Current Research on Slope Stabilization with In-situ Reinforcement

J. Erik Loehr

Department of Civil EngineeringUniversity of Missouri - Columbia

Ongoing Research Projects

Slope Stabilization Using Recycled Plastic Pins– Missouri Department of Transportation– Epoch Composite Products– The Judy Company

Stabilization of Earth Slopes Using Reticulated In-situ Reinforcement– National Science Foundation

In-situ Reinforcement of Slopes

Railway

Slip Surface

Soil Nails

ReticulatedMicropiles

Firm Stratum

Fill

Stiff ClayRelic ShearSurface

Soil Dowels

after Bruce and Jewell, 1986

SoilNails

Shotcrete

Key Issues being investigated

Limiting soil pressure – Influence of member spacing– Influence of member size

Axial vs. lateral load transfer– Influence of member orientation– Effect on overall stability

Group/network effects

Field Demonstration Sites

SiteSlope Angle

General Characteristics

I-435 (Wornall Rd.) 2.2:1 Zoned embankmentI-435 (Holmes Rd.) 2.5:1 Zoned embankmentUS 36 (Stewartsville) 2.2:1 Zoned cutI-70 (Emma) 2.5:1 Homogeneous fillUS 54 (Fulton) 3.2:1 Homogeneous cut

All surficial failures!!

I435-Wornall Rd Slide

I435-Wornall Rd. Site Layout

I435-Wornall Rd. Completed Installation

US36-Stewartsville Slide

US36 Stewartsville Site Layout4.5' x 3' 6' x 6' 6' x 4.5' 4.5' x 6'

54 pins 67 pins 78 pins161 pins

slope crest

slope toe

30 ft6 ft

Approx. Slide Extent

Instrumented Members

US36-Stewartsville Completed Installation

Large-scale Laboratory Modeling

Purpose of Large-scale Tilt Box

Intermediate to full-scale field tests and centrifuge testing

Will permit– Rapid evaluation of alternative reinforcement

scenarios and methods at near field scale– Construction using “field-like” equipment– Calibration of numerical models

Small-scale Tilt Device

Other Activities Back-analysis of case histories

Numerical modeling

Stability prediction contest

THANKS!