综掘巷道超前支护装备双组支撑支护特性实验研究

为提高综掘巷道的掘进效率、改善支护工艺,设计一种用于综掘巷道迎头顶板支护的迈步式超前支护装备。通过对装备工作原理的分析,建立其三维模型。为检验装备的支护效果,设计了支护特性实验方案,构建实验平台,基于实验平台进行了双组支撑状态下的支护实验。实验结果表明:顶板上离固支边越远处动态位移变形量越大,接触力波动也越大; 在双组支撑状态下,顶板变形量最大达到9 mm,接触力最大幅值达到5.84 kN,位置均为顶板纵向中线位置处,在被支护后,该位置最迟趋于稳定; 在双组支撑状态下,顶板变形及接触力经历2~3 s波动后都将趋于平稳; 超前支护装备对顶板的稳定性能起到良好的控制作用,能提高顶板的安全性,为后续产品研发及工业实验提供依据。     

深部顶板夹煤层巷道变形破坏分析及其控制

为了探究深部顶板夹煤层软岩巷道大变形破坏问题,以平煤六矿三水平戊二胶带运输巷为工程背景,开展夹煤层巷道围岩破坏分析及控制对策的研究。首先,构建原支护体系组合拱力学模型,推导出直墙半圆拱形巷道稳定判别式;其次,提出“锚网索-梁-注浆-组合砂浆锚索”联合返修控制对策,即沿戊₈煤层顶板进行巷道扩刷,采用锚网索、梯子梁完成基本支护,对围岩进行深浅孔注浆加固、顶板及两帮关键部位布置组合砂浆锚索等加强支护,并通过数值模拟分析返修前后应力、位移场分布特征;最后,开展工业性试验,并监测矿压。结果表明：两帮及顶底板最大收敛量分别为93、 112 mm,后期变形速率均低于1 mm/d,围岩变形得到有效控制,返修效果良好。     

深部高应力煤层卸压开采相似材料模拟试验

处于深部开采且煤层位于轴部构造的矿井,巷道变形量大、变形速度快且持续时间长,巷道维护十分困难。卸压开采技术是控制矿山压力的有效手段。以大安山煤矿为工程背景,采用相似材料模拟进行卸压开采及非卸压开采两组模型对比试验,研究下保护层轴9煤层开采对被保护层轴10煤层的卸压效果,通过监测保护层开采过程中及开采稳定后轴10煤层卸压系数变化特征、岩层裂隙发育程度及变形情况来检验卸压效果。结果表明:卸压开采条件下,轴10煤层顶板应力普遍降低,峰值应力降低9.4%;岩层裂隙发育密度及煤岩层变形量大,岩层最大裂隙密度为14条/cm,上升16.7%;岩层最大下沉量为54.6 mm,上升21.6%,表明岩层受卸压作用,应力明显减小,弹性能释放程度较好,有利于减弱强矿压现象。     

巷道蝶叶塑性区顶板冒落特征与层次支护研究北大核心CSCD

针对巷道蝶叶塑性区顶板破坏深度大、变形剧烈、冒顶事故频发等问题,综合现场调研、理论分析、数值模拟等方法,考虑巷道顶板不同服务阶段的变形破坏特点,研究分析了巷道顶板破坏失稳机理和不同层位顶板的控制要点,提出了以冒顶控制为主的顶板层次控制技术,阐明了辅助支护材料、普通长度锚杆、接长锚杆、长锚索对不同层位顶板的层次控制原理。据此,在保德矿81306工作面回采巷道蝶叶塑性区顶板进行了层次支护设计,并进行了顶板下沉量和接长锚杆支护力监测,结果表明:以冒顶控制为主的巷道顶板层次支护体系较好的维护了顶板整体稳定,保证了巷道安全与正常服务。     

巷道蝶叶塑性区顶板冒落特征与层次支护研究

针对巷道蝶叶塑性区顶板破坏深度大、变形剧烈、冒顶事故频发等问题,综合现场调研、理论分析、数值模拟等方法,考虑巷道顶板不同服务阶段的变形破坏特点,研究分析了巷道顶板破坏失稳机理和不同层位顶板的控制要点,提出了以冒顶控制为主的顶板层次控制技术,阐明了辅助支护材料、普通长度锚杆、接长锚杆、长锚索对不同层位顶板的层次控制原理。据此,在保德矿81306工作面回采巷道蝶叶塑性区顶板进行了层次支护设计,并进行了顶板下沉量和接长锚杆支护力监测,结果表明:以冒顶控制为主的巷道顶板层次支护体系较好的维护了顶板整体稳定,保证了巷道安全与正常服务。     

巷道特厚泥质顶板失稳因素分析及控制技术

为研究巷道特厚泥质顶板失稳因素及其敏感性,通过现场调研和理论分析,确定6个影响特厚泥质顶板稳定的主控因素;以黄岩汇煤矿15107工作面为工程背景,采用有限差分软件FLAC5.0开展6因素3水平正交试验,运用方差分析方法研究各影响因素的敏感性;提出针对性的控制措施并开展现场应用。研究结果表明:影响特厚泥质顶板变形的各因素敏感性排序为:直接顶强度巷道宽度顶板支护强度直接顶厚度帮部支护强度煤层强度;直接顶强度、顶板支护强度及巷道宽度对巷道顶板变形的影响高度显著;煤层强度和帮部支护强度对巷道帮部变形的影响高度显著;提出的强化顶板承载结构及帮顶协同控制的支护对策,现场应用效果较好。     

中义隧道片理化玄武岩段大变形控制技术研究*

为进一步探究高地应力隧道软岩大变形控制技术,以中义隧道主洞片理化玄武岩段为工程背景,提出大变形Ⅰ型支护、大变形Ⅱ型支护、大变形Ⅱ型支护（围岩加固）3种大变形控制方案,以现场试验段监测为辅助验证,采用数值仿真对3种控制方案的控制效果进行对比分析。结果表明:适宜的支护成环时间具有减缓大变形的作用;在衬砌各部位累计最大变形控制方面,控制方案3较其他方案衬砌最大变形最少减小20.8%,且变形时程曲线最终收敛;围岩最大日变形量控制方面,经过开挖断面的进一步优化以及边墙部位塑性区围岩自承能力的提高,控制方案3最大日变形量较其他支护方案至少减小20.8%。结果显示控制方案3能够稳定控制片理化玄武岩大变形,且效果最好,研究结果可为类似工程提供设计依据。     

高应力煤巷卸压孔布置方式对卸压效果影响分析

高应力是造成深部煤巷大变形的主要因素。钻孔卸压已成为高应力区围岩稳定性控制的主要方法之一。基于钻孔卸压原理,以实际工程为背景,设计了三种卸压孔布置方式,并采用数值模拟的方法对不同卸压孔布置方式的卸压效果进行计算和对比分析。结果表明:卸压孔布置方式对卸压效果影响显著,卸压孔五花布置时,卸压效果最为明显;卸压孔周围形成卸压圈,卸压圈相互叠加,卸压范围增大;巷帮布置卸压孔使巷道周边形成的应力峰值向远离巷道的围岩深部移动,五花布置卸压孔时,不仅能够使应力峰值向深部转移,而且降低了应力峰值,有效改善围岩应力环境;卸压孔产生的卸压区,为巷道围岩提供给了一定的变形补偿空间,减小了巷道变形,卸压孔五花布置时,巷道变形最小,与无卸压孔时相比,巷道实体煤帮整体变形量减小了73.9%,顶板最大沉降量减小了40%,控制变形效果明显。     

超前支护与巷道围岩耦合动力学研究

为研究综掘巷道超前支护装备与巷道围岩耦合动力问题,基于薄板理论的顶板动力学模型,建立巷道顶板力学模型。简化超前支护装备,通过各部件的运动微分方程建立整机动力学模型;最后建立考虑多点支护条件下的超前支护-顶板体系耦合动力学模型。用多体系统动力学仿真软件Recur Dyn研究多种工况下耦合动力模型的动态响应过程。结果表明,在支护的压力冲击、振动以及综掘截割扰动等因素影响下,侧帮和顶板位移变形较剧烈。在有效支撑区段,变形小于未支护顶板的位移最大值;非有效支撑区段的位移极值小于未支护顶板的位移极值,表明超前支护对顶板变形有一定的控制作用。     

考虑煤柱黏弹塑性流变的煤柱-顶板力学模型

为研究房柱式开采和条带开采的老采空区煤柱-顶板体系的稳定性,预测煤矿采空区煤柱-顶板体系稳定时间,将煤柱简化为满足西原模型的黏弹塑性体,将采空区顶板简化为弹性薄板,建立考虑煤柱黏弹塑性流变变形的采空区煤柱-顶板体系力学模型,在此模型基础上推导采空区煤柱-顶板体系稳定时间的微分方程,并采用伽辽金法进行求解。将该模型应用于某房柱式开采的老采空区稳定时间预测中,验证了力学模型的可靠性。研究表明,煤柱的黏弹塑性流变变形是导致煤柱-顶板体系失稳的重要原因,煤柱的流变变形随时间的推移而增大,最终导致煤柱-顶板体系的失稳。     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.     

HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。     

Nighttime pedestrian fatalities: A comprehensive examination of infrastructure,user, vehicle,and situational factors

Introduction: Pedestrian fatalities in the United States increased 45.5% between 2009 and 2017. More than 85% of those additional pedestrian fatalities occurred at night. Method: We examine Fatality Analysis Reporting System (FARS) data for fatal pedestrian crashes that occurred in the dark between 2002 and 2017. Within-variable and before/after examinations of crashes in terms of infrastructure, user, vehicle, and situational characteristics are performed with one-way analysis of variance (ANOVA) and two-sample t-tests. We model changes in crash characteristic proportions between 2002–2009 and 2010–2017 using linear regressions and test for autocorrelation with Breusch-Godfrey tests. Results: The increase in fatal nighttime pedestrian crashes is most strongly correlated with infrastructure factors: non-intersection unmarked locations (saw 80.8% of additional fatalities); 40–45 mph roads (54.6%); five-lane roads (40.7%); urban (99.7%); and arterials (81.1%). In addition, SUVs were involved in 39.7% of additional fatalities, overrepresenting their share of the fleet. Increased pedestrian alcohol and drug involvement warrant further investigation. The age of pedestrians killed increased more (18.1%) than the national average (3.2%). Conclusions: By identifying factors related to the increase in nighttime pedestrian fatalities, this work constitutes a vital first step in making our streets safer for pedestrians. Practical Applications: More research is needed to understand the efficacy of different solutions, but this paper provides guidance for such future research. Engineering solutions such as road diets or traffic calming may be used to improve identified infrastructure issues by reducing vehicle speeds and road widths. Rethinking vehicle design, especially high front profiles, may improve vehicle issues. However, the problems giving rise to these pedestrian fatalities are likely a result of not only engineering issues but also interrelated social and political factors. Solutions may be correspondingly comprehensive, employing non-linear, systems-based approaches such as Safe Systems.     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

AHP与GA-SVM耦合模型在滑坡预警中的应用*

为了减少滑坡造成的损失,提高滑坡预测的准确性,通过搭建灾害模拟平台获得滑坡的实验数据,在获得多组模拟实验数据后,分析各变量的特性。首先,通过层次分析(Analytic Hierarchy Process,AHP)算法,对滑坡进行危险度划分;然后,通过支持向量机(Support Vector Machine,SVM)建立模型,遗传算法(Genetic Algorithm,GA)再优化SVM参数,提出1种层次分析法与GA-SVM相耦合的模型。研究结果表明:AHP方法划分后的数据,通过GA与SVM结合建立的模型精度较好,实验预测结果与实际结果较为吻合,与单一SVM相比,精度更高,结果更好,更加适用于多变量的复杂非线性滑坡预警。     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Occupational Safety and Health in Finland

In Finland, occupational safety is the responsibility of the employer, while the occupational safety and health laws are enforced by the Labour Inspection Service, an organization of the state. The Labour Inspection is divided in 11 administrative districts, and it employs 360 professionals. They are mandated to carry out site visits without prearranged appointments to inspect safe work situations, working hours, construction safety, or any aspect of accident risks. The inspectors are also mandated to verify the existence of sufficient occupational health services as prescribed by the Occupational Health Services Act for all employees. The occupational health services are typically provided by enterprise-owned medical departments, by mutually owned health care centers, by private practitioners, or by municipal health care centers. The latter are required by law to provide all services as prescribed by the legislation to anyone who comes to the facility. This situation is prevalent in the countryside, where there are very few private caregiving centers. Declaring occupational accidents and disease cases is mandatory, and the Inspection districts examine all accidents to establish causes and consequences, and to initiate prosecution in case of criminal negligence. Labour Inspection Districts are also notified of the new occupational disease cases as they are declared to insurance companies. Insurance for occupational disease, accidents, and death is an obligation of the employer, although they can choose the insurance company. The medical confidentiality between the workers and their occupational health care providers is very strict. Official statistics are maintained by the state Statistics Finland organization, and they may be used, for example, for research purposes by scientific institutes like the Finnish Institute of Occupational Health. Construction industry accounts for 25% of all fatal accidents (120 cases per 1 million working hours), followed by mechanical, wood, metal, machinery, and pulp and paper industry (10% each of fatal accidents) with rates ranging from 100–160 cases per 1 million working hours. There are some 5,000 occupational disease cases per year (rate 22/10,000 employed). The major disease categories include repetitive strain injuries (1,300 cases), respiratory allergies (600 cases), occupational skin diseases (1,000 cases), and 900 cases of noise-caused hearing loss. In 1998, 589 cases of asbestos-related diseases were reported.     

森林地表火蔓延模拟方法及其计算机实现

进行了森林火蔓延的研究,对传统的经验公式和模型进行改进,明显发现改进的模型有更好的结果,用计算机巧妙准确地实现了模拟模型,在风力不是特别大,地形变化不是特别剧烈时,该模型有较高精度;并结合火蔓延的主要因素（气象因子、气候、地形等）,进行系统分析,写出算地,编制实现地表火蔓延的预测预报计算机系统软件。这对于有效的组织扑救、减少火灾损失、计算森林火灾的损失评估有重要意义。     

公路隧道火灾逃生疏散研究

以苍岭隧道为背景,首先采用经验计算理论和计算软件building EXODUS相结合的方式,从被困人员的安全疏散时间、高温烟气的影响、隧道横通道的利用率以及人员的疏散行为特性进行了研究。结果表明:中小规模火灾情况下的安全疏散时间控制在8 min之内,高温烟气影响不大,但横通道的利用率不平均,且人员疏散路线相对集中。然后对存在的逃生疏散问题提出针对性建议以及其他相关建议,旨在为更大程度降低事故的严重性和经济财产损失。