The influence of towing speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is investigated.Two field trials were undertaken;the first trial used three EPCs placed at varying depths...The influence of towing speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is investigated.Two field trials were undertaken;the first trial used three EPCs placed at varying depths between 0.5 m and 1.5 m with towing speeds of 9-12 km/h.The second used three EPCs placed at a uniform depth of 0.8 m,with towing speeds of 5-15 km/h.The findings from the two trials confirmed that towing speed influences the pressure imparted to the ground and hence compactive effort.This paper proposes that the energy imparted to the ground is best described in terms of work done,which is the sum of the change in both potential and kinetic energies.Current practice of using either kinetic energy or gravitational potential energy should be avoided as neither can accurately quantify rolling dynamic compaction(RDC)when towing speed is varied.展开更多
The typical shear behaviour of rough joints has been studied under constant normal load/stress （CNL） boundary conditions, but recent studies have shown that this boundary condition may not replicate true practical s...The typical shear behaviour of rough joints has been studied under constant normal load/stress （CNL） boundary conditions, but recent studies have shown that this boundary condition may not replicate true practical situations. Constant normal stiffness （CNS） is more appropriate to describe the stress-strain response of field joints since the CNS boundary condition is more realistic than CNL. The practical implications of CNS are movements of unstable blocks in the roof or walls of an underground excavation, reinforced rock wedges sliding in a rock slope or foundation, and the vertical movement of rock-socketed concrete piles. In this paper, the highlights and limitations of the existing models used to predict the shear strength/behaviour of joints under CNS conditions are discussed in depth.展开更多
Government buildings are responsible for a significant proportion of energy consumption worldwide,for example, in Australia, up to 41.5 PJ energy was consumed by government buildings in 2011–2012. While the newly con...Government buildings are responsible for a significant proportion of energy consumption worldwide,for example, in Australia, up to 41.5 PJ energy was consumed by government buildings in 2011–2012. While the newly constructed buildings may be energy efficient,the existing buildings, which account for more than 85% of the total building stock, were built prior to the time when energy rating systems was put in practice and are consequently energy inefficient to a large degree. Reducing the energy consumption in existing government buildings is essential, as it will not only reduce the costs and environmental impacts, but also show governments' strong commitment towards the reduction of greenhouse gas emission. Furthermore, successful building energy retrofit projects are the showcases to the general public, encouraging other sectors(e.g. commercial) to conduct building retrofits for energy savings. Recognising these benefits,several state governments in Australia have introduced building energy efficiency policies and programs. This paper reviewed the energy efficiency policies/programs in five States in Australia: Victoria, New South Wales, South Australia, Western Australia, and Queensland in terms of respective policies and targets, implementation methods and current progress. The lessons learned from these programs were also discussed. This research revealed that the key factors for a successful government buildingenergy retrofitting program are 1) having a properly enforced energy efficiency mandate with clear energy saving targets, 2) establishing an expert facilitation team and 3) implementing suitable financing and procurement methods.展开更多
文摘The influence of towing speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is investigated.Two field trials were undertaken;the first trial used three EPCs placed at varying depths between 0.5 m and 1.5 m with towing speeds of 9-12 km/h.The second used three EPCs placed at a uniform depth of 0.8 m,with towing speeds of 5-15 km/h.The findings from the two trials confirmed that towing speed influences the pressure imparted to the ground and hence compactive effort.This paper proposes that the energy imparted to the ground is best described in terms of work done,which is the sum of the change in both potential and kinetic energies.Current practice of using either kinetic energy or gravitational potential energy should be avoided as neither can accurately quantify rolling dynamic compaction(RDC)when towing speed is varied.
文摘The typical shear behaviour of rough joints has been studied under constant normal load/stress （CNL） boundary conditions, but recent studies have shown that this boundary condition may not replicate true practical situations. Constant normal stiffness （CNS） is more appropriate to describe the stress-strain response of field joints since the CNS boundary condition is more realistic than CNL. The practical implications of CNS are movements of unstable blocks in the roof or walls of an underground excavation, reinforced rock wedges sliding in a rock slope or foundation, and the vertical movement of rock-socketed concrete piles. In this paper, the highlights and limitations of the existing models used to predict the shear strength/behaviour of joints under CNS conditions are discussed in depth.
基金funding this project under SBEnrc Project 1.43 "Retrofitting Public Buildings for Energy and Water Efficiency"
文摘Government buildings are responsible for a significant proportion of energy consumption worldwide,for example, in Australia, up to 41.5 PJ energy was consumed by government buildings in 2011–2012. While the newly constructed buildings may be energy efficient,the existing buildings, which account for more than 85% of the total building stock, were built prior to the time when energy rating systems was put in practice and are consequently energy inefficient to a large degree. Reducing the energy consumption in existing government buildings is essential, as it will not only reduce the costs and environmental impacts, but also show governments' strong commitment towards the reduction of greenhouse gas emission. Furthermore, successful building energy retrofit projects are the showcases to the general public, encouraging other sectors(e.g. commercial) to conduct building retrofits for energy savings. Recognising these benefits,several state governments in Australia have introduced building energy efficiency policies and programs. This paper reviewed the energy efficiency policies/programs in five States in Australia: Victoria, New South Wales, South Australia, Western Australia, and Queensland in terms of respective policies and targets, implementation methods and current progress. The lessons learned from these programs were also discussed. This research revealed that the key factors for a successful government buildingenergy retrofitting program are 1) having a properly enforced energy efficiency mandate with clear energy saving targets, 2) establishing an expert facilitation team and 3) implementing suitable financing and procurement methods.
