Analysis On Rock Mechanics And Rheological-damage Character In Depth Mine Of Jinchuan No.2 Minging District

With the increaseing demand for energy resources and advancing technology, mining engineering has turned to increasing depth level. Rock engineering in depth level owns its special'high'features- high ground stress, high temperature and high seepage pressure. Comparing to shallow level, mechanical properties of rock engineering in depth level vary greatly, the manifestation of which is that: rheological property of rock is more evident and some physical phenomena occurs-like crushing induced by rock expansion when unloading, which may gives rise to fracture propagation and connection hence induces degradation of rock mechanical properties. Water is another active factor may induce disaster in underground engineering, which can change structure and formation of geo-materials from micro-level view, leading to increase in porosity and then affecting permeability and pore pressure, at last macro mechnical properties changes. Water inducing damage is an indisputable fact and sometimes its destructive effect oversteps any external mechanical factors.This paper conducts research on mechanica properties of rock in depth level of Jinchuan, based on project of'Research on Rock Mechanics Under Condition of Deep and Hi-impact Mining in Jinchuan ore', and the main endeavor of this paper is following:1. Engineering geology survey had been conducted in Jinchuan No.2 district, and rock samples has been conllected to do experiments.2. Swelling experiment has been conducted using utrobasic rocks soaking in water condition. Results show that utrobasic rock swells when encountering water and generates internal swelling stress and large deformation, leading to decrease in compressive strength, shearing strength and elastic modulus.3. It is found that remarkable differences of rock mechanical properties exist between depth level and that of upside by doing normal rock mechanics experimental comparison. Double torsion experiment has also been conducted so as to measure velocity of subcritical crack growth and fracture toughness. Result shows that the curve of 1gKI-1gV presents good linear relationship. The result also finds that water action leads to acceleration of subcritical crack growth.4. Creep experiment under dry condition and that of under water condition has respectively been conducted to analyse rheological behavior of rock, by introducing data processing method which simultaneously takes into account the instant elasticity, instant plasticity, viscoelasticity and viscoplasticity and using multi-step incremental cycling loading and unloading method. This paper introduces modified K-B model and proposes an nonlinear constitutive model of viscous body, and sets up a rheological model suited for local mining aera.5. Cycle loading and unloading experiments has been conducted under dry and water condition respectively using RYL-600 testing machine. Expetimental results have been used to do energy analysis and damage analysis and found that creep deepen damage of rock inducing reduce in stability of surrounding rock.