Numerical Investigation on the Mechanism of Rock Directional Fracturing Method Controlled by Hydraulic Fracturing in Dense Linear Multiholes

Abstract EN

Rock directional fracturing is one of the difficult problems in deep mines.

Directional fracturing controlled by hydraulic fracturing in dense linear multiboreholes is a novel directional fracturing technology of rock mass, which has been applied to the ground control in mines.

In this paper, a physical model experiment was performed to study the fracture propagation process between multiboreholes.

The results show that the intersecting of fractures between boreholes caused the sharp fluctuation of injecting water pressure.

A directional fracturing plane was formed along with the direction of boreholes layout, and the surface of the fracturing plane is relatively flat.

The dynamic initiation and propagation process of cracks between boreholes during directional hydraulic fracturing were simulated.

The evolution of poroelastic stress and pore pressure between multiboreholes was analyzed.

The numerical results indicated that a poroelastic stress concentration zone and pore pressure increase zone appeared between boreholes in the direction of boreholes layout.

The pore pressure distribution is generally an elliptical seepage water pressure zone with the long axis along the direction of the boreholes layout.

After the hydraulic fractures are initiated along the direction of the boreholes layout, the poroelastic stress on both sides of fractures decreases.