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Dynamic response of cross-sea bridge pile foundation under the coaction of wave and current

International Journal of Earth Sciences and engineering 2016年第4期9卷 1383-1387页

作者： Wen, Huang Jie, Chen Qian, Song Feng, Xu School of Urban Construction Wuhan University of Science and Technology Wuhan China China United Northwest Institute for Engineering Design & Research Co. Ltd Xian China School of Resource and Civil Engineering Wuhan Institute of Technology Wuhan China

Bridges under the circumstances of marine environments are subject to extremely complicated loads. The precise calculation and estimation of two most important loads in deep sea, ocean waves and currents, is of essential influence to the construction of cross-sea bridges. On the basis of analyzing the effect of currents on the motion of waves and considering fluid-solid coupling effect, the paper derives the structural dynamics equation under the combined influence of waves and currents. Then, the finite element model for columns under the coaction of wave and current is constructed, and the corresponding computation program is compiled with MATLAB. The model can simultaneously estimate the drag force of current on the structure and the effect of structural deformation on the inertial force applied on it. Through model experiment, and comparing the varying effect of waves and currents on pile foundation with the changes of velocity, pile diameter and incident angle, the paper analyses the interactive effects between waves and currents, and the basic rules by which waves and current forces change with parameters. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.

关键词： Dynamic response

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New solution of elastic and plastic mechanics of surrounding rock considering strain softening

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International Journal of Earth Sciences and engineering 2016年第5期9卷 2234-2240页

作者： Lou, Peijie School of Civil and Architectural Engineering Anhui University of Science and Technology HuainanAnhui232001 China Center for Post-doctoral Studies of Civil Engineering Anhui University of Science and Technology HuainanAnhui232001 China Henan Province Colleges Universities Deep Mine Construction Key Discipline Open Laboratory JiaozuoHenan454000 China Engineering Research Center of Underground Mine Construction Ministry of Education HuainanAnhui232001 China

By introducing rock mass strength softening modulus, the elastic-plastic mechanical analysis model of round roadway surrounding rock with consideration of strain softening condition under static pressure and mining pressure was set up. Then, the stress and new displacement explanation of elastic-plastic three area of roadway surrounding rock under static pressure and dynamic pressure were deduced. The new explanation example shows that strain softening modulus has remarkable impact on surrounding rock ‘three areas’ scope, which can objectively reflect the features of roadway surrounding rock strength decrease along with strain increase under static pressure and dynamic pressure. This is the mechanical mechanism of large deformation for this kind of roadway. If reasonable rock physical and mechanics parameters are selected, then more reasonable analytic solutions can be obtained in theory. By improving residual strength status of fracture zone, the fracture zone radius can be effectively controlled. It is the mechanical mechanism of the roadway surrounding rock stability control, which can provide effective gist for the roadway arrangement and supporting design construction under static pressure and dynamic pressure. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.

关键词： Fracture

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Research on Stability of Coal Pillars in Wongawilli Mining Area of Ganhe Colliery

Research on Stability of Coal Pillars in Wongawilli Mining A...

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2016 4th International Conference on Management Science,Education technology,Arts,Social Science and Economics(MSETASSE 2016)

作者： Liang Tian Minzu Li Shaopeng Jiao Dongsheng Yang Xianghui Kang School of Mechanics and Civil Engineering China University of Mining and Technology (Beijing) The 4th construction Co. Ltd of China Railway NO.5 Engineering Group

ISBN: (纸本)9781510834071

In order to find a suitable technology for recovery of bound coal in China's Shanxi province, the Wongawilli mining method is applied in Ganhe colliery. Recovery rate depends on reasonable deign of rooms and pillars. Geological conditions of pilot area is complex, such as great burial depth, poor integrality and latent underground water. In consideration of that, the study was carried out in 2013. Site sampling, SEM(scanning electron microscope), XRD(X-Ray Diffraction) and some other mechanical equipment were used to test physical and mechanical parameters of surrounding rocks. The RQD(rock quality designation) is lower than 30%, so the integrality of rocks is quite poor, the compressive strength is of high discrete. Then theory of simply supported beam and theory of clamped beam were used to acquire the reasonable span of roof rock. Finally, numerical models were founded to analyse deformation, plastic zone and stress evolution by FLAC3 D. Three different size of coal pillar were compared. We come to a conclusion that the suitable width of little pillar is 1.5 m in this mining area, it can guarantee stability of stope, meanwhile recovery rate is the highest.

关键词： Bound coal Wongawilli mining method Coal pillars Numerical simulation Coal pillar numerical simulation mining areas Coal mines geological condition clamped beam pilot test area simply supported beam Subsurface Water Compressive strength rocks mechanical parameter Rooms Coal rock quality designation

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Stiffness Matrix of Thin-Walled Open Bar Subject to Bending, Bending Torsion and Shift of Cross Section Middle Surface

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IOP Conference Series: Materials Science and engineering 2017年第1期262卷

作者： N N Panasenko A V Sinelschikov Engineering and Technology of Land Transport Astrakhan State Technical University 16 Tatischeva St. Astrakhan 414056 Russia Industrial and Civil Construction Astrakhan State University of Civil Engineering 18 Tatischeva St. Astrakhan 414056 Russia

One of the main stages in the analysis of complex 3D structures and engineering constructions made of thin-walled open bars using FEM is a stiffness matrix developing. Taking into account middle surface shear deformation caused by the work of tangential stresses in the formula to calculate a potential energy of thin-walled open bars, the authors obtain an important correction at calculation of the bar deformation and fundamental frequencies. The results of the analysis of the free end buckling of a cantilever H-bar under plane bending differ from exact solution by 0.53%. In the course of comparison of the obtained results with the cantilever bar buckling regardless the middle surface shear deformation, an increase made 16.6%. The stiffness matrix of a thin-walled open bar developed in the present work can be integrated into any software suite using FEM for the analysis of complex 3-D structures and engineering constructions with n-freedoms.

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Updating Linear Schedules with Lowest Cost: a Linear Programming Model

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IOP Conference Series: Materials Science and engineering 2017年第7期245卷

作者： Sławomir Biruk Piotr Jaśkowski Agata Czarnigowska Lublin University of Technology Faculty of Civil Engineering and Architecture Department of Construction Methods and Management ul. Nadbystrzycka 40 20-618 Lublin Poland

Many civil engineering projects involve sets of tasks repeated in a predefined sequence in a number of work areas along a particular route. A useful graphical representation of schedules of such projects is time-distance diagrams that clearly show what process is conducted at a particular point of time and in particular location. With repetitive tasks, the quality of project performance is conditioned by the ability of the planner to optimize workflow by synchronizing the works and resources, which usually means that resources are planned to be continuously utilized. However, construction processes are prone to risks, and a fully synchronized schedule may expire if a disturbance (bad weather, machine failure etc.) affects even one task. In such cases, works need to be rescheduled, and another optimal schedule should be built for the changed circumstances. This typically means that, to meet the fixed completion date, durations of operations have to be reduced. A number of measures are possible to achieve such reduction: working overtime, employing more resources or relocating resources from less to more critical tasks, but they all come at a considerable cost and affect the whole project. The paper investigates the problem of selecting the measures that reduce durations of tasks of a linear project so that the cost of these measures is kept to the minimum and proposes an algorithm that could be applied to find optimal solutions as the need to reschedule arises. Considering that civil engineering projects, such as road building, usually involve less process types than construction projects, the complexity of scheduling problems is lower, and precise optimization algorithms can be applied. Therefore, the authors put forward a linear programming model of the problem and illustrate its principle of operation with an example.

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Experimental Studies on Thermo-mechanical Coupled Behavior of Pile-Clay Interface

Experimental Studies on Thermo-mechanical Coupled Behavior o...

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作者： Jingkai Wang Zhichao Zhang School of Civil Engineering Chongqing University Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityMinistry of Education

The thermo-mechanical coupled behavior of pile-soil interface is very important for the mechanical performance of energy *** is studied in this paper by the thermo-mechanical coupled direct shear tests with a temperature controllable concrete specimen in the top shear box and a Kaolin clay specimen in the bottom shear *** results show that the strength of pile-clay interface significantly depends on the temperature,the temperature cycle number and the over-consolidation ratios of *** the heating-cooling cycles,the interface strength can increase and decrease monotonically or non-monotonically depending on the stress state and history of clay,which is generally a thermo-elasto-plastic *** is shown that the thermo-mechanical coupled pile-clay interface behavior is the net effect of the pore water transportation and the rearrangement of clay particles near the interface as well as the thermal consolidation/expansion of clay.

关键词： energy pile temperature cycle pile-clay interface direct shear test

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Basic Principles of Thin-Walled Open Bars Taking into Account Where Influence Shifts of Cross Sections are Concerned

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IOP Conference Series: Materials Science and engineering 2017年第1期262卷

The finite element method is considered to be the most effective in relation to the calculation of strength and stability of buildings and engineering constructions. As a rule, for the modelling of supporting 3-D frameworks, finite elements with six degrees of freedom are used in each of the nodes. In practice, such supporting frameworks represent the thin-walled welded bars and hot-rolled bars of open and closed profiles in which cross-sectional deplanation must be taken into account. This idea was first introduced by L N Vorobjev and brought to one of the easiest variants of the thin-walled bar theory. The development of this approach is based on taking into account the middle surface shear deformation and adding the deformations of a thin-walled open bar to the formulas for potential and kinetic energy; these deformations depend on shearing stress and result in decreasing the frequency of the first tone of fluctuations to 13%. The authors of the article recommend taking into account this fact when calculating fail-proof dynamic systems.

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Risk Management in construction Project: Taking Fairness into Account

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IOP Conference Series: Materials Science and engineering 2017年第7期245卷

作者： Jarosław Górecki Jadwiga Bizon-Górecka Department of Construction Engineering and Management Faculty of Civil and Environmental Engineering and Architecture University of Science and Technology Bydgoszcz Al. prof. S. Kaliskiego 7 85-796 Bydgoszcz Poland

Risk management requires a comprehensive review of possible hazards, their possible outcomes as well as some recommendations about minimizing the risk. The study emphasises that the project risk management refers to an analysis of the risk factors and a creation of the strategy minimising negative effects of the risk. It was pointed out that a construction project is this kind of projects that can be defined as a unique process of high complexity (design documentation, various stages of creating the building), which has clearly defined time frames and a given financial limit. It is executed as a team work, by qualified or highly qualified specialists of different matters, for example masonry, precast, etc. Additionally, it requires a use of modern equipment and an adequate preparation of the investment. Therefore, the risk management focuses on the problems allowing for troubleshooting. A basis of the risk management is to recognise the fundamentals, which are crucial for the construction project management, i.e. an object perspective, including technological, supporting and management processes as well as an entity perspective – project stakeholders. construction projects require also an acquaintance with the specificity of the branch. The article refers to the risk management in construction project and, in particular, a phenomenon of participants' fairness in such projects. The problem of fairness of the entities involved in a project should be understood as a fair play, according to the arrangements agreed in a contract and compatible with current formal procedures and social rules. It was indicated that fairness can be treated as an important factor in predicting the success of such projects. Interviews conducted among contractors in Kuyavian-Pomeranian region showed varied fairness requirements put to individual participants of construction projects. The article presents results of the research. It shows a desired attitude of the surveyed enterprises towards a

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Sustainable Impact of Landfill Siting towards Urban Planning in Malaysia

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IOP Conference Series: Materials Science and engineering 2017年第5期245卷

作者： Jia Sin Tey Kai Chen Goh Peniel Soon Ern Ang Dept of Construction Management Universiti Tun Hussein Onn Malaysia 86400 Dept of Civil Engineering Technology Universiti Tun Hussein Onn Malaysia 86400

Landfill is one of the most common, widely used waste management technique in Malaysia. The ever increasing of solid waste has made the role of landfill become prominent despite the negative impacts that caused by the landfill is unavoidable. The public and government regulations are getting more aware with the negative impacts that could be brought by the landfill towards the community. It led to the cultural shift to integrate the concept of sustainability into the planning of siting a landfill in an urban area. However, current urban planning tends to emphasize more on the environmental aspect instead of social and economic aspects. This is due to the existing planning guidelines and stakeholder's understandings are more on the environmental aspect. This led to the needs of incorporating the concept of sustainability into the urban planning. Thus, this paper focuses on the industry stakeholders view on the negative impacts that will cause by the landfill towards the urban planning. The industry stakeholders are those who are related to the decision-making in the selection of a landfill site in the government department. The scope of the study is within the country of Malaysia. This study was conducted through the semi-structured interviews with a total of fifteen industry stakeholders to obtain their perspective on the issues of impacts of siting a landfill in the urban area. The data obtained was analysed using the software, QSR NVivo version 10. Results indicate that landfill bought significant sustainability-related impacts towards landfill siting in urban planning. The negative impacts stated by the respondents are categorized under all three sustainable aspects such as environmental, social and economic. Among the results are such as the pollution, such as the generation of leachate, the objection in siting a landfill site against by the public, and the negotiating and getting money contribution from local authorities. The results produced can be served as a

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Minimizing Project Cost by Integrating Subcontractor Selection Decisions with Scheduling

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IOP Conference Series: Materials Science and engineering 2017年第7期245卷

Subcontracting has been a worldwide practice in the construction industry. It enables the construction enterprises to focus on their core competences and, at the same time, it makes complex project possible to be delivered. Since general contractors bear full responsibility for the works carried out by their subcontractors, it is their task and their risk to select a right subcontractor for a particular work. Although subcontractor management has been admitted to significantly affect the construction project's performance, current practices and past research deal with subcontractor management and scheduling separately. The proposed model aims to support subcontracting decisions by integrating subcontractor selection with scheduling to enable the general contractor to select the optimal combination of subcontractors and own crews for all work packages of the project. The model allows for the interactions between the subcontractors and their impacts on the overall project performance in terms of cost and, indirectly, time and quality. The model is intended to be used at the general contractor's bid preparation stage. The authors claim that the subcontracting decisions should be taken in a two-stage process. The first stage is a prequalification – provision of a short list of capable and reliable subcontractors; this stage is not the focus of the paper. The resulting pool of available resources is divided into two subsets: subcontractors, and general contractor's in-house crews. Once it has been defined, the next stage is to assign them to the work packages that, bound by fixed precedence constraints, form the project's network diagram. Each package is possible to be delivered by the general contractor's crew or some of the potential subcontractors, at a specific time and cost. Particular crews and subcontractors can be contracted more than one package, but not at the same time. Other constraints include the predefined project completion date (the project is not allowe

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