建筑物拆除作业的安全技术

对旧建筑物拆除,诸如墙体、基础、砖石建筑物、地板、油罐等容器、铜结构和特殊结构建筑物的拆除中的一般安全技术措施、拆除设施的设置、警告装置、安全装置,均作了较具体而明确的要求;对机械法拆除和爆破法拆除两种拆除方法中的安全技术要求,也有简要论述。     

旧房拆除的安全技术措施

随着我国城市建设的进一步发展,旧城改造的任务越来越重,旧有建筑物的拆除工程量越来越大,拆除难度也越来越高,迫切需要对拆除施工进行规范化管理。根据我国拆除工程的发展趋势,北京建工集团研究编写了拆除技术规程,提高了拆除速度和安全性,使文明施工程度与经济效益得到了同步     

RC结构物拆除工程"零排放"研究

分析了钢筋混凝土结构物的生命周期规律,阐述了建筑业拆除工程中零排放概念.深人研究拆除工程零排放框架及其工程体系,确立了拆除现场零排放的管理机制.以建筑拆除中产生量最大的混凝土碎料为例,剖析了循环再利用方法和资源循环流程.结合某体育馆的拆除实例.分析了实施零排放的工程经验.为探索我国拆除行业实现零排放和环境负荷最小化提供...     

拆除爆破中的安全防护

随着一座座陈旧建筑的拆除,一幢幢新大厦拔地而起,随着城市化进程日益加快,拆除爆破越来越多地运用到拆除作业的工程之中.     

建筑拆除工程为何事故频发

近年来,随着城镇旧房改造的持续升温,房屋拆除工程量大增,拆除事故频频发生.2004年11月10日、14日,河南登封市大冶镇卫生院和湖南郴州市第一人民医院先后发生拆除工程坍塌事故,均死亡3人以上,占当月全国建筑业重大事故总起数(6起)的三分之一;2004年,四川南充市发生三起建筑拆除事故,三起事故共导致10人死亡、8人受伤,拆除事故死亡人数占2004年度该市建筑事故死亡总人数的50%以上.建筑物拆除事故呈现多发的趋势,拆除工程的安全已成为当前建筑施工安全中的薄弱环节.     

210m钢筋混凝土烟囱控制爆破拆除数值模拟研究

通过采用LS-DYNA动力学有限元程序,模拟210 m钢筋混凝土烟囱的控制爆破拆除倒塌过程。采用数值模拟方法,不仅可以对控制爆破拆除工程中构筑物倾倒、破坏的重要影响因素进行分析,对有关理论研究结果的正确性和有效性进行验证,还能优化爆破拆除方案、预测实际爆破拆除效果,提高爆破拆除设计与施工的经济性、可靠性和安全性。     

英国发布有关建筑物拆除、消防安全风险解决方案和应急逃生照明设备标准

最近,英国发布了有关建筑物拆除、消防安全风险解决方案和应急逃生照明设备几项新标准．它们是：（1）BS6187：2011《建筑物整体和局部拆除实用规范》是一项新的英国标准．该标准为利用设备进行建筑物及其框架拆除（整体和部分拆除）提供了很好地解决方案,还适用于针对建筑物翻新工程中的拆除工作。新标准替代了旧标准。     

爆破安全法规标准讲析

1 编制《拆除爆破安全规程》的必要性 近十年来,我国拆除爆破技术得到突飞猛进的发展和广泛应用。多层楼房的拆上保下、拆下保上、拆左保右、扩前保后,高耸建（构）筑物的定向塌落,环境极其复杂条件下的爆破拆除工程（如北京华侨大厦的爆破拆除）等,均获得了成功。爆破拆除具有施工速度快、经济效益好等优势。因此,近几年,在我国以拆除爆破为主要业务的爆破公司纷纷成立。这些爆破公司,对拆除爆破技术的发展和普及起到了推动作用。但是,也有不少爆破公司,由于缺乏拆除爆破经验和管理不善,导致     

建筑物拆除作业的安全技术

对旧建筑物拆除,诸如墙体,基础,砖石建筑物,地板,油罐等容器,铜结构和特殊结构建筑物的拆除中的一般安全技术措施,拆除设施的设置,警告装置,安全装置,均作了具体明确的要求,对机械法拆除和爆破法拆除两种方法中的安全技术要求,也有简要论述。     

拆除爆破中的安全防护

随着一座座陈旧建筑的拆除 ,一幢幢新大厦拔地而起 ,随着城市化进程日益加快 ,拆除爆破越来越多地运用到拆除作业的工程之中。与常规应用的风镐、重锤、液压杆工具拆除方式相比 ,爆破拆除具有快速、安全、低污染、少扰民的极大优势。然而 ,现代科学技术带给人们巨大效益的同时     

Evaluation of the power of the distributed blast type explosive

Many works have been done on power evaluation of explosives and some evaluation methods presented. However, because of the differences of the explosion characteristics between distributed blast and common condensed explosive, a more reasonable way for evaluating the power of distributed blast is needed. In the paper, for a given range in space, a TNT equivalency method is proposed. Both the physical and mathematical meaning of power are considered in the method. Instead of giving equivalency of some individual points, TNT equivalent value for a certain space range can be obtained based on the method.     

A study of the blast wave shape from elongated VCEs

Elongated congestion patterns are common at chemical processing and petroleum refining facilities due to the arrangement of processing units. The accidental vapor cloud explosion (VCE) which occurred at the Buncefield, UK facility involved an elongated congested volume formed by the trees and undergrowth along the site boundary. Although elongated congested volumes are common, there have been few evaluations reported for the blast loads produced by elongated VCEs. Standard VCE blast load prediction techniques do not directly consider the impact of this congested volume geometry versus a more compact geometry.This paper discusses an evaluation performed to characterize the blast loads from elongated VCEs and to identify some significant differences in the resulting blast wave shape versus those predicted by well-known VCE blast load methodologies (e.g., BST and TNO MEM). The standard blast curves are based on an assumption that the portion of the flammable gas cloud participating in the VCE is hemispherical and located at grade level. The results of this evaluation showed that the blast wave shape for an elongated VCE in the near-field along the long-axis direction is similar to that for an acoustic wave generated in hemispherical VCEs with a low flame speed. Like an acoustic wave, an elongated VCE blast wave has a very quick transition from the positive phase peak pressure to the negative phase peak pressure, relative to the positive phase duration. The magnitude of the applied negative pressure on a building face depends strongly on the transition time between the positive and negative phase peak pressures, and this applied negative phase can be important to structural response under certain conditions. The main purpose of this evaluation was to extend previous work in order to investigate how an elongated VCE geometry impacts the resultant blast wave shape in the near-field. The influence of the normalized flame travel distance and the flame speed on the blast wave shape was examined. Deflagration and deflagration-to-detonation transition regimes were also identified for unconfined elongated VCEs as a function of the normalized flame travel distance and flame speed attained at a specified flame travel distance.     

Blast wave clearing behavior for positive and negative phases

The purpose of the research was to improve prediction of response of buildings to blast waves by including the negative phase and considering clearing of both positive and negative phases. Commonly used structural design practices, which trace their origins to military design manuals, often ignore the negative phase as well as positive phase clearing. For high explosive threats, this approach is conservative in most circumstances. However, negative phase clearing had not previously been studied for blast waves, and the implications for structural response had not been evaluated. This paper presents results of modeling negative phase blast clearing behavior for a typical blast wave and discusses the differences from positive phase clearing. The implications of including positive and negative phase clearing in building blast damage analysis are also investigated through single-degree-of-freedom (SDOF) analyses.Blast waves from explosion sources like a vapor cloud explosion (VCE), pressure vessel burst or high explosive exhibit both positive and negative phases, and the relative magnitude of the positive and negative phases varies among explosion sources and the specific circumstances of each source. A fully reflected blast wave is produced if an incident blast wave were to strike an infinitely tall and wide wall in a normal orientation. Both the positive and negative phases of the blast wave are enhanced by the reflection process. However, when an incident blast wave strikes a wall of finite size in a normal orientation, rarefaction waves are created at the edges of the wall, and the rarefactions sweep down from the roof and inward from sides. The rarefaction waves result in a clearing effect for both the positive and negative phases.Clearing relieves some of the applied blast load on the reflected wall for the positive phase. However, this is not always the case for the negative phase. As shown by the results presented in this paper, clearing may either relieve or enhance the applied negative phase blast load, depending on the duration of the blast wave and the wall dimensions.The impact of negative phase clearing on structural response for generic building components was also investigated. Nonlinear SDOF methods were used to characterize response in terms of peak positive and negative displacements. It was found that the influence of the negative phase is significant and the peak structural response can occur during negative (outward) displacement.     

安钢高炉煤气干式净化长袋脉冲除尘技术

干式脉冲煤气布袋除尘作为“十五”国家重点推进的40项冶金节能环保技术的措施之一,成为国内在建高炉优先选择的工艺技术,也是目前高炉改造湿法除尘工艺的技术方向,近几年此技术已成功应用于各大型高炉。较湿法除尘相比各类效益明显,已成为今后大型高炉煤气除尘技术发展的趋势,安钢6#、7#高炉（450 m^3）自使用该技术以来,经过实践摸索,逐渐取得了一些较先进的经验。     

Using computational fluid dynamics (CFD) for blast wave predictions

Explosions will, in most cases, generate blast waves. While simple models (e.g., Multi Energy Method) are useful for simple explosion geometries, most practical explosions are far from trivial and require detailed analyses. For a reliable estimate of the blast from a gas explosion it is necessary to know the explosion strength. The source explosion may not be symmetric; the pressure waves will be reflected or deflected when hitting objects, or even worse, the blast waves may propagate inside buildings or tunnels with a very low rate of decay. The use of computational fluid dynamics (CFD) explosion models for near and far field blast wave predictions has many advantages. These include more precise estimates of the energy and resulting pressure of the blast wave, as well as the ability to evaluate non-symmetrical effects caused by realistic geometries, gas cloud variations and ignition locations. This is essential when evaluating the likelihood of a given leak source as cause of an explosion or equally when evaluating the potential risk associated with a given leak source for a consequence analysis.In addition, unlike simple methods, CFD explosion models can also evaluate detailed dynamic effects in the near and far field, which include time dependent pressure loads as well as reflection and focusing of the blast waves. This is particularly valuable when assessing actual near-field blast damage during an explosion investigation or potential near-field damage during a risk analysis for a facility. One main challenge in applying CFD, however, is that these models require more information about the actual facility, including geometry details and process information. Collecting the necessary geometry and process data may be quite time consuming. This paper will show some blast prediction validation examples for the CFD model FLACS. It will also provide examples of how directional effects or interaction with objects can significantly influence the dynamics of the blast wave. Finally, the challenge of obtaining useful predictions with insufficient details regarding the geometry will also be addressed.     

石方爆破作业爆破冲击波事故分析

在进行工程爆破时,爆破所产生的飞石、振动、空气冲击波、噪音和毒气是公认的爆破公害,尤其是振动和飞石在爆破过程中是不可避免的危害.针对在实际工程中,由于爆破冲击波造成的人员伤害和设备的损害以及引起该事故发生的危险因素,采用事故树分析方法得到影响顶事件的最小割集,通过计算基本事件的结构重要度,确定了影响爆破冲击波事故的主要因素,并提出相应的安全措施,对降低爆破冲击波效应的影响以及降低露天爆破安全事故有重要意义.     

A new standard for predicting lung injury inflicted by Friedlander blast waves

An important blast injury mechanism is the rupture of the lungs and the gastrointestinal tract. In explosives safety studies and threat analysis the empirical model of Bowen is often used to quantify this mechanism. The original model predicts the lethality for a person in front of a reflecting surface caused by simple Friedlander blast waves. Bowen extended the applicability to persons in prone position and standing in the free field by making assumptions about the pressure dose at these positions. Based on new experimental data, some authors recently concluded that the lethality for a person standing in the free field is the same as for a person in front of a reflecting surface, contrary to Bowen's assumptions.In this article, we show that only for a short duration blast wave, the load on a person standing in the free field is comparable to that on a person in front of a reflecting surface. For long positive phase durations, a safe and conservative assumption is that the load on a person standing in the free field is the sum of the side-on overpressure and the dynamic pressure. This hypothesis is supported by common knowledge about blast waves and is illustrated with numerical blast simulations.In a step by step derivation we present a new standard for the prediction of lethality caused by Friedlander blast waves, which will be included in the NATO Explosives Safety Manual AASTP-4. The result is a comprehensive engineering model that can be easily applied in calculations.     

Propagation and intensity of blast wave from hydrogen pipe rupture due to internal detonation

The coupled fluid-structure-rupture model was developed to study the propagation and intensity of blast wave from hydrogen pipe rupture due to internal detonation. The dynamic rupture of pipe and propagation of blast wave were well coupled together in every timestep during the simulation. The numerical model was validated with experiments in terms of both typical rupture profiles and blast overpressures. Results reveal that crack branching of pipe can dramatically increase the rupture opening rate which controls the intensity and shape of the resultant blast wave. Due to the process of crack initiation and extension, the blast wave out of the pipe first forms and then is strengthened by the subsequent compression waves. This makes the maximum peak overpressure appears at a certain standoff distance above the rupture. Despite consuming some percentages of energy, the dynamic rupture of pipe generally presents positive effects (up to 2–3 times) on the blast wave intensity along the jetting direction due to the convergence effect of rupture opening on the release of internal high-pressure gas. Finally, through defining normalized overpressure and impulse based on the same hydrogen detonation in open spaces, the quantitative influences of pipe rupture on the blast wave intensity in cases of different detonation pressures and standoff distances are clarified.     

泄漏油气燃爆灾害下FPSO结构响应分析

为评估FPSO泄漏油气燃爆事故中结构损伤风险,采用等效TNT法结合AUTODYN软件分析结构在爆炸冲击波下动态响应,分析其塑性、变形及应力分布,评估不同工况下结构损伤程度。结果表明,TNT起爆后冲击波高速传播,10ms时已覆盖工艺I区,经反射叠加耦合后破坏力增强;原油热处理器和电脱盐器发生失效和变形,生产甲板边缘位置受约束较小,发生较大变形,部分区域屈曲破坏;参与反应的油气越多,相同结构等效应力及变形越大,大应力、大变形区域分布越广;d=60mm时部分结构完全失效。     

Numerical study of medium to large scale BLEVE for blast wave prediction

So far, the prediction of blast wave generated from the Boiling Liquid Expanding Vapour Explosion (BLEVE) has been already broadly investigated. However, only a few validations of these blast wave prediction models have been made, and some well-established methods are available to predict BLEVE overpressure in the open space only. This paper presents numerical study on the estimation of the near-field and far-field blast waves from BLEVEs. The scale effect is taken into account by conducting two different scale BLEVE simulations. The expansion of pressurized vapour and evaporation of liquid in BLEVE are both modelled by using CFD method. Two approaches are proposed to determine the initial pressure of BLEVE source. The vapour evaporation and liquid flashing are simulated separately in these two approaches. Satisfactory agreement between the CFD simulation results and experimental data is achieved. With the validated CFD model, the results predicted by the proposed approaches can be used to predict explosion loads for better assessment of explosion effects on structures.