Procedure to evaluate total lateral earth load of self-drilling rock bolts

Step 2.Assign shear strength and unit weight to each soil and/or rock layer.

Step 3.Select limit equilibrium method of self-drilling rock bolts that satisfies both force and moment equilibrium and appropriate critical surface search parameters.

Step 4.Apply surcharge or concentrated force(s) to wall or slope face (Method 1) or model the self-drilling rock bolts as reinforcements (Method 2). For vertical walls, model the wall face with a slight batter to avoid anomalous numerical instabilities.

Step 5.Evaluate critical surface and factor of safety for the load applied in Step 4.

Step 6. Repeat steps 4 and 5, increasing the surcharge or concentrated force(s) (Method 1) or reinforcement tension (Method 2), until the target factor of safety is obtained.

Both of these methods for evaluating the total stabilizing load for an anchored wall or slope are described herein. The analyses should be performed for each critical design cross section. Noncircular (i.e., planar) failure surfaces should be used where the soils are predominantly cohesionless or where the failure surface is located along a well-defined interface. 

For analysis of temporary walls constructed in weak (i.e., soft to medium) cohesive soils, a circular failure surface should be used. Table 16 provides a general outline for performing the analysis.

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