SHEAR STRENGTH OF MUNICIPAL SOLID WASTE FOR STABILITY …€¦ · Triaxial compression (TXC) test...

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International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 7, July 2017, pp. 122–133, Article ID: IJCIET_08_07_014

Available online at http:// http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=8&IType=7

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

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SHEAR STRENGTH OF MUNICIPAL SOLID

WASTE FOR STABILITY ANALYSIS

R.K Kaushal

Assistant Professor, Civil Engineering Department,

Bundelkhand Institute of Technology, Jhansi

Rohit Kumar

Research Scholar,

Department Civil Engineering,

National Institute of Technology, Manipur

Rohit Yadav

Assistant Professor,

Civil Engineering Department,


Ritu Rai

Student-M. Tech, Civil Engineering Department,

Madan Mohan Malaviya University of Technology, Gorakhpur

Sachin Kumar Shakya

Student-M. Tech,

Civil engineering department,


ABSTRACT

In this research work, investigate the shear strength properties of the municipal

solid waste retrieved from a landfill in the Pandya Khari site in Ujjain city, Madhya

Pradesh using laboratory testing program Direct Shear Test. The objective of this study

was to evaluate the effects of waste composition and decomposition on the shear

strength of municipal solid waste. Shear strength of municipal solid waste is a function

of many factors such as waste type, composition, compaction, daily cover, moisture

content, age, decomposition, overburden pressure. The municipal solid waste is a

heterogeneous mixture of various kinds of solid waste which are not transported with

water as sewage, and may include biodegradable (putrescible) food waste called

garbage, and the non–putrescible solid wastes like paper, glass, rags, metal, items etc.

called rubbish.

Shear Strength of Municipal Solid Waste For Stability Analysis


The results obtained from the Triaxial shear laboratory tests on ten samples on

Solid waste material and the relationships between shear strength parameters such as

cohesion intercept (c) and degree of internal friction (φ) are estimates from the plots

between normal stress and shear stress for all ten samples. These strength parameters

and relationships are compared with the other solid waste parameters such shear stress

vs normal stress, mobilized shear stress vs unit weight, shear stress vs axial strain, shear

strength vs normal stress.

The final findings indicated that shear strength of the solid waste material collected

for the Ujjain city, MP depends on moisture content, dry unit weight of material,

composition of solid material (cardboard, polythene, stone etc.), and rate of loading,

age and compactness of material.

Key words: Municipal Solid Waste, Triaxial Shear Test, Shear Strength, Solid Waste

Material.

Cite this Article: R.K Kaushal, Rohit Kumar, Rohit Yadav, Ritu Rai and Sachin Kumar

Shakya, Shear Strength of Municipal Solid Waste For Stability Analysis, International

Journal of Civil Engineering and Technology, 8(7), 2017, pp. 122–133.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=7

1. INTRODUCTION

Solid waste is the unwanted or useless solid materials generated from combined residential,

industrial and commercial activities is classified as municipal solid waste. The municipal

solid waste (MSW) is term usually applied to a heterogeneous collection of wastes produced

from urban areas. Urban wastes can be divided in two major components organic and inorganic.

In general, the organic components of urban solid waste can be classified into three categories:

putrescible, fermentable and non-fermentable. Putrescible wastes tend to decompose rapidly

and unless carefully controlled, decompose with the production of objectionable odours and

visual unpleasantness. Fermentable wastes tend to decompose rapidly, but without the

unpleasant accompaniments of putrefaction. Non-fermentable wastes tend to resist

decomposition and therefore, break down very slowly. Analysis of Shear strength of municipal

solid waste is very difficult because of its heterogeneous mixture of landfill materials, difficulty

in specimen sample preparation, testing and particle size, time dependent properties, such as

the age of municipal solid waste and decomposition state, unit weight of material, and water

content ratio in the material.

Municipal solid wastes are dumped at site or place which is far away from the city or village

without any planning and management technique. Due to improper planning or technique of

the dump site, the waste material spreads in the nearby area due to failure of slopes of the

dumped site due to which creates bed odour in rainy season in the nearby area and effect on

environmental and health impacts. The failure of the slope of the dumped site occurred due to

the improper design of the slopes and the characteristics of dumped material. Therefore, this

research work includes investigation of the shear strength of characteristics of municipal solid

waste site at nearby of Ujjain city of Madhya Pradesh are considered which is based on

Triaxial shear test method.

This research work based on the laboratory results, and comparison between other journals

results data, the shear strength parameters cohesion and degree of internal friction are

determined and these parameters are also correlates with different parameters of MSW material.

According to Machado et al (2010), the typical composition of solid waste with different

percentage are presented below in table 1.

R.K Kaushal, Rohit Kumar, Rohit Yadav, Ritu Rai and Sachin Kumar Shakya


Table 1. Municipal Solid Waste Composition (Machado et al. 2010a)

Component Average percentage –wet basis

Average Standard Deviation Coefficient of variation

Wood 5.31 3.27 0.62

Stone/ceramic 5.72 3.72 0.65

Textile 4.25 2.16 0.51

Rubber 0.37 0.40 1.07

Plastic 18.85 3.84 0.20

Glass 1.66 0.72 0.44

Metal 1.45 0.70 0.48

Paper/cardboard 20.07 4.30 0.21

Paste 42.32 7.23 0.17

Table 2 MSW composition of Pandya Kheri site, Ujjain city, MP

S No. Paste Paper Metal Glass Plastic Textile Stone Wood

1 35.2 16.2 3.2 3.9 21.1 4.63 10.5 5.27

2 34.73 17.34 2.82 3.63 20.45 4.31 10.65 6.04

3 42.32 20.07 1.45 1.66 18.65 3.91 8.0 3.94

4 37.8 18.65 3.8 1.8 17.0 5.13 11.55 4.27

5 40.9 19.7 1.5 1.7 20.7 4.6 5.8 5.1

6 46.7 15.6 2.2 1.52 16.95 3.56 6.7 6.77

7 49.7 15.1 5.6 1.0 20.9 3.5 0.4 4.1

8 52.8 10.8 1.5 2.8 12.38 2.15 9.20 8.34

9 59.6 11.02 1.6 3.1 13.04 2.49 6.8 2.35

10 66.3 10.4 2.6 2.4 10.7 3.42 2.1 2.08

Test

Ten solid waste samples were collected from the site in the nearby area of Ujjain city are used

to perform the triaxial tests in the laboratory.

2. RESULTS AND CONCLUSIONS

Table 3

Sample

No σσσσ3

(Kg/cm2)

Failure

DGR

Failure

Load

Failure Stress

(σσσσ1-σσσσ3)

(Kg/cm2)

Failure

Stress

(σσσσ1)

(Kg/cm2)

(σσσσ1+σσσσ3)/2

(Kg/cm2)

(σσσσ1-σσσσ3)/2

(Kg/cm2)

1 0.1 12.5 43.75 3.86 3.96 2.03 1.93

0.17 14.5 50.75 4.48 4.65 2.41 2.24

2 0.1 12 42 3.70 3.80 1.95 1.85

0.17 14 49 4.32 4.49 2.33 2.16

3 0.1 17 59.5 5.25 5.35 2.72 2.62

0.17 18 63 5.56 5.73 2.95 2.78

4 0.1 14.5 50.75 4.48 4.58 2.34 2.24

0.17 16 56 4.94 5.11 2.64 2.47

5 0.1 16 56 4.94 5.04 2.57 2.47

0.17 18 63 5.56 5.73 2.95 2.78

6 0.1 29 101.5 8.95 9.05 4.58 4.48

0.17 30 105 9.26 9.43 4.80 4.63



Sample

No σσσσ3

(Kg/cm2)

Failure

DGR

Failure

Load

Failure Stress

(σσσσ1-σσσσ3)

(Kg/cm2)

Failure

Stress

(σσσσ1)

(Kg/cm2)

(σσσσ1+σσσσ3)/2

(Kg/cm2)

(σσσσ1-σσσσ3)/2

(Kg/cm2)

7 0.1 48 168 14.81 14.91 7.51 7.41

0.17 55 192.5 16.98 17.15 8.66 8.49

8 0.1 21.5 75.25 6.64 6.74 3.42 3.32

0.17 34 119 10.49 10.66 5.42 5.25

9 0.1 42.5 148.75 13.12 13.22 6.66 6.56

0.17 44 154 13.58 13.75 6.96 6.79

10 0.1 40 140 12.35 12.45 6.27 6.17

0.17 45 157.5 13.89 14.06 7.11 6.94

Table 4

Moisture

Weight

(gm)

c

(kg/cm2)

φφφφ

(deg)

γγγγd

(kg/cm2)

ττττ

(kg/cm2)

Mean

Normal

Stress

Dry Weight

(gm)

Water

Content

143 0.3 30 1.18 2.701 2.22 100 43.00

144 0.25 31 1.21 3.771 2.14 103 39.81

147 0.8 29 1.15 3.793 2.84 98 50.00

145 0.4 29 1.15 3.008 2.49 98 47.96

148 0.4 34 1.23 3.938 2.76 105 40.95

142 1.5 31 1.18 7.188 4.69 100 42.00

149 0.5 33 1.28 9.104 8.08 109 35.70

155 0 35 1.28 5.996 4.42 109 42.20

149 1.6 28 1.26 8.693 6.81 107 39.25

148 0.2 32 1.27 6.69 6.69 108 37.04

3. COHESION-FRICTION ANGLE

The shear strength parameter c and Φ are estimated from the plot between normal stress and

shear stress. These results are presented in the figures. 1 to 10.

Figure 1 c and Φ of MSW sample 1



4. WASTE COMPOSITION EFFECTS

Triaxial compression (TXC) test specimens were prepared in the same manner as the direct

shear test specimen (i.e., with different percentage of fibrous waste particles to evaluate the

effects of waste composition on stress strain and strength response). Representative results

are shown in Fig. 4.11 for a specimen that was prepared with the same compaction effort,

subjected to an isotropic confining stress of 75 KPa, and sheared at an axial strain rate of 0.5

%/min. Although the same compaction effort was applied to each specimen, their unit

weight differed due to their different composition. Specimen S-1 had a unit weight 11.8 KN/m3

prior to shearing. The upward curvature of stress-strain response is similar to the trend observed

results data compared with Bray et al (2009), this factor likely most contributes to most of the

scatter in the strength data reported in this study, so it should be considered. How-ever, the

shear strength of MSW materials tested in this study and by others for waste with constituents

that are larger than 20mm did not appear to vary significantly due to waste content when

consistently interpreted. Waste composition does greatly influence the shape of the stress-

strain response observed in TX testing with specimens with larger amounts of waste products,

such as plastic, and wood, having a greater tendency to exhibit upward response curvature

Figure 11 Response of MSW varying composition (modified from Bray et al. 2009)

5. STRESS PATH

To examine the effects of stress path on mobilized shear strength, a series of Triaxial unloading

tests were performed on reconstituted specimens of MSW from the Pandya Kheri, landfill near

by Ujjain city. The tests included isotropically unconsolidated undrained tests in which the

specimen was isotropically unconsolidated and then the vertical stress was reduced until failure

and then the horizontal stress was gradually reduced until failure. The stress- strain curve in

Triaxial shear compression test was hyperbolic in shape, with some tests exhibiting a slightly

reduction in mobilized shear stress beyond the peak stress for specimens S-1 and S-3, indicates

the shear stress and axial strain relationship as shown in figure 4.12



Figure 12 Stress-strain response in Triaxial test (modified from Bray et al. 2009)

6. UNIT WEIGHT EFFECTS

The initial (as compacted) MSW unit weight and the associated compaction effort also affect

the stress-strain response on MSW in the triaxial compression test. Specimen with lower

initial unit weight has a softer initial response and lower mobilized shear strengths at a specified

strain level. For example, two specimens with the same composition and total unit weights prior

to shearing of 11.8 and 12.8 KN/m3

, respectively, were tested. The denser specimen had secant

friction angles of 29 to 35 degree at 20 % axial strain (measured from the isotropic stress

state), respectively, whereas the looser specimen had a friction angle that was lower by 8 degree

at each strain level. The difference in the interpreted friction angle is smaller if measured from

an anisotropic initial stress state, but still the effect of the unit weight on the shear resistance

of the waste can be significant.

TXC strength envelope defined on the basis of mobilized shear stress at an axial strain of

20 % as shown in fig 4.13, 4.14 and 4.15. Waste composition is typically an important factor

in estimating MSW properties. Unit weight was also shown to be an important factor in this

study. Variations in unit weight of 5-20% could produce similar variations in the measured

shear strength of similarly prepared MSW of similar composition.

Figure 13 Mobilized shear strength in large-scale TXC (modified from Bray et al. 2009)



Figure 14 MSW mechanical behaviour (modified from Mehran et al. 2011)

Figure 15 Effect of the unit weight on the MSW (modified from Mehran et al. 2011)

7. SHEAR BEHAVIOUR OF MUNICIPAL SOLID WASTE

The shear strength envelopes from isotropically unconsolidated Triaxial compression tests on

MSW obtained from this study summarized below for various levels of axial strain. The

strength envelope corresponds to an axial strain of 20%. Fig 4.16 and 4.17 shows shear stress

versus normal stress relationships from isotropically unconsolidated undrained Triaxial

compression tests. The data and shear strength envelopes presented in fig. 4.14 show clearly

the stress-dependent nature of the Mohr-Coulomb strength envelope of the MSW.

To evaluate the effect of the fiber content on the MSW shear parameters, the results were

analysed using the Mohr-Coulomb criterion. Because of the strain hardening nature of MSW

the shear strength was calculated using a strain based failure criterion (20% of axial strain).

This study illustrates the shear strength envelopes for each fiber content and drainage condition



adopted in the experimental program. This study obtained results of MSW friction angle and

cohesion intercept for different levels of axial strain in undrained condition. It can be said that

the presented shear strength envelops are compared to other results reported in literature. In

spite of the different failure criteria adopted, one of the probable reasons for the relatively low

shear strength parameters is the waste composition of the samples used which presents high

organic and water contents. This study shows the results of unconsolidated undrained tests.

Figure 16 Strength envelope of MSW in TXC (modified from Stark et al. 2009)

Figure 17 MSW with different fiber contents (modified from Mehran et al. 2011)

8. CONCLUSIONS

The results obtained from the Triaxial laboratory test on the ten MSW samples collected from

the Pandya Kheri site, Ujjain, MP site. Shear strength characteristics of MSW material

collected from the Pandya Kheri site, Ujjain, MP site depends on many factors, such as waste

type, composition, and compaction, daily cover material, moisture conditions, leachate

management, age and overburden pressure and these factors influence the shear strength



properties in the design of embankment to retain the solid waste material. A comprehensive

large-scale laboratory testing program using Triaxial shear test was performed to develop

insights and a framework for interpreting the shear strength of MSW that is below its field

capacity. The results of this testing program emphasized the important issues of waste

composition and unit weight, fibrous particles orientation and stress path, shear strength

parameters, cohesion, degree of internal friction, shear behavior, strength envelop of MSW,.

The ten samples tests results from this study and other studies indicate that the static shear

strength of MSW for this shearing Coulomb strength criteria with: c=16 kPa, the triaxial

conservative strength envelope is intended for use in practice for stability analyses in absence

of site-specific testing. Other shearing modes that engage the fibrous materials within MSW

produce higher friction angles. Laboratory or in situ shear strength data should reflect the level

of shear displacement or axial strain that corresponds to the reported shear strength value

because MSW shear resistance usually increases with increasing displacement/strain. This

trend is more shear pronounced in Triaxial compression than direct shear testing results.

According to the obtained results, the mechanical response of MSW materials is rate dependent.

The samples showed a higher shear strength when they were sheared at higher loading rate in

UU tests. It is recommended that an axial strain 20% used in MSW shear testing to mobilize

a shear resistance that may be representative of the peak shear strength of MSW. The peak

shear strength of MSW is high as evident from at or vertical landfill slopes for a considerable

time. materials underlying the MSW, e.g. underlying geo-synthetics and native soils, unless a

weak, continuous layer of waste is present.

REFERENCES

[1] Bray, J.D., Zekkos, D., Jr. E.K, Athanasopoulos G.A, and Riemer M.F (2009). Shear

Strength of Municipal Solid Waste, Journal of Geotech. Geoenvirontal Eng., 709-722.

[2] Bureau of Indian Standards: IS 2720 (Part 12)-1981. Methods of Test for Soils.

[3] Reddy K. R., Hettiarachchi H., Janardhanan Gangathulasi, Jean E. Bogner. Geotechnical

properties of municipal solid waste at different phases of biodegradation, Waste

Management (2011), 2275-2286.

[4] Krishna R. Reddy, Hettiarachchi H., Parakalla N.S., Gangathulasi J, Geotechnical

properties of fresh municipal solid waste at Orchard Hills Landfill, USA, Waste

Management (2009) 952-959.

[5] Fard M.K., Machado S.L., Shariatmadari N., Noorzad A., A laboratory study on the MSW

mechanical behaviour in Triaxial apparatus, Waste Management (2011) 1807-1819.

[6] Manual on Municipal Solid Waste management (2000).

[7] Mathivanan Periasamy, Behavior of Tensile, Flexural and Interlaminar Shear Strength of

Microfilled Aluminium-Glass Fiber Reinforced Plastic Sandwich Panels, International

Journal of Mechanical Engineering and Technology, 7(6), 2016, pp. 604–608.

[8] V. Divya Sri, G. Senthil Kumar and S. Prakash Chandar, Experimental Study on the Shear

Strength of Recycled Aggregate Concrete. International Journal of Civil Engineering and

Technology, 8(4), 2017, pp. 185–192.

[9] R. Deby Linsha, Y. Preethy Dharanya, V. Vinodhini and C. Pavithra, Improvement of Shear

Strength of Soil Using Bitumen Emulsion. International Journal of Civil Engineering and

Technology, 7(6), 2016, pp.156 – 165.

[10] PART-1: Principles of Municipal Solid Waste Management.

[11] Stark T. D., Sarihan N.H. and Li G., (2009).Shear Strength of Municipal Solid Waste for

Stability Analyses, Journal of Geotech. Geoenvirontal Eng., 57:1911-1923.

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