Yu Y.-X.,Xian University of Science and Technology |
Wang B.-Q.,Ccteg Xian Research Institute
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2015
To provide reference for design and construction of sidewall and floor, sidewall was regarded as a half infinite load-bearing beam and its soft and weak floor rock mass was simplified to a continuous elastic foundation, according to sidewall stratum and its mechanical characteristics of the tunnel. By setting up Winkler elastic foundation beam model of the sidewall under high bearing pressure, the distribution law of deflection, rotation, bending moment and shear force of sidewall on any interface of rock mass was analyzed and the relations between the limit equilibrium zone width and tunnel buried depth, the elastic characteristic value of floor rock, overburden rock mass density as well as stress concentration factor, elastic zone width and the shear strength of rock mass on elastic-plastic interface of the sidewall were derived. The maximum plastic failure depth of the weak floor under the squeeze of sidewall was discussed after the limit equilibrium zone width was certain. The result shows that the maximum plastic failure depth is closely related to the tunnel buried depth, stress concentration factor, the limit equilibrium zone width of the tunnel wall, the volume-weight of overburden rock mass and floor, the cohesion and internal friction angle of the floor. ©, 2015, Xi'an Highway University. All right reserved.
Zhu W.,Yangtze University |
Shan R.,Ccteg Xian Research Institute
Applied Geophysics | Year: 2016
Transmitted ultrasonic wave simulation (TUWS) in a digital core is one of the important elements of digital rock physics and is used to study wave propagation in porous cores and calculate equivalent velocity. When simulating wave propagates in a 3D digital core, two additional layers are attached to its two surfaces vertical to the wave-direction and one planar wave source and two receiver-arrays are properly installed. After source excitation, the two receivers then record incident and transmitted waves of the digital rock. Wave propagating velocity, which is the velocity of the digital core, is computed by the picked peak-time difference between the two recorded waves. To evaluate the accuracy of TUWS, a digital core is fully saturated with gas, oil, and water to calculate the corresponding velocities. The velocities increase with decreasing wave frequencies in the simulation frequency band, and this is considered to be the result of scattering. When the pore fluids are varied from gas to oil and finally to water, the velocity-variation characteristics between the different frequencies are similar, thereby approximately following the variation law of velocities obtained from linear elastic statics simulation (LESS), although their absolute values are different. However, LESS has been widely used. The results of this paper show that the transmission ultrasonic simulation has high relative precision. © 2016, Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.
Liu G.Q.,Ccteg Xian Research Institute
Advanced Materials Research | Year: 2014
Workflow is a key technology of process management and process control in PDM system. It introduce the definition of workflow and the workflow management model,and define standard process of all kinds of documents management graphically and task nodes of different business process, which include design flow and drawings change process. It makes the manageability enhanced, and improve the automatization and the efficiency of flow execution, realize the workflow management in the design of drilling rig. © (2014) Trans Tech Publications, Switzerland.
Wang Y.-B.,Ccteg Xian Research Institute
Wutan Huatan Jisuan Jishu | Year: 2016
At present, the CSAMT study is based on the assumption of the line source is horizontal. However in undulating mountain areas, the line source can hardly be kept on horizon. For this case, the calculation formulas of rolling source and discusses the measuring field, apparent resistivity and phase with rolling are introduced in the forward modeling in this paper. The results show that the rolling source has strongly influence on the field data and the apparent resistivity and phase data of near-field, but a little influence on the transition-field data and far-field data. However the apparent resistivity and phase data of near-field also has much difference, so it is necessary to consider rolling source when it applied in near-field data.
Yang P.,Xian Jiaotong University |
Yang P.,University of Texas at Austin |
Gao J.,Xian Jiaotong University |
Wang B.,Ccteg Xian Research Institute
Computers and Geosciences | Year: 2014
GPU has become a booming technology in reverse time migration (RTM) to perform the intensive computation. Compared with saving forward modeled wavefield on the disk, RTM via wavefield reconstruction using saved boundaries on device is a more efficient method because computation is much faster than CPU-GPU data transfer. In this paper, we introduce the effective boundary saving strategy in backward reconstruction for RTM. The minimum storage requirement for regular and staggered grid finite difference is determined for perfect reconstruction of the source wavefield. Particularly, we implement RTM using GPU programming, combining staggered finite difference scheme with convolutional perfectly matched layer (CPML) boundary condition. We demonstrate the validity of the proposed approach and CUDA codes with numerical example and imaging of benchmark models. © 2014 Elsevier Ltd.