Rock Bolt Anchorage Capacity Calculator

Underground Ground Support: Compute steel tensile yield ($T_{\text{yield}}$), resin/grout bond pullout resistance ($T_{\text{bond}}$), and dead-weight rock block safety factors ($SF$).

Rock Bolt & Grout Geometry

Bolt Rebar Diameter $d_b$ (mm):

Drill Hole Diameter $D_h$ (mm):

Steel Yield Strength $f_y$ (MPa):

Bond Length $L_b$ (m):

Interfacial Bond Shear Strength $\tau_b$ (MPa): Typical: Polyester resin ~ 2.0-3.5 MPa; Cement grout ~ 1.2-2.0 MPa

Dead-Weight Rock Load

Bolt Pattern Spacing $s_x \times s_y$ (m):

Unstable Roof Block Thickness (m):

Rock Unit Weight $\gamma_r$ (kN/m³):

Capacity & Support Factor of Safety

Governing Bolt Capacity ($T_{\text{cap}}$)

-- kN

-- metric tons

Support Factor of Safety ($SF$)

Design requirement: SF ≥ 1.50

Steel Yield Capacity ($T_{\text{yield}}$)

-- kN

Ultimate Break T_ult: -- kN

Grout Bond Pullout ($T_{\text{bond}}$)

-- kN

Balanced Bond Length: -- m

Load & Failure Mode:

• Tributary rock block load per bolt: -- kN (-- t)

• Controlling failure mode: Steel Yielding (Ductile)

• Annular resin gap thickness: -- mm

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Rock Bolt Anchorage Capacity Calculator

Rock Bolt & Grout Geometry

Dead-Weight Rock Load

Capacity & Support Factor of Safety

Frequently Asked Questions