Numerical modeling of in-situ stress calculation using borehole slotter test

V. Saati, A. Mortazavi

Research output: Contribution to conferencePaper

Abstract

A stress calculation method was proposed for the new stress measurement technique using the borehole slotter device. The 2D borehole slotter is an instrument which is used in HQ boreholes (96-104 mm diameter), and allows calculation of 2D stress tensor in a plane normal to the borehole axis. This instrument enables calculation of in-situ stress tensor using three boreholes without the need for mounting strain gauges on the borehole wall. The borehole slotter technique requires cutting of half moon shaped slots at different orientations parallel to the test hole axis using a small diamond impregnated blade and monitoring of the strains which are relieved normal to the slot direction. The aim of this paper is to evaluate the effects of key test parameters on the slotter test results. A precise 3D numerical model of typical slotter test condition was constructed using the FLAC3D code. The effects of variations in rock mass deformation modulus on the strain/stress relaxation, and thus borehole slotter test results, were investigated numerically. The validity of numerical findings were discussed and compared against practical observations. Accordingly, the borehole slotter tests conducted at Bakhtiari dam site-Iran, was simulated numerically. A very good agreement was achieved between numerical and field test results. The obtained numerical results provided valuable insights in selecting the governing in-situ stress condition from the recorded field data.

Original languageEnglish
Publication statusPublished - Jan 1 2009
Externally publishedYes
EventISRM International Symposium on Rock Mechanics 2009, SINOROCK 2009 - Hong Kong, China
Duration: May 19 2009May 22 2009

Conference

ConferenceISRM International Symposium on Rock Mechanics 2009, SINOROCK 2009
CountryChina
CityHong Kong
Period5/19/095/22/09

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ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Saati, V., & Mortazavi, A. (2009). Numerical modeling of in-situ stress calculation using borehole slotter test. Paper presented at ISRM International Symposium on Rock Mechanics 2009, SINOROCK 2009, Hong Kong, China.