大当量浅埋地下爆炸抛掷成坑效应的缩比模拟实验装置

针对当前地下爆炸物理模型实验无法模拟大当量地下爆炸抛掷弹坑和疏松鼓包现象的难题,基于相似理论,采用地下爆炸效应真空室模型实验方法,研制了考虑重力影响的大当量地下爆炸效应模拟实验装置。整套装置由容器罐体、快开门密闭机构、爆源系统、真空泵组、量测控制系统等组成,提出的新型爆源模拟装置可以实现精确起爆控制。该装置可模拟0.1~100 kt TNT、埋深20~400 m范围内不同比尺的地下核爆炸成坑和隆起实验,同时也能够模拟不同装药配置方案、不同地质条件下的大当量地下浅埋化爆抛掷实验。典型的核爆抛掷成坑模型实验结果表明,装置实验参数精确可调,实验过程可控,实验结果可信,为钻地核武器地下爆炸毁伤效应分析和大型工程爆破效果预测预报提供了实验室模拟和科学研究设备,填补了爆炸离心机无法模拟大当量地下爆炸抛掷成坑效应的空白。     

地下强爆炸诱发地表塌陷的试验模拟与应用

地下核爆炸后会在地表产生下陷弹坑、塌陷带等不可逆变形爆炸后效应,利用地表形变信息对地下核试验进行有效监控和评估具有十分重要的意义。基于考虑重力影响的地下强爆炸塌陷成坑相似理论,利用陆军工程大学自主研制的地下爆炸效应真空室模拟试验装置,对2017年9月3日朝鲜地下核试验诱发的地表不可逆变形进行了模型试验。试验结果表明,地表塌陷带半径为257 m,下陷弹坑的半径为154 m,与美国、前苏联等国家已有的地下核试验经验公式的数据结果基本相当,并且符合天基雷达TS-InSar卫星监测数据的估算结果,验证了地下爆炸真空室模型试验在地下强爆炸诱发地表不可逆变形区域模拟和评估的可行性,成为有效补充地震波和卫星监测地下强爆炸的一种研究手段。     

不同介质地下爆炸的地震耦合效应

对黄土、砂砾石和花岗岩等几种不同介质中的地下爆炸实验进行了地表速度测量,利用实测数据 获得爆炸源频谱以及以折合速度势低频稳态值表示的地震耦合强度。实验结果表明,对于相同当量、相当比 例埋深下的地下爆炸,地震耦合强度和源区介质特性有着强烈的依赖关系,其中介质强度是影响地震耦合效 率的最主要因素,而介质的干孔隙率和水饱和度也是影响地震耦合效率的重要因素。考察了M.D.Denny等 提出的经验公式在估算100kg级当量地下爆炸地震耦合强度的适用性和局限性。     

The determination of the crater for an explosion in ground with angular and curvilinear free boundaries

One of the simple mathematical models in the theory of the deformation of continuous media in an explosion is the solid—liquid model [1, 2]. This does not describe the dynamics of the ground and so enables us to determine only approximate characteristics of the crater. This model has now been used to study a wide range of problems in determining a crater in a continuous medium with various tensile properties and various positions of the explosive [3–5]. We consider below within the framework of the solid—liquid model boundary-value problems in determining a crater in the explosions of point explosives and uniformly distributed explosives on the surface and deep within an isotropic ground with angular and curvilinear free boundaries. The desirability of studying problems such as these was pointed out by Il'inski.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 3–9, January–February, 1985.     

Numerical prediction of rock mass damage due to accidental explosions in an underground ammunition storage chamber

Accidental detonations in an underground ammunition storage chamber inside a rock mass may cause severe damage to the rock mass around the chamber, adjacent tunnels and chambers, ground surface, and in the worst case cause sympathetic detonation of explosives in adjacent storage chambers. To prevent such damage, underground ammunition storage chambers are often situated at minimum depth below the ground surface, and spaced at minimum distance from each other, so that damage, should it occur, is limited to the accidental chamber. Different codes and regulations for ammunition storage chambers specify minimum embedment depth and separation distance for underground ammunition storage chambers. They are usually given in terms of the rock mass properties and the weight of explosive stored in chambers. Some empirical formulae, usually based on the peak particle velocity of the stress wave or the maximum strain of the rock mass, are also available to estimate the damage zones in the rock mass from an explosion. All these empirical methods do not include the effects of explosion details, such as the loading density, chamber geometry and explosive distribution. In this paper, a previously calibrated numerical model is used to estimate the damage zones in a granite mass resulting from an accidental explosion in an underground ammunition storage chamber. Effects of various explosion conditions on rock mass damage are investigated. On the basis of the numerical results, some empirical formulae are derived to predict damage zones around the explosion chamber, as well as safe embedment depth of the storage chamber and safe separation distance between adjacent chambers. The numerical results are also compared with available empirical formulae and code specifications. It should be noted that the characteristics of stress wave propagation around an ammunition storage chamber has been published in a preceding paper (Int. J. Blast. Fragm. 5:57–90, 2001.     

神经网络状态方程在强爆炸冲击波数值模拟中的应用

强爆炸数值模拟的主要挑战在于如何准确地描述爆炸产物状态方程。利用BP神经网络和强爆炸产物状态数据对神经网络产物状态方程进行训练,并将得到的状态方程植入自编的一维球对称数值模拟程序,对强爆炸冲击波参数进行了计算。结果显示,计算得到的冲击波峰值超压、冲击波到时、正压时间与标准值吻合较好,证明将神经网络状态方程应用于强爆炸冲击波数值模拟是可行的。研究结果对确定强爆炸数值模拟方法具有很好的借鉴意义。     

低含水率砂土和饱和砂土场地爆炸成坑特性实验

爆坑是土中爆炸荷载作用下的主要响应形式,基于大型爆炸实验场地,开展了一系列低含水率砂土和饱和砂土中的爆炸成坑现场实验,研究了药量、埋深及含水率等因素对土中爆坑效应的影响。研究结果显示:根据药包的比例埋深,低含水率砂土场地的最终爆坑形态可以分为隐爆、塌陷型漏斗坑和抛掷型爆坑3类,发生封闭爆炸的临界比例埋深为2.3 m/kg1/3;形成抛掷型爆坑的条件为比例埋深小于1.5 m/kg1/3;当比例埋深为1.5~2.3 m/kg1/3时,形成塌陷型漏斗坑。土中孔隙水压力的增大导致坑壁周围土体发生了液化流动、坍塌,最终造成爆坑横向尺寸的扩大。相同爆源条件下,饱和砂土场地形成的坑面直径比低含水率砂土场地提高了25%~35%,饱和砂土场地发生封闭爆炸的极限比例埋深可达2.5 m/kg1/3。     

Investigating ground effects on mixing and afterburning during a TNT explosion

In this paper, the unconfined and semi-confined condensed phase explosions of TNT will be studied using large eddy simulations based on the unsteady, compressible, reacting, multi-species Navier–Stokes equations to gain further understanding of the physical processes involved in a condensed phase explosion and the effect of confinement on the physical processes involved. The analysis of the mixing and afterburning of TNT explosions in free air (unconfined) and near the ground (semi-confined) indicates that the combustion region of detonation products and air is determined by the vorticity patterns, which are induced by the Richtmeyer–Meshkov instabilities that arise during the explosion. When the explosive is detonated in the vicinity of a surface, the surface affects the shock propagation by creating complex shock systems, thereby changing the orientation of the vorticity, giving the afterburning a mushroom shape, and increasing performance of an explosive charge by prolonging the existence of the mixing layer and thereby the afterburning.     

混凝土板在接触爆炸作用下的震塌和贯穿临界厚度计算方法

采用刚塑性模型描述介质的动力学行为，结合不可压缩条件和质量守恒条件及边界条件，构造塑性区的动力学许可速度场；利用极限平衡原理推导动力学许可速度场所对应的介质抗力的量纲一表达式；根据初始条件和边界条件，求解运动方程，分别得到爆炸震塌的临界厚度和爆炸贯穿的临界厚度，并推得能够反映爆炸源参数和材料参数综合性质的量纲一冲击因子。将推得的计算公式与经验公式对比分析，证明本文计算结果合理，推导的计算公式揭示了经验公式的物理本质，且具有较为广泛的适用范围。     

岩石中化学爆炸气体渗漏行为的实验研究

通过小药量化爆模拟实验,研究了岩石中满足缩比关系的不同药量化学爆炸一氧化碳渗漏时间、渗漏份额与药量的关系。研究结果表明:相同介质中缩比爆炸实验气体渗漏时间大致与药量的三分之二次方成正比,渗漏停止时间也大致与药量的三分之二次方成正比;封闭空间内化学爆炸在爆室内产生的高温能够使爆室内一些物质分解产生非冷凝气体;对于不同药量的缩比实验,小药量实验的气体渗漏份额不小于大药量实验的气体渗漏份额。根据此研究结果,可以用小药量地下爆炸气体渗漏行为的监测结果预估大药量实验的气体渗漏行为。     

开采覆岩破坏工程地质预测的理论与实践

煤层开采造成的覆岩破坏范围和高度是水体下采煤留设防水煤岩柱和老采空区基岩稳定性评价的重要依据，本文以岩体工程地质力学为理论依据，对覆岩破坏机理和判据等进行了研究，详细分析了覆岩工程地质类型及其组合、岩体结构特征、地层倾角、地质构造、地应力、地下水及开采条件对覆岩破坏高度及发育规律的影响。文中提出了覆岩破坏预测的工程地质学方法，并给出了应用实例。     

Dynamic response of a reinforced concrete slab subjected to air blast load

Reinforced concrete is the principal material for military engineering and nuclear power plant containment. However, impacts and explosions could completely destroy such structures, causing tremendous casualties and property loss. Hence, this study conducts an analysis on the propagation law of a blast pressure wave and the dynamic response of reinforced concrete structures under explosive pressure wave effects. This study uses proper state material parameters and equations and then applies the nonlinear finite element analysis software LS-DYNA to conduct a numerical simulation of a free-field explosion model. After comparison with the computed results from empirical equations and validating the reliability of the numerical analysis model, the destruction and influencing factors on reinforced concrete slabs, under the effects of a blast pressure wave, are investigated. The results can serve as a reference for future analysis and design.     

触、近水面爆炸自由场冲击波特性的试验研究

本文通过药量为0.05kg至32kgTNT的触、近水面化爆试验,介绍了空中、水中冲击波的测量方法和传播特性,并总结出一些计算冲击波参数的实用的经验公式。     

Secondary shock features for large surface explosions: results from the Sayarim Military Range,Israel and other experiments

A series of surface explosions was designed and conducted by the Geophysical Institute of Israel at the Sayarim Military Range in the Negev desert, including two large-scale explosions: approx. 82 tons of high explosives in 2009, and approx. 100 tons of low-grade ANFO explosives in 2011. The main goal of the explosions was to provide large controlled sources for calibration of global infrasound stations designated for monitoring nuclear tests; however, the geophysical experiment also provided valuable observations for shock wave research. High-pressure gauges were deployed at distances between 100 and 600 m to record air blast properties and to provide reliable estimation of the true charge yield compared to the design value. Secondary shock phenomena were clearly observed at all near-source gauges as characteristic shock wave shapes. Secondary shocks were also observed at numerous seismic and acoustic sensors deployed in the range 0.3–20 km as acoustic phases. Empirical relationships for standard air blast parameters (peak pressure and impulse) and for a new parameter called secondary shock time delay, as a function of distance, were established and analyzed. The standard parameters, scaled by the cubic root of the estimated TNT yield, were found to be consistent for all analyzed explosions. However, the scaled secondary shock delays were clearly separated for the 2009 and 2011 explosions, thus demonstrating dependence on the explosive type. Additionally, air blast records from other experiments were used to extend the charge and distance ranges for the secondary shock observation, and showed consistency with the Sayarim data. Analysis and interpretation of observed features of the secondary shock phenomenon are proposed and a new empirical relationship of scaled secondary shock delay versus scaled distance is established. The results suggest that the secondary shock delay can be used as a new additional waveform feature for simple and cost-effective explosive yield estimation.     

基于Elman型神经网络的金川二矿地表岩移时序预测 模型

建立于煤矿开采基础之上的矿山开采沉陷理论和预测方法并不适用于象金川这样厚大、陡倾的金属矿床开采的岩移问题,因此,本文探讨利用神经网络来对地表岩移进行预测。根据Elman神经网络能够逼近任意非线性函数的特点和具有反映系统动态特性的能力,提出了利用Elman神经网络建立地表岩移时序预报模型的方法。利用金川二矿区GPS监测所得到的时间序列数据,通过对Elman神经网络模型预测值与GPS实测值之间的比较,结果表明模型预测显示了良好的准确性,特别是在时间步长较短情况下,应用于实际预测一定程度上可以弥补金属矿山岩移预测方法不足的缺憾。     

Effect of the impulse of a meteorite on the dimensions of the impact crater

Formulas for the diameter and depth of an explosion crater are obtained which take into account the energy and impulse of the explosion products, rock strength, burial depth of the explosive charge, and gravity. Using the explosive-shock analogy, the obtained relations are extended to the case of meteorite (impactor) impact on the planet’s crust (target). It is shown that in the gravity cratering regime, the influence of the impulse of the impactor is significant and increases with increasing its size. In the strength cratering regime, the impulse has little effect on crater dimensions. It is established that crater dimensions are determined mainly by the kinetic energy of the impactor and, to a lesser degree, by its impulse.     

二级高压驱动阵列弹珠同步弹射微型爆源的研制

针对当前大当量地下爆炸真空室模拟试验中爆源起爆方式高度依赖火药制品等问题，基于地下爆炸相似理论和二级气炮原理，自主研制了二级高压驱动阵列弹珠同步弹射微型爆源装置。装置利用二级高压气体驱动弹珠同步击碎玻璃球壳，释放球内高压气体，以模拟真实爆炸气体生成物的推出。整套爆源装置的发射参数:高压气室充气压力4 MPa，玻璃球壳内残余稳态气体压力约为3 kPa，能够用于0~20 kt当量地下爆炸成坑效应的真空室模拟。爆源适用性试验验证表明，该爆源装置的爆破机制和爆破效果满足大当量地下抛掷爆炸真空室模拟试验的功能需求，且具有较高的安全性、可控性和可操作性，为开展相关模拟试验提供了新的技术方法。     

Model of the soil and computational complex for the analysis of underground explosions

In underground explosions executed in the interests of ejection, downcomer funnel or bulging hillock formation, the soil properties influence not only the quantitative parameters substantially, but also the qualitative pattern of the explosion. Thus, under the same conditions of charge embedding and power, a downcomer funnel or bulging hillock can be formed depending on the properties of the rock. The majority of explosions are performed in hard rock. Hence, the model of the soil should be suitable to describe its fundamental properties. A model of rocky soil is presented in this paper, the scheme for a numerical computation of the problem is described, and results of certain computations are presented.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 153–160, May–June, 1979.     

Application of background oriented schlieren for quantitative measurements of shock waves from explosions

This paper describes application of a background oriented schlieren technique in order to obtain quantitative measurements of shock waves from explosions by processing high speed digital video recordings. The technique is illustrated by an analysis of two explosions, a high explosive test and a hydrogen gas explosion test. The visualization of the shock front is utilized to calculate the shock Mach number, leading to a predicted shock front pressure. For high explosives the method agreed quite well with a standard curve for side-on shock pressures. In the case of the gas explosion test we can also show that the shock front is non-spherical. It should be possible to develop this technique to investigate external blast waves and external explosions from vented gas explosions in more details. This paper is based on work that was presented at the 21th International Colloquium on the Dynamics of Explosions and Reactive Systems, Poitiers, France, July 23–27, 2007.     

基于量纲分析理论的煤尘爆炸能量预测模型

为预测煤尘爆炸能量,基于量纲分析理论建立煤尘爆炸能量预测模型。选取爆炸能量E、空气密度ρ和大气压强p的量纲为导出量纲。根据量纲分析Π定理得出含有待定参数λ的具有普适性的能量预测模型。通过小型煤尘爆炸性实验设计,测定10次爆炸最长火焰长度平均值l₀、10次最长火焰长度出现时间平均值t₀与该小型煤尘爆炸中释放能量E₀,确定模型中参数λ为0.467。对模型变量t、E、l的函数关系进行合理性检验。通过实测的15组不同时刻的火焰长度进行模型变量t、l幂指关系检验。检验结果表明:量纲选取完备,预测模型科学合理。