1、翻译部分 英文原文STRESS DISTRIBUTION AROUND MINE WORKINGSV. V. Gaidachuk1, V. I. Koshel2, and P. Z. Lugovoi2Abstract：The finite-element method is used to determine the stress state around arched mine workings in a mineral bed. Both presence and dip of the mineral bed have a strong effect on the stress state
2、 around the mine working. Recommendations for design of mine-working support are for mulatedKeywords: arched mine working, stress state, finite-element method, mineral bed, mine-working supportIntroductionNowadays, mankind consumes 3.7J of energy a year, which is equivalent to burning of 170 million
3、 barrels of oil a day. This energy goes from the following six sources: oil (44%), natural gas (26%), coal (25%), water power (2.4%), nuclear power (2.4%), power of wind, Sun, etc. (0.2%) 5. Since the resources of oil and gas are depleted very quickly, it may be concluded that the contribution of co
4、al to the power supply of mankind would constantly increase. The complicated conditions of coal and metal mining are due to high fluctuations in the thickness and dip of beds, ore bodies, variability of the hardness of enclosing rocks and ores, nonuniform distribution and composite relief of mineral
5、 beds. The mine field is a mechanical system whose state is constantly affected by regular coal mining, accompanying technological factors, and tectonic and rheological phenomena and is a network of stress concentrators that has a significant effect on the stressstrain state of the mined rock mass.
6、The geologic heterogeneity of mineral deposits anisotropy and stratification of the rock mass, faults, etc.) is also a critical factor for the mining of coal and other minerals 6. At great depths, the mining conditions are much worse because of high rock pressure and its dynamic manifestations such
7、as rock bursts 1. A typical feature of deep mining is the commensurability of the stresses in structures and the ultimate strength of the mined beds. Therefore, the qualitative analysis of the stability of structural elements of the mining method and its relation to the coal-field development plan,
8、as is the case at shallow depths, gives way to a rigorous quantitative analysis of the stress field at all stages of mining and a search for directional methods to affect this field so as to localize or remove dangerous stresses in those structures without which excavation is impossible. At great de
9、pths, there is a need for methods of affecting the stress state of the stoping area either by changing the geometry and arrangement of structural elements of the mining method or by changing their properties so as to provide partial absorption of their energy in elastic compression. Therefore, for a
10、ccident prevention, it is necessary to analyze in detail the above-mentioned factors and to do excavation in the direction in which the risk that the mine workings will lose stability is minimum.We will analyze the stress state around mine workings in a mineral bed, which will allow us to formulate
11、recommendations on support design and to indicate ways to reduce the probability of catastrophes that may lead to fatal accidents. If the boundary of a mine working has varying curvature or mechanical properties, the stress concentration factor may change abruptly, which may result in rock breaking.
12、 Moreover, local irregularities of the boundary due to the presence of the bed additionally change the stress concentration factor, which may have a significant effect on the stability of exposed rock. Fig.1 We will consider long drift mines. Since they are extended, the effect of the extremities of
13、 mines can be neglected at its middle. For numerical purposes, an area is isolated in the middle part of the mine working and a plane strain problem is formulated, since the strains in an elastic rock mass along the mine axis are assumed equal to zero. Similar problems were considered in 3, 4, 7, 8.
14、 To solve this problem, we will employ the finite-element method 2, which is used to solve static and dynamic problems for rock masses. Spatial (three-dimensional) and plane (two-dimensional) problems of elasticity are usually considered, with preference being given, whenever possible, to the latter
15、 because plane problems make it possible to study multiparameter systems. 1. Problem Formulation and Problem-Solving Method. In the static case, the equations of elasticity for the rock mass near a mine working are the following:the equilibrium equations for stresses （1） or Where is the vector of body forces; is the differentiation matrix; is the stress vector .The virtual work done by the internal forces in a rock mass of unit thickness is determined from the equality （2）and the work done by external forces is given by （3）It is assumed that th
