Para explosiones subterr\u00e1neas, una capa de poco o mediano espesor cerca de la cavidad de una explosi\u00f3n se puede considerar como una estructura de c\u00e1scara te\u00f3rica. Los productos de detonaci\u00f3n transmiten la energ\u00eda efectiva de los explosivos a esta c\u00e1scara, que se expandir\u00e1 produciendo la deformaci\u00f3n irreversible del medio circundante. Basados en la conservaci\u00f3n de masa, las zonas incompresibles y las condiciones de contorno, se pueden establecer los campos de velocidad cinem\u00e1tica factibles en la zona pl\u00e1stica. A partir de la teor\u00eda del equilibrio l\u00edmite, este trabajo determina las ecuaciones de resistencia de los materiales correspondientes a los diferente campos de velocidad cinem\u00e1tica posibles. Combinado con las condiciones iniciales y condiciones de l\u00edmite, se resuelven las ecuaciones de movimiento y de resistencia de materiales, respectivamente. Se encuentra que la profundidad cr\u00edtica de entierro est\u00e1 relacionada positivamente con un factor sin dimensiones de impacto, que refleja las caracter\u00edsticas de los explosivos y el medio ambiente. Por \u00faltimo, se da un ejemplo, lo que sugiere que este m\u00e9todo es capaz de calcular la profundidad cr\u00edtica de enterramiento y los resultados calculados son consistentes con los resultados emp\u00edricos.<\/p>\n
1. Introduction<\/strong><\/p>\n Underground explosions have been studied for different purposes [1]. They can be classified into contained explosions (or camouflet explosions), bulging explosions, and cratering explosions. Contained explosions occur when the depth of burial of the explosive is sufficiently deep [2] and the model best suited to such conditions is an explosion in an infinite medium [3]. Bulging explosions occur when the depth of burial of the explosive is within a certain range [4] and are best modelled as explosions in a semi-infinite medium. Cratering explosions may occur in various ways when the depth of burial of the explosive is relatively shallow and they are best modelled as explosions in a semi-infinite medium [5]. A widely accepted zonal model divides the medium near the cavity into a grinding zone, a radial cracking zone, and an elastic zone [6], which can be the basis for the study of bulging and cratering explosions. Owing to their significant military and engineering application, bulging and cratering explosions have arisen widespread concern for a long time. Actually, bulging and cratering explosions are more complex subjects which should take the influence of the free facet into consideration in dynamic models.<\/p>\n At present, the cratering mechanism of blasting can be divided into three kinds of effects: compressional stress wave effects, tensile reflected wave effects, and gas pressure effects. Since crushing and plastic deformation are omnipresent in the medium surrounding the explosive source, compressional stress wave effects predominate. After Hino [7] proposed the concept of blastability coefficient, reflected tensile wave effects have been widely accepted and increasingly investigated by other researchers. To clarify the role of gas pressure in the fragmentation of an underground blast, Kutter and Fairhurst [8] designed a system of model tests in which the combustion products were simulated by pressurised oil. They concluded that the gas pressure played an important role in blasting. Hagan agreed with this view and coined the term \u201cpneumatic wedging\u201d to describe previous observations [9, 10]. Meanwhile, many other researchers, such as Dally et al. [11], Dally et al. [12], and Harries [13], verified the reasonability of the aforementioned view in different ways. However, these research findings exhibit fundamental mechanisms of explosive cratering and cannot be used to solve most practical problems. Therefore, researchers have to formulate different hypotheses or conduct many tests to obtain any more practical computational formulae.<\/p>\n Nowadays, the widely used theories for calculating the explosive charge or the depth of burial of cratering explosions include Livingston\u2019s crater theory [14, 15], Boreskov\u2019s formula [16], Langefors\u2019 formula [17, 18], Vlasov\u2019s formula [19, 20], and Pokrovskii\u2019s formula [21, 22]. However, these theories cannot… Leer m\u00e1s >><\/a><\/p>\n