Numerical Simulation and Numerical Differentiation Analysis of Slope Deformation Due to Mining

Abstract

It's important to analysis accurately the deformation of the mountain slope due to mining. An example of the iron mine in Jidong area was given, and then the stability and deformation of mountain slope influenced by mining were calculated by means of numerical simulation and numerical differentiation, and besides, basis of quantitative analysis was given for safety assessment of power line on mountain slope. The method that was validated by the effect of corresponding example was rational and efficient. Tangshan, Hebei Province in northern surface topography mostly is of mountains, hills, mountains are low, medium cutting, complex terrain, and rolling hills. Abundant iron ore resources within the area belonging to the Anshan-type deposit type metamorphosed sedimentary iron ore. After useful ore was mined, Rock original stress equilibrium around mining area are destructed, stress redistributing, gob rock avalanche, with rock moving and deformation. if the impact develop to the ground, it will produce a continuous or discontinuous ground deformation inducing a series of environmental geotechnical problems, causing a huge impact and loss of production and life of the people in mining area, leaving a huge hidden trouble for future mine construction projects at the same time (1) . Because the disturbance caused by underground mining of rock, its influence on the stability of rock overlying the upper slope would induce the slope body sliding, causing decreased stability of the mountain; posing the mountain slope hazards, causing mountain deformation, destroying the structure on the mountain (2). Even deep underground mined area, the ground will cause significant movement and deformation (3). In the mountains, research of impact mechanism has little done in secondary stress field of underground mining. Therefore, it is important to study the ground subsidence deformation influenced by under mountain gob deformation for further understanding of the basic law of mining subsidence and rational seam exploitation as well as safety assessment for the upper slopes. In this paper, taking actual situation of underground iron ore mining in a northern mountainous area of Tangshan as an example to analyze the influence the underground mining to the mountain slope. Mine is located in the North China Platform Malan Yu Yanshan fold belt Qianxi dome anticline fold compound beam west. Strata exposed in the main mining area for the next Malan Qianxi Group Archean gneiss valley group system, mainly in the fine-grained biotite hornblende hypersthene plagioclase gneiss, hornblende-plagioclase gneiss, biotite-hornblende-plagioclase tablets Ma rocks. Followed by exposed north and south the Great Wall lines Changzhougou Formation, the lithology is basal conglomerate, conglomerate, quartz sandstone, and quartzite. Quaternary is distributed in the mountain valley areas, mainly alluvial layer, sub-plot of the residual slope and extent of the slope is not laminated. Ore bodies are buried in the hillside which is a hidden ore body, angle 60~65°, thick ore body. There is a supply lines on the slope which is hanging wall of the mine, using concrete pole erection; there are chestnut trees and farmland on lower part of slope. Ground movement caused by underground mining can cause deformation of power lines tilt, inducing the slope upper body sliding in the condition of severe deformation, destructing the agricultural land and of trees on the lower part.