A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed w...A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.展开更多
Most finite element models of small arms focus on an idealized barrel,typically one with a perfectly straight bore centerline.Using five different experimentally measured bore centerlines,this investigation analyzes t...Most finite element models of small arms focus on an idealized barrel,typically one with a perfectly straight bore centerline.Using five different experimentally measured bore centerlines,this investigation analyzes the effect centerline nonlinearity has on projectile exit conditions.This includes the effect of rotating a centerline through several orientations.Modeled using Abaqus/Explicit,this dynamic analysis simulates a single firing cycle for each centerline.Projectile jump is calculated for each model as a measure of the effects of warped centerlines.The warped centerlines have a small effect on barrel dynamics.展开更多
A novel surface-repairing technique for gun bore was investigated, which was combined with the merits such as anti-erosion wear, damage-repairing, and etc. It was accomplished by adhering a special rare earth nanocomp...A novel surface-repairing technique for gun bore was investigated, which was combined with the merits such as anti-erosion wear, damage-repairing, and etc. It was accomplished by adhering a special rare earth nanocomposite evenly to the micro-surface of gun bore. The effectiveness of this technique was approved by the target-firing using a domestic automatic rifle with chromium-coated bore. Its characteristics were discussed based on the surface analyses of the rifle bore by secondary ion mass spectrometry(SIMS),scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.展开更多
A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the per...A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.展开更多
The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump ari...The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.展开更多
针对深部金属矿隧道掘进机(tunnelling boring machine,TBM)开拓岩爆微震监测与预警自动化、智能化不足的问题,开展了基于深度机器视觉DPED(drilling profile ellipse detection)-AT(accurate location of drilling multidimensional fe...针对深部金属矿隧道掘进机(tunnelling boring machine,TBM)开拓岩爆微震监测与预警自动化、智能化不足的问题,开展了基于深度机器视觉DPED(drilling profile ellipse detection)-AT(accurate location of drilling multidimensional features based on anchor tracking)方法的钻孔多维参数识别研究、微震传感器自动拆装装置研发与决策系统设计,实现了TBM开拓微震传感器自动拆装;研发了微震智能变频采集技术,实现了岩爆孕育过程岩石破裂信息连续、保真采集;研发了改进神经网络破裂信号识别与到时实时拾取算法,及岩爆孕育微震源概率场三维表征算法,初步实现TBM开拓岩爆孕育信息智能解译与精细化预警,最终建立了融合钻孔智能识别、传感器自动拆装、信号智能采集-解译的岩爆智能监测预警技术体系.招金矿业瑞海金矿应用表明,该技术初步实现了岩爆微震自动监测、解译与预警,为深部金属矿TBM开拓的少人化、无人化提供有力支撑.展开更多
基金Foundation item： Project（2009-K3-2） supported by the Ministry of Housing and Urban-Rural Development of China
文摘A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.
文摘Most finite element models of small arms focus on an idealized barrel,typically one with a perfectly straight bore centerline.Using five different experimentally measured bore centerlines,this investigation analyzes the effect centerline nonlinearity has on projectile exit conditions.This includes the effect of rotating a centerline through several orientations.Modeled using Abaqus/Explicit,this dynamic analysis simulates a single firing cycle for each centerline.Projectile jump is calculated for each model as a measure of the effects of warped centerlines.The warped centerlines have a small effect on barrel dynamics.
文摘A novel surface-repairing technique for gun bore was investigated, which was combined with the merits such as anti-erosion wear, damage-repairing, and etc. It was accomplished by adhering a special rare earth nanocomposite evenly to the micro-surface of gun bore. The effectiveness of this technique was approved by the target-firing using a domestic automatic rifle with chromium-coated bore. Its characteristics were discussed based on the surface analyses of the rifle bore by secondary ion mass spectrometry(SIMS),scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.
基金Project(51278216) supported by the National Natural Science Foundation of ChinaProject(2013BS010) supported by Henan University of Technology Fund for High-level Talent,China
文摘A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.
文摘The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.
文摘针对深部金属矿隧道掘进机(tunnelling boring machine,TBM)开拓岩爆微震监测与预警自动化、智能化不足的问题,开展了基于深度机器视觉DPED(drilling profile ellipse detection)-AT(accurate location of drilling multidimensional features based on anchor tracking)方法的钻孔多维参数识别研究、微震传感器自动拆装装置研发与决策系统设计,实现了TBM开拓微震传感器自动拆装;研发了微震智能变频采集技术,实现了岩爆孕育过程岩石破裂信息连续、保真采集;研发了改进神经网络破裂信号识别与到时实时拾取算法,及岩爆孕育微震源概率场三维表征算法,初步实现TBM开拓岩爆孕育信息智能解译与精细化预警,最终建立了融合钻孔智能识别、传感器自动拆装、信号智能采集-解译的岩爆智能监测预警技术体系.招金矿业瑞海金矿应用表明,该技术初步实现了岩爆微震自动监测、解译与预警,为深部金属矿TBM开拓的少人化、无人化提供有力支撑.
