In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body bel...In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body below 1 100 m regarded as research objects based on the original design project, and nine calculation schemes on different mining sequence and different fill body strength were put forward based on cement-sand ratio of 1 ： 4, 1： 12 and 1 ： 24. Calculation parameters were got by the back analysis method of field monitoring data, and the FLAC2D program was applied to compute for these schemes, stress and displacement of ground settlement, shaft and stope roof were analyzed, and some conclusions were got. Results show that the intensity of filling body and the mining technique have very important effect on controlling settlement and stability of surrounding rock; Developing of lean ore have some influences to the 16th return air filling shaft, especially for 1 500--1 400 m of the shaft; The best project is the first project. This research supply some technique references and safety appraisals for the mining of lean-ore of No.II Mining Jinchuan.展开更多
The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tension...The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tensioning to attach the walls to the foundation, along with employing energy dissipating shear connectors between the walls. Using acceptance criteria defined in terms of inter-story drift, residual drift, and floor acceleration, this study presents a multiplelevel performance-based seismic evaluation of two five-story unbonded post-tensioned jointed precast wall systems. The design and analysis of these two wall systems, established as the direct displacement-based and force-based solutions for a prototype building used in the PREcast Seismic Structural Systems （PRESSS） program, were performed at 60% scale so that the analysis model could be validated using the PRESSS test data. Both buildings satisfied the performance criteria at four levels of earthquake motions although the design base shear of the direct displacement-based jointed wall system was 50% of that demanded by the force-based design method. The study also investigated the feasibility of controlling the maximum transient inter-story drift in a jointed wall system by increasing the number of energy dissipating shear connectors between the walls but without significantly affecting its re-centering capability.展开更多
Cyclists belong to the group of vulnerable road users and, thus, need particular protection in road traffic. One way to enhance cyclists’ safety is to use urban data (e.g., infrastructure data, accident statistics) t...Cyclists belong to the group of vulnerable road users and, thus, need particular protection in road traffic. One way to enhance cyclists’ safety is to use urban data (e.g., infrastructure data, accident statistics) to inform cyclists about potentially dangerous areas, allowing them to better adjust to the situation and elevate their self-protection. However, the question is how to inform cyclists about such dangerous areas. In this paper, we present the results of two field studies, investigating two wearables (headphones vs. smart glasses) and different signal options to inform cyclists about dangerous areas. Study participants were cycling along a predefined track and could experience the different wearables and signals. The main aim of the studies was to find out how cyclists perceive and experience the different approaches. Participants’ impressions were captured with questionnaires and interviews. Our results show a clear preference of the headphones over the smart glasses and signaling with intermittent audio while being in the dangerous area. However, we also found that participants’ acceptance of the approach was influenced by the additional perceived benefit the respective wearable would have in daily life. Using a wearable solely to be warned, although this would increase safety, was less acceptable. We discuss the implications of these findings for the design of cyclist warning systems.展开更多
基金Supported by Key Projects in the Province Science & Technology Program of Hunan (2009FJ2005)Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period(2008BAB32B01)Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body below 1 100 m regarded as research objects based on the original design project, and nine calculation schemes on different mining sequence and different fill body strength were put forward based on cement-sand ratio of 1 ： 4, 1： 12 and 1 ： 24. Calculation parameters were got by the back analysis method of field monitoring data, and the FLAC2D program was applied to compute for these schemes, stress and displacement of ground settlement, shaft and stope roof were analyzed, and some conclusions were got. Results show that the intensity of filling body and the mining technique have very important effect on controlling settlement and stability of surrounding rock; Developing of lean ore have some influences to the 16th return air filling shaft, especially for 1 500--1 400 m of the shaft; The best project is the first project. This research supply some technique references and safety appraisals for the mining of lean-ore of No.II Mining Jinchuan.
文摘The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tensioning to attach the walls to the foundation, along with employing energy dissipating shear connectors between the walls. Using acceptance criteria defined in terms of inter-story drift, residual drift, and floor acceleration, this study presents a multiplelevel performance-based seismic evaluation of two five-story unbonded post-tensioned jointed precast wall systems. The design and analysis of these two wall systems, established as the direct displacement-based and force-based solutions for a prototype building used in the PREcast Seismic Structural Systems （PRESSS） program, were performed at 60% scale so that the analysis model could be validated using the PRESSS test data. Both buildings satisfied the performance criteria at four levels of earthquake motions although the design base shear of the direct displacement-based jointed wall system was 50% of that demanded by the force-based design method. The study also investigated the feasibility of controlling the maximum transient inter-story drift in a jointed wall system by increasing the number of energy dissipating shear connectors between the walls but without significantly affecting its re-centering capability.
文摘Cyclists belong to the group of vulnerable road users and, thus, need particular protection in road traffic. One way to enhance cyclists’ safety is to use urban data (e.g., infrastructure data, accident statistics) to inform cyclists about potentially dangerous areas, allowing them to better adjust to the situation and elevate their self-protection. However, the question is how to inform cyclists about such dangerous areas. In this paper, we present the results of two field studies, investigating two wearables (headphones vs. smart glasses) and different signal options to inform cyclists about dangerous areas. Study participants were cycling along a predefined track and could experience the different wearables and signals. The main aim of the studies was to find out how cyclists perceive and experience the different approaches. Participants’ impressions were captured with questionnaires and interviews. Our results show a clear preference of the headphones over the smart glasses and signaling with intermittent audio while being in the dangerous area. However, we also found that participants’ acceptance of the approach was influenced by the additional perceived benefit the respective wearable would have in daily life. Using a wearable solely to be warned, although this would increase safety, was less acceptable. We discuss the implications of these findings for the design of cyclist warning systems.
