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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.


Pan Z.,China Construction Fifth Engineering Division Corporation | Zhang F.,China Construction Fifth Engineering Division Corporation | 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.


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.


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.


Lei M.,Central South University | Lei M.,China Construction Fifth Engineering Division Corporation | 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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