Effectiveness analysis of methane-drainage by deep-hole controlled pre-splitting blasting for preventing coal and gas outburst

In the study of the application effectiveness of deep-hole controlled pre-splittingblasting technology,it was found through laboratory micro test and field study on a mine insouth China that under the technology,coal masses produce many irreversible cracks.Afterblasting,the nearer the distance from blasting hole,the larger the BET surface areaand volume ratio of the infiltration pore are;they increased by 11.47%and 5.73%,respectively.The coefficient of air permeability is increased 4 times.After 3 months,the gasdrainage rate was increased by 66%.In the first 15 days,the cumulative pumped gas was1.93 times of blasting before.The average absolute gas emission decreased by 63.46%.Experimental results show that deep-hole controlled pre-splitting blasting not only preventscoal and gas outburst,but also gives good economic results.

覆岩高位整层爆破卸压“人造预裂层”源头防治冲击地压技术体系及应用

主动卸压防冲是落实强化煤矿冲击地压源头治理的重要措施。现行的主动卸压防控方式,或采用回采工作面平巷布孔卸压,或采用井下原位水力压裂技术,具有卸压保护范围有限、卸压施工进度制约等不足;或采用地面水力压裂防冲系统,具有卸压范围广时效长等优点,也需要解决前期投入等。因此,秉持源头防治、防患未然、经济高效的一体化的防冲卸压创新战略思想,研究一种实践易行、效果显著、可全面推广的新型区域卸压源头防冲技术体系势在必行。提出了覆岩高位超前整层爆破卸压技术体系,针对可产生动载荷的较高位关键层,创新高位岩巷、高位钻场、爆破钻孔布置,将高位坚硬岩层超前、整体、均匀爆破预裂,从而形成“人造预裂层”。该方法突破了一般的长钻孔距离限制,使得岩层爆破的卸压高度、卸压范围、卸压效果均大幅提高,可形成覆盖整个工作面区域甚至多个工作面的超前工作面开采的高位“人造预裂层”。高位爆破“人造预裂层”首先使得该高位坚硬岩层的来压步距和来压强度大幅减弱,其次也缓冲减弱了其上硬岩层向下传递的矿山压力,最后还可降低其下方硬岩层的来压步距。在陕西长武亭南煤业3409工作面首次进行了覆岩高位整层爆破卸压“人造预裂层”技术试验后,现场实测效果表明采用该方法较之常规爆破卸压区域,支架的平均来压强度、来压步距、来压持续距离和压力报警频次均大幅减少;巷道深孔和浅孔应力也均减少;微震事件总能量、大能量微震事件大幅度减少,且密集程度显著降低,工作面中段的微震事件尤为稀疏;地音高能事件、震源CT获得的冲击风险区域也有减少,各种实测手段均验证了高位爆破人造预裂层卸压防冲技术的优越性。

Study on the Occurrence and Epidemic Regularity and Region Division of Rice Blast in Nanchong City

With the aim to improve the level of monitoring and warning as well as the comprehensive control of rice blast disease, and to feasibly reduce the disease threat in Nanchong City, the methods of GPS and GIS, systematical monitoring and field survey, rice blast resistance identification, physiologic races of rice blast monitoring, and meteorological data analysis were performed to study the occurrence and epidemic region division, precise demarcation and occurrence and epidemic regularity of rice blast in Nanchong City. This study first completed the epidemic region division and precise demarcation; first clarified the initial affection（beginning period） locations, occurrence characteristics, epidemic trends and characteristics; explicated the existence of four epidemic peak periods of rice blast in the field, where the damage areas of first peak period played a decisive role during the blast epidemic years; in late May, the cumulative occurrence areas and annual occurrence areas presented higher positive correlation with the correlation coefficient of 0.817;and established a prediction model of occurrence areas per year based on the disease field rate at the end of boot stages and the diseased plant rate at dough stages. The results of investigation on the impact factors investigation of blast disease in Nanchong in recent years suggested that the internal causes were the decrease or loss of blast resistance of the rice cultivars, as well as the increase of physiological races with strong resistance to rice blast and the emergence of new virulent physiologic varieties; the external causes were suitable temperature, too much rainy, and sunlight shortage. Between 2010 and 2015, the short-term forecast accuracy for rice blast in Nanchong was up to 100%, and medium-and long-term forecast accuracy was also up to 98% and 95%, respectively, which increased by 5-15% than that before 1997, thereby making the control effect of rice blast in Nanchong increased by 15-30%.

场平工程开挖爆破的动力传播规律研究

高填深挖大面积场平工程爆破施工过程中,地表振动将对周边建筑造成剧烈的扰动作用。以深圳市某高填深挖大面积场平工程项目为依托背景,研究76、115、140 mm炮孔直径药包爆破过程的动力传播特性。测试76 mm和115 mm炮孔直径药包作用下的场地振速,基于萨道夫斯基公式拟定场地系数K和α值。采用有限元软件Midas/GTS建立三维数值模型,将数值模拟的振速结果与实测拟合公式对比,分析爆破过程中振速和应力的传播特性。结果表明:数值模拟与现场监测的结果基本吻合;3种炮孔直径的药包振速在距爆心100 m外衰减程度逐渐稳定,且水平振速大于垂直振速,满足规范要求;3种炮孔直径的药包应力值在距爆心50 m内衰减程度较快,差值较大,距爆心100 m时差值较小,衰减程度趋于稳定。

隧道平整度控制光面爆破及“刮刀+三刮两平”工艺优化施工技术研究

在隧道施工的过程中,隧道初支平整度是隧道施工质量控制的关键,隧道初支平整度与隧道二次衬砌的质量密切相关,例如二次衬砌厚度不足、背后脱空等严重的质量缺陷,为确保隧道初支平整度,隧道施工过程中采用聚能光爆和“三喷两刮一扫面”工艺进行施作,初支平整度效果良好。

Safety of engineered structures against blast vibrations： A case study

Blasting used for rock excavation is associated with ground vibrations having potential damage to surrounding structures.The extent of damage produced in a structure depends largely on ground motion characteristics,dynamic characteristics of structure and the type of geological strata on which it is founded.The safety of surrounding structures against blast vibrations is a cause of concern.However,use of a systematic approach to rock blasting helps to complete the excavation safely in time without endangering the safety of surrounding structures.Various steps are commonly adopted at construction sites to ensure safety of engineered structures against blast vibrations,e.g.adopting a suitable safe vibration level,developing site-specific attenuation relation,estimating safe charges for different distances,designing blasting pattern,and monitoring vibrations during actual blasting.The paper describes the details of studies conducted for ensuring safety of an 85 years old masonry dam and green concrete of varying ages during excavation of about 30,000 m;of hard rock in Maharashtra,India.The studies helped to complete the rock excavation safely in time and the safety of the dam was ensured by monitoring blast vibrations during actual rock excavation.

Numerical Modeling of Response and Damage of Masonry Walls to Blast Loading

To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.

Cap rock blast caving of cavity under open pit bench

A laser technique based scanning system was employed to make a comprehensive scanning through borehole forunmapped cavity under open pit bench,then the three-dimensional data will be obtained,and these data were used for theoreticalanalysis and numerical simulation to analyze the stability of cap rock.Acoustic emission techniques were also adopted to carry outlong term real time rupture monitoring in cap rock.Therefore,a complete safety evaluation system for the cap rock was establishedto ensure safe operation of subsequent blasting processes.The ideal way of eliminating collapse hazard of such cavity is cap rockcaving through deep-hole blasting,thus,two deep-hole blasting schemes named as vertical deep-hole blasting scheme and one-timeraise driving integrated with deep-hole bench blasting scheme were proposed.The vertical deep-hole blasting scheme has moreexplosive consumption,but the relatively simple blasting net work structure can greatly reduce workloads.However,the one-timeraise driving integrated with deep-hole bench blasting scheme can obviously reduce explosive consumption,but the higher technicalrequirements on drilling,explosive charging and blasting network will increase workloads.

Optimum Level of Replacement Slag in OPC-Slag Mortars

The present paper reports the testing of 14 OPC-slag mortars and 2 controls OPC and slag mortars. The main aim is to determine the optimum level of replacement slag for achievement to the highest early strength with reasonable flow. Variable was the level of GGBFS in the binder. In this experimental work, two types of sands were used that are： silica and mining sands. It is determined that the optimum level of replacement slag is 40% and use of silica sand in OPC is preferable to mining sand and reversely, use of mining sand is preferred in GG100 to silica sand. All mortars had W/B and S/B 0.33 and 2.25, respectively.

External blast load factors for dome structures based on reliability

Dome structures have been used extensively for industrial,residential,and military infrastructure.Therefore,it is necessary to understand the damage risk potential for such structures for blast-resistant design considerations.This paper investigates the effect of blast load variability on the design value and the structural dynamic response.Therefore,the sources of uncertainty in the external blast load on dome structures were discussed firstly.Then based on the probabilistic blast load model for the dome,the rationality of a deterministic mass-increase safety method was assessed.It was found that previous deterministic design method cannot provide a consistent and sound assurance factor or reliability index on the entire dome roof.In addition,it was also proved that the assurance-based load method fails to ensure compliance with structural safety design standards on the dome roof when compared with the reliability-based blast method.A sensitivity analysis on the probabilistic blast load was conducted,and the results indicate that stand-off distance and explosive mass both act as dominant sources to influence the mean and variability of blast load.Therefore,based on the Latin hypercube sampling method,a reliability-based external blast load factor technique was proposed.This technique was further used to estimate structural damage levels of a single-layer reticulated dome under different reliability requirements,associated with a low,medium,and high level of protection grades for a specific explosion scenario,and it indicated that this technique can be useful in the building design to achieve a higher structural anti-explosion capacity.This study herein can serve as a reference for the calculation method of designed blast load.

硅溶胶结合碳化硅灌注料在某2500m3高炉炉底的应用

高炉炉底找平层材料应具有良好的体积稳定性,强度满足要求且具有较高的导热系数。某2500 m^(3)高炉2015年大修时,炉底找平层材料选用了硅溶胶结合碳化硅灌注料,投产后炉底温度一直处于正常状态。该灌注料的施工过程包括:清除原炉底炭素捣打料、灌注施工、焊接炉底封板及填充空隙、安装扁钢、灌注及找平等步骤,从灌注开始至修补完成,灌注料施工共耗时约14h。该灌注料具有易施工、体积稳定性好、导热性优异、流动性和悬浮性良好、施工周期短、固化强度高、环保等特点,应用于高炉炉底找平层,可节省施工时间、提高炉底传热系统导热性能,有利于降低炭砖热面工作温度、减缓砖衬侵蚀。

基于模糊层次和改进灰色关联度耦合算法的隧道爆破风险评价

在隧道开挖过程中,对隧道掌子面爆破工程进行风险因子的识别及评价,可以达到评价整个隧道施工安全风险的目的。以石柱至黔江高速公路万寿山隧道为研究对象,从影响隧道爆破安全的角度出发,确定4个一级指标和14个二级指标。然后,结合模糊理论和改进灰色关联度分析方法,建立了模型矩阵以及模糊互补矩阵,确定了各因子的权重和矩阵特征向量。最后,再运用模糊理论多层次分析方法对隧道爆破施工风险开展评价,确定了各风险分级。结果表明:各因子的权重由大至小依次为掌子面爆破、爆破管理、地质条件、爆破设计。同时,隧道爆破风险综合等级为高风险;各一级指标中,地质条件为高风险,掌子面爆破为极高风险,爆破管理和爆破设计为中风险。基于风险类型和风险评价结果,可制定分级管控措施及北斗一体化监测系统方案,实时了解隧道围岩变形情况,实行风险分级管控,为隧道开挖动态施工的安全提供保障。

包钢1^(#)高炉安全环保空料线停炉实践

本次停炉采用空料线停炉操作法,通过活跃炉缸、计算分析装轻负荷料、前期采用大风量尽可能的快速燃烧焦炭、改进雾化装置减少炉顶打水量、细化炉前出铁、合理控制压量关系、缩短煤气放散时间、高效组织、安全放残铁工作、协调各系统等,降料线过程总体比较顺利,达到了全程无爆震、安全、环保、快速停炉。

基于爆破漏斗试验在马坑铁矿VCR成井爆破技术中的应用

高位溜井的施工一直是一个技术难题,为简易、安全、高效地施工高位溜井,马坑铁矿拟采用VCR成井爆破技术,解决高位溜井施工环境差、通风困难等施工难题。以利文斯顿爆破漏斗理论为基础,对马坑铁矿进行单孔爆破漏斗试验,试验采用2#岩石乳化炸药,药量分别为150 g和300 g。试验结果得出药包最佳埋置深度及爆破漏斗半径,根据药包比例埋深及对应的漏斗半径,经单位炸药量爆破漏斗体积公式换算,确定VCR成井技术的炮孔合理间距、装药长度及孔底堵塞长度。

基于不同爆炸风险水平的FPSO生活楼抗爆结构设计

油气爆炸是海洋平台主要风险之一,基于爆炸风险的结构设计是设计技术发展趋势。该文梳理风险分析相关的技术法规、规范,总结了爆炸风险评估流程、结构抗爆性能评估方法及流程;以某浮式生产储卸油装置(floating production storage and offloading unit,FPSO)海洋平台生活楼为依托对象,利用结构有限元分析软件,分别开展了筛选分析、强度水平分析和塑性水平分析,完成基于爆炸风险的生活楼结构性能评估;基于功能性、作业、生命安全这3个性能水平,开展不同爆炸风险水平的结构设计,得到满足各性能水平衡准的设计方案。

青岛特钢2号高炉快速降料面停炉实践

介绍了青岛特钢2号高炉停炉前的准备工作、快速降料面的控制原则和具体操作措施。降料面操作过程中,风量、顶温、顶压等关键操作参数控制得当,炉内无爆震、无管道气流、无悬料,风口无烧损、无灌渣,整个过程历时16 h,顺利将料面降至风口以下,26个风口全部露出,实现安全、高效、环保停炉。

高放废物地质处置库巷道掘进安全技术综述

该文介绍高放废物地质处置库的基本情况,并论述高放废物地质处置库巷道掘进过程中产生有害因素的研究现状。依据巷道掘进过程中产生的炮烟、粉尘、氡3种主要有害因素介绍掘进过程中有害因素的扩散规律,并从不同角度提出相应的应对措施。依据研究现状提出目前研究存在的不足。

高炉料罐雷达料位计安装方式的改进及应用

对高炉料罐雷达料位计使用情况进行跟踪分析。结果表明,雷达料位计喇叭口内积灰是影响其故障率高、在线运行时间短的主要原因。通过改变其安装结构,增设导波管及吹扫气源,减少了雷达料位计喇叭口内积灰、降低了料位计故障率、延长了其在线使用寿命。

舟山鱼山岛鱼山末站场平工程爆破施工安全管理

舟山鱼山岛鱼山末站场平工程周边环境复杂,西侧分布有石化基地污水处理厂、10kV高压电线等,且邻近交通要道,车流人流密集,爆破安全隐患大。爆破实施过程中,应采取科学合理的爆破施工方法和安全可靠的技术措施控制爆破,减少对周边环境的影响。综合考虑工程特点、周边环境、爆破安全及工期等因素,采用深孔及浅孔控制爆破,边坡采用光面一次爆破成型技术,同时对爆破有害效应进行计算,提出了相应的防护措施,确保爆破安全。

鲁宝空压站节能降噪技术的应用研究

阐述了鲁宝钢管有限责任公司空压站设备现状、存在问题、采取的节能降噪措施、实施情况及达到的效果,介绍了零气损外鼓风式吸附干燥机和电子液位零气损冷凝液自动排除器的工作原理及设备性能。鲁宝空压站通过采取将微热再生式干燥机更换为零气损外鼓风式干燥机、将空压机冷却器的手动排水阀更换成电子液位零气损冷凝液自动排除器、根据外供压缩空气需求量合理配置大小空压机的开启、将工况压力控制在最低标准范围以避免空压机加、卸载等措施,降低了空压站站内压缩空气损耗,减少了噪声,空压站电能损耗明显降低,取得了较好效果。