An innovative stormwater master plan based on low impact development LID is proposed.Unlike the traditional urban drainage plan this plan employs a sustainable stormwater management approach in communities utilizing L...An innovative stormwater master plan based on low impact development LID is proposed.Unlike the traditional urban drainage plan this plan employs a sustainable stormwater management approach in communities utilizing LID practices to reduce runoff and pollution load. An integrated hydraulic model which combines the traditional drainage sewer system with LID practices is adopted to assess the master plan.Through a long-term continuous simulation for 20 years the results reveal that the runoff volume will be reduced by over 80% following full implementation of this plan. Combining with the local conditions technical guidelines are established to provide assistance in implementing the stormwater master plan. Bioretention facilities for three main roads are constructed and other areas of development are being implemented sequentially under the guidance of the plan. This project provides an alternative method of stormwater management through the implementation of LID and it acts as a good example for other developing districts in China.展开更多
Surface mining activities may introduce damages to nearby infrastructure. Concerns are put forward by the power company about structural integrity of electric power transmission structures in areas where coal mining a...Surface mining activities may introduce damages to nearby infrastructure. Concerns are put forward by the power company about structural integrity of electric power transmission structures in areas where coal mining activities cause strong ground vibrations. Common practice in the power industry is to limit ground motion by specifying maximum Peak Particle Velocity. So far, there is a lack of industry-wide recognized guidelines on how ground vibration limits should be set for the transmission structures. In order to develop a defense strategy to protect power transmission lines against strong ground motions in mining areas, a systematic research work was conducted to establish strong ground vibration characteristics and to study impacts of ground excitations on transmission pole structures. Ground movements were recorded using geophones and wireless tri-axial sensing units. The process of generating ground motion response spectra via analyzing actual ground motion measurements is described in the paper. These spectra developed based on peak particle velocities were used as a basis for spectral analysis performed using validated Finite Element models to obtain structural displacements, reactions and stress states of the transmission pole structures in the mining sites. A quantitative ground motion limit was established by comparing structural responses with the corresponding design requirements.展开更多
The RMR system is still very much applied in rock mechanics engineering context. It is based on the evaluation of six weights to obtain a final rating. To obtain the final rating a considerable amount of information i...The RMR system is still very much applied in rock mechanics engineering context. It is based on the evaluation of six weights to obtain a final rating. To obtain the final rating a considerable amount of information is needed concerning the rock mass which can be difficult to obtain in some projects or project stages at least with accuracy. In 2007 an alternative classification scheme based on the RMR, the Hierarchical Rock Mass Rating(HRMR) was presented. The main feature of this system was the adaptation to the level of knowledge existent about the rock mass to obtain the classification of the rock mass since it followed a decision tree approach. However, the HRMR was only valid for hard rock granites with low fracturing degrees. In this work, the database was enlarged with approximately 40% more cases considering other types of granite rock masses including weathered granites and based on this increased database the system was updated. Granite formations existent in the north of Portugal including Porto city are predominantly granites. Some years ago a light rail infrastructure was built in the city of Porto and surrounding municipalities which involved considerable challenges due to the high heterogeneity levels of the granite formations and the difficulties involved in their geomechanical characterization. In this work it is intended to provide also a contribution to improve the characterization of these formations with special emphasis to the weathered horizons. A specific subsystem applicable to the weathered formations was developed. The results of the validation of these systems are presented and show acceptable performances in identifying the correct class using less information than with the RMR system.展开更多
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2010BAK69B16)
文摘An innovative stormwater master plan based on low impact development LID is proposed.Unlike the traditional urban drainage plan this plan employs a sustainable stormwater management approach in communities utilizing LID practices to reduce runoff and pollution load. An integrated hydraulic model which combines the traditional drainage sewer system with LID practices is adopted to assess the master plan.Through a long-term continuous simulation for 20 years the results reveal that the runoff volume will be reduced by over 80% following full implementation of this plan. Combining with the local conditions technical guidelines are established to provide assistance in implementing the stormwater master plan. Bioretention facilities for three main roads are constructed and other areas of development are being implemented sequentially under the guidance of the plan. This project provides an alternative method of stormwater management through the implementation of LID and it acts as a good example for other developing districts in China.
文摘Surface mining activities may introduce damages to nearby infrastructure. Concerns are put forward by the power company about structural integrity of electric power transmission structures in areas where coal mining activities cause strong ground vibrations. Common practice in the power industry is to limit ground motion by specifying maximum Peak Particle Velocity. So far, there is a lack of industry-wide recognized guidelines on how ground vibration limits should be set for the transmission structures. In order to develop a defense strategy to protect power transmission lines against strong ground motions in mining areas, a systematic research work was conducted to establish strong ground vibration characteristics and to study impacts of ground excitations on transmission pole structures. Ground movements were recorded using geophones and wireless tri-axial sensing units. The process of generating ground motion response spectra via analyzing actual ground motion measurements is described in the paper. These spectra developed based on peak particle velocities were used as a basis for spectral analysis performed using validated Finite Element models to obtain structural displacements, reactions and stress states of the transmission pole structures in the mining sites. A quantitative ground motion limit was established by comparing structural responses with the corresponding design requirements.
文摘The RMR system is still very much applied in rock mechanics engineering context. It is based on the evaluation of six weights to obtain a final rating. To obtain the final rating a considerable amount of information is needed concerning the rock mass which can be difficult to obtain in some projects or project stages at least with accuracy. In 2007 an alternative classification scheme based on the RMR, the Hierarchical Rock Mass Rating(HRMR) was presented. The main feature of this system was the adaptation to the level of knowledge existent about the rock mass to obtain the classification of the rock mass since it followed a decision tree approach. However, the HRMR was only valid for hard rock granites with low fracturing degrees. In this work, the database was enlarged with approximately 40% more cases considering other types of granite rock masses including weathered granites and based on this increased database the system was updated. Granite formations existent in the north of Portugal including Porto city are predominantly granites. Some years ago a light rail infrastructure was built in the city of Porto and surrounding municipalities which involved considerable challenges due to the high heterogeneity levels of the granite formations and the difficulties involved in their geomechanical characterization. In this work it is intended to provide also a contribution to improve the characterization of these formations with special emphasis to the weathered horizons. A specific subsystem applicable to the weathered formations was developed. The results of the validation of these systems are presented and show acceptable performances in identifying the correct class using less information than with the RMR system.
