METHOD OF DETERMINATION OF ROCK LOCAL STRESSES Russian patent published in 2003 - IPC

FIELD: rock research; applicable in determination of stresses acting in rocks. SUBSTANCE: method includes drilling in rock of hole, its filling with washing fluid rendering regulated pressure on hole walls resulting in replacement of the first local stress in definite part of rock with other stress depending on said regulated pressure acting on hole walls. Taken from said part of rock is specimen having the first, second and third base directions coinciding with directions of the first, second and third local stresses respectively, acting on specimen up to its taking from rock. Specimen is subjected to testing. In conduction of each test, specimen is subjected to regulated stresses along base directions with aim to determine specimen failure surface. In this case, value of regulated stress along the first base direction is equal to value of said other stress. Determined by failure surface is, at least, one local stress - the second or third. Direction of the first local stress is vertical, and direction of the second and third local stresses are horizontal. Said part of rock may be located below bottom of borehole and primary stress is determined by pressure of fluid column in borehole and weight of rock volume located between borehole bottom and the place from which rock specimen was taken. Specimen may be taken from bottom region of borehole. In execution of each test point of failure surface may be determined by acoustic emission coming from specimen. EFFECT: increased accuracy of determination of stresses acting in rocks. 5 cl, 4 dwg