East China Investigation and Design Institute

Gouda, Netherlands

East China Investigation and Design Institute

Gouda, Netherlands
Time filter
Source Type

Ding Y.,East China Investigation and Design Institute | Zheng Z.,Large Dam Safety Supervision Center
Advances in Science and Technology of Water Resources | Year: 2013

In order to ensure the safety and reliability of CFRD's plinth placed on the bank slope of completely weathered bedrock, this paper analyses four key technical issues, including the bearing capacity of foundation, the seepage control of foundation, the stability of plinth, and the differential settlement of plinth. With the engineering example of Vietnamese Tuyen Quang CFRD, some appropriate engineering measures were proposed, which include improving the bearing capacity of foundation, strengthening the connection between plinth and completely weathered bedrock, ensuring the seepage stability of foundation and setting plinth expansion joints in different bedrock junctions. The dam safety monitoring results show that the seepage volume of Tuyen Quang CFRD is small, and the deformation regularity of the dam is normal. By application of the engineering measures proposed in this paper, placing the plinth on completely weathered bedrock is safe and feasible.

Jiang Q.,CAS Wuhan Institute of Rock and Soil Mechanics | Feng X.-T.,CAS Wuhan Institute of Rock and Soil Mechanics | Chen J.,CAS Wuhan Institute of Rock and Soil Mechanics | Huang K.,East China Investigation and Design Institute | Jiang Y.-L.,East China Investigation and Design Institute
Engineering Geology | Year: 2013

Stress-induced failures have typically been considered as engineering disasters in deep underground excavations. This paper highlights the importance of stress-driven rock failures as a means to estimate the in-situ rock stress at the depth. The method, which is based on the observation and documentation of a failure mode referred to here as "spalling" in deep tunnels or caverns, is put forward and presented to estimate the macro-scale rock stress. Using the proposed method, the orientation of the principal stresses in-situ can be deduced by the spalling intensity and associated stress-induced spalling veins in the rock mass surrounding the opening, and the magnitude of the principal stresses can be estimated by the assumed crack initiation stress required to generate spalling in the given rock by careful documentation of spalling failure characteristic in the field. A real case study at Baihetan powerhouse site has been carried out and indicates that the proposed method is an available way to enriching recognition of in-situ rock stress and a helpful supplement to traditional methods of stress measurements after strictly numerical verification. Analysis of the regional tectonic setting as well as measurements of in-situ stress supports the results by the suggested approach. © 2012.

Jin C.-Y.,East China Investigation and Design Institute | Jin C.-Y.,CAS Wuhan Institute of Rock and Soil Mechanics | Feng X.-T.,CAS Wuhan Institute of Rock and Soil Mechanics | Zhang C.-S.,East China Investigation and Design Institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2010

A planned Baihetan hydropower station on the lower reaches of the Jinsha River, located between the hydropower stations of Wudongde and Xiluodu, is the third biggest hydropower station following the Three Gorges project and the Xiluodu power station. The station will have an installation capacity of 10 million kW. Baihetan hydropower station uses underground powerhouse, of which height and span respectively are 78.5 m and 32 m. To guarantee stability of wall rock of underground cavern, it is necessary to know the magnitude and direction of initial in-situ stress field exactly. Based on geological structure analysis and field testing, it is found that the directions of initial in-situ stress fields of both banks of Baihetan hydropower station, which are influenced by factors, such as fluvial erosion and slope unloading deflect from NWW to NE partly. Numerical inverse method is used to inverse boundary conditions of study area, it has rationality and veracity by comparing with measuring values.

Liang Z.-M.,Hohai University | Guo Y.,Hohai University | Hu Y.-M.,Hohai University | Tang C.-Y.,East China Investigation and Design Institute
Shuikexue Jinzhan/Advances in Water Science | Year: 2012

The operation of the Three Gorges Reservoir (TGR) could potentially affect the flow regime in the Poyang Lake and its adopted flood control plan. In this paper, the theory of copula function is used to establish the joint probability distribution functions for hydrological variables in the "Yangtze River-Poyang Lake-five rivers" system without considering the TGR operation. These conditional probability distribution functions are then derived. It is assumed that the conditional distribution function remains unchanged in the system after the TGR operation. The new probability distribution functions for hydrological variables can be obtained after the TGR operation through analyzing the probability distribution function of discharges of the Yangtze River after the TGR operation and combining the new discharge probability distribution function with the previously established conditional probability distribution. The difference in the probability distribution functions before and after the TGR operation can be seen as the TGR impact on the flood control in the Poyang Lake. Results show that the pre-releases from the TGR in May and June will increase the water level of the Poyang Lake. The increase in average water level will be greater than that of the maximum water level, and the low water increase will be greater than that of the high water. Under the influence of the TGR operation, the water level is unlikely to exceed the currently adopted design value. Thus, the flood protection standard of the embankments for the Poyang Lake will remain unchanged after the TGR operation.

Di S.-J.,Hohai University | Xu W.-Y.,Hohai University | Wang W.,Hohai University | Shi A.-C.,East China Investigation and Design Institute
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2011

A constitutive model of a transversely isotropic, columnar jointed rock mass is presented. The methods of composite material mechanics were used to consider staggered joints, inner disturbed belts, coordinate deflection, and other factors. Equivalent elastic parameters were calculated from the model. An in situ test at a dam for a hydro-power station showed the impact of the inner disturbed belts and of the joints of a columnar jointed rock mass. It appears that the inner disturbed belts have a large effect upon the elastic parameters of the columnar jointed basaltic mass located at the dam site. This impact reduces the elastic modulus more than 50% in the vertical direction. The effect of dip angle is obvious. In this case the dip angle is 15 degrees and so the equivalent vertical elastic modulus is reduced by about 19%. This approach allows an improved description of the anisotropic columnar jointed rock mass. The field application shows the horizontal elastic modulus is larger than the vertical elastic modulus.

Di S.-J.,Hohai University | Xu W.-Y.,Hohai University | Wang W.,Hohai University | Wu G.-Y.,East China Investigation and Design Institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

The value of joint stiffness based on in-situ deformation experimental results of columnar jointed rock mass in Baihetan dam region was discussed. The value of columnar joint stiffness is obtained by using experimental data of flexible central hole deformation test. The regulation and deformation properties of rock single concept model are analyzed. Rock deformation is made up of two parts, one of rock and one of rock joint, and its hysteretic properties are determined by joints' mechanical behavior. Moreover, the formula of deformation deduced can calculate the equivalent elastic modulus of multi-set intersection joint rock and describe the anisotropic characteristics of jointed rock. A random model of columnar jointed rock mass is established. The rock mass is stimulated by using discrete element method and the stiffness of reverse calculation; and equivalent deformation parameters obtained are in the range of test results.

Tan B.,Wuhan University | Yang J.,East China Investigation and Design Institute | Lu H.,Wuhan University | Wen X.,Wuhan University
Gaodianya Jishu/High Voltage Engineering | Year: 2013

In order to solve the problem that the ground potential rise (GPR) of some grounding grids with designing difficulties is too high, firstly, we analyzed the deficiency of currently setting GPR limit according to arresters' power frequency withstand voltage in China. Then, we established a model of a grounding grid's backflash on a 10 kV arrester by means of the software ATPdraw, by which computation of the arrester's discharge current and energy when ground potential rise backflashed the 10 kV arrester was simulated. The results indicate that if one set of YH5WZ-17/45 arresters or YH2.5WD-13.5/31 arresters is arranged in a 10 kV power system, the discharge current is 61.94 A and 113.5 A, respectively, and the absorbed energy is 3 101.9 J and 13 947 J, respectively, which are all within the arresters' flowing energy allowance. By comparing the absorbed energies under different GPRs with the arresters' allowable flowing energy, the withstand GPR limits of the two arresters, YH5WZ-17/45 and YH2.5WD-13.5/31, are derived as 11.7 kV and 10.2 kV, respectively, which can be a reference for setting reasonable GPR limits in grounding grid designs.

Ji F.,Chengdu University of Technology | Lu J.,Chengdu University of Technology | Shi Y.,Chengdu University of Technology | Zhou C.,East China Investigation and Design Institute
Natural Hazards | Year: 2013

There are two kinds of excavation methods in underground engineering: the tunnel boring machine (TBM) and the drill-blasting method. A large number of studies have shown that the deformation and failure, the degree of disturbance, the stability and the reinforcement measures of surrounding rock using the TBM and drill-blasting method vary from each other. To accurately master these macroscopic damages, it is necessary to focus on the investigation of the micro-mechanical responses of the surrounding rock. Scanning electron microscopy tests, acoustic emission tests and tunnel acoustic detection tests were carried out to analyze the mechanical response of surrounding rock of tunnels, which were excavated in marble by, respectively, the TBM and the drill-blasting method. The tests results showed that most of the rock fractures cut by TBM is wipe along the crystal, and the failure mechanism is mainly cutting, while most of the rock fractures induced by the TBM coincide with crystal planes, its mechanism is mainly tensile. The stress-strain curves of rocks cut by the TBM method are rather flat around the peak strength, which means a strong resistance to deformation around the peak load. The response of AE for the rock cut by the TBM method appears after larger strains than the response of the rock constructed by the drill-blasting method. This suggests that the resistance to damage is higher under TBM excavation conditions. The relaxation depths of the tunnel excavated by the drill-blasting method are larger than the tunnel excavated by the TBM method. The research can provide more insight into tunnel failure mechanisms and provide a framework for reinforcement measures. © 2012 The Author(s).

Liu N.,East China Investigation and Design Institute | Zhang C.-S.,East China Investigation and Design Institute | Chu W.-J.,East China Investigation and Design Institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

When the tunnel is excavated, the surrounding rock will be damaged and the damage zone will be formed around the profile where the acoustic velocity will weaken. Direct at the damage zone formed after diversion tunnel #3 of Jinping hydropower station, the distribution characteristic is discussed and the stress paths of characteristic points are monitored by simulation method. The stress states of characteristic points and locations of acoustic velocity weakened are confirmed. According to above work, the drill holes of detecting acoustic wave are arranged. The depth of damage zone is determined by single hole detection method. In order to realize the simulation of damage zone by the particle flow code (PFC), the microscopic parameters are confirmed by triaxial compression test. The damage zone distribution is described by PFC. The local damage and damage extent are also analyzed by PFC. The simulated results are well consistent with the detections. The exact description of damage zone characteristics can be achieved by PFC. The research results can direct the detection of damage zone and support optimal design.

Qian M.,East China Investigation and Design Institute
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

In recent years, with the development of computer technology and numerical theory of geotechnical engineering, numerical simulation analysis is more and more applied in geotechnical engineering. Based on a deep foundation pit in Qingdao, the geotechnical finite element soft PLAXIS is used to simulate the whole process of double-row piles. The change trend of horizontal displacement is analyzed and compared with the measured data. At the same time the single-row pile supporting method is compared and analyzed, the double-row piles are proved to have obvious advantages in restricting the horizontal displacement. Therefore, the numerical simulation may provide effective help for selection of supporting methods and stability analysis of foundation pits.

Loading East China Investigation and Design Institute collaborators
Loading East China Investigation and Design Institute collaborators