Shotcrete
To include Shotcrete support in an SWedge analysis:
- Select the Shotcrete option in the Support menu.
- In the Shotcrete dialog, select the check box, and enter the Thickness and Shear Strength of the shotcrete (see below for information about estimating shotcrete shear strength).
- Select OK to re-compute the analysis.
All views of the current document will be updated with the latest results, including the effect of the shotcrete support.You can use the Apply button to re-compute the analysis without closing the dialog.
How Shotcrete is Implemented in SWedge
Shotcrete is implemented in an SWedge analysis as follows:
- The maximum force which the shotcrete can exert on the wedge is obtained by adding the trace lengths of Joint 1 and Joint 2 on the slope face and multiplying by the shotcrete thickness and shear strength.
EXAMPLE: If the trace length of Joint 1 on the slope face = 10 meters, and the trace length of Joint 2 on the slope face = 12 meters, and shotcrete thickness = 0.1 m and shear strength = 100 tonnes / m2, then the shotcrete force used in the analysis = ( 10 + 12 ) * 0.1 * 100 = 220 tonnes.
- The DIRECTION of this force is NORMAL to the slope face and directed INTO the slope.
- As with all other forces in SWedge (e.g. bolts, external, seismic), this force is applied through the centroid of the wedge.
- The shotcrete force is included as a PASSIVE force in the safety factor calculation. See the How Bolts are Implemented in SWedge topic, for a discussion of how ACTIVE and PASSIVE forces are defined in SWedge.
Estimating Shotcrete Shear Strength
To estimate the value of shotcrete shear strength, there are a variety of different codes that relate concrete compressive strength to shear strength. The Canadian CSA simplified standard is shear strength(MPa) = 
where f'c is the 28-day compressive strength in MPa. For example, given 35MPa unreinforced shotcrete, the shear strength is approximately 1.2 MPa (120 tonnes/m2). ACI and Eurocode are similar.