randy post, pe september 16, 2016 geotechnical...

Geotechnical Aspects of Polyurethane Grouting

Randy Post, PE September 16, 2016

About Randy

September 15, 2016 2

Geotechnical / Geological Engineer

15 Years of Experience Transportation Specialty Not a URETEK Salesman URETEK Champion/Advocate

Apologies for botched terminology!

Geotechnical Aspects of Polyurethane Grouting - Overview

URETEK Deep Injection in Geotechnical Terms Modes of Ground Improvement Improvements in Shear Strength Other Benefits of Polyurethane (PU) Grouting Challenges of Geotechnical Characterization Comparison With Other Types of Grouting More Novel Opportunities for URETEK Applications


URETEK Deep Injection™ Overview

UDI Typical Spacing Injection of Two-Component

Structural Polyurethane Exothermic Reaction Creates

CO2 and Causes Expansion Rapid Cure Right Material For The Job Movement Monitored at Surface


UDI – Grouting / Ground Improvement

Classifies as Chemical Grouting Another Tool in the Toolbox Ground Improvement Modes

Void Filling Permeation / Infiltration /

Binding Geopolymer Lattice (“Grout

Skeleton”) Densification


Small Footprint – Rapid Installation


Void Fill Without Overexcavation

Storm Drains, Catch Basins, etc Settlement

Low Unit Weight Geologic Features (Karst) Abandoned Utilities


Permeation / Binding / Infiltration

Coarse-Grained Soil Few Fines Filling Void Space Cementing Agent Creating Artificial Sandstone or

Conglomerate


Permeation Mode


Karol, R. H. 2003. Chemical Grouting and Soil Stabilization. 3rd ed.

PU Replacing Air and Water in Void Space


Geopolymer Lattice

Lower Permeability Soil Veins, Stringers, Webs Random Pattern Follow Path of Least Resistance


Densification

Requires Confinement Changing Soil Fabric Benefits of Increasing Soil

Density Increased Shear Strength Increased Stiffness Reduced Permeability


Injection pipe

The expansion of the foam is resisted by the natural ambient confining pressure in the ground created by the unit weight of the soil

When Do You Get The Different Modes?

Function of Soil Type Coarser Soil – Infiltration /

Binding Finer Soil – Lattice Function of Confinement Check with Eagle Lift/URETEK


What’s My Shear Strength Increase?

Most Asked Question? Exact Answer Difficult Theoretical Basis for

Improvement

486STAR-4BD (3pcf, UCS=30 psi) 486STAR-8 (8pcf, UCS=176 psi) Shear Strength = ½ UCS


Volume Replacement Ratio Concept

Borrowed from stone columns VRR = ΣVred / Vgreen

Pro-Rate Properties


Increase in Shear Strength


0

5

10

15

20

25

30

35

0 5 10 15 20 25

Shea

r Str

engt

h, τ

(psi

)

Normal Stress, σn (psi)

Phi = 30°Phi = 35°Phi = 40°Stiff ClayHard Clay

30 feet of overburden



0

5

10

15

20

25

30

35

0 5 10 15 20 25

Shea

r Str

engt

h, τ

(psi

)


Phi = 30°Phi = 35°Phi = 40°Stiff ClayHard Clay486STAR-4BD (UCS = 60 psi)486STAR-8 (UCS = 175 psi)

486STAR-8

0

5

10

15

20

25

30

35

0 5 10 15 20 25

Shea

r Str

engt

h, τ

(psi

)


Phi = 30°Phi = 35°Phi = 40°Stiff ClayHard Clay486STAR-4BD (UCS = 60 psi)486STAR-8 (UCS = 175 psi)Phi = 30, 3% 486STAR-8

c = (3% * 175 psi) / 2 = 2.6 psi

c



(Or about 10% ReplacementWith 486STAR-4BD)



0

5

10

15

20

25

30

35

0 5 10 15 20 25

Shea

r Str

engt

h, τ

(psi

)


Phi = 30°Phi = 35°Phi = 40°Stiff ClayHard Clay486STAR-4BD (UCS = 60 psi)486STAR-8 (UCS = 175 psi)Phi = 30, 3% 486STAR-8Phi = 30, 15% 486STAR-8

More Dense Means Higher Strength


NAVFAC (Department of the Navy, Naval Facilities Engineering Command). 1986a. Design Manual 7.01 - Soil Mechanics

Increase in Stiffness

UDI Common To Remediate What About Pre-Construction

Treatment? Densify Loose Soil Fill Voids Provide Restraint and Additional

Resistance


1 - SM2 - GP-GM

3 - SW4 - SW

5 - SP-SM6 - SP-SM

7 - SP-SM8 - SM

9 - CL10 - SM

11 - SC12 - SM

13 - CL14 - CL

15 - SM16 - SC17 - CL

18 - SW-SC19 - SC20 - CL21 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC22 - SC

0

20

40

60

80

100

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0

20

40

60

80

100

0 500 1000 1500 2000 2500 3000

Influence Factor (Iz)

Dep

th (f

t)

Es (ksf)

Es

Iz

Reduction in Permeability of Soil/PU Mix

Seepage Control Effluent Pond Embankment Southeast Texas

Cutoff Wall Applications Injectable Barrier℠ 8 Sites Independent Study (HCR) USF Research


HCR Study – Palm Beach County

Handex Consulting & Remediation, LLC

2013 Florida Remediation Conference

Palm Beach County, SR 704 Depth to Water – 9 feet Fine Sand 0-40 feet (SP) Dewatering to 15 feet 7 Days of Dewatering


Image Credit: Handex Consulting & Remediation, LLC

Cut-Off Wall Plan



Cut-Off Wall Installation

3 Foot Horizontal Spacing 8, 11, 14, 17 and 20 feet Depth


Cut-Off Wall Results



Sealing / Driving Out WaterGo Watch the Videos!

Sealing a Utility Vault https://youtu.be/v04-0tiMZ5I


https://youtu.be/v04-0tiMZ5I

Sealing / Driving Out WaterGo Watch the Videos!

Sealing Around Leaking Manhole

https://youtu.be/_Qj-e8dGQLs

Saturated Rail Track Bed https://youtu.be/NPchWQbM9ng


https://youtu.be/_Qj-e8dGQLs

https://youtu.be/NPchWQbM9ng

Comparison With Other Types of Grouting


Image Credit: Ground Improvement Methods, FHWA NHI Course No. 132034 Reference Manual (Rock)

PU Chemical Grouting

Structural PU Hydro-Insensitive Rapid cure time Expansion many times its

original volume

Permeation Grouting

Cement or Sodium Silicate Hydro-Sensitive Longer cure time No expansion




Single Injection Points Surgical Injection Relies only on reaction

chemicals

Permeation Grouting

Grout Manifold Relies on in-situ conditions

Temperature Water Void Ratio Catalyst




High Mobility Grout Compaction Effect Variable Grout Shape Pressure Due to Reaction

Influences Compaction Effect

Compaction Grouting

Low Mobility Grout Compaction Effect Fairly Uniform Grout Column Injection Pressure Influences

Compaction Effect




Movement at Ground Surface Indicates Stage Complete

Confining Pressure Important Depth Limitation ~ 30 feet Not Impacted by Excess Water Rapid Process / Light Footprint

Compaction Grouting

Movement at Ground Surface Indicates Stage Complete

Confining Pressure Important Ineffective at shallow depths Impacted by Water Lengthy Process / Big Footprint,

Messy




Grout “skeleton” formation depends on soil properties

Applied to foundation stabilization and lifting

Keep records of quantity of material injected at each location

Surface deformations carefully monitored

Fracture/Compensation Grouting

Grout “skeleton” formation depends on soil properties

Applied to urban tunneling projects

Detailed monitoring of grout pressure/volume with time

Surface deformations carefully monitored




Able to lift settled structures Short gel time Surface deformations carefully

monitored Potential application to slope

stabilization

Fracture/Compensation Grouting

Able to lift settled structures Long gel time Surface deformations carefully

monitored Potential application to slope

stabilization (“lense grouting”)



“Lense Grouting” Application


Image Credit: Ground Improvement Methods, FHWA NHI Course No. 132034 Reference Manual after Chandler, S.C. (1997)

Challenges of Geotechnical Characterization



3 Modes of Soil Improvement Improvements Not Homogenous Follows Path of Least

Resistance



Pressure at Gun Not The Same as Pressure in Soil

Soil Sampling Field Tests




“When measuring the soil improvement by compaction grouting, a single test at any location in an area treated by limited mobility grouting is unlikely to be representative of the entire soil mass.” – Michael Byle

Byle, Michael J. 2005. “Quality Assurance for Limited Mobility Grouting.” In Innovations in Grouting and Soil Improvement, GSP No. 136, 1–12. Austin, Texas: American Society of Civil Engineers. doi:10.1061/40783(162)2.

So What Do You Do?

Test-Grouting Program With Excavation Track Material Quantities Use Volume Replacement Ratio Concept

Shear Strength Modulus

Before/After In-Situ Permeability Testing Use Boreholes/DCP/Lab Testing With Caution Publish Your Data if Possible


Opportunities for URETEK Applications

Abandoned Mine Reclamation (Void Fill, Bulkheads)

Pre-construction Applications Collapsible Soils Excessive Settlements Poor Bearing Capacity Saturated Soil Preventative Sealing Around Drainage Structures Stabilize Existing Structures or Soils Before Excavation


Opportunities for URETEK Applications

“Lagging” In Between Soldier Piles for Shoring Applications

Treatment of Cut Slopes To Prevent Erosion and Eliminate Retaining Walls

Treating Landslide / Slope Failure Slip Plane

Sealing Leaking Sheet Pile Joints

Cut-off Wall Applications


Geotechnical Aspects of Polyurethane Grouting

Randy Post, PE September 16, 2016

Thank You! Questions?

[email protected] 520-332-1414

mailto:[email protected]

randy post, pe september 16, 2016 geotechnical...

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