The Lancang Old Factory Galena Soft Rock Roadway Deformation Mechanism Analysis

Lancang Lead Mine Old Works is located in Lancang Lahu nationality Autonomous County, in the southwest of Yunnan Province, which has a long mining history. In recent years, with the deep exploiting of resources, the ground pressure is growing, it led to the deformation and failure of the soft rock roadway Of the mining transport becomes more and more serious. As the truff with the characteristics of compressive strength, large deformation, to pressure quickly, easily combines with water and form deformation and failure, it impact on the exploitation and transport of mines seriously. At present, the deformation and damage of the tuff roadway has already been threated to the safety of mine production and mine personnel,, therefore, the studying on the mechanism of the deformation and failure of the soft rock roadway in the mining area is No time to lose.In this paper, take the Lancang Lead Mine Old Works tuff roadway as the main object of study, through on-site geological survey, a more comprehensive study of the mine's geological background and the background of mining engineering geology have been done, and the distribution of the tuff in all middle section also have been summarized.Using the engineering analogy method, first divide the mining tuff into soft-rock mining tuff by the classification standards of water conservancy and hydropower rock strength, and according to the previous experience of analogy we can see soft rock with a low compressive strength and it prones to deformation and failure; second, Through genetic types classify the tuff as the secondary type, and according to the previous experience of analogy we can see secondary rocks are the products of long-term weathering and hydration, and its intensity is low, and prone to deformation and failure; then through the engineering classification divide the tuff into high-stress and expansion of complex soft rock, under the action of high-stress and swelling the tuff are more susceptible to deformation and failure; through the rock RMR divide the tuff into V Class, this type of rock are seriously affected by the geological structure, and it is easy expansion with water deformation, and its engineering quality is very poor. Using the micro-analysis method, analysis the deformation mechanism of the old factoriesmines of tuff from the tuff itself, mineral composition, physical properties of water, internal and external expansion and other aspects. From the view of the microscopic point, description the deformation mechanism of the tuff roadway,and prove that the deformation of tuff roadway is closely related with the composition, water physical properties, internal and external expansion.Using the mechanical analysis method, according to the on-site survey data, summed up the law of tuff roadway deformation, using the FLAC model to do the analog computation and simulating the stress redistribution after the excavation of roadway, under the effect of ground stress, rock on both sides of roadway first to be compressed, the sinking of both sides squeeze the bottom, and deformation and damage occurs, leading to the bottom heave, the deformation of both sides is proportional to the deflection of bottom heave, the tuff roadway of Lancang Lead Mine Old Works is damaged in the form of bottom heave and lateral extrusion, and the simulation results are basically consistent.