Correlation between the stability of surrounding rocks and ratio of rock breakdown pressure to geostress

摘要

To analysis the correlation between the ratio of breakdown pressure (Pb) to horizontal minimum compression stress (Sh) and stability of surrounding rocks. Attempt to use the ratio to estimate the stability of surrounding rocks. The elementary results indicate: the higher the ratio, the more stable the wall rock. When Pb/Sh ≥1.8,the stability of surrounding rocks was well. When Pb/Sh ≤1.50, hard rock is potential to happen rock burst, soft rock is easy to convergent distort. When 1.8 >Pb/Sh >1.50, the wall rock was in the critical condition of distortion. On the basic theory of hydraulic fracturing stress measurement, the definition of breakdown pressure (Pb) and instantaneous shut-in pressure (Ps) is explicit. The value is correctable, reliable and easy to acquire. The ratio reflects the effect of stress, intensity of tension resistance to stability of surrounding rocks. The method based on measurement of in-situ rock stresses and engineering information feedback, the stability of surrounding rocks is estimated in the engineering survey or preliminary design stage. All those may provide the basis data for the projects design and construction.