03 short ppt stabilizing embankment slopes

8/17/2019 03 Short PPT stabilizing embankment slopes

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at the Highway 5 and Route 20

Interchange

Williams, California

Caltrans

Landslide

All Ramps have minor to severe cracks parallel to shoulder.

Wetland



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Project Description

• Approximately 1.5 miles of unstable slopes• Slope inclination 2:1 to 1.6:1.0• Max slope height 30 feet• Existing interchange approximately 10 years

old.

Ramp Fill Properties• Soil Type = CL‐CH

= o • UC = 2000 psf • Cohesion = 75 psf • o

•

Active zone/slide

plane

=

5ft.• Corrosion Potential corrosive to unprotected steel



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Plastic Fill Embankments Exhibit Distress

• Shallow Landslides• Slope Creep• Cyclic Shrink/Swell

Shallow Slides Threaten Guard Rail



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Deep Shrinkage Cracks Form in Summer



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Restricted Wetland Area at Base of Slope



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Pavement Edge Cracking Due to Creep

PL3

1

2

1

Expansive Clay Fill

Wetland

Shallow Slides Threaten Guard Rail



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Proposed Repair Alternatives

1. Lime Treated 18 inch thick layer plus 24 inch ‐ .

2. Remove 36 inches of clay and replace with non ‐expansive fill.

3. Remove 5 feet of clay fill and replace with a Rock Slope Protection Layer.

4. Reinforce slope with closely spaced vertical steel elements to eliminate creep and shallow failures. (Platepiles)

Alternative #1



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Alternative # 2

Alternative # 3



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Concept: Divide Slopeinto Small Increments

Alternative # 4

Slope IncrementSupported by EachPlate Pile

Unstable Layer

Platepile Slope Stabilization Concept

Platepiles

Stable Material Material



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Shoulder Displacement and Edge

Cracking Due

to

Slope

Creep

&

Shallow SlidesPavement Edge Cracking

Due to Creep

PLATEPILES3

1

2

1 Wetland

Typical Ramp Cross SectionTypical Ramp Cross Section

xpans ve ay

Original Grade

Existing Grade

Slide Surface

1. Excavate Slide Area2. Push slide debris back and

compact by track rolling.

Slide Repair Procedure

3. Place and compact 24 inches of AB at top of slide under pavement.

4. Install Platepiles5. Pave and replace guard

rail.

SLIDE REPAIR



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Platepile Layout on 4’ X 8’ GridPlatepile Layout on 4’ X 8’ Grid

10’‐long

Platepiles

Construction Construction Summer 2010Summer 2010

6’‐long Platepiles

9,000 10 foot and 6 foot Platepiles

Production Rates: 400 6‐foot per day max. 200 10‐foot per day

Platepile Layout Flags



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Installing 10‐foot Platepiles with Vibratory Hammer

Driving 10‐foot Platepiles Using Hydraulic

Hammer



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Summary

• 9000 Platepiles installed in 60 days• Savings to owner approximately $3,000,000• No import needed.• Wetlands not touched.• Two excavators installed Platepiles.

03 short ppt stabilizing embankment slopes

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