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Wu H.,Guangdong University of Technology | Zhao Q.,Guangdong University of Technology | Zhao Q.,China Construction Fifth Engineering Division Corporation | Ma Z.,Guangdong University of Technology
ICCREM 2014: Smart Construction and Management in the Context of New Technology - Proceedings of the 2014 International Conference on Construction and Real Estate Management | Year: 2014

Determining the CO2 emission factor is the foundation of accounting for fossil fuel CO2 emissions. Carbon content, carbon oxidation ratio and heat value are the three main elements of CO2 emission factor by the emission factor calculation model. This paper - based on methods of literature review, comparative analysis, and theory with practice - compares and analyzes those three elements affecting CO2 emission factor released by domestic and foreign authoritative institutions, selecting the numerical values suitable for Chinese construction process and applies calculation model to obtain CO2 emission factors of the main fossil fuels released in the Chinese building construction phase, therefore providing references on CO2 emissions calculation. © 2014 American Society of Civil Engineers.


Zhang Z.,Guangdong University of Technology | Zhao Q.,China Construction Fifth Engineering Division Corporation | Ma Z.,Guangdong University of Technology
ICCREM 2014: Smart Construction and Management in the Context of New Technology - Proceedings of the 2014 International Conference on Construction and Real Estate Management | Year: 2014

Carbon emission in construction phase is a significant part of the construction industry. Therefore, aimed at the construction process, this paper establishes a theoretical analysis and calculation methods of carbon emission of four aspects: (1) materials and equipments transport to site; (2) site construction; (3) on-site management; and (4) waste treatment. With this theory and these methods, the situation of carbon emission can be reflected upon and measures to reduce carbon emission can be carried out specifically. © 2014 American Society of Civil Engineers.


Zhang B.,Shandong University | Li S.-C.,Shandong University | Yang X.-Y.,Shandong Urban Construction Vocational College | Wang B.,China Construction Fifth Engineering Division Corporation | Li M.-T.,Shandong Jiaotong University
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

The uniaxial compression mechanical properties and anchoring effect of jointed rock mass with different crack fillings were analyzed. The influences of different crack fillings on jointed rock mass mechanical properties and anchoring effect were studied through similar material pieces uniaxial compression testing and numerical computation. The research results show that in a certain extent the compressive strength peak values increase with the increment of crack fillings elastic modulus; the less the differences between crack filling elastic modulus and that of matrix material, the better the jointed rock mass post-peak plasticity properties; there are little influences affected by crack fillings on bolted jointed rock mass post-peak plasticity properties; the more the differences between crack filling elastic modulus and that of matrix material, the more rapidly the stresses decrease after peak; the tensile stress begins to appear along the loading direction when the elastic modulus of crack filling is less than that of matrix material, the tensile stress peak values and distribution areas increase with the decrease of crack filling elastic modulus.


Pan Z.,China Construction Fifth Engineering Division Corporation Ltd. | Zhang F.,China Construction Fifth Engineering Division Corporation Ltd. | Wan F.,Beijing Jiaotong University
Modern Tunnelling Technology | Year: 2013

Based on the Zhongliangshan tunnel of the Chongqing Rail Transport Line 1, the engineering characteristics of gypsum strata were analyzed and the construction techniques for safe driving in gypsum strata are introduced in detail. The construction schemes were studied by numerical simulation and significant knowledge regarding the design and construction tunnels in swelling surrounding rock was obtained.


Liu N.-W.,Zhejiang University | Gong X.-N.,Zhejiang University | Yu F.,Zhejiang Sci-Tech University | Tang H.-S.,China Construction Fifth Engineering Division Corporation Ltd.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

Excavation will cause additional stress and deformations to the surrounding buildings. A series of field monitoring exercise of a deep foundation pit are conducted, including lateral wall deflections, soil settlements and building settlements. Field data indicate that the maximum wall deflections increase as the excavation depth increases, and the maximum wall deflection occurs near the excavation face. The wall deflection is accounted for 91.8% of the final wall displacement when the slab is cast in place. The settlement increases firstly and decreases sharply as the value of x/He increases (x, the distance from the wall in the horizontal direction; He, excavation depth). The soil settlement is relatively large, while the differential settlement is small when x < 16 m, however, the soil settlement is relatively small, while the differential settlement is large when 10 m < x < 28 m. The building settlements at the time the slab is cast in place is accounted for 76.6%, 71.5%, 56.8% of the final building settlements with the value of x being 9.6 m, 27.6 m, 45.2 m, respectively. The settlement profile of the five-storey building varies with x and is different from that of soil settlement. However, the settlement profile of the two or three-storey building varies when x is similar to that of soil settlement. The building settlement is relatively large, while the differential settlement is large when y < 30 m (y, the distance from the excavation corner in the longitudinal direction), however, the building settlements are relatively small, while the differential settlement is small when y > 30 m.


Shi C.,Central South University | Cao C.,Central South University | Lei M.,Central South University | Lei M.,China Construction Fifth Engineering Division Corporation | And 2 more authors.
Tunnelling and Underground Space Technology | Year: 2015

The waterproofing performance of rubber gaskets degrades with time and exerts a great influence on the water resistance of tunnel segment joints. As such, the time-dependent performance of rubber gaskets is an important study topic. Based on the service environment of tunnel segment joints, an accelerated ageing test was performed for EPDM rubber in groundwater environment to obtain the rule of its performance degradation. In this study, a time-dependent constitutive model of an ethylene propylene diene monomer (EPDM) rubber gasket used for segment joints was proposed according to the change rule of the mechanical properties of materials after ageing, and the results of laboratory-scale ageing tests were used to obtain expressions of the time-dependent parameters of the rubber gasket in the model. The transformation relations between time and temperature of material ageing in the laboratory and service environment were subsequently established. Finally, the established model was used to analyse the time-dependent parameters of EPDM and determine the attenuation rule of its mechanical properties. When the increase rate of model parameters exceeded the degradation speed of material performance, stress relaxation influenced the performance degradation of segment joints. © 2015 Elsevier Ltd.


Li Y.,Central South University | Li Y.,China Construction Fifth Engineering Division Corporation Ltd. | Lei M.,Central South University | Lu G.,China Construction Fifth Engineering Division Corporation Ltd. | Huang G.,China Construction Fifth Engineering Division Corporation Ltd.
Modern Tunnelling Technology | Year: 2014

Considering the three factors of rock classification, crossing angle, and rock pillar height, 100 cases were assumed to implement numerical modeling calculation and the law of the three factors affecting construction of intersected tunnels was discussed regarding crown settlement and internal force change of the primary support in an existing tunnel. Study results show that crown settlement and shotcrete axial force present a trend of significantly increasing with the enlargement of the crossing angle. When the rock pillar height increases and rock mass is poor, the induced crown settlement of the existing tunnel becomes larger while the increasing rate of the shotcrete axial force becomes smaller. The structural deformation of existing tunnels can be used as a key review indicator during the design and construction of intersected tunnels.


Li Y.,Central South University | Li Y.,China Construction Fifth Engineering Division Corporation Ltd. | Peng L.,Central South University | Lei M.,Central South University | Lei M.,China Construction Fifth Engineering Division Corporation Ltd.
Modern Tunnelling Technology | Year: 2015

In this paper, key dynamics problems regarding crossing tunnels on high-speed railways are presented based on their classification and combination, and the current state and existing problems of research on train vibration, aerodynamic effects, seismic shock, etc. are summarized. This study indicates that future research should focus on the following: 1) a quantitative safety assessment using a 3D train-track-crossing tunnel model and considering the strata parameters and the structures of the cross-linked tunnels; 2) train-tunnel aerodynamic research for providing safe construction measures and tunnel safety assessments under the superposition of aerodynamic load and other loads; 3) seismic response research for providing the dynamic characteristics of crossing tunnels and relevant aseismic design schemes; and 4) the establishment of a calculation model considering rock dynamic damage and its constitutive relationship with concrete. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.


Lei M.,Central South University | Lei M.,China Construction Fifth Engineering Division Corporation | Omer J.,Kingston University
Geotechnical and Geological Engineering | Year: 2015

Using a dynamic finite difference method, the dynamic response of double arch tunnel in Kast region of Baiyunshan tunnel on the Yichang–Wanzhou railway in China was analyzed. The method of analysis for the cumulative deformation of Kast foundation under long-term train loading was discussed further based on Dingqing Li plastic strain model. The results demonstrated that the vibrations at specific positions of the Baiyunshan double arch tunnel in Kast region are small, and both the tensile and compressive peak value and the displacement are less than the design values. Under the long-term train loading (i.e. 100 a), the cumulative plastic deformation of Kast foundation was shown to be <20 mm, which satisfies the requirement for riding comfort of low to high speed trains. © 2014, Springer International Publishing Switzerland.


Lei M.,Central South University | Lei M.,China Construction Fifth Engineering Division Corporation Ltd. | Peng L.,Central South University | Shi C.,Central South University
Tunnelling and Underground Space Technology | Year: 2015

The similitude criterion for the model used in this study was derived from similarity theory and elasticity mechanics equations. An experimental program was designed and used to simulate the excavation of three unsymmetrical loading model tunnels with different bias angles. The change laws and distribution forms of structural stress and surrounding rock pressure, and the failure mechanism of lining and surrounding rock on shallow buried tunnels under unsymmetrical loading were then studied systematically. Results show that the surrounding rock pressure and structural stress both change constantly in the process of tunnel excavation, and the surrounding rock stress releases obviously near the excavation face, which presents a noteworthy biased feature and time-space effect. As bias angle increases, the difference of surrounding rock pressure between the shallow and deep side of tunnel increases, and compared with the Code method, the difference obtained from the model test and field test results are increasing at a faster pace, especially, the vertical surrounding rock pressure. Thus it can be seen that the solution of Code method underrates the bias feature of surrounding rock pressure, causing the tunnel to be underdesigned. The existence of unsymmetrical load transforms the state of structural stress, and the failure form differs in location. Moreover, owing to the effect of bias angle, the development of the morphologic traits of the lining structure should be closely monitored during tunnel construction, so as to take specific measurements. The failure process over the entire construction process can be described as follows: local movement. →. superficial crack in tensile area of deep side. →. shear slip develops in deep ground. The failure mode presents as an inverted cone, with the tunnel as the top and the slope as the bottom. And owing to the effect of bias angle, the rupture angle of shallow side is smaller than that calculated by the Code method, whereas the reverse is true for the deep side. © 2014 Elsevier Ltd.

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