Analysis of Borehole DITF Regime with Geomechanical and Thermal Factors

抄録

We have investigated many axial DITF traces on the borehole wall over the depth range of 400~700 m, where a NX borehole was drilled in granite region during the winter season. Considering geomechanical and especially thermal factors, we have analysed the condition of axial DITF regime and have established the parametric relationship estimating axial DITF range with depth. With the general range of thermal stress factor of granite (0.5~1.0 MPa/℃), the seasonal temperature and geothermal gradient at the site, and in-situ stress state and tensile strength of rock mass measured by field hydraulic fracturing, the induced tensile thermal stress could generate the axial DITF for a depth range associated with the field case.