Deterministic and probabilistic failure analysis of simple geosynthetic reinforced soil slopes

Abstract

Reinforced slopes with horizontal layers of geosynthetic reinforcement can have different mechanisms of failure. In this paper two major mechanisms of failure of reinforced slopes are investigated. External mechanisms occur when the critical slip surface passes beyond the reinforced zone. Internal mechanisms are characterised by failure surfaces that intersect all of the reinforcement layers. For a target value of the factor of safety and a specific value of the reinforcement length, there is a minimum value of the reinforcement tensile strength that will generate only external mechanism types. For greater reinforcement strength values, there is no change in the mechanism of failure and the value of the factor of safety. On the other hand, increasing the minimum reinforcement length, while keeping the reinforcement tensile strength equal to or less than the minimum value obtained for an external failure mechanism, will generate an internal mechanism type with the same mean value of factor of safety. In this study, probabilistic slope stability analysis of these two mechanisms is carried out using Monte Carlo simulation of slopes with different purely frictional and cohesive-frictional (c − ϕ) soils and different slope angles. Margins of safety are expressed in terms of a conventional factor of safety and in terms of maximum probability of failure. Cross correlation between soil strength parameters is also considered in this paper. It is shown that considering practical values of cross correlation coefficient reduces the maximum probability of failure for both internal and external failure mechanisms.

Probabilistic Slope Stability Analysis: A Case Study

“…In recent years, probabilistic approaches are more and more widely used for the safety assessment of slopes [3][4][5][6][7][8][9]. It is noted by various researchers that a slope with a deterministic factor of safety (FS) larger than 1.00 may have a probability of failure larger than 0% [7,9].…”

“…[8] also mentioned that crosscorrelation between random values of soil properties can reduce the PF for simple slope cases. In their study, [8] investigated cohesive slopes with cross-correlation between cohesion and unit weight and compared the results with the cases without cross-correlation.…”

“…Negative cross-correlation between cohesion and friction angle and positive cross correlation between cohesion and unit weight, and friction angle and unit weight were considered [8]. Results for cohesive soil slopes indicated that PF decreased for increasing negative cross-correlation between cohesion and friction angle, and increasing positive correlation between cohesion and unit weight, and friction angle and unit weight.…”

“…[9] noted that considering the cross-correlation between cohesion and friction angle significantly decreases PF for slopes having FSdeterministic>1.00, but increases for others. [8] also mentioned that crosscorrelation between random values of soil properties can reduce the PF for simple slope cases. In their study, [8] investigated cohesive slopes with cross-correlation between cohesion and unit weight and compared the results with the cases without cross-correlation.…”

Reliability Analysis of an Embankment Built and Reinforced in Soft Ground Using LE and FE

“…Ref. [28] used the MC simulation to investigate the probabilistic stability analysis of a reinforced slope, considering the external and internal mechanisms of failure. Ref.…”