SOIL NAILING FOR SLOPE STABILIZATION

by Amal Anto · Published January 12, 2021 · Updated January 12, 2021

INTRODUCTION

Slope failure – downward movement of soil ØShear stresses > Shear strength ØShear strength is the function of cohesion & internal friction >

Slope stability – represented in terms of factor of safety ØSafety factor = Resisting force / Driving force ØIf FOS > 1, then safe or stable slope Ø If FOS < 1, then unsafe or unstable slope

LEM – Based on static equation of forces Ø Soil mass above the slip surface is divided into slices Ø Shear & normal inter slice forces are determined v

FEM – Based on the concept of stress strain relationship ØStructure is divided into smaller elements called finite elements ØProperties of these elements are formulated & combined to obtain solution for the entire structure

AIM

ÒSlope stability analysis using LEM & FEM methods

SCOPE

Soil nailing provides: ÒHigh durability, reduced maintenance cost and highly resistant against environmental influences ÒImproved infrastructure in terms of speed & ease of construction, economy, aesthetics etc. ÒIncreased interaction with soil ÒControl erosion and landslides

OBJECTIVES

ÒSlope stability analysis using Swedish Circle Method ÒFEM model study using PLAXIS 2D ÒVerification of effect of nail length, nail inclination, nail configuration and spacing of nails

STABILITY ANALYSIS – SWEDISH CIRCLE METHOD

Procedure v\

Draw the slip surface vTo locate the most critical circle, Fellenius line AB

is drawn vTo draw Fellinius line AB, B is located at a depth H and at a

distance 4.5H from point P at toe of the slope