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Shen X.,BGI Engineering Consultants Ltd | Cai Z.,Nanjing Hydraulic Research Institute | Cai G.,Nanjing Southeast University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2016

Continuously deepened applications of the predominantly used new in-situ testing techniques in recent years are reviewed in this paper, which focuses on the techniques of CPTU series and some geophysical methods applied in common civil engineering projects and for meeting the new demands for useful extended geotechnical analyses. It is strongly advocated to develop and use more in-situ tests in engineering practices in the light of providing cost-effective and trustable site investigation and evaluation for solving complicated engineering problems. © 2016, Editorial Office of China Civil Engineering Journal. All right reserved.

Han X.,BGI Engineering Consultants Ltd. | Li N.,Xi'an University of Technology | Standing J.R.,Imperial College London
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011

The urban deep excavation and subway tunneling work can cause ground movement and the deformation or even damage of the nearby buildings or other structures. However, little research has been reported on the characteristics and mechanism of the building deformation based on the studies on real building behavior, which is very important to establish the efficient structural deformation prediction procedure and damage assessment system. A method to evaluate the building deformation modes, i. e. shearing or bending, is proposed in this paper based on the theoretical analysis using a newly suggested parameter 'bending deformation ratio'. From the observation of the measured data of two real buildings in London applying the method suggested, it is found that these two buildings mainly underwent shearing deformation during tunneling excavation. In the subsequent further analyses, it is concluded that for the general multiple-storey building affected by excavation, it is more likely to experience shearing deformation rather than bending. According to this conclusion, it is suggested to use the shearing stiffness to consider the structural effects in the related analyses, which is different from commonly adopted assumption that building deformation is dominated by bending. Also, the structural stiffness ratio E/G is calculated for the first time, which also adds the knowledge on the real characteristics of building deformation by excavation work in the vicinity.

Yang R.,China University of Mining and Technology | Zhang Z.,China University of Mining and Technology | Yang L.,China University of Mining and Technology | Guo Y.,BGI Engineering Consultants Ltd.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

In order to test adaptability and directed blasting parameters of slotted cartridge in rock driving, firstly, design of blasting parameters is optimized, and making the hole utilization rate reach more than 90%, the requirements of rapid driving and smooth blasting are reached. Secondly, after the success of blasting program, the both-sides comparison experiment of the surrounding holes and all surrounding holes comparison experiment are made, hole mark rate can reach 90%. At the same space, the best charge is 0.5 kg, and it can be less 16.7% and 37.5% than smooth blasting and ordinary blasting. At the same charge, blast-hole space can be extended from 450 mm to 550 mm, improvement rate is more than 22%. The experiment results show that control blasting using the simple slotted cartridge can be better for forming and taking more benefits for enterprise; it is suitable for spread in rock rapid driving.

Han X.,BGI Engineering Consultants Ltd. | Liu C.,BGI Engineering Consultants Ltd. | Standing J.R.,Imperial College London
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2012

Because of the rapid growth of urban subway system both at home and abroad, a more frequently encountered situation is that the new tunnel needs to pass through existing tunnel(s), which may cause considerable risk to the existing tunnel structure and the safety of the train. A modified stiffness method is proposed for predicting the structural settlement of existing tunnel caused by new tunnel excavated underneath, based on observations from field monitoring data. Some key factors, such as the depth of the existing tunnels, the structural stiffness, are studied and discussed. The suggested method can be served as a new approach to evaluation of the risk caused by construction of tunnels in urban environment.

Wang X.,BGI Engineering Consultants Ltd. | Han X.,BGI Engineering Consultants Ltd. | Zhou H.,BGI Engineering Consultants Ltd.
Modern Tunnelling Technology | Year: 2014

Based on the Xi'an Metro Line 2, metro traffic loading is simulated by establishing an analytical model of a subgrade train-track system and a material mechanical model of a loess soil mass under the effects of long-term cyclic loading is derived and introduced according to the results of a dynamic triaxial test. Reasonable calculating parameters for the studied object are set, especially a series of numerical calculating conditions, such as artificial nonlinear viscoelasticity boundary conditions, to establish the numerical analytical model considering the dynamic interaction between a tunnel and surrounding soil and to study the regularity of the ground vibration response under metro traffic loading in a loess area. In addition, the variation of the ground vibration response under different speeds and various loads is analyzed and compared with respect to one-way and two-way metro traffic modes.

Liu Z.-R.,Xi'an University of Architecture and Technology | Cui G.-Q.,Xi'an University of Architecture and Technology | Wang X.,BGI Engineering Consultants Ltd.
International Journal of Geomechanics | Year: 2014

Considering the interaction mechanisms between a subway tunnel's structure and the surrounding soil, a new theoretical method was established to analyze the vibration characteristics of the tunnel structure. The tunnel structure is assumed to be a moderately thick cylindrical shell that was never previously used, and all following researches were done on this basis. To begin, the vibration equation of the tunnel structure was established based on the moderately thick cylindrical shells theory, which takes into account transverse shear deformation. Then, a motion equation was set up for the soil around the tunnel in the framework of Navier's wave theory, applicable to a homogeneous, isotropic, linear elastic medium. Based on said analysis and combined with a wave-propagation approach, the vibration control equation of the tunnel structure was established by considering soil-structure dynamic interaction according to the interface conditions. Using the dispersion characteristic equation, the vibration characteristics of the tunnel structure were analyzed. Through the comparison of the analytical results with those obtained based on thin shell theory or the FEM, the effectiveness of this research was verified. Finally, the influences of tunnel radius, wall thickness, and length on the vibration characteristics of tunnel structure were analyzed. Some important findings are drawn as follows: (1) The natural frequencies of each order, calculated using the method proposed in this paper, are close to the solutions based on FEM, and the relative error is less than 10%; (2) The natural frequencies of the tunnel structure that were calculated based on this theory are lower than those based on the thin shell theory; (3) Additional stiffness is the main influencing factor of the soil medium on the vibration characteristics of tunnel structure; (4) When the lower order is dominating in one-modal analysis, it would produce a larger error if soil-structure interaction is ignored; and (5) The natural frequency of tunnel structure decreases with the increase of tunnel radius, wall thickness, and length. © 2014 American Society of Civil Engineers.

Zheng Y.F.,China Coal Research Institute | Wang T.N.,BGI Engineering Consultants LTD.
Advanced Materials Research | Year: 2014

Reasonable matching with each accessories' mechanical adaptability of anchor bolting system is the basis for the protection of support effect in roadways. In this paper, taking Huozhou mine area for example, load process of four kind of bolt bars with different spec, bearing capacity of circular pallets, and transformation test of bolts pretension moment were compared and analyzed by loading method in laboratory. The results show that, pallet arch structure significantly impact on its bearing capacity. the two kind spec of circular pallets' bearing capacity were not sufficient to match tensile force requirements of the high strength bolt, the pallet arch height needs to increase to meet the high load demand. Various anti-friction components significantly improve pretension transformation for bolt moment, in which, nylon gasket can increase the conversion efficiency with more than 30%, and the steel ball bearing with one multiple nearly. © (2014) Trans Tech Publications, Switzerland.

Wang X.,BGI Engineering Consultants LTD | Han X.,BGI Engineering Consultants LTD
Recent Advances in Environmental Vibration - Proceedings of 6th International Symposium on Environmental Vibration, ISEV 2013 | Year: 2013

In recent years, along with the constant enlargement of the urban subway construction scale, the citizens have become less tolerant of disturbances due to the construction, especially the influence of the vibration. As a result, reliable analysis of the vibration impact on the environment produced by shield tunneling activities is indispensable for the constructors. Especially for the historic and old buildings, the influence, generally, would be much greater. In this paper, Beijing subway No. 8 lines construction is taken as the research background. First of all, the field monitoring of the vibration source near the working face of the shield construction has been accomplished, and then, the amplitude and the frequency characteristics of the vibration source have been analyzed. Secondly, the field testing study on regularities of the dynamic response; of the historic- and old buildings induced by the shield tunneling under different conditions, including the time-domain and the frequency-domain analysis of the vibration level, research on the distance attenuation regularities and the frequency attenuation characteristics of the dynamic response, have been carried out. The above researches, can be used as the basic work of the evaluation and the analysis of the environment vibration caused by the metro shield construction, and consequently, can provide reliable basis for the reasonable planning, design and construction of the subway project.

Zhang Z.,BGI Engineering Consultants Ltd. | Zhang Z.,Beijing University of Technology | Han X.,BGI Engineering Consultants Ltd.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011

Buildings and other structures will be subjected to ground movement caused by the construction of subway tunnels or other underground structures in the vicinity. The study of the deformation and damage analysis of buildings is not adequate. This paper focuses on the analysis of multiple-storey masonry building damage induced by tunnelling. Based on the experience in Beijing area, the study started in the 1970's, and according to the previous studies of the settlement characteristics of green field buildings and the modified stiffness method for building deformation prediction, a new approach for evaluating the damage of buildings is presented, in which a more rational parameter, the minimum curvature, is employed in the assessment procedure. The distribution characteristics of the tensile strain and the curvature of the building are studied using the proposed method. The results are in good agreement with those from the conventional method where the parameter tensile strain is used.

Wang L.,Water Resources University | Wang L.,BGI Engineering Consultants Ltd. | Hu F.,Water Resources University | Yin L.,Xian Geology Investigation Institute | And 2 more authors.
Environmental Earth Sciences | Year: 2013

The Yinchuan plain is located in the arid climate zone of NW China. The western margin of the plain is the Helan mountain connecting a series of normal slip faults. The eastern margin of the plain connects with the Yellow River and adjacents with the Ordos platform. The south of the plain is bordered by the EN fault of the Niushou mountain. The bottom of the plain is the Carboniferous, Permian, or Ordovician rocks. Based on the analysis of groundwater hydrochemical and isotopic indicators, this study aims to identify the groundwater recharge and discharge in the Yinchuan plain, China. The hydrochemical types of the groundwater are HCO3-SO4 in the west, HCO3-Cl in the middle, and Cl-SO4 in the east. The hydrochemical types are HCO3-SO4 in the south, HCO3-Cl and SO4-HCO3 in the middle. The hydrochemical types are complex in the north, mainly SO4-HCO3 and Cl-SO4. Deuterium, 18O, and tritium values of groundwater indicate that groundwater recharge sources include precipitation, bedrock fissure water, and irrigation return water. Groundwater discharges include evaporation, abstraction, and discharge to surface water. According to the EW isotopic profile, the groundwater flow system (GFS) in the Yinchuan plain can be divided into local flow systems (LFS) and regional flow systems (RFS). Groundwater has lower TDS and higher tritium in the southern Yellow River alluvial plain and groundwater age ranges from 6 to 25 years. The range of groundwater renewal rates is from 11 to 15 % a-1. The depth of the water cycle is small, and groundwater circulates fast and has high renewal rates. Groundwater has higher TDS and lower tritium in the northern Yellow River alluvial plain. The range of groundwater age is from 45 to 57 years, and renewal rate is from 6 to 0.1 % a-1. The depth of the water cycle is larger. Groundwater circulates slowly and has low renewal rates. © 2012 Springer-Verlag Berlin Heidelberg.

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