Deformation and Failure of the Salt Rocks during Relieving


B.V. Laptev, Dr. Sci. (Eng.), Senior Research Assistant, laptevbv@mail.ru STC «Industrial Safety» CJSC, Moscow, Russia

Annotation:

Review of a number of developments on the establishment of the rock failure mechanism during their relieving from compression stresses is performed, and the main factors effecting this mechanism are shown.
The results of studies on the establishment of the phenomena of the inverse creep and elastic aftereffect in the rocks at their relieving from the rock pressure are presented.
These phenomena are conditioned by the presence of «memory» in the rocks about the previous loads. The hypothesis of the effect of elastic aftereffect on the gas-dynamic phenomena occurring in the salt rocks is put forward.
The values of the elastic aftereffects and inverse creep, on which depends the degree of rocks resistance of mine workings, are largely determined by the inversion process. If the treated layers were «floated» to the earth surface over a geological time period, then in their rocks the relaxation of stresses and the inverse creep occurred, i.e. they were releived. The inverse process took place at «immersion» — the growth of stress and direct creep, the loads in the rocks were increasing, and the resistance to deformations in them was decreasing according to Bauschinger effect.
The process of rock failure during releiving is observed at drilling wells with core sampling in outburst-prone rocks, when the core is a plate of convex-concave shape with the thickness much less than the diameter. This effect is the basis of the local method of forecasting outburst-prone and rock-bump hazardous zones in various rocks: sandstones, bauxites, salts, quartzites.

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DOI: 10.24000/0409-2961-2018-4-58-60
Year: 2018
Issue num: April
Keywords : salt rocks deformations stresses in the rocks gas dynamic phenomena elastic aftereffect inverse creep
Authors:
  • Laptev B.V.
    Laptev B.V.
    Dr. Sci. (Eng.), Senior Research Assistant, laptev.borislfptev@yandex.ru STC «Industrial Safety» CJSC, Moscow, Russia