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10.4 MICROPILE SLOPE STABILIZATION Micropiles can be used to resist unstable slope forces through a combination of axial resistance developed at
the grout-to-ground interface, both above and below the slip surface, and structural shear and bending resistance of the pile element. The shear resistance that an individual pile provides is assumed to correspond to the maximum shear force in the pile at its nominal bending resistance. The resistance of individual piles can be increased by designing
the piles on a batter, whereby the upslope leg will be in tension and the downslope leg will be in compression. Piles are typically battered 30 degrees from vertical in an A-frame configuration with a reinforced concrete cap beam, as shown by Figure 2-11. If necessary, the resisting force can be
supplemented by ground anchors, tied back to stable ground below the slip surface. Detailed procedures for designing micropiles for soil slope stabilization, along with an introductory discussion of the advantages and constraints associated
with the design method, are included in Chapter 6 of this report.
