Limit States Design Checks for Geotechnical Loads

Abstract

A limit states design approach has been developed for geotechnical loads. The approach uses a strain based design format and requires the user to develop probability distributions for the maximum strain demand and minimum strain capacity. Checks are provided for both local buckling and tensile rupture, which are calibrated to meet specified risk-consistent reliability targets. The safety factor and the criteria used to define the characteristic strain demand and capacity are defined as functions of the reliability target and the coefficients of variation of the strain demand and capacity. The checks are calibrated for a wide range of target reliability levels and distributions to cover most cases related to slope creep, landslides, frost heave and thaw settlement. They can also be applied to seismic deformations, subject to confirmation that the strain demand and capacity distributions fall within the range of calibrated cases. The design checks provide guidance on how to account for the spatial and temporal characteristics of different geotechnical loading processes, including distinction between sudden and gradual load application, and between known and randomly located loading sites. The limit states checks can be used to design new pipelines and assess the safety of existing ones. Application to slope movements is demonstrated by a set of examples.