Qingdao, China
Qingdao, China

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Zhang G.,University of Science and Technology Beijing | Zhang G.,Guangdong Hongda Blasting Engineering Co. | Du Z.,Qingdao Metro Corporation | Song J.,Guangdong Hongda Blasting Engineering Co. | And 3 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

Zhongshan Park Station of Qingdao subway line No.3, which is constructed by arch cover method, locates in soil-rock composite layer. The maximal excavation depth is about 27.24 m. Upper overburden is composed of quaternary and highly weathered granite, and the lower part is consisted of medium-slightly weathered granite and granite-porphyry. The thickness of partially highly weathered rock layer is large and the medium-slightly weathered rock surface is partly steep, which makes the contact surface unstable. To ensure the excavation work, the ground subsidence was monitored and analyzed at the station. Results indicate that the subsidence emerges before the tunnel working face reaches to about 20 m in front of monitoring sections when the arch cover method was adopted. With the decrease of distance between the tunnel working face and monitoring sections, the subsidence velocity continues to increase. Generally, the value of subsidence is 7-15 mm when the excavation face was going through the monitoring sections. The velocity of ground subsidence increases to the maximum until the working face passes through the monitoring sections for 5-10 m. After the working face passes through the monitoring section for more than 10 m, the subsidence velocity begins to fall. Most of observation points have the trend to be stable after the working face passes through the monitoring sections for about 20 m. Supporting should be exerted and closed as early as possible to make sure that the supporting can play a good role. In addition, there is a interrelationship between the left and right pilot tunnels. It is indicated that the appropriate distance between the left and right pilot tunnels should be 2.5 times of the diameter of pilot tunnel. According to the monitoring and analysis results, a series of control measures are put forward, which are proved to be feasible and effective by practice.

Weiqing W.,Qingdao Metro Corporation | Huanqin W.,WuhanUniversity of Technology
Applied Mechanics and Materials | Year: 2013

In order to determine that the effect of geometric error to the machining accuracy is an important premise for the error compensation, a sensitivity analysis method of geometric error is presented based on multi-body system theory in this paper. An accuracy model of five-axis machine tool is established based on multi-body system theory, and with 37 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The analysis result shows that the presented method can identify the important geometric errors having large influence on volumetric error of machine tool and is of help to improve the accuracy of machine tool economically. © (2013) Trans Tech Publications, Switzerland.

Wu H.Q.,Wuhan University of Technology | Wang W.Q.,Qingdao Metro Corporation
Applied Mechanics and Materials | Year: 2013

The machine tool bed is an important component of the center. The function is components of support column, worktable and so on. The machining accuracy can be influenced by the function machine tool bed. To establish the finite element model of horizontal machining center by "Solid works". And the first six orders modal can be analyzed by "Ansys". The dynamic sensitivity analysis is used to determine the parameters of stiffened plate by sensitivity optimization method. The better structure parameters can be getting by making a structural optimization design for the analysis. Finally, the dynamic characteristics and function of the machine tool bed can be improved. © (2013) Trans Tech Publications, Switzerland.

Li S.-C.,Shandong University | Zhao Y.,Shandong University | Zhao Y.,Qingdao Metro Corporation | Li L.-P.,Shandong University | And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

Tunnel excavation will lead to surrounding rock loose and exert certain load on the structure in the meantime. In the excavation process, the load of structure releases continuously in the stress adjustment process till the structure and rock mass stabilizing. Numerical analysis and model test are carried out to research the load releasing process of the whole section in the construction of ultra-large section railway tunnel. The load fluctuation rules of key points in bench excavation are studied firstly, then concepts of section comprehensive load release rate and difference coefficient of load release that characterizes the state of load release of the whole section are defined; and the load fluctuation rules in the process of construction are summarized via the two parameters. With monitoring of change laws of radial pressure at key points of rock mass in the geomechanical model test, the conclusions obtained by numerical analysis are testified; and the principle that the section must be regarded as a whole is realized to make the study of load release more comprehensive.

Zhihui L.,Shandong University | Qingzhi J.,Shandong Electric Power Research Institute | Hang C.,Qingdao Metro Corporation | Xuelong D.,Shandong University | Zhizhen L.,Shandong University
Applied Mechanics and Materials | Year: 2012

As the energy crisis becoming more and more serious, electric vehicles has become an important way to solve this problem. The difference of Popularity, type, charge time, charge style and charge characteristics of Electric vehicles make different effect on the Regional power grid, especially quick charge technology. In this paper, through the establishment of regional power grid model and the forecast of quick charge station load curve, we analysis the impact of charge station on voltage of the user side, furthermore, we analysis voltage loss and impulse current when the large power charger connected to the power grid, and verify the analysis by simulation. In order to reduce the impact on the grid, we should rationally plan the charge station and the reactive power compensation, thus enhance stability of power system. © (2012) Trans Tech Publications, Switzerland.

Wang X.D.,Tongji University | Yuan Y.,Tongji University | Wu X.F.,Qingdao Metro Corporation | Du Z.J.,Qingdao Metro Corporation
ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers | Year: 2012

Metro stations located in composed of soil and weathered rock stratum have obvious stiffness changes. Under this condition, it is necessary to divide and evaluate the covering layer reasonably before determine metro station's depth. The objective of this paper is to study the rational depth determining method of metro station in composed of soil and weathered rock stratum. Two side wall drift heading method in specific stratum was studied as the main object and Finite Element Method is used for analysis. The variations of thickness-span ratio and rockiness-span ratio are employed to investigate how the thickness of soils and rocks impact on the displacement of stratum during construction and the plastic strains of surrounding rocks and the loading condition of initial support. The sensitivities of thicknessspan ratio and rockiness-span ratio are studied. A double-index method for determining the rational depth of metro station is proposed. Study results show that in the covering layer soil and rock have different reaction to the safety of tunnel construction, the loading condition of initial support and ground deformation will be enlarged by increasing the thickness-span ratio. The safety of subsurface construction of metro station tunnel is more sensitive to rockiness-span ratio than thickness-span ratio, the double-index method should be taken in the evaluation of the covering layer.

Du Z.-J.,University of Science and Technology Beijing | Du Z.-J.,Qingdao Metro Corporation | Gao Y.-T.,University of Science and Technology Beijing | Wang L.-B.,China Railway 16th Bureau Group Co. | Du X.-W.,University of Science and Technology Beijing
Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing | Year: 2011

Aiming at analyzing the tunnel excavation problem in representative silty clay stratum in Beijing, triaxial consolidation drainage tests were carried and the mechanical characters under different stress paths were analyzed. Then, a two-dimensional numerical tunneling model with general engineering parameters was established. The stress of grid points and Gauss points was calculated, and the stress changes of typical points were tracked. After that, the action zones of the stratum were classified, and the final ground settlements which consider action zones were calculated by turning the test results of strength into the corresponding action zone model. At last, a centrifuge test model was constructed, and the final surface settlement value was recorded. By contrasting test results with simulation results, the correctness of action zoning in silty clay stratum was verified.

Li S.-C.,Shandong University | Zhao Y.,Shandong University | Zhao Y.,Qingdao Metro Corporation | Xu B.-S.,Shandong University | And 4 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

The construction of subsea tunnel is high risky and water inrush is one of the main risk sources. If water inrush into the tunnel, it will have an important influence on the safety of construction as well as the control of operation cost after the subsea tunnel is completed. So making water inrush forecast is very important in the construction phase. Numerical analysis is the most popular method used in the prediction of water inrush at present, of which ascertaining the permeability coefficient is one key problem. Taking Qingdao Jiaozhouwan Subsea Tunnel as the project background, this paper deals with water inrush forecast during the subsea tunnel construction period by comprehensive usage of numerical computation, model test and local monitoring data analysis. Firstly, variation curves of the water inrush are got by monitoring the water inrush after tunnel excavation. Then numerical method is used to calculate the water inrush. During the process of calculating, parameters are adjusted constantly to fit the curve successfully. The permeability coefficient obtained is reasonable; it should be used in the numerical computation. Combined with the model geology, the relationship between the reasonable permeability coefficient and the permeability coefficient which is got from geological packer test in the early stage is obtained by comparison. Then model test is used to verify above conclusions. Finally, the conclusions can be used to other sections of subsea tunnel to make water inrush forecast. The result has significance for practice reference.

Zhao Y.,Identification Center for Engineering Design of the Ministry of Railways | Li S.,Shandong University | Zhao Y.,Shandong University | Zhao Y.,Qingdao Metro Corporation | Li L.,Shandong University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

Against the background of the Liangshui tunnel of Lanzhou-Chongqing line and based on 3D large-scale geomechanical model test of excavation and support on large cross-section tunnel, the process of surrounding rock load releasing during tunnel excavation is studied. New similar material is developed according to the field geological condition, which is proved by the laboratory tests to be similar to original rock materials on mechanical properties and meets the test requirement. Construction methods of excavation and support on different sections are various and the load releasing processes of surrounding rock on full-face excavation and bench-cut excavation are compared firstly. Through analyzing the test data, the features and differences of load releasing processes with different excavation methods are revealed. There are great differences in load releasing processes at different locations of the same section using the same excavation method. Meanwhile, the load releasing process at the same locations of the same section are various when different excavation methods are used. Secondly, the phenomenon of first load concentration occurs in front of tunnel face affecting by the excavation. The degree of first load concentration is related with the excavation method and section form. High degree of load concentration in front of tunnel face would aggravate the crowding-out effect, which is unfavorable to surrounding rock stability. Lastly, by comparing the load releasing processes of support excavation and non-support excavation, it is known that support can response the first load concentration effectively, reduce the load releasing amount, and optimize the load releasing process of surrounding rock in construction.

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