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Zhou X.,Wuhan University of Technology | Zhang G.,Tongliao City Naiman Section of the Local Road Management | Liu R.,China Railway Tunnel Stock Co. | Zheng L.,Xilingol Pledge Taibus County Road Maintenance Work Area
Key Engineering Materials | Year: 2014

Aging of asphalt is a serious problem of asphalt damage and occurs throughout its service life. In general, a common method is to use different additives or modifiers for anti-aging. The objective of this study was to investigate the effects of layered double hydroxides(LDHs) additives on anti-aging mechanism using molecular simulations. Molecular dynamic simulations were used to simulate the changes of physical properties and structure before and after aging. Results showed that the degradation of asphalt was dominant reaction and modified asphalts had a high-temperature stability at thermal aging without oxygen. Owing to the difference of polarity between LDHs and asphalt components, phase separation phenomenon would occur at thermal oxidative aging. LDHs also increased the orderliness of asphalt binder. © (2014) Trans Tech Publications.

Liu K.,Wuhan University of Technology | Dong J.,Xilingol Pledge Qiantu Traffic Design Co. | Liu R.,China Railway Tunnel Stock Co. | Zheng L.,Xilingol Pledge Taibus County Road Maintenance Work Area
Key Engineering Materials | Year: 2014

As the asphalt pavement has excellent road performance, in the past decade, modified asphalt has more and more applications in highway. In this paper, an anti-rut agent was used as a modifier to add into base asphalt and its effects on the property of the asphalt were investigated. A shear blender was used to ensure the anti-rut agent equally distributed. The conventional physical properties test and Dynamic Shear Rheometer (DSR) test were used to evaluate the properties of the asphalt. The results showed that the softening point and rutting parameter increases significantly, the ductility and penetration decrease due to the introduction of the anti-rut agent. Besides, the result of fatigue test showed that excess anti-rut agent may lead a deterioration in the fatigue life. © (2014) Trans Tech Publications.

Guo W.,China Railway Tunnel Group Co. | Liang K.,China Railway Tunnel Stock Co. | You Y.,China Railway Tunnel Stock Co.
Modern Tunnelling Technology | Year: 2015

Regarding the sea-crossing, shield-driven intake tunnel of the Taishan nuclear power project, four risks of sea -crossing shield tunnelling, i.e., geology, shield adaptation, environment and construction, were determined from the perspective of project risk management. Based on successful engineering practice, the risk management schemes and technological countermeasures are discussed in detail in this paper for each risk factor. The results show that: 1) the selection of a sea-crossing tunnel construction method is essential for avoiding project risks; 2) project risks should be resolved based on detailed geological investigation, and by the seismic reflection method with high frequency and density it can get good results in the detection of boulders and bedrock; 3) good geological adaptability of the shield machine is key for eliminating project risks; 4) in light of the domestic technological level of shield tunnelling at present, construction risks can be resolved smoothly based on a detailed geological investigation and good geological adaptability of the shield machine; 5) in terms of the slurry treatment scheme with two-stage screening+two-stage rotational flow+filter pressing, a zero-discharge of waste slurry was achieved, thereby providing a reference for the environmental protection schemes of similar projects. © 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Wu F.-Z.,China Railway Tunnel Group Co. | Fu Z.,China Railway Tunnel Stock Co.
Journal of Railway Engineering Society | Year: 2014

Research purposes: Tongzhai tunnel entrance was affected by the same high stress, and other geological factors carbonaceous slate role in the early stages to I18 steel support parameters based support, the construction of large deformation occurs, arch distortion, shotcrete off, seriously affecting construction safety and progress.This paper is finding solutions to large deformation method to provide a reference for the subsequent construction. Research conclusions: (1)In the stress deformation by the engineering test, take the anti - supporting measures, adhere to the "strong first and optimization late" principle, support in place at a time, so as to control the deformation. (2) Soft surrounding rock after excavation is timely supported, enclosing to ring as soon as possible, and timely radial grouting to effectively strengthen loose rock, improve the surrounding rock properties, reduce rock pressure effected on the supporting structure, the support and surrounding rock stress system has formed, to restrain the deformation of tunnel. (3) Reduce the times of the excavation, set the inverted arch as early as possible, control the initial support closing time strictly. (4) The control measures of deformation of tunnel carbonaceous slate can provide reference for similar engineering.

Ye X.-W.,Hong Kong Polytechnic University | Ye X.-W.,Zhejiang University | Ding P.,Hong Kong Polytechnic University | Ding P.,Xiamen University | And 4 more authors.
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2013

In order to grasp the temperature and strain fields of frozen soils during freezing construction of the metro-tunnel cross-passage, a method for real-time monitoring of freezing construction using fiber Bragg grating (FBG) sensing technology is proposed. Under the condition of low temperature and high humidity, FBG sensors have the advantages in terms of accuracy, sensitivity and stability in comparison with the traditional electrical sensors. In this connection, the design scheme and installation method of a novel freezing monitoring device integrated with FBG sensors is addressed. FBG sensors are deployed in freezing monitoring holes at both sides of the frozen soil wall of the cross passage to timely monitor the temperature and strain of the frozen soils in the process of freezing construction. The original temperature and strain monitoring data are analyzed based on the FBG sensing principle by use of the wavelet transform de-noising approach. The distribution pattern of the temperature and strain of the frozen soils in thickness and depth directions are recognized, which will provide a basis for further digesting the formation and expansion mechanism of frozen soil walls.

Yang J.-S.,Central South University | Zou Z.-L.,Beijing Urban Construction Design and Development Group Co. | Liang K.-S.,China Railway Tunnel Stock Co. | You Y.-F.,China Railway Tunnel Stock Co. | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

The shield cutter cannot effectively break the rock with the slurry shield tunneling in the high-strength granites, while pretreatment of the bedrock by controlled blasting can strictly control the broken block size to enhance stronger rock breaking capacity, but the relationship between tunneling parameters and rock is very complicated during shield construction. Based on the intake tunnel of Taishan Nuclear Power Station, the field parameters are studied to analyze selection features of thrust force and torque of cutter head and tunneling rate. On this basis, the parameter conversion indices FPI, TPI and specific energy are introduced for analysis. The results show that the rock is too hard in the high-strength granites, the thrust force is close to its peak value, however the penetration is lower, it is too difficult to give full play of the torque capacity of the cutter head. The bedrock is destroyed by blasting to a certain extent, thus the slurry shield can take full advantage of its torque force as well as the thrust. In this situation, the tunneling performance is improved. Therefore the thrust and torque are adjusted to better adapt to the strata within the workload scope of the shield machine according to the fragmentation effect of blasting so as to achieve efficient and safe excavation.

Yang J.-S.,Central South University | Xiao X.-W.,Central South University | Zhang C.,Central South University | Zou Z.-L.,Beijing Urban Construction Group Co. | And 3 more authors.
Journal of Railway Engineering Society | Year: 2016

Research purposes: To explore the stress characteristics of double lining in undersea shield tunnel, taking undersea water-intaking shield tunnel of Taishan Nuclear Power Plant as background, this paper makes the field monitoring of double lining structure force, and based on field test data, proposes a method which can accurately calculate the undersea shield tunnel design load of soft soil layers. Research conclusions:(1) Monitoring results show that large cross section slurry pressurized balance shield and new lining construction method have many advantages such as quick construction and high quality. (2) Secondary lining of water-intaking shield tunnel mainly withstand internal water pressure, tunnel surrounding rock pressure is mainly borne by the segment. Segmental lining external water and soil pressure is affected by construction and formation conditions significantly. During construction, the earth pressure exists three periods like acceleration, deceleration and acceleration stabilized, and acceleration is the most critical period; soil pressure of stable period showed the next big small shape in whole, pressure distribution of measuring points is uneven distribution. Water seepage pressure distribution is consistent with the tunnel region, but affected by tunnel surrounding rock strata, water pressure distribution also has a certain randomness. The impact of secondary lining concrete solidification shrinkage weakens with time by the impact of second lining weight, the contact pressure between the double lining of vault is smaller, and arch foot is larger. (3) When the depth H≤1.7D, vertical earth pressure=1.31×γh, horizontal earth pressure=1.65×λγh; When the depth of 1.7D2.2D, vertical earth pressure=0.63×γh, horizontal earth pressure=0.61×λγh. (4) The research results can provide guidance for the design and construction of undersea shield tunnel linings. © 2016, Editorial Department of Journal of Railway Engineering Society. All right reserved.

Zhang Z.-M.,Zhejiang University | Lin C.-G.,Zhejiang University | Wu S.-M.,Hangzhou Qing chun Road Cross river Tunnel Co. | Liu G.-S.,Hangzhou Qing chun Road Cross river Tunnel Co. | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

Slurry shield has been widely used in construction of cross-river tunnels. One big challenge is how to traverse the embankment without impacting its regular service and safety. Based on the field settlement monitoring data in construction of Hangzhou Qingchun Road cross-river tunnel, ground settlements induced by shield tunneling under greenfield and the embankment are compared. The results show that the settlements of the embankment are larger, for which for the shielding disturbance to the surrounding soils, the complexity of the embankment structure, the vehicle travelling on the embankment and sustained rainfall are accounted. Peck equation's applicability to predict the ground settlements due to shield tunneling in Hangzhou is evaluated, and the values of the ground trough-width parameter and the volume loss in this project are suggested. By combining the successful experience of crossing the embankment in this tunnel, some practical and effective measures are suggested for slurry shield to traverse the embankment. These results will provide a scientific reference for the design and construction of similar shield tunnels in practice.

Peng Z.,China Railway Tunnel Stock Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

Subsurface excavation tunnel at Punan section of phase I project of Xiamen airport road is a shallow-buried, large-span and soft rock tunnel, the surrounding construction environment is complex. Building #34 is a key protection object during tunnel traverses buildings. According to the structures, foundation rocks and surrounding environment of building #34, the ground tracking grouting method is adopted to protect buildings during construction by systematically analyzing the reliabilities and operabilities of various building protection schemes. The sleeve valve pipe grouting is adopted for building #34 according to grouting test results of buildings #104, #105.Monitoring points of building subsidence and crack development have been set in order to control the subsidence and crack development of building #34 and guide the construction timely. Monitoring results show that grouting uplift can control houses subsidence effectively. Finally, the total subsidence value of each monitoring point is controlled within 25 mm; the differential subsidence of each monitoring point is controlled within 1‰. The building #34 structures are in control state when tunnel traverses. Therefore, the grouting uplifting is a very important method to protect existing buildings traversed by tunnel. This study results will provide some references for similar tunnel projects.

Teng J.,Huazhong University of Science and Technology | Wu X.,Huazhong University of Science and Technology | Qin Y.,Huazhong University of Science and Technology | Hou T.,China Railway Tunnel Stock Co. | Zhang L.,Huazhong University of Science and Technology
Engineering Economist | Year: 2015

Reducing energy and resource consumption as well as emissions by building projects are important goals in sustainable development of modern society. In this article, a method based on the concept of life-cycle ecological footprint is proposed to assess the efficiency of the incremental cost brought about by eco-footprint saving measures taken in building projects. This method is then utilized to provide guidelines for school building decision makers to select design plans with higher ecological and financial efficiency. In this method, a set of eco-footprint models is developed to compute the efficiency of incremental cost. Two indices are presented and adopted for assessing the life-cycle incremental cost-efficiency of eco-footprint-saving measures: the life-cycle eco-efficiency index and financial efficiency index for per unit incremental cost. The procedure for applying this method to assessing projects aimed at improving the efficiency of building energy consumption is also introduced. A case study of a school building in China is used to demonstrate the features of this method and the advantages of adopting the method. The results show that this method helps to identify inefficient design plans and provide an effective tool for decision making. Copyright © 2015 Institute of Industrial Engineers

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