In the past two decades,numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers,great bridges or to retain soil in potential geological hazard areas.However,drilling...In the past two decades,numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers,great bridges or to retain soil in potential geological hazard areas.However,drilling large-diameter rock-socketed pile holes with conventional drilling method such as rotary drilling or cable tool drilling is time-consuming and the cost is usually very high.In order to drill large-diameter rock-socketed pile holes faster at relatively low cost,the FGC15A large-diameter DTH air hammer drilling system was developed in 1987 and was given the second-class award by Ministry of Geology and Mineral Resources in 1991.Since it was innovated the drilling system has been used in more than twenty important and tough projects on land,and wonderful results were acquired.At the same time the large-diameter DTH air hammer drilling system was improved continuously.The FGC15D is the latest version of the technique.展开更多
Air down-the-hole(DTH)hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill,especially in some hard rocks such as granite,sandstone,limestone,dolomite,etc.wit...Air down-the-hole(DTH)hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill,especially in some hard rocks such as granite,sandstone,limestone,dolomite,etc.with the same weight on bit(WOB)and rotations per minute(RPM).So,it has been widely used in many drilling fields including mineral resource exploration drilling,oil and gas drilling and geothermal drilling.In order to reduce drilling cost by selecting optimal drilling parameters,rate of penetration(ROP)should be estimated accurately and the effects of different factors on ROP should be analyzed.In this research,ANN model with several multi-layer perception back propagation(BP)networks for predicting ROP of air DTH hammer drilling was developed using controllable parameters such as impact energy,impact frequency,WOB,RPM and bit operating time for the formations with a certain drillability index of rock.Several BP neural networks with the different neurons in hidden layers were developed and compared for selecting optimal architecture of ANN.The effects of the drilling parameters such as impact energy,impacting frequency,WOB,RPM and bit operating time on the ROP of air DTH hammer drilling were investigated by trained ANN.From the analyses,the optimum range of drilling parameters for providing high ROP were determined and analyzed for a formation with a certain drillability index of rock.The methodology proposed in this study can be used in many mathematical problems for optimization of drilling process with air DTH hammer.展开更多
Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas. In order to expand the applications of the technology,the authors further studied t...Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas. In order to expand the applications of the technology,the authors further studied the principle and analyzed the mechanism of reverse circulation drilling technique with air DTH hammer to get the perfect assembles of equipments by optimizing working parameters. No parameter seemed more important than the air volume because it could maintain the working performance stability. The minimum air volume is related to the parameters such as depth and pressure,which was calculated under the actual conditions. It was solved for the air injection flow tables of the air DTH Hammer working at the different pressures. According to the data tables,operators could adjust the air volume to meet the demand on this technique,which had a realistic guiding significance. So it could build up a set of systematic and complete hi-technique.展开更多
To solve water hammer problems in pipeline systems,many numerical simulation approaches have been developed. This paper improves a flux vector splitting( FVS) scheme whose grid is the same as the fixedgrid MOC scheme....To solve water hammer problems in pipeline systems,many numerical simulation approaches have been developed. This paper improves a flux vector splitting( FVS) scheme whose grid is the same as the fixedgrid MOC scheme. The proposed FVS scheme is used to analyze water hammer problems caused by a pump abrupt shutdown in a pumping system with an air vessel. This paper also proposes a pump-valve-vessel model combining a pump-valve model with an air vessel model. The results show that the data obtained by the FVS scheme are similar to the ones obtained by the fixed-grid method of characteristics( MOC). And the results using the pump-valve-vessel model are almost the same as the ones using both the pump-valve model and the air vessel model. Therefore,it is effective that the proposed FVS scheme is used to solve water hammer problems and the pump-valve-vessel model replaces both the pump-valve model and the air vessel model to simulate water hammer flows in the pumping system with the air vessel.展开更多
文摘In the past two decades,numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers,great bridges or to retain soil in potential geological hazard areas.However,drilling large-diameter rock-socketed pile holes with conventional drilling method such as rotary drilling or cable tool drilling is time-consuming and the cost is usually very high.In order to drill large-diameter rock-socketed pile holes faster at relatively low cost,the FGC15A large-diameter DTH air hammer drilling system was developed in 1987 and was given the second-class award by Ministry of Geology and Mineral Resources in 1991.Since it was innovated the drilling system has been used in more than twenty important and tough projects on land,and wonderful results were acquired.At the same time the large-diameter DTH air hammer drilling system was improved continuously.The FGC15D is the latest version of the technique.
文摘Air down-the-hole(DTH)hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill,especially in some hard rocks such as granite,sandstone,limestone,dolomite,etc.with the same weight on bit(WOB)and rotations per minute(RPM).So,it has been widely used in many drilling fields including mineral resource exploration drilling,oil and gas drilling and geothermal drilling.In order to reduce drilling cost by selecting optimal drilling parameters,rate of penetration(ROP)should be estimated accurately and the effects of different factors on ROP should be analyzed.In this research,ANN model with several multi-layer perception back propagation(BP)networks for predicting ROP of air DTH hammer drilling was developed using controllable parameters such as impact energy,impact frequency,WOB,RPM and bit operating time for the formations with a certain drillability index of rock.Several BP neural networks with the different neurons in hidden layers were developed and compared for selecting optimal architecture of ANN.The effects of the drilling parameters such as impact energy,impacting frequency,WOB,RPM and bit operating time on the ROP of air DTH hammer drilling were investigated by trained ANN.From the analyses,the optimum range of drilling parameters for providing high ROP were determined and analyzed for a formation with a certain drillability index of rock.The methodology proposed in this study can be used in many mathematical problems for optimization of drilling process with air DTH hammer.
基金supported by the project of the feasibility study on air reverse circulation drilling system,research foundation for out standingteachers,Jilin University(No.2006220100003435)
文摘Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas. In order to expand the applications of the technology,the authors further studied the principle and analyzed the mechanism of reverse circulation drilling technique with air DTH hammer to get the perfect assembles of equipments by optimizing working parameters. No parameter seemed more important than the air volume because it could maintain the working performance stability. The minimum air volume is related to the parameters such as depth and pressure,which was calculated under the actual conditions. It was solved for the air injection flow tables of the air DTH Hammer working at the different pressures. According to the data tables,operators could adjust the air volume to meet the demand on this technique,which had a realistic guiding significance. So it could build up a set of systematic and complete hi-technique.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51208160)the Natural Science Foundation of Heilongjiang Province(Grant No.QC2012C056)
文摘To solve water hammer problems in pipeline systems,many numerical simulation approaches have been developed. This paper improves a flux vector splitting( FVS) scheme whose grid is the same as the fixedgrid MOC scheme. The proposed FVS scheme is used to analyze water hammer problems caused by a pump abrupt shutdown in a pumping system with an air vessel. This paper also proposes a pump-valve-vessel model combining a pump-valve model with an air vessel model. The results show that the data obtained by the FVS scheme are similar to the ones obtained by the fixed-grid method of characteristics( MOC). And the results using the pump-valve-vessel model are almost the same as the ones using both the pump-valve model and the air vessel model. Therefore,it is effective that the proposed FVS scheme is used to solve water hammer problems and the pump-valve-vessel model replaces both the pump-valve model and the air vessel model to simulate water hammer flows in the pumping system with the air vessel.
