditions, the slope structures have important controlling effect on the development of geological hazards. Generally, soil slopes, strong-weathered rock slopes and slopes with outward-inclined discontinuities are easier to failure.
Wang Y.-F.,Beijing Jiaotong University |
Wu H.-L.,Chinese Research Institute of Highway
Journal of Composites for Construction | Year: 2011
Most previous studies on concrete short columns confined with fiber-reinforced polymer (FRP) composites were based on small-scale testing, and size effect of the columns still has not been studied thoroughly. In this study, 99 confined concrete short columns wrapped with aramid FRP (AFRP) jackets and 36 unconfined concrete short columns with circular and square cross sections were tested under axial compressive loading. The circular specimens were divided into six groups, and the square specimens were divided into five groups, with each group containing different levels of the AFRP's confinement. In each group, the specimens were geometrically similar to one another and had three different scaling dimensions. Statistical analyses were used to evaluate the size and interaction effects between the specimen size and the AFRP's confinement, and a size-dependent model for predicting the strength of the columns was developed by modifying Baznt's size-effect law. The experimental results showed that the size of a specimen had a significant effect on the strength of AFRP-confined concrete short columns, lesser effect on the axial stress-strain curves, and slight effect on the failure modes. The modified Baznt model was in good agreement with the experimental data. © 2011 American Society of Civil Engineers.
Liu G.G.,Chinese Research Institute of Highway
Applied Mechanics and Materials | Year: 2014
In the ear of information society, network security have become a very important issues. Intrusion is a behavior that tries to destroy confidentiality, data integrality, and data availability of network information. Intrusion detection systems are constructed as a software that automates the automatically detects possible intrusions. In this paper, we present the existing intrusion detection techniques in details including intrusion detection types, firewalls, etc. © (2014) Trans Tech Publications, Switzerland.