To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general predic...To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general prediction frameworks.This study employs an integrated approach that combines true-triaxial unloading experiments with three-dimensional grain-based discrete element modeling(PFC3D-GBM)to examine the effects of σ_(2) on strain systematically burst and elucidate the underlying mechanisms.Through this dual experimental–numerical methodology,the strainburst characteristics under varying σ_(2) are analyzed in detail regarding mechanical responses,failure evolution and patterns,microscope fracture mechanisms,and energy partitioning.The results indicate that elevated σ_(2) can enhance the bearing capacity of rock,thereby necessitating a higher stress condition required for strainburst.However,it also enlarges the potential strainburst intensity,manifesting as deeper rockburst pits and more violent ejection of rock fragments.An increasing σ_(2) facilitates the microscope transgranular fractures,inhibits intergranular tensile fractures,and raises the kinetic energy conversion ratio slightly.It affects the intensity of strainburst through the following mechanisms,including the increase of energy storage limit,the intensification of Poisson effect for lateral expansion,and the enhancement of the transgranular fracturing mechanism.In practical engineering,the depth and range of support needs to be ensured under high σ_(2) conditions,and it is recommended to use prestressing techniques to control the development of significant slabbing.展开更多
井工开采过程中,覆岩运动、应力演化及能量释放是影响安全生产的重要矿压与动力现象,但其隐蔽性、复杂性、间接性等特点给防灾减灾专业的教研教学带来了一定难度与挑战。传统教学方式受限于条件假设和不可视性,制约了学生对灾害机理的...井工开采过程中,覆岩运动、应力演化及能量释放是影响安全生产的重要矿压与动力现象,但其隐蔽性、复杂性、间接性等特点给防灾减灾专业的教研教学带来了一定难度与挑战。传统教学方式受限于条件假设和不可视性,制约了学生对灾害机理的深度理解与应用能力。基于此,该文将FLAC3D(fastlagrangian analysis of continua in 3D)数值模拟技术引入防灾减灾教学体系,阐述FLAC3D在教学中的实用价值,通过两个案例实验演示解释其在教学过程中的可视化、易接受的矿压响应特征、灾害诱因、优化防控措施,并评估教学质量的应用成效,给出优化建议。实践表明FLAC3D数值模拟技术可有效提升学生对矿山岩石力学与矿压响应特征的理解能力,培养其灾害预警与防范思维,以及工程决策能力。未来,随着具备强大数据处理和分析能力的AI技术的快速发展,可进一步与FLAC3D数值模拟基础软件深度联合,解析煤矿开采过程中复杂的数据信息,构建基于数据驱动的煤矿安全+教学与战略人才培养新模式。展开更多
目的:探究3D全腹腔镜根治术治疗Ⅲ期远端胃癌的疗效及安全性。方法:收集2021年2月至2024年2月收治的Ⅲ期远端胃癌患者的临床资料。将接受腹腔镜辅助远端胃癌根治术的患者纳入对照组,将接受3D全腹腔镜辅助远端胃癌根治术的患者纳入观察组...目的:探究3D全腹腔镜根治术治疗Ⅲ期远端胃癌的疗效及安全性。方法:收集2021年2月至2024年2月收治的Ⅲ期远端胃癌患者的临床资料。将接受腹腔镜辅助远端胃癌根治术的患者纳入对照组,将接受3D全腹腔镜辅助远端胃癌根治术的患者纳入观察组,采用倾向性评分匹配法以最邻近匹配原则1∶1进行匹配,最终两组各纳入60例。比较两组手术情况、术后恢复情况、术后疼痛程度评分(VAS)、围手术期应激反应指标、胃肠功能指标及并发症发生情况。结果:与对照组相比,观察组切口长度、消化道重建时间、术后首次排气时间、自主下床活动时间及住院时间更短,使用镇痛药物患者比例更低,切口美容评分更高,术后并发症发生率更低(P<0.05)。术后8、24、48、72 h两组VAS均低于治疗前,且观察组低于对照组(P<0.05)。观察组术后24、72 h ACTH、PGE2升高幅度和MTL、GAS降低幅度均小于对照组(P<0.05)。结论:3D全腹腔镜根治术治疗Ⅲ期远端胃癌创伤小、术后并发症少,有利于胃肠功能早期恢复,且具有切口美观的优势。展开更多
基金supported by the National Natural Science Foundation of China(No.42507210)the Fundamental Research Funds for the Central Universities(No.2025XJSB01)+1 种基金the State Key Laboratory for Tunnel Engineering(No.SKLTEK202421)the Foundation of Key Laboratory of Deep Coal Resource Mining(China University of Mining and Technology),Ministry of Education(No.KLDCRMMOE24KF11).
文摘To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general prediction frameworks.This study employs an integrated approach that combines true-triaxial unloading experiments with three-dimensional grain-based discrete element modeling(PFC3D-GBM)to examine the effects of σ_(2) on strain systematically burst and elucidate the underlying mechanisms.Through this dual experimental–numerical methodology,the strainburst characteristics under varying σ_(2) are analyzed in detail regarding mechanical responses,failure evolution and patterns,microscope fracture mechanisms,and energy partitioning.The results indicate that elevated σ_(2) can enhance the bearing capacity of rock,thereby necessitating a higher stress condition required for strainburst.However,it also enlarges the potential strainburst intensity,manifesting as deeper rockburst pits and more violent ejection of rock fragments.An increasing σ_(2) facilitates the microscope transgranular fractures,inhibits intergranular tensile fractures,and raises the kinetic energy conversion ratio slightly.It affects the intensity of strainburst through the following mechanisms,including the increase of energy storage limit,the intensification of Poisson effect for lateral expansion,and the enhancement of the transgranular fracturing mechanism.In practical engineering,the depth and range of support needs to be ensured under high σ_(2) conditions,and it is recommended to use prestressing techniques to control the development of significant slabbing.
文摘井工开采过程中,覆岩运动、应力演化及能量释放是影响安全生产的重要矿压与动力现象,但其隐蔽性、复杂性、间接性等特点给防灾减灾专业的教研教学带来了一定难度与挑战。传统教学方式受限于条件假设和不可视性,制约了学生对灾害机理的深度理解与应用能力。基于此,该文将FLAC3D(fastlagrangian analysis of continua in 3D)数值模拟技术引入防灾减灾教学体系,阐述FLAC3D在教学中的实用价值,通过两个案例实验演示解释其在教学过程中的可视化、易接受的矿压响应特征、灾害诱因、优化防控措施,并评估教学质量的应用成效,给出优化建议。实践表明FLAC3D数值模拟技术可有效提升学生对矿山岩石力学与矿压响应特征的理解能力,培养其灾害预警与防范思维,以及工程决策能力。未来,随着具备强大数据处理和分析能力的AI技术的快速发展,可进一步与FLAC3D数值模拟基础软件深度联合,解析煤矿开采过程中复杂的数据信息,构建基于数据驱动的煤矿安全+教学与战略人才培养新模式。
文摘目的:探究3D全腹腔镜根治术治疗Ⅲ期远端胃癌的疗效及安全性。方法:收集2021年2月至2024年2月收治的Ⅲ期远端胃癌患者的临床资料。将接受腹腔镜辅助远端胃癌根治术的患者纳入对照组,将接受3D全腹腔镜辅助远端胃癌根治术的患者纳入观察组,采用倾向性评分匹配法以最邻近匹配原则1∶1进行匹配,最终两组各纳入60例。比较两组手术情况、术后恢复情况、术后疼痛程度评分(VAS)、围手术期应激反应指标、胃肠功能指标及并发症发生情况。结果:与对照组相比,观察组切口长度、消化道重建时间、术后首次排气时间、自主下床活动时间及住院时间更短,使用镇痛药物患者比例更低,切口美容评分更高,术后并发症发生率更低(P<0.05)。术后8、24、48、72 h两组VAS均低于治疗前,且观察组低于对照组(P<0.05)。观察组术后24、72 h ACTH、PGE2升高幅度和MTL、GAS降低幅度均小于对照组(P<0.05)。结论:3D全腹腔镜根治术治疗Ⅲ期远端胃癌创伤小、术后并发症少,有利于胃肠功能早期恢复,且具有切口美观的优势。
文摘随着自动驾驶的发展,多传感器融合得到广泛应用。CLOCs是基于后融合的3D目标检测网络,但它对遮蔽物体的检测性能较差。针对此问题,提出一种融合双目测距和门控循环单元(Gated Recurrent Unit,GRU)的3D目标检测网络,其在CLOCs网络融合3D和2D的交并比(Intersection over Union,IoU)的基础上,在2D目标检测网络中引入双目测距来关联2D和3D的深度信息,在卷积之后加入GRU网络,用来捕捉时序数据的依赖关系。采用kitti数据集进行验证,实验结果表明检测精度得到了提升。
