Model of a strong volcanic blast and a method of estimating the mass ejected     

N.N.Myagkov 《Geophysical Journal International》1998,133(1):209-211

A hydrodynamic model of a strong volcanic blast associated with large (caldera-forming) ash–gas-flow eruptions is presented. We show that the mass erupted from a vent influences considerably the damping of the shock wave. If the ejected mass flux is constant, the shock amplitude as a function of distance will decrease slower (in accordance with the inverse 4/3 power law) than that of an atomic explosion (the inverse cube power law). From the modelling, we extract a relation connecting the effective energy of a blast with the mass ejected during the blast phase. The mass released during the largest explosion of the 1883 eruption of Krakatau, and the lateral blast energy at Mount St. Helens on 1980 May 18 are estimated on the basis of the equation obtained.  相似文献   

钻塔喷砂除锈及防腐措施          下载免费PDF全文

张西坤  拓瑞  高占听  靳益民  马红月 《探矿工程》2014,41(11):46-51

概述了钻塔喷砂除锈及防腐措施的主要类型、工艺流程、验收评价标准,分析了钻塔喷砂除锈及防腐措施中重要程序和注意事项,对常见的问题给出了处理方案。根据美国石油学会API验收规范标准,结合生产工作实际,对钻塔除锈、喷涂防腐和质量检验进行了分析总结和详细阐述。  相似文献   

A high strain‐rate constitutive model for sand and its application in finite‐element analysis of tunnels subjected to blast     

William Higgins  Tanusree Chakraborty  Dipanjan Basu 《国际地质力学数值与分析法杂志》2013,37(15):2590-2610

The paper presents a constitutive model for simulating the high strain‐rate behavior of sands. Based on the concepts of critical‐state soil mechanics, the bounding surface plasticity theory and the overstress theory of viscoplasticity, the constitutive model simulates the high strain‐rate behavior of sands under uniaxial, triaxial and multi‐axial loading conditions. The model parameters are determined for Ottawa and Fontainebleau sands, and the performance of the model under extreme transient loading conditions is demonstrated through simulations of split Hopkinson pressure bar tests up to a strain rate of 2000/s. The constitutive model is implemented in a finite‐element analysis software Abaqus to analyze underground tunnels in sandy soil subjected to internal blast loads. Parametric studies are conducted to examine the effect of relative density and type of sand and of the depth of tunnel on the variation of stresses and deformations in the soil adjacent to the tunnels. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

聚能爆破在石材切割应用中的试验研究   总被引：1，自引：0，他引：1  

季荣生 《现代地质》1998,12(1):138-142

摘 要 简单分析了聚能爆破装药在孔内爆破的力学效应‚阐明了聚能爆破对岩石定向破裂 的控制机理。在聚能爆破切割石材过程中‚聚能射流起到前期切割出定向裂缝的作用‚石材 的最终开裂由后期爆破产生的气体的准静态胀楔作用来完成。通过提高炸药爆速、增大装药 密度等方法可以提高聚能装药爆炸后形成射流的能量和改善聚能爆破切割石材的效果。  相似文献   

Stabilization of Expansive Clays Using Granulated Blast Furnace Slag (GBFS) and GBFS-Cement   总被引：1，自引：0，他引：1  

Erdal Cokca  Veysel Yazici  Vehbi Ozaydin 《Geotechnical and Geological Engineering》2009,27(4):489-499

Expansive clays undergo swelling when subjected to water. This can cause damage, especially to light weight structures, water conveyance canals, lined reservoirs, highways, and airport runways unless appropriate measures are taken. In this study, granulated blast furnace slag (GBFS) and GBFS-cement (GBFSC) were utilized to overcome or to limit the expansion of an artificially prepared expansive soil sample (sample A). GBFS and GBFSC were added to sample A in proportions of 5–25% by weight. The effects of these stabilizers on grain size distribution, Atterberg limits, swelling percentage and rate of swell of soil samples were determined. GBFS and GBFSC were shown to successfully decreasing the total amount of swell while increasing the rate of swell.  相似文献   

超小净距隧道爆破振动现场监测及动力响应分析研究   总被引：1，自引：0，他引：1  

朱正国  孙明路  朱永全  孙星亮 《岩土力学》2012,33(12):3747-3752

以南京地铁超小净距隧道为工程背景,结合国内外现有研究成果和规范,研究确保小净距先行隧道安全稳定的后行隧道爆破施工控制技术。以现代信息化施工理论为依据,充分运用现场监控量测,对先行隧道爆破质点振动速度进行监测分析和施工中爆破采用减振和隔振两方面控制技术;最终现场监测结果表明,优化后的循环进尺、段最大装药量与分段爆破差等爆破参数设计合理,该爆破设计在施工中未对先行隧道安全产生较大影响;同时,通过三维数值模拟计算,得到先行隧道壁面的质点振动速度随时间的变化规律,所得最大振速符合规范要求,也再次验证了优化后的爆破设计是合理的。通过数据分析得出隧道边墙的切向和径向振速比拱脚相应振速大,爆破面前方先行洞衬砌受爆破振动的影响稍大于后方衬砌,临近爆破点的左线隧道衬砌表面振动大于远离爆破点的衬砌表面振动。该研究成果为本工程施工提供了科学依据与技术指导,也可为类似隧道工程的爆破掘进工程在理论和施工方法上提供参考借鉴。  相似文献   

Hybrid finite-discrete element modelling of dynamic fracture and resultant fragment casting and muck-piling by rock blast     

《Computers and Geotechnics》2017

A state-of-the-art review is conducted to highlight the fracture mechanism in rock blast and advantages and limitations of various methods in modelling it. A hybrid finite-discrete element method (FEM-DEM) is implemented to simulate rock fracture and resultant fragment muck-piling in various blasting scenarios. The modelled crushed, cracked and long radial crack zones are compared with those in literatures to calibrate the hybrid FEM-DEM. Moreover, the hybrid modelling reproduces the rock fragmentation process during blasting. It is concluded that the hybrid FEM-DEM is superior to continuous and discontinuous methods in terms of modelling dynamic fracture of rock under blast-induced impact load.  相似文献   

爆炸波在高饱和度饱和土中传播规律的研究   总被引：1，自引：1，他引：0  

穆朝民  任辉启  李永池  辛凯 《岩土力学》2010,31(3):875-880

通过在? 2.5×5 m模拟爆炸装置中进行饱和土爆炸试验,得到了变埋深条件下饱和土中的压力实测波形,实测到了冲击波和弹性波,二者之间具有较明显的分界,爆炸近区和远区荷载形式具有较大的区别。通过综合分析给出了饱和土中波的传播规律,揭示饱和土中爆炸冲击波传播时出现流体动力区和冲击波形成等性质,建立了饱和土双线性递增硬化本构关系,确定了由冲击波向弹性波转换的分界压力。  相似文献   

爆炸荷载下土石坝动力响应特征的数值模拟   总被引：3，自引：0，他引：3  

刘军  刘汉龙  张正珺 《地震学刊》2010,(1):10-16

土石坝在爆炸荷载下的力学响应是一个非常复杂的力学问题,相关研究甚少。在LS-DYNA软件框架内,以两河口土石坝为研究对象,把坝体材料简化为混凝土、心墙、反滤层与堆石体等4种,用500 kg TNT在坝顶接触爆炸时的瞬态荷载作为荷载源,针对不同材料建立适合于爆炸高加载率特征的本构模型,用数值方法分析了土石坝在潜在爆炸荷载下的破坏与损伤演化规律。结果表明,在爆炸荷载作用下,由于土石坝材料组成的多样性,应力波传播规律异常复杂,土石坝的力学响应呈现出显著的分区特征。  相似文献   

爆破地震波作用下尾矿坝的有限元动力分析   总被引：1，自引：0，他引：1  

张峰  郭晓霞  杨昕光  邵磊 《地震学刊》2010,(3):281-286

为了了解某钼矿进行爆破采矿是否会对近距离的尾矿坝产生破坏作用,结合实际勘探资料,在二维静力非线性有限元分析的基础上,进行爆破地震波作用下坝体的动力反应分析,综合研究了动位移、动应力和加速度时程等关键物理量变化的规律性,并在此基础上进一步结合试验资料对坝体进行了液化判断及稳定性分析。分析结果表明,该钼矿在规定的爆心距、药量范围内进行爆破采矿时,相邻的尾矿坝是安全稳定的。本文的研究结果对爆破设计、现场采矿及尾矿坝体运行维护均具有一定的指导意义。  相似文献