Methods that can efficiently model the effects of rock joints on rock mass behavior can be beneficial in rock engineering. The suitability of equivalent rock mass(ERM) technique based upon particle methods is investig...Methods that can efficiently model the effects of rock joints on rock mass behavior can be beneficial in rock engineering. The suitability of equivalent rock mass(ERM) technique based upon particle methods is investigated. The ERM methodology is first validated by comparing calculated and experimental data of lab triaxial compression test on a set of cylindrical rock mass samples, each containing a single joint oriented in various dip angles. The simulated results are then used to study the stress-strain nonlinearity and failure mechanism as a function of the joint dip angle and confining stress. The anisotropy and size effects are also investigated by using multi-scale cubic ERM models subjected to triaxial compression test. The deformation and failure behavior are found to be influenced by joint degradation, the micro-crack formation in the intact rock, the interaction between two joints, and the interactions of micro-cracks and joints.展开更多
A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the ...A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the influence zones created by remnant pillars and gob-solid boundaries. Though coal outburst is generally associated with heavy loading of coal pillars,its occurrence is difficult to predict. Risk management provides a proactive tool to minimize coal outburst in room-and-pillar mining under deep cover. Risk assessment is the first step in identifying and quantifying outburst risk factors. The primary risk factors for coal outburst are overburden depth,roof and floor strength,geological anomalies,mining type,multi-seam mining,and panel width. A risk assessment chart can be used to proactively screen out mining sections with high risk of coal outburst for further analysis. Gob-solid boundaries and remnant pillars are critical factors in evaluation of the coal outburst risk of multi-seam mining. Risk identification,risk assessment,geologic influence mapping,geotechnical evaluation,risk analysis,risk mitigation,and monitoring are essential elements of coal outburst risk management process. Training is an integral part of risk management for risk identification and communication between all the stakeholders including management,technical and safety personnel,and miners.展开更多
The construction industry works under conditions of uncertainties and risks leading to poor performance, increased cost and time and decreased quality. In these conditions, the dynamic identification and assessment of...The construction industry works under conditions of uncertainties and risks leading to poor performance, increased cost and time and decreased quality. In these conditions, the dynamic identification and assessment of project risks among a vary range of potential factors is considered of vital importance. The introduction of RBS (risk breakdown structure) as a hierarchically organized depiction of identified risks was considered a suitable tool in risk management, especially in construction, due to its many advantages in synthetic representation and dynamic nature. This paper presents a user-oriented implementation of RBS to assist the project managers in identifying and assessing potential risk factors affecting construction process. The evidential analogies between WBS (work breakdown structure) and RBS are captured and used in the proposed framework which interconnects them into a 2D (two dimensional) matrix used to associate risks to the specific project activities. The proposed framework is applied to a government funded design-bid-build project. The obtained results clearly demonstrate the advantages in identifying the most risky activities, as well as the most important risk factors affecting the whole project.展开更多
With the continuous development of the construction industry, the scale and volume of the construction project is expanding. And the project management of the construction project still has the big risk problem which ...With the continuous development of the construction industry, the scale and volume of the construction project is expanding. And the project management of the construction project still has the big risk problem which influenced by many factors. These risks will not only bring unnecessary interference to the construction of the project, but also may jeopardize the safety of people's life and property. It is the focus of this article to do a good job in risk aversion in the management of construction projects.展开更多
基金Projects(51074014,51174014) supported by the National Natural Science Foundation of China
文摘Methods that can efficiently model the effects of rock joints on rock mass behavior can be beneficial in rock engineering. The suitability of equivalent rock mass(ERM) technique based upon particle methods is investigated. The ERM methodology is first validated by comparing calculated and experimental data of lab triaxial compression test on a set of cylindrical rock mass samples, each containing a single joint oriented in various dip angles. The simulated results are then used to study the stress-strain nonlinearity and failure mechanism as a function of the joint dip angle and confining stress. The anisotropy and size effects are also investigated by using multi-scale cubic ERM models subjected to triaxial compression test. The deformation and failure behavior are found to be influenced by joint degradation, the micro-crack formation in the intact rock, the interaction between two joints, and the interactions of micro-cracks and joints.
文摘A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the influence zones created by remnant pillars and gob-solid boundaries. Though coal outburst is generally associated with heavy loading of coal pillars,its occurrence is difficult to predict. Risk management provides a proactive tool to minimize coal outburst in room-and-pillar mining under deep cover. Risk assessment is the first step in identifying and quantifying outburst risk factors. The primary risk factors for coal outburst are overburden depth,roof and floor strength,geological anomalies,mining type,multi-seam mining,and panel width. A risk assessment chart can be used to proactively screen out mining sections with high risk of coal outburst for further analysis. Gob-solid boundaries and remnant pillars are critical factors in evaluation of the coal outburst risk of multi-seam mining. Risk identification,risk assessment,geologic influence mapping,geotechnical evaluation,risk analysis,risk mitigation,and monitoring are essential elements of coal outburst risk management process. Training is an integral part of risk management for risk identification and communication between all the stakeholders including management,technical and safety personnel,and miners.
文摘The construction industry works under conditions of uncertainties and risks leading to poor performance, increased cost and time and decreased quality. In these conditions, the dynamic identification and assessment of project risks among a vary range of potential factors is considered of vital importance. The introduction of RBS (risk breakdown structure) as a hierarchically organized depiction of identified risks was considered a suitable tool in risk management, especially in construction, due to its many advantages in synthetic representation and dynamic nature. This paper presents a user-oriented implementation of RBS to assist the project managers in identifying and assessing potential risk factors affecting construction process. The evidential analogies between WBS (work breakdown structure) and RBS are captured and used in the proposed framework which interconnects them into a 2D (two dimensional) matrix used to associate risks to the specific project activities. The proposed framework is applied to a government funded design-bid-build project. The obtained results clearly demonstrate the advantages in identifying the most risky activities, as well as the most important risk factors affecting the whole project.
文摘With the continuous development of the construction industry, the scale and volume of the construction project is expanding. And the project management of the construction project still has the big risk problem which influenced by many factors. These risks will not only bring unnecessary interference to the construction of the project, but also may jeopardize the safety of people's life and property. It is the focus of this article to do a good job in risk aversion in the management of construction projects.