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Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University, China Sept. 21 st , 2017 Sustainability in Geotechnical Engineering Workshop

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Page 1: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Sustainable Soil Stabilization in

Geotechnical Engineering of China

Y.-J. Du

Southeast University, China

Sept. 21st, 2017 Sustainability in Geotechnical Engineering Workshop

Page 2: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

• NSFC Funding and industry partners

• Colleagues: Prof. Liu and Cai

• Graduate students

• International partners: Prof.

Horpibulski, Arul, Reddy

ACKOWLDEMENTS

Page 3: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Yan-Jun Du PhD, PE

Expertise:

• Remediation and reuse of contaminated soils and sediments

• Vertical cutoff walls in geoenvironmental applications

• Modelling coupled thermal-hydraulic-stress-chemical responses of

remediated soils at urban areas

• Resilience and sustainability of innovative geomaterials in geotechnical

and geoenvironmental engineering

• Structural response of buried flexible pipelines

Education:

• Bachelor and Master, Nanjing University, 1994, 1997

• PhD, Geotechnical Engineering, Saga University, Japan, 2001

Working Experience

• 2008-: Southeast University

Committee Memberships

• Member, Committee on Geoenvironmental Engineering, American

Society of Civil Engineers/Geo-Institute (2014-Present).

Editorships and Editorial Boards:

• Canadian Geotechnical Journal (EBM)

• ICE Environmental Geotechnics (EBM)

• Lowland Technology International (AE)

Funding and Projects:

• 5 NSFC grants, 1 863 Projects, 2 Jiangsu Province NSF grants.

Awards/Honors:

• Award of Mao Yi-Sheng (茅以升) Science and Technology.

• Second Grade Award of Technology Invention, China Ministry of

Education.

• Second Grade Award, China National Technology Invention.

• Natural Science Foundation for Distinguished Young Researchers of

Jiangsu Province

Yan-Jun Du

Prof. Director

Institute of Geotechnical Engineering

School of Transportation

Southeast University

Can. Geotech. J. Outstanding

Reviewer for 2016

Page 4: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

CONTENTS

Research background

Industrial wastes

Case studies

Concluding Remarks

Page 5: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Research background

Stabilization of problematic soils

Relatively High

Cost

Environmental Problems

Cement production

leads to ~1 Gt CO2/yr

Challenges in Problematic Soil

Stabilization

Industrial Wastes

China Statistics Press 1997

and 2003, SEPA 2000

Annual Increase

Soil and

Groundwater

Pollution

Non-renewable Materials

Reuse industrial wastes to

stabilize soils

SOLUTION

Page 6: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Industrial wastes

Industrial wastes Main source Output in China Main component

Calcium carbide residue

(CCR)

By-product of

acetylene

~ 20 million tons

in 2016

CaO (up to ~70%)

Fly ash Coal-fired

power plant

~ 300 million tons

per year

SiO2 (up to ~70%), Al2O3

(up to ~40%), CaO (up to

~20%),

Ground granulated

blastfurnace slag (GGBS)

steel

production

~ 90 million tons

per year

CaO (30% ~ 42%),

SiO2 (35% ~ 38%),

(Al2O3 (10% ~ 18%)

Lignin Waste from

paper industry

Accounting for

20%~30% of total

waste water

Active functional group:

hydroxyl group (-OH),

carbonyl group (-C=O),

carboxyl group (-COOH),

methyl group (-CH3 ), etc.

Industrial wastes frequently used for soil stabilization in China

Page 7: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

South China

East China

Pan-Yellow

River area

Case study 1: over-wet clay stabilization using

calcium carbide residue (CCR)

Characteristics:

1. Relatively high water content, clay fraction and compressibility

2. Difficulty in compaction

3. Poor water-soaking durability

Conventional binders: quicklime, cement, quicklime + fly ash

Page 8: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Physical and mechanical properties

compaction degree = 96%

compaction

degree = 96%

0

4000

8000

12000

16000

20000

45%

Mo

du

lus

of

resi

lien

ce,

E0 (

kP

a)

Curing time (d)

Untreated soil

CCR 6%

Lime 6%

7 28

30%

96% Compaction degreecompaction

degree = 96%

8 10 12 14 16 18 201.60

1.65

1.70

1.75

1.80CCR content

4%

6%

8%

Dry

den

sity

(g/c

m3)

Water content (%)

CCR stabilized soils possess superior mechanical and durability

performance than quicklime in terms of qu, water durability, CBR,

and resilient modulus (E0).

Curing time

Page 9: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

CCR-stabilized clay shows greater durability under wetting-

drying and freezing - thawing cycles.

FT=0 FT=3 FT=6 FT=9 FT=12 FT=16 FT=20400

800

1200

1600

2000

2400

Number of cycle

qu (

kP

a)

Untreated soil

CCR treated soil (6%)

Lime treated soil (6%)?

CCR (7 d)

CCR (28 d)

Lime (7 d)

Lime (28 d)

CCR-stabilized clay

Number of wetting-drying cycles M

ass

loss

(%

)

CCR-

stabilized

clay

Quicklime-

stabilized

clay

freezing and thawing cycle

Physical and mechanical properties

Quicklime-stabilized clay

Page 10: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

0 20 40 60 80 100 12012.3

12.4

12.5

12.6

12.7

12.8

pH

Curing time (d)

6% CCR

6% Lime

Mechanisms

6% Lime

pH

qu(M

Pa)

6% CCR

Ca + 2OH- + SiO2 → CSH

Ca + 2OH- + Al2O3 → CAH

0 100 200 300 400 500 600 700 80092

94

96

98

100

温度(oC)

C

(b)

CAH/CASH

-0.04

-0.02

0.00

0.02

TGA

DTG

DTG

TGA

92

94

96

98

100

(a)

C

-0.04

-0.02

0.00

0.02

dm

/dt

(%/o

C)

质量

m (

%)

CSH

CSH

Ca(OH)2

Ca(OH)2

6% CCR (120 d)

6% Lime (120 d)

Untreated clay (180 d) lime-stabilized clay (180 d) CCR-stabilized clay (180 d)

CCR stabilized clay possesses higher amount of Ca(OH)2 and

CSH/CASH, and therefore denser structure.

Page 11: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Mechanisms

0%

20%

40%

60%

80%

100%

不同大小孔隙百分含量

(a) (b) (c) (d) (e) (f)

35~300μm

0.9~35μm

0.007~0.9μm

0~0.007μm

6%

Lime

(28 d)

6%

CCR

(28 d)

6%

Lime

(60 d)

6%

CCR

(60 d)

6%

Lime

(120 d)

6%

CCR

(120 d)

Pore size

Pro

po

rtio

n (

%)

30 35 40 45 50 55 601.8

1.9

2.0

2.1

2.2

2.3

2.4

35 40 45 50 55 60 65

28 d

28 d

60 d

60 d

60 d

28 d

qu (

MP

a)

Pore size distribution (%)

d < 0.9 m

6% CCR

6% Lime

28 d

120 d

120 d

120 d

120 d

0.9 m < d < 200 m

6% CCR

6% Lime

60 d

Proportion of micropore (d < 0.9 mm) in CCR-stabilized clay is

larger than lime stabilized clay.

Page 12: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

CONTENTS

Research background

Industrial wastes

Case studies

Concluding Remarks

Page 13: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Field trials

Shanghai

Nanjing

CBR

DCP

Deflection

Page 14: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Constructions

(1) Spreading soil (2) Paving CCR (3) Paving lime

(4) Mixing by plow (5) Enhanced mixing by dozer (6) Compacting by vibrating roller

Construction duration is 17 days with compaction degree of 94%.

No dust during CCR paving.

Page 15: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Field Trials

CCR-stabilized clay display higher CBR, E0, and light dynamic

cone penetration resistance regardless of curing time

CCR

Quicklime

CCR

Quicklime

Page 16: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

CCR

Quicklime Deflection

DCP

Page 17: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Quicklime CCR

CCR

Quicklime

Page 18: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Environmental quality valuation

Metal Lime CCR 4% Lime 6% Lime 6% CCR

Cu 5.8 1.48 25.6 24.1 25.3

Zn 33.2 3.21 81.3 71.9 81.2

Ni 5.68 2.1 34.8 33.1 35.3

Cr 23.9 2 68.1 64.2 69.3

Ba 1078 31 512 440 479

Pb 7.9 <0.2 11.7 13.4 18.5

Cd 1.35 <0.01 0.167 0.076 0.165

Hg 0.018 <0.005 0.025 0.026 0.03

As 84.2 0.4 15.1 11.5 15.7

Se 0.978 <0.04 <0.04 <0.04 <0.04

Metal concentration in raw materials and stabilized clay

(mg/kg)

Metal concentrations of target

metals in CCR- and lime-

stabilized clays are all lower

than limit values of Level III

soil stipulated by Chinese

Environmental Quality

Standard For Soils (GB

15618-1995).

Sample

ID

Leaching

solution

pH Metal concentration in leachate (mg/L)

Cr Cu Ni Pb Zn

6%

CCR

Acid rain 5.05 <0.061 <0.054 <0.15 <0.42 <0.018

DIW 7.0 <0.061 <0.054 <0.15 <0.42 <0.018

6%

Lime

Acid rain 5.05 <0.061 <0.054 <0.15 <0.42 0.02

DIW 7.0 <0.061 <0.054 <0.15 <0.42 <0.018

Metal concentration in leachate from stabilized clay

Testing method: batch-type leaching, USEPA

Metal concentrations in

leachate from CCR- and lime-

stabilized clays are all lower

than limit values stipulated by

RCRA, US.

Page 19: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Case study 2: Silty soil stabilization using lignin

Stabilized silt used for roadway subgrade filling

Dafeng

Nanjing

Yancheng

N

0 100 km

Shanghai

Lianyungang

Location of

Testing Site

Regions with Silt

Construction procedure flow chart of the lignin

stabilized embankment Zhang et al. 2017, Zhang et al. 2016, Liu et al. 2016, etc.

Page 20: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Case study 2: silt stabilized using lignin

The use of lignin as a stabilization chemical mixture for silty soil is

one of the viable answers to the reuse of biobased organic by-

product in civil engineering.

12% lignin stabilized silt

8% quicklime stabilized silt

12% lignin stabilized silt

8% quicklime stabilized silt

blow counts

pen

etra

tion

dep

th (

cm).

12% lignin

stabilized

silt

8%

quicklime

stabilized

silt

12% lignin stabilized silt exhibits

superior mechanical performances

than 8% quicklime stabilized silt

Page 21: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Case study 3: soil stabilized using GGBS + MgO

optimum content

for clayey silt

optimum content

for sand

permeability of

stabilized sand

k range of soil

stabilized with PC

SEM of 10% binder

stabilized sand with PC (28 d)

SEM of 10% binder

stabilized sand with GGBS +

MgO (28 d)

GGBS hydration

activated by MgO

Optimum GGBS:MgO ratio of stabilized soil generally ranges from 19:1 to 4:1.

28-day UCS of soil stabilized with GGBS + MgO is ∼1.3 to 4 times that of PC

stabilized soil. Yi et al. 2016, 2013, 2012, Du et al. 2016, etc.

Challenges in

drying-wetting cycle !

Page 22: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Case study 4: lead contaminated clay stabilized by

GGBS-MgO

UCS of GGBS-MgO stabilized clay is approximately 12%-43% higher than

that of the cement solidified clay.

Effective diffusion coefficient of lead (De) of lead contaminated clay stabilized

by GGBS-MgO is lower than that of cement stabilized clay Bo et al. 2015, etc.

Comparison of UCS between GGBS-MgO and

cement stabilized specimens

UC

S (

kP

a)

De

(m2/s

)

Initial pH of leachate

Page 23: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

CONTENTS

Research background

Industrial wastes

Case studies

Concluding Remarks

Page 24: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

Concluding Remarks

Industrial wastes (e.g., calcium carbide residue, fly ash,

ground granulated blastfurnace slag, and lignin) have

been successfully applied in soil stabilization in China.

Soil stabilized with industrial wastes generally shows

comparable and even better performances in terms

of strength, modulus of resilience, water soaking and

wetting-drying durability.

Environmental quality evaluation (e.g., leaching test,

acid rainfall infiltration test) and solute transport

modelling are necessary to assess potential impacts to

surrounding environment.

Page 25: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

[email protected]

• ResearchGate: https://www.researchgate.net/profile/Yan_Du8/info

• Google Scholar:

https://xues.glgoo.com/citations?user=ykIVrpEAAAAJ&hl=zh-CN&oi=ao

• ORCID: http://orcid.org/0000-0001-9533-8976?lang=en

• Mendeley: https://www.mendeley.com/profiles/yan-jun-du/

• Wechat: dyj2640929283

Thanks for your listening!

Page 26: Sustainable Soil Stabilization in Geotechnical Engineering of China · 2017-11-21 · Sustainable Soil Stabilization in Geotechnical Engineering of China Y.-J. Du Southeast University,

• CCR stabilized soils-field trials: Du et al. (2016) Soils Foundations

• CCR stabilized soils-lab scale: Jiang et al. (2016) Can. Geotech. J.

• Activated GGBS stabilized soils: Yu et al. (2016) Du et al. (2017).

ASCE J. Mat. Civil Engrg.

• Solidification/stabilization of heavy metal contaminated soil: Du

et al. (2012, 2014) J. Hazard. Mat.; Du et al. (2014) Can. Geotech.

J.

• Slurry-trench wall: Yang et al. (2017) Can. Geotech., J. ASCE

JGGE (2017); Fan et al. (2017) ASCE JGGE (2017)