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Yu X.,Wuhan University of Science and Technology | Luo M.X.,Hubei Water Resources Technical College
Applied Mechanics and Materials | Year: 2013

The method of retaining piles working as an anti-floating piles has advantages of lesser environmental impact, high utilization of resources and good in economic benefits, but the method effecting on underground structure was worthy of further study and exploitation. According to the practical underground projects, this paper has proposed three possible connections between underground structure, shear connectors and retaining piles. The analysis showed that the internal force and displacement of underground structural is affected distinctly by the method. In addition, characters and applicable ranges of the three different connections is introduced with the finite element analysis and calculation of stress and displacement of the main parts like base plate, top plate,and so on. © (2013) Trans Tech Publications, Switzerland.

Li C.-H.,Wuhan University | Li C.-H.,Hubei Water Resources Technical College | Jiang Q.-H.,Wuhan University | Zhou C.-B.,Wuhan University
Gongcheng Lixue/Engineering Mechanics | Year: 2014

Mohr-Coulomb criterion leads to convergence difficulties in the numerical calculation due to the presence of singularity. Firstly, the singularity problem is mainly caused by the principal stress's nonsmoothness when Lode angle changes, and then the theoretical basis of the principal stress space are given. Mohr-Coulomb criterion's equivalent complementary model is presented in the principal stress space based on Koiter's rule, and the Fischer-Burmeister complementarity function is used to describe the model, which makes the Newton algorithm be successfully solved. The proposed algorithm can remove the singularity of the Mohr-Coulomb criterion and avoid the trial process of the conventional methods, and it also improves the accuracy of the Mohr-Coulomb criterion. Examples verify the validity and reliability of this method.

Chen C.,Hubei Water Resources Technical College | Zhao C.,Huazhong Agricultural University | Zhang J.,Huazhong Agricultural University | Ding S.,Huazhong Agricultural University | Xu J.,Huazhong Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to solve the cooling problem for greenhouse in the humid and hot area in summer, liquid dehumidifying and cooling system with CaCl 2 liquid was proposed. Under the condition that the dehumidifying and cooling system was operated in greenhouse, the experimental target about the relative humidity of the air on the spray room exit was determined, and the factors affecting on the experimental indexes were analyzed, such as inlet air flow, liquid desiccant flow concentration and temperature, inlet air temperature and humidity and so on. By the single factor and multi-factor orthogonal experiment, when the system was operating, the significant factors included desiccant concentration and temperature, inlet air temperature and humidity. Through the regression analysis, the mathematical model of spraying and dehumidifying with CaCl 2 was established and verified, and the maximum relative error of model was less than 5%. This paper provides a reference for greenhouse cooling under high temperature and high humidity condition in summer in the South China.

Sun T.,Wuhan University | Zhang L.,Wuhan University | Chen W.,Wuhan University | Tang X.,Hubei Water Resources Technical College | Qin Q.,Wuhan University
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2013

The aim of this paper is to propose a more practical mountain fire spread model for fire behavior prediction and management in Southwest forest area of China. These areas are covered mainly with spatial heterogeneous flammable forest and are characterized by undulating terrain and steep slopes. This model can produce more accurate fire propagation maps by combining CA (Cellular Automaton) framework with Wang Zhengfei fire physical velocity model in fine scale. Considering the inherent uncertainties of fire propagation, the model has been built on multi-dimension geophysical and environmental components and also sound knowledge of fire spread physical mechanism. Regarding small fuel patches as spatial homogenous cells, this approach makes it easier to generate higher level complex fire behavior maps from CA simple local rules and local behavior integrated with high resolution vegetation images, fine scale terrain maps and surface wind field. Because the model focuses primarily on the study of surface fire front propagation behavior, it attempts to simplify complex fuel modeling. Additionally, this Wang-Geophysical-CA model is able to analyze the time series spatial pattern of fire-front spread and model local behavior instead of the final fire spread pattern of the conventional approach. In this work, not only single influence verification tests have been made, but also simulation tests with multiple influences are carried out to demonstrate the capability of the model with fine scale vegetation maps, surface wind field, terrain, moisture content and man-made structures. © 2008-2012 IEEE.

Li C.-H.,Wuhan University | Li C.-H.,Hubei Water Resources Technical College | Jiang Q.-H.,Wuhan University | Zhou C.-B.,Wuhan University
Yantu Lixue/Rock and Soil Mechanics | Year: 2013

Strength reduction technique by finite element method is an effective method for slope stability evaluation; and it has been used more and more widely. There are many factors influence the result of this method; the order of finite element is an important one of them. The effect of element order on the strength reduction method is analyzed through three classical examples, i.e. 2D foundation problem, 2D slope stability problem and 3D slope stability problem. The results show that both linear element and quadratic element will approach to the exact solution from the upper side as the number of elements increases; but for linear element is too 'rigid'; and it will overestimate the safety factor, so it is dangerous for engineering practice. The error with linear element is about eight times larger than that of quadratic element under the same meshes. The shortage of strength reduction method with linear element can be made up by replacing the linear element with quadratic element based on the convergence of the maximum displacement in the system as the stability criteria. Quadratic element is more suitable than linear element for the shear strength reduction finite element method.

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