Role of Clay Content and Liquid Limit in Assessing the Liquefaction Susceptibility of Fine Grained Soil

Role of Clay Content and Liquid Limit in Assessing the Liquefaction Susceptibility of Fine Grained Soil

Yagyesh Narayan Shrivastava1

1 Student ME Geotechnical Engineering, Department of Civil Engineering, Jabalpur Engineering College, Jabalpur.

1. K.Yadav2

   2Associate Professor, Department of Civil Engineering,

   Jabalpur Engineering College, Jabalpur.

   1. K. Dubey3

3Professor,

Department of Civil Engineering, Jabalpur Engineering College, Jabalpur.

Abstract – This paper puts light on the role of clay content and Liquid limit in regarding a sample of soil as liquefiable or Non-liquefiable. Liquefaction susceptibility of fine grained soil is one of the important thrust area in the world of Geotechnical Engineering. A lot of research has been done by a lot of researchers over the last 45 years on this vary topic, different researchers have used different approaches and criterions to determine the liquefaction susceptibility out of which Modified Chinese Criteria has been used in this study. This study has been undertaken in the city of Jabalpur, samples of soil have been collected from 20 locations at different depths and tested in the laboratory for Liquid limit, Plastic limit, Grain size distribution, DFS, NMC and calculation for Plasticity Index has also been done and liquefaction susceptibility of soils of various locations is determined through Modified Chinese Criteria given by Andrews & Martin in the year 2000.

INTRODUCTION

Liquefaction is an amazing phenomena in which soil flows like water, evolution of gases takes place. This has been observed that liquefaction occurs generally in association with an earthquake, its spatial impact can be felt widespread. Liquefaction is transformation of granular material from solid state into liquefied state with a significant increase in pore water pressure until effective stress reaches to zero. It is evident from the cases of liquefaction that a lot of destruction is caused due to this. So, this phenomena has become a matter of attraction for the researchers all over the world. The layers of liquefaction are getting unfolded day by day yet there is a lot of scope for further unfolding as complete understanding of the phenomena hasnt been achieved specially for the fine grained soil. Researchers have developed criterions to study liquefaction susceptibility of fine grained soil taking various parameters. This has been found that clay content and Liquid limit are the key parameters influencing the susceptibility of soil towards

liquefaction. Jabalpur is a fast developing city and multistory buildings are also emerging in the city now. On the other side, cases of liquefaction were also reported in the city during the earthquake of 22nd May, 1997. So, the knowledge about liquefaction susceptibility of the city is the need of time in view of these facts this study is undertaken.

LITERATURE REVIEW

Efforts of researchers are continued since last five decades in order to find liquefaction susceptibility of soil and factors responsible for this amazing phenomena.

In this line, kishida (1970) studied grain size distribution of boils ejected at Nanaeham Beach Japan during the 1968 earthquake at Tokachiki. He found that boils consisted of sandy silt with clay content less than 10% . Similarly Wang (1979) showed that 15% of clay content as a cut off to liquefaction of soil. Zhou (1981) conducted detailed study of liquefaction occurred during the Tangshan earthquake of 1976 in China. He conducted particle / grain size distribution analysis of soil of various layers and conducted that clay content must be less than 10%. Similar Studies were under taken by Tokimatsu & Yoshini (1983) and Tutten et al. (1990). Seed & Idriss(1982) took Wangs work as a basis and developed popular Chinese Criteria which states that a soil containing (a) less than 15% clay fraction (finer than 0.005 mm) (b) Liquid limit less than 35% and (c) Water content higher than 90% LL.

Later, Andrews & Martin (2000) modified the existing Chinese criteria and thus, modified Chinese criteria came into existence. Morto & Soon (2012) reviewed many approaches of assessing liquefaction susceptibility and considered modified Chinese Criteria acceptable globally and according to ASTM international.

MATERIALS & METHODS

Jabalpur city is taken as the area of this study.This city is located in the central part of Madhya Pradesh on the bank of river Narmada (2300957.8N &07905705.5 E) at an elevation of 411 meters.

Twenty locations as shown in Fig. 1 were selected randomly in the entire city for this study. Samples of soil were collected from different depths at each location. Analysis of the samples was undertaken at the Geotechnical laboratory of Jabalpur Engineering College for Liquid limit, Plastic limit, DFS, NMC and Grain size distribution as per the relevant I.S code of practice.

Fig. 1 Map showing the sampling stations

Table:-1 Description of sampling stations

(Source : Google Earth)

Liquefaction susceptibility of soils of the study area was ascertained on the basis of criteria suggested by Andrews& Martin (2000), popularly known as the Modified Chinese criteria given below in Table 2.

Table 2: Modified Chinese Criteria

Notes:

1. Liquid Limit determined by Casagrande-type percussion apparatus

2. Clay defined as grains finer than 0.002mm

Based on this criteria, each sample was classified as susceptible/Not susceptible & Further studies required.

RESULTS & DISCUSSIONS

In order to determine liquefaction susceptibility of the soil of Jabalpur city sampling was done at twenty various locations. Liquid limit, Plastic limit, Particle size distribution, DFS & NMC were determined using the relevant code of practice in the departmental laboratory taking Modified Chinese Criteria as the deciding criteria. Susceptibility to liquefaction of the soil of study area is ascertained and presented in Table 3.

Table:-3 Liquefaction susceptibility of the soil at the selected stations & depths.

It is clear from Table- 3 that soils of Amkhera at 3m depth and Science College & Bargi Hills at 2m depth are found to be susceptible to liquefaction. Soils at Victoria & Bargi Hills at 3m depth are recommended for further studies.

Kalimath remains the only location where soil at 2m as well as at 3m are recommended for further studies.

CONCLUSION/p>

Large area of Jabalpur city is not susceptible to liquefaction. The samples collected from the areas of Amkhera at 3m and Science college & Bargi Hills at 2m depth showed susceptibility to Liquefaction.

REFERENCES

1. Kishida, H. (1970). Characteristics of Liquefaction of Level Sandy Ground During the Tokachioki Earthquake. Soils And Foundations, Vol. 10, No. 2, Pp 103-111.

2. Wang.W (1979). Some Findings in Soil Liquefaction, Report Water Conservancy and Hydro-electric Power Scientific Research Institute, Beijing, China, pp 1-17.

3. Zhou, S. G. (1981). Influence of Fines on Evaluating Liquefaction of Sand by CPT. Proceeding: International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, Vol. 2, pp 167-172

4. Seed H.B, and Idriss I. M:(1982). Ground Motions and Soil Liquefaction during Earthquakes Earthquake Engineering Research Institute Monograph, Oakland, California.

5. Tokimatsu. K. and Yoshimi, Y. (1983). Empirical Correlation of Soil Liquefaction Based on SPT N-Values andFines Content. Soils and Foundations, Vol. 23, No. 4, pp 56-74.

6. Tuttle, M., Law, K. T., Seeber, L. and Jacob, K. (1990). Liquefaction and Ground Failure Induced by the 1988 Saguenay, Quebec, Earthquake. Can. Geotech. J. 27, pp 580-589.

7. Andrews. D.C.A., and Martin G.R. (2000). Criteria for Liquefaction of Silty Soils, Proc. 12th WCEE, Auckland, New Zealand

8. Marto A. and Soon T.C. (2012) Short Review on Liquefaction Susceptibility , International Journal of Engineering Research and Application, Vol. 2 Issue 3, May-June 2012, pp. 2115-2119.