Time filter

Source Type

Zhi-Hong Z.,North China University of Water Conservancy and Electric Power | Shi-Bao L.,Shenzhen Government Investment Project Evaluation Center
Lecture Notes in Electrical Engineering | Year: 2012

Risk assessment methodologies seek to assess the maximum potential change in the value of a portfolio of financial instruments with a given probability over a pre-set horizon resulting from changes in market factors, credit risk, This paper provides a methodology to assess credit risk. credit transition matrix has a great impact. It will affect the credit rating changes. Credit Change this index ranged from zero when the critical state has a different default status, when the credit quality index greater than zero, the rise in the value of its credit; if the credit quality index is less than zero, the credit quality of the index on the lower Level; If zero, credit rating is to maintain the normal status. © 2012 Springer-Verlag.


Wei M.,North China University of Water Conservancy and Electric Power | Lu S.,Shenzhen Government Investment Project Evaluation Center | Zheng Z.,North China University of Water Conservancy and Electric Power
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

Project of agricultural water conservancy construction is an open and complex system with huge investment, long construction period, complex internal structure and many participants, and which is restrained by time, resources, environment, and so on. The paper aimed to establish a 3-layer structure system of the risks of agricultural water conservancy construction by applying Analytic Hierarchy Process and analyze risks of the construction of a water conservancy project by using Monte Carlo simulation. The results indicate that the main risks of the project are the deformation and leakage of the dam, leakage and penetration objects of the dam foundation. Therefore, for the agricultural water conservancy projects that are mainly used for social and ecological benefits, more strategies should be applied to avoid dam leakage and deformation of engineering so as to reduce the risks of the project.


Zhang A.-J.,South China University of Technology | Zhang A.-J.,Shenzhen Government Investment Project Evaluation Center | Mo H.-H.,South China University of Technology | Zhu Z.-D.,Hohai University
Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science) | Year: 2012

Large lateral soil movement usually occurs in many unstable slopes due to the excavation or rainfall, which results easily in additional displacement and bending moment in adjacent stabilizing piles. In order to solve this problem, based on the Winkler foundation beam model, the simplified elasto-plastic constitutive relation of the pile-lateral soil is adopted to simulate the nonlinear pile-soil interaction, and a set of four-orders differential governing equations based on the elasto-plastic subgrade reaction method are devised to describe the stabilizing pile-soil slope interaction. Then, the matrix expression of the analytical solutions of the pile response is deduced according to its continuity conditions on the sliding face and boundary conditions at the top and bottom of the pile. Finally, the analytical solutions obtained through the proposed method and the existing measured values in model tests are compared, thus verifying the reliability of the proposed analytical method.


Zhang A.-J.,South China University of Technology | Zhang A.-J.,Shenzhen Government Investment Project Evaluation Center | Mo H.-H.,South China University of Technology | Zhu Z.-D.,Hohai University | Zhang K.-Y.,Hohai University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

In order to analyze mechanical mechanism of passive pile-soil interaction in slope, based on the Winkler elastic model which assumes that soil displacement is elastic, a fourth-order differential equation considering passive pile-soil interaction is presented to describe the stabilizing pile subjected to an arbitrary profile of residual thrust, and the analytical solution is derived. The procedure is programmed with Matlab code. Meantime, the computed values are in good agreement with the in field monitoring data, which means that the suggested analytical solutions are reliable. Finally, the model is conducted in a case history of Shenzhen to verify the proposed analytical solution. The analysis is carried out to investigate the effects of subgrade modulus and distribution function of residual thrust on behavior of passive piles embedded in slope considering the interaction between passive piles and soils. The results show that the triangular distribution forms of residual trust will have the largest moment of passive piles, followed by a parabola, uniform distribution of the smallest. The relatively large gap can be up to 47%. Under the same level of subgrade modulus conditions, the uniform distribution of residual trust has large displacement of passive piles at the top around the piles than that of triangle and parabola distribution. The approach can provide theoretical helpful for calculating internal forces and displacements of stabilizing piles.


Xiang W.,Harbin Institute of Technology | Zhang A.-J.,Shenzhen Government Investment Project Evaluation Center | Zhang A.-J.,South China University of Technology | Gao W.,Shenzhen Geotechnical Investigation and Surveying Institute
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The excavation deformation of deep foundation pits is predicted by 5 kinds of different models. Compared with the test data, the results show that the short-term prediction accuracy of the metabolic GM(1, 1) model, grey Markov chain model and BP model can meet the requirements of the engineering. But their long-term prediction accuracy is unreliable. It is proved that the residual GM(1, 1) model and the grey Markov chain model are suitable for the medium-term and long-term predictions. The excavation deformation control methods for deep foundation pits are summarized.


Zhang A.,South China University of Technology | Zhang A.,Shenzhen Government Investment Project Evaluation Center | Mo H.,South China University of Technology | Li A.,Shenzhen Geotechnical Investigation and Surveying Institute Co. | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

Foundation pit excavation in the building compact district of urban will absolutely induce soil lateral movement, which may generate the additional deflections and bending moments in the adjacent pile shaft, and may lead to their superstructures distress, even failure. To avoid the drawbacks of three-dimensional numerical analysis, such as complexity modeling and time consuming, the two-stage method(TSM) is presented for determining the behavior of adjacent pile caused by foundation pit excavation. Firstly, the additional lateral displacement of soil mass due to adjacent foundation pit excavation is calculated by the virtual image technique. Secondly, the governing differential equations are built up based on Winkler model and their analytical solution of matrix is derived. Finally, analysis of case histories show that the calculated results of analytical solution are reasonable and could be used to analyze the influence of excavation on adjacent pile foundations.


Zhang A.-J.,South China University of Technology | Zhang A.-J.,Shenzhen Government Investment Project Evaluation Center | Mo H.-H.,South China University of Technology | Xiang W.,Shenzhen Government Investment Project Evaluation Center
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

For many unstable slopes, local or transient large displacement often occurs, even collapse due to excavation, rainfall or earthquake. The large lateral soil displacement may generate additional internal forces and deflection in stabilizing piles. Based on the two-stage method, the Winkler's model is adopted to simulate the effect of pile-soil interaction, and the horizontal displacement control equations of a single pile are established. By considering the continuity condition and the boundary conditions, the analytical solutions of control equations are obtained and verified by monitoring data and Poulos's elastic continuum method. Finally, with the typical engineering accident, the influence of lateral soil movements on adjacent stabilizing piles in slope is investigated by parametric analysis. It shows that the pile deflection and bending moment are obviously affected by soil lateral movement model, such as maximum displacements, distribution shapes and center of gravity, displacements energy, etc, on which it should be pay more attention practically.


Lu S.-B.,Water Resources University | Lu S.-B.,Shenzhen Government Investment Project Evaluation Center | Huang Q.,Water Resources University | Wu C.-G.,Water Resources University | Gao F.,Water Resources University
Journal of Natural Disasters | Year: 2010

This paper seeks for a solution to reduce the ice jams hazard in Ningxia-Inner Mongolia reaches of the Yellow River. The reservoir can be used to raise the water level, increase the discharge capacity of drifted ice, reduce the pondage in the river channel, lower the ice peak discharge in river-ice breakup period and avoid a great quantity of ice discharge. The discharge can be reduced via controlling the ice peak discharge and flood discharge. In the meantime, the role of reservoir in controlling the hazard of river ice can be fully exerted via adjusting the flow velocity variation of river reach in winter based on the relation between the hydraulic factors and development of ice condition, so as to relieve the ice hazard. After operation of Liujiaxia Reservoir, the river-ice-breakup day in Shizuishan station with most serious ice hazard is one day earlier than it was before. After operation of Longyanxia Reservoir, the river - ice breakup day in Ningxia-Inner Mongolia reaches is 7 - 10 days earlier than it was before, prevention of ice by reservoir is an effective method. After construction and operation of Liujiaxian Reservoir, the number of ice dam in river-ice breakup period is decreased to 4. 3 from the previous annual average 14 before construction of reservoir, and the ice hazard is reduced obviously.

Loading Shenzhen Government Investment Project Evaluation Center collaborators
Loading Shenzhen Government Investment Project Evaluation Center collaborators