9-IJAEST-Vol-No.4-Issue-No.2-CORRELATION-BETWEEN-VERTICAL-ELECTRIC-SOUNDING-AND-CONVENTIONAL-METHODS by ISERP ISERP

RAJIV KHATRI, et al. / (IJAEST) INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING SCIENCES AND TECHNOLOGIES Vol No. 4, Issue No. 2, 042 - 053

“CORRELATION BETWEEN VERTICAL ELECTRIC SOUNDING AND CONVENTIONAL METHODS OF GEOTECHNICAL SITE INVESTIGATION” RAJIV KHATRI

V.K.SHRIVASTAVA

Life Member Indian Society for Earthquake Technology, IIT Roorkey,AMIE (I), Member IGS Jabalpur Chapter,Jabalpur Professor & Head Department of Civil Engineering, Hitkarini College of Engineering & Technology,Dumna Airport Road, Jabalpur,M.P. Pin 482001; Email-khatri_rajiv1@yahoo.co.in;

Geo-technologist, Chairman IGS Jabalpur Chapter, Professor (Retired) Government Engineering College Jabalpur M.P. Email - Prof_vinay@yahoo.co.in

DR. RAJEEV CHANDAK

Professor, CE Deptt., Jabalpur College of Engineering, Jabalpur,M.P.;. Email- rajeevchandak2003@yahoo.com

The geomaterials are the natural materials and have very complex structure. According to Terzaghi also –

ABSTRACT :-

Geotechnical site investigation is one of the important part of design of any Civil Engineering construction project. A large number of field investigation methods, are available, for detailed field investigations for, civil engineering construction purposes. These conventional methods is, in general, give results based on empirical interpretation of test data. These conventional methods, suffer from limitations of their application to difficult terrains, steep hill slopes, marshy and swampy areas, coastal regions and areas where a frequent variation of soil and rock materials exist in the areas to be investigated. As such a strong need is being felt to develop and put in practice the Geo-physical methods of sub-surface investigation for a more precise and fast assessment of large area characteristics, economically, for all areas and particularly where conventional methods cannot be used. These Geo-physical methods require proper interpretation of data which in turn needs a high degree of experience and expertise for making the interpretation. With the availability of computer aided interpreting software, the interpretation of the geo-physical methods data can also be done easily. Now that, we have entered into a phase, where large and big sized structures are required to be built in weak and difficult and sensitive areas, we have to take recourse to the Geo-physical methods and develop them into a popular tool for the enhancement and benefit of the civil engineering activities which require better and more information of every inch of the area. In this respect there is a great need to correlate the results of Vertical Electric Sounding method with that of conventional test results, particularly Standard Penetration Test results. The paper proposes to assign special property indii (SPI) for the soils for their proper classification based on VES data so as to have proper understanding of the behavior under in-situ conditions and thus to have correlation with results of other conventional methods. The paper also proposes to highlight the effectiveness of Vertical Electrical Sounding technique for geo-technical site investigation. Key Words : Vertical Electric Sounding (VES), Vertical Electric Coring (VEC), Standard Penetration Test (SPT), Cone Penetration Test (CPT), Special Property Index (SPI)

“Unfortunately, soils are made by nature and not by man, and the products of nature are always complex.” Karl von Terzaghi, 1936

The fundamental behavior of the geomaterials depends on their permeability, compressibility and shear strength characteristics. Both in-situ and laboratory test were employed for obtaining these properties. The accuracy of the results obtained from the laboratory tests to represent the field behavior is highly depends on the quality of sample and the sampling technique applied. Obtaining reasonably good undisturbed sample from the materials like clean cohesionless sands, residual soils, glacial tills and soft or heavily jointed rock masses is quite challenging. In such a scenario the engineering properties of these materials can be obtained using in-situ methods. Compared to traditional drilling, sampling and laboratory testing procedures, in-situ testing has several important benefits like – in-situ tests are performed in the natural condition of moisture and stress with minimum disturbance and on large volume of soil. They are also generally quicker and cost effective relative to the quality and quantity of data acquired.

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The conventional laboratory and in-situ tests are often time consuming, cost intensive, require sophisticated equipments and skilled personal in the field and lab as well as for the interpretation. Majority of times, planners and engineers are interested only in sufficiently accurate estimate of different engineering properties of geomaterials with or without conducting the expensive experiments. In view of the above facts number of correlations has been developed to estimate the engineering properties of different geomaterials from their index properties. 3. CONVENTIONAL METHODS FOR TECHNICAL SITE INVESTIGATION :-

1. PREAMBLE :-

“Engineers have a significant role in planning, designing, building and maintaining a sustainable future. We provide the bridge between science and society, in this role; we must participate in interdisciplinary teams, applying technology to issues and challenges that require environmentally sustainable strategies and solutions.” American Society of Civil Engineers (2001).

Various field methods are prescribed in the Codes of Practice which are conventionally adopted in different types of terrains. These common methods are – 1. 2. 3. 4.

2. INTRODUCTION :-

5. 6. 7.

Site investigation is the process by which geological, geotechnical, and other relevant information which might affect the construction or performance of a civil engineering or building project is acquired.

Plate Load Test, Standard Penetration Test, Cone Penetration Test, Auguring, drilling and collection of cores of soils & rocks, & testing in Lab Pressure Meter Test, Permeability Test, Dilatometer Test etc.

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GEO-

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arrival of the shock waves at recording stations arranged in many patterns equidistant from the centre. This is done to investigate continuity of geomaterials and (or) presence of cavities, channels and holes along the path of the seismic waves arriving at some of the receiving stations. Reflective and refractive shooting, reciprocal shooting are some of the variations that can be used during investigations. Generation of shear waves in soil strata for ascertaining their liquefaction vulnerability is also done through the seismic methods. The system works mostly on exactly identifying and locating the anomalies.

All these methods belong to the category of destructive or semi-destructive testing tools. Table (1) gives the relative merits of these methods. 4. GEOPHYSICAL METHODS FOR TECHNICAL SITE INVESTIGATIONS :-

GEO-

There has been a steady growth in the application of geophysical techniques to geo-civil, geo-earthquake engineering and geo-environmental engineering studies. Geophysical methods have proven useful as rapid means of obtaining subsurface information on a continuous profiling basis, over large areas. They are generally non-destructive in nature and can be carried out from the ground or water surface, and / or from within boreholes. Geophysical methods rely on a significant contrast in physical properties such as density, resistivity or electrical conductivity, magnetic susceptibility and velocity of shock waves being present in the subsurface materials under investigation..

In gravity measurements, a simple gravimeter is used to find out the value of „g‟ at any place corresponding to any theoretically obtained value of „g‟ for that area. During actual ground measurements +ve & -ve departure values can be obtained and on a regular grid pattern these +ve and –ve anomalies are plotted similar to the plotting of contours and the interpretation regarding presence of excessive or deficient mass distribution below the ground surface can be found leading to identifying the buried structures like domes, folds, faults and paleo channels etc. accurately.

Geophysical techniques offer the chance to overcome some of the problems inherent in more conventional ground investigation techniques. Many methods exist with the potential of providing profiles and sections, so that (for example) the ground between boreholes can be checked to see whether ground conditions at the boreholes are representative of those elsewhere. Geophysical techniques also exist which can be of help in locating cavities, backfilled mineshafts, and dissolution features in carbonate rocks, and there are other techniques which can be extremely useful in determining the stiffness properties of the ground.

5. GEOPHYSICAL INSTRUMENTATION METHOD FOR SUB-SURFACE EVALUATION :Since the construction activity has now been taken to all types of ground locations and conditions, these destructive conventional tools no longer serve the purpose. Geophysical instrumentation is gradually being preferred as a viable and more versatile tool which can provide all important information of these subsurface areas up to any depth, as an alternative to the destructive methods and tools.

Geophysics plays a vital role between geologic interpretation of ground and its structure and geotechnical & other relevant field information vitally required for the construction or performance of Civil Engineering projects. As geophysical methods are non-destructive in-situ field exploration methods & from the array of methods available any one method or a combination of methods can be chosen to get a proper and fuller information from the subsurface up to any desired depths. Various problematic conditions might exist below the ground such as discontinuities of strata, cavities, mine shafts, solution channels, buried channels and back filled parts of earlier use of land like mining etc. Geophysical methods are also very useful under such conditions. Geophysical techniques are relatively cheap, and are also highly regarded in such a speculative environment.

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An electrical measurement through Geophysical Instrumentation is a non-destructive or non-invasive methodology which is capable of being used in any type of terrain / topographic conditions and it has, practically, no limitations. The instrument used are handy and can be carried any where. The instrumentation can be done in much smaller time frame as compared to any of the destructive equipments; it is economical, dependable and is repeatable. In the Middle Amur sedimentary basin (MASB) Vertical Electrical Sounding method has been used for discovery of lacustrine sediments in the southwestern and eastern parts of the MASB. The Correlation of seismic and drilling data confirmed the correctness of the interpretations and showed that boreholes penetrated a thin sequence of deep-water lacustrine sediments.

Common geophysical methods employed for geotechnical site investigation can be classified as – 1. Electrical Methods 2. Seismic Methods 3. Gravity Methods

Vertical Electrical Sounding Method has also been used in the city of Burdur in southwestern part of Turkey for determining the settlement properties of the soil and for defining the zones vulnerable for liquefaction in the city. The VES data has also provided very useful information on vertical and horizontal extends of geologic units and water content in the subsurface.

Electrical methods consists of measurements of resistivity / conductivity measurements, locating water table positions, measurement of self potential along ground profile for generating pseudo sections and for electrical logging of bores and wells and for measuring telluric currents.

6. CORRELATION BETWEEN VERTICAL ELECTRIC SOUNDING DATA AND CONVENTIONAL METHODS OF GEOTECHNICAL SITE INVESTIGATION :-

Seismic methods consists of generating artificial shock waves in the ground at any depth and measuring the time of

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Among the emerging trends of field investigation methods used for geotechnical site investigation in Civil Engineering practices Vertical Electric Sounding (VES) is finding a vide acceptance due to its versatility of the method as also the comparable results obtained through this method and the other conventional field methods like SPT etc. As Vertical Electric Sounding method for geotechnical site investigations is becoming popular, an attempt is made to correlate these data with that of conventional geotechnical site investigations data. One case study is presented here o illustrate this.

Geology of the Area :-

The land belonging to the AKVN, Jabalpur where HPCL plant was to be constructed forms a raised plateau in the basaltic terrain which has been formed due to multiple lava flows cutting across the Lameta sedimentary formation, overriding them up to a thickness of approximately 400 ft. or more. The top layer has been weathered over a period of time and formed brownish and black top soil varying in thickness from 1 m to 2 m. Below the soil cover exist a layer of weathered rock consisting of rounded detached boulders in a matrix of soil. This is followed downwards by massive continuous bed rock of basalt at a depth of about 5 to 6 m below the ground surface.

7. CASE HISTORY :-

The area is occupied by Basaltic rocks which are capped by soil cover and at nowhere the rock out crop is visible. The thickness of the soil cover is variable from place to place and lot numbers of sink holes are present which indicate heavy water infiltration from the top soil to the weathered rock below. The sink – holes have interconnection at a depth of about 1 m.

In order to illustrate the effectiveness of the method case history of one of the investigation sites are is being presented here.

Case History – Geotechnical Site investigation for the LPG Filling Plant, Maneri, Niwas Road, Mandla (M.P.) of Hindustan Petroleum Corporation Limited, Mumbai, had been carried out at the premises of A.K.V.N. at Maneri Village Niwas Road, Distt. Mandla (M.P.). The work included geotechnical explorations covering the following aspects :(i) Geotechnical Investigations :- Which included the tests for bearing capacity of soil, drilling for core – logging up to 10 m depth, tests for index properties of soil etc. (ii) Geological Investigations : which include the electrical resistivity logging location of ground water tube well, soil profiling etc. (iii) Chemical tests for soil and water . (iv) Interpretations of collected data.

The drilling plan consisted of drilling four boreholes at the central part of the area and the remaining six bore holes to be drilled elsewhere within the area. The location of these bore holes has been clearly marked in Map (1). In order to bring in the VES methodology for the purpose of direct correlation, five VES cross sections were preferred. These have also been marked in the reference Map (1). The first cross section was chosen to be in the close proximity of bore holes No. 7, 8, 9 and 10 for the initial calibration of the electrical resistance values of various geomaterials present in this part. The Calibration VES log, which has been generated from the electrical apparent resistivity data, is given in Fig (3) and the corresponding actual bore log for the bores 7, 8, 9 and 10 near its vicinity is given in Fig (2). A close observation of these two would reveal the fact. Further four other VES cross sections were subsequently selected and VES logs were prepared from the electrical resistivity data obtained at those locations. Their logs are also given in fig (3).

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For the purpose of correlation between the values obtained through VES method and those obtained with conventional methods supported by laboratory test results, it was decided to run parallel test at Maneri (the industrial township of AKVN, M.P. Jabalpur where a LPG bottling plant had to be built on a land area of approximately 37.5 acres. The author was the part of this investigation team of GEC, Jabalpur and had done the VEC work for the investigation.

From the calibration the Special property indii range has been prepared to indicate the identity of different geomaterials arranged in the depth. The values are given in the Table.

For conducting the conventional tests it was planned to have 10 number of bore holes drilled in the area, to collect soil samples, to conduct SPT during drilling of bore holes at an interval of 1.5 m and to arrange the core so that actual bore log could be obtained at all the 10 drilling locations. Calyx method of core drilling was preferred up to the depth of hard rock (approximately 4 to 5 m below ground level). Certain test were also proposed to be conducted on the rock cores in the laboratory such as crushing strength test, RQD and other routine tests like density, water absorption etc.

SPT were conducted and the values of N obtained, (corrected N) have been used to indicate the Safe Bearing Capacity and compressive strength values respectively for soils, decomposed rock or fresh rocks materials. Values close to the N values have also been obtained from the computations of the true resistivity value for different strata as obtained in the VES test and it has been found that they are more or less in the same range. Soil Tests

Since the area under the investigation was very large and testing was to be conducted in the entire area, there were constraints of time and funds. At this juncture it was decided to conduct geophysical tests for supplementing and for corroborating the results and specifically for the opportunity for establishing a correlation between the findings of the conventional methods and VES method.

As the basaltic rock up to the drilled depth is traversed by multiple joints, the core recovery was poor. Besides the Calyx drilling was not helpful in obtaining proper core under the same conditions through double or triple split core barrel diamond drilling methods. As such RQD was neither possible nor desired as per the specifications.

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have been assigned to such geomaterials as shown in the table below –

The soil profile has been presented on the basis of VEC method, covering the entire area and representing the top soil layer according to its thickness in terms of thickness contours, as shown in the drawing No. (2) having contour interval of 0.5 m. The thickness of the layer of weathering has also been represented as profile of weathering on this drawing. The allowable bearing capacity values has been obtained for soils, weathered rock and fresh rock at various levels. As there is uniformity in the material present at different depths, this soil profile and the bearing capacity data, as given in Table (4) can be used as ready reckoner to find the safe bearing capacity at any point. Interpretation of Resistivity Data In resistivity instrumentation normally the field data is obtained in the form of apparent resistivity values. The interpretation of vertical electrical soundings data basically involves converting / transforming apparent electrical resistivity values recorded at different current penetration depths (electrode separations, a) into true resistivity and thicknesses of various subsurface strata through which the electric current passes. The true electrical resistivity (ρ) is fundamental property of the material, which is independent of volume and remains constant for the isotropic and homogeneous material. For an-isotropic, non-homogeneous and stratified/layered subsurface materials the resistivity does not remain constant throughout the depth of such deposit. The effective resistivity value measured for layered deposit is referred as mean or apparent resistivity (ρa). The apparent resistivity is a function of true resistivities and thicknesses of various subsurface strata through which current flows Interpretation for various information can be obtained from this data provided a thorough knowledge of the local geologic conditions and stratigraphic setup is known to the investigator. For more precise field data required for engineering characteristics of the geomaterials true resistivity values have to be obtained from the apparent resistivity values using various empirical relationships available.

SN 1

SPI 0-4

4 to 5

3 4 5

5 to 6.28 6.25 to 7.53 7.53 to 8.24

8.24 to 9.42

9.42 to 11.30

11.30 to 12.56

12.56 to 15.00

10 11

15.00 to 25.00 > 25

Description Clear sand / Gravel / Sand soil with more than 60% of sand, showing saturated condition Sandy-silty clayey soil 40-50%, Saturated Clayey Soil, Saturated Black Cotton Soil, Saturated Compact Clayey Soil / Stiff Clay, Saturated Detached Boulders / Highly saturated permeable zone Detached Boulders / Highly saturated permeable zone Partly saturated compact impervious clayey soil Transition zone between soil and weathered rock, partly saturated Weathered Rock Rocks

Factor of safety taken in the case of conventional methods and that taken for the VES values was 2 for the soils and 6 for the rock materials.

8. INTERPRETATION :-

During the Vertical Electrical Sounding the data obtained for each 1.0m thick layer represented the apparent resistivity values for all subsequent layers except the top 1.0 m layer. The values had to be converted into true resistivity values for each layer and also from the values the identity of the geotechnical character of the material was also interpreted and is given in the log.

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For generating safe compressive strength values for the layer, the true resistivity values were processed considering the confinement conditions of the layer and with the help of the suitable multiplication factor, the values for ultimate compressive strength for the layer were computed and safe compressive strength values were obtained using a factor of safety of 5 or 6. On the basis of the generalized VES log it is inferred that the top soil cover is very thin and is underlain by layers of pebbles and boulders of variable thickness which merges imperceptibly into thick layer of boulders and ledges resting on thick slabs of basalt. With this type of arrangement and the data analysis from the laboratory test sufficient information regarding the type of foundation which can be provided to any structure being planned on such terrains and of course the foundation depth of the structure can also be decided depending upon the details of the structure.

Whether true or apparent resistivity values for qualitative interpretation of the data, the apparent resistivity values have been found to be adequate e.g. distinction between soil (different stratifications) and bed rock position or even for distinguishing different major soil strata within the soil formation can also be distinguished. Thickness of backfill over the natural ground surface can be determined along with the profile of such backfill over the natural ground surface. Similarly, weathered rock zones sandwiched between the soil overburden and the bed rock, in the case of soil formed in-situ as undisturbed residual soils is also accurately possible to be determined.

9. CONCLUSION :From the above study of the terrain and instrumentation it is clear that Vertical Electrical Sounding data if carefully obtained, processed and interpreted in the light of the terrain characteristics, it is possible to generate numerical values for safe bearing capacity or safe compressive strength, as the case

Through the intensive resistivity survey in different areas and in different geologic & meteorological conditions it has been found that different geomaterials invariably always identify themselves by certain numerical values obtained as apparent resistivity values. Special Property Indices (SPI)

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may be, without using the conventional field equipments and the laboratory support needed by such equipments. This also is evidently clear that such terrains are not friendly to the use of conventional tools and methods, yet the terrain has to be characterized for the engineering behaviour of the materials present.

Yadav, G.S., Dasgupta, A.S., Sinha, R., Lal, T., Srivastava, K.M., Singh, S.K. (2010), “Shallow sub-surface stratigraphy of interfluves inferred from vertical electric soundings in western Ganga plains, India”, Quaternary International k) Khalil, M.A., Hafez, M.A., Santos, F.M., Ramalho, E.C., Mesbah, H.S.A., El-Qady, G.M. (2010), “An approach to estimate porosity and groundwater salinity by combined application of GPR and VES: A case study in the Nubian sandstone aquifer”, Near Surface Geophysics 8 (3), pp. 223-233 l) Kate Dr. J.M. IITD (1984) “Comparison of True Resistivity Values with SPT Generated N Values”, International Seminar, Tokyo, Japan, 1984. m) Shrivastava V.K. and Khare D.K. (1999) “Umar Aqueduct :Success Story of a Geotechnically Difficult and Forbidden Project.” IGS and ISSMFE 1999 – International Seminar held at Seoul, Korea n) Shrivastava V.K. and Khare D.K. (2000) “Difficulties in Assessing the Bearing Capacity of Soils.” IGC 2000 Millennium Seminar held at IIT Mumbai, o) Shrivastava V.K. (2002) “Use of Electrical Resistivity in Geotechnical Explorations.” National Seminar on Recent Trends in Civil Engineering at MBM Engineering College, JNV University, Jodhpur, 2002. p) Mościcki, W.J., Sokołowski, T. (2010), “Electric resistivity and compactness of sediments in the vicinity of boreholes drilled in the years 2007-2008 in the area of Starunia palaeontological site (Carpathian region, Ukraine)”, Annales Societatis Geologorum Poloniae 79 (3), pp. 343355 q) C. Subbarao, and N. V. Subbarao, “Delineation of effluent contaminated zones by electrical surveys at two industrial sites in Visakhapatnam, India” (1994), Environmental Geology, Volume 24, Number 4 / December, 1994, 281286 r) Coduto, D.P. (2001) . Foundation Design- Principles and Practices (Second Edition), Pearson Educational International , New Jersey. s) Clayton, C.R.I. (1990). “SPT Energy Transmission : Theory, Measurement and Significance”, Ground Engineering, Vol. 23, No. 10, pp. 35-43 t) Kulhawy F.H. and Mayne, P.W. (1990). Manual on Estimating Soil Properties for Foundation design , Report No. EL-6800, Electric Power Research, Palo Alto,CA. u) Liao , S.S.C. and Whitman, R.V. (1985). Overburden correction factors for SPT in sand”, Jl. Of Geotechnical Engineering, ASCE, Vol. 112, No. 3, pp. 373-377.

REFERENCE :a)

b) c)

Seed, H. Bolton, Tokimastu, K., Harder, L.F., and Chung R.M. (1985) “Influence Of SPT Procedures in Soil Liquefaction Resistance Evaluations”, ASCE Jl. Of Geotechnical Engineering, Vol. 111, No. 12,pp. 14251445. Skemption, A.W. (1986). “ Standard Penetration Test Procedures and the Wroth, C.P. and Wood , D.M. (1978), “The Correlation Of Index Properties with some Basic Engineering Properties Of Soils”, Canadian Geotechnical Journal , Vol. 15 (2), pp.137-145. Kate J.M. & Shamsher F.H. (2007) “Electrical Resistivity Behavior of Layered Soil System”, Indian Geotechnical Journal 37(4), 2007, 321-339. Khatri Rajiv, Shrivastava V.K. & Chandak Dr. Rajeev, (2011), “Geophysical - Vertical Electrical Sounding Method In The Evaluation Of Difficult Terrains”, (IJAEST) International Journal Of Advanced Engineering Sciences And Technologies Vol No. 3, Issue No. 2, 138 - 141 M.Desai (India) (1994), “Geophysical Instrumentation for Engineering Field Tests”. Proceedings of the XII International Conference on Soil Mechanics and Foundation Engineering, Vol.6, page 103 RJ Whitley Australia (1994), Proceedings of the XII International Conference on Soil Mechanics and Foundation Engineering, Vol. 5 page 195 Y Iwaskai, Japan (1994), Proceedings of the XII International Conference on Soil Mechanics and Foundation Engineering,Vol.5, page 199 A.K. Dhawan (1994), “Geophysical Investigation of Tehri Dam”, Proceedings of the XII International Conference on Soil Mechanics and Foundation Engineering, Vol.4, page 1345.

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10.

From the above comparative parallel studies it becomes evidently clear that the logs prepared using VEC data are identical with the actual Bore Logs. Similarly the compressive strength values for rocks and safe bearing capacity values for soil materials are found to lie within the close range of values as obtained through the Conventional Methods and Laboratory tests, thereby indicating that the Vertical Electric Coring data is a suitable and dependable replacement for the field data obtained through a cumbersome, costly and time consuming process involving large number of equipments and manpower. It may even be claimed that the applicability of Geophysical Electrical Instrumentation is unrestricted for any type of geological terrain having any geomaterial and for any topographic conditions where most of the conventional methods, probably, can not be moved in field for the investigations.

h) i)

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DRAWING (1) – REFERENCE MAP FOR RESISTIVITY SURVEY OF MANERI

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DRAWING (2) – CONTOUR MAP SHOWING SOIL PROFILE AT MANERI SITE

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TABLE (1) – COMPARITIVE MERITS OF VARIOUS METHODS OF GEOTECHNICAL SITE INVESTIGATION

Equipment Availability & Use in Practice Potential for Future Development

CPT

Pressure meter

Simple; Rugged

Complex

Dilatometer Complex; Moderately Rugged Easy

Simple; Rugged

Complex; Rugged

Complex; Delicate

Easy

Point

Continuous

Point

Continuous

Empirical; Theory

Difficult to locate; used on special projects

Empirical; Theory All except gravels Difficult to locate; used on special projects

Empirical; Theory

All except gravels Universally Available; used routinely

Empirical; Theory All except gravels Generally Available; used routinely

Universally Available; used routinely

Limited

Great

Unlimited

Empirical

All

VEC

Easy

All

Suitable Soils

SPT

Description Simplicity & Durability of Apparatus Ease of Testing Continuous Profile or Point Value Basis for Interpretation

TABLE (2) LABORATORY TEST RESULTS AS PER CONVENTIONAL METHODS SN

BH -1 BH -2 BH -3 BH -4 BH -5 BH -6 BH -7 BH -8 BH -9 BH - 10

3 4 5 6 7 8 9

Soil Classification

Specific Gravity

Liquid Limit

Plastic Limit

Plasticity Index

Shrinkage Limit

Shrinkage Ratio

2.25

2.10

***

2.00

***

2.10

***

2.27

2.10

6.03% 5.66%

88.31%

2.35

2.10

3.91% 5.93%

90.16%

2.56

2.10

3.59% 6.49%

89.92%

***

2.10

2.28

1.90

***

2.00

2.24

2.10

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Bore Hole No.

% Gravel

% Sand

3.08% 2.78%

***

4.09% 2.17% ***

***

5.24% 5.92%

% Fine <75µ

94.14%

*** 93.74% *** 88.84%

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TABLE (3) ALLOWABLE BEARING CAPACITY AT VARIOUS DEPTHS AS PER SPT VALUES (AS PER CONVENTIONAL METHODS) SPT RESULT SN

Bore Hole No.

1 2

Depth

BH - 1

1.50 m

110 kN/sqm

BH - 2

2.00 m

500 kN/sqm

1.50 m

250 kN/sqm

3.20 m

500 kN/sqm

4.50 m

750 kN/sqm

2.00 m

110 kN/sqm

1.50 m

290 kN/sqm

2.70 m

1.50 m

3.30 m

1.80 m

130 kN/sqm

3.00 m

800 kN/sqm

1.60 m

170 kN/sqm

2.10 m

600 kN/sqm

1.60 m

200 kN/sqm

2.60 m

900 kN/sqm

240 kN/sqm

3.30 m R R = Refusal

900 kN/sqm

BH - 3 BH - 4

BH - 5

BH - 6

BH - 7

BH - 8

BH - 9

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1600 kN/sqm 200 kN/sqm 800 kN/sqm

Allowable Bearing Capacity

Corrected N-Value

BH - 10

1.60 m

TABLE (4) ALLOWABLE BEARING CAPACITY AT VARIOUS DEPTHS AS PER VERTICAL ELECTRIC SOUNDING VALUES (AS PER VEC METHOD) SN

Depth

Allowable Bearing Capacity

Material

1.00 m

120 kN/sqm

Soil

2.00 m

250 kN/sqm

Soil

3.00 m

550 kN/sqm

Soil - WR Interface

4.00 m

660 kN/sqm

5.00 m

1200 kN/sqm

6.00 m & more

1500 kN/sqm

Rock

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FIG (1) LABORATORY TEST RESULTS – PARTICLE SIZE DISTRIBUTION - AS PER CONVENTIONAL METHODS Particle Size Distribution Curve BORE HOLE - 1, HPCL Maneri

100% 90% 70% 60% 50% 40%

30%

% Finer ---->

80%

20% 10%

0.010

0.100 1.000 Particle Size (mm) ---->

0.001

0% 10.000

Particle Size Distribution Curve

0.001

0.010

100% 90% 80% 70% 60% 50% 40% 30%

% Finer ---->

IJ A

BORE HOLE - 4, HPCL Maneri

20% 10%

0.100 1.000 Particle Size (mm) ---->

0% 10.000

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RAJIV KHATRI, et al. / (IJAEST) INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING SCIENCES AND TECHNOLOGIES Vol No. 4, Issue No. 2, 042 - 053

Particle Size Distribution Curve BORE HOLE - 5, HPCL Maneri

100% 90% 70% 60% 50% 40% 30%

% Finer ---->

80%

20% 10%

0.010

0.100 1.000 Particle Size (mm) ---->

0.001

0% 10.000

Particle Size Distribution Curve

0.001

0.010

100% 90% 80% 70% 60% 50% 40% 30%

% Finer ---->

IJ A

BORE HOLE - 6, HPCL Maneri

20% 10%

0.100 1.000 Particle Size (mm) ---->

0% 10.000

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RAJIV KHATRI, et al. / (IJAEST) INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING SCIENCES AND TECHNOLOGIES Vol No. 4, Issue No. 2, 042 - 053

Particle Size Distribution Curve BORE HOLE - 8, HPCL Maneri

100% 90% 70% 60% 50% 40% 30%

% Finer ---->

80%

20% 10%

0.010

0.100 1.000 Particle Size (mm) ---->

0.001

0% 10.000

Particle Size Distribution Curve

0.001

0.010

100% 90% 80% 70% 60% 50% 40% 30%

% Finer ---->

IJ A

BORE HOLE - 10, HPCL Maneri

20% 10%

0.100 1.000 Particle Size (mm) ---->

0% 10.000

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RAJIV KHATRI, et al. / (IJAEST) INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING SCIENCES AND TECHNOLOGIES Vol No. 4, Issue No. 2, 042 - 053

FIG (2) BORE LOG DETAILS AS PER CONVENTIONAL METHODS

IJ A

FIG (3) BORE LOG DETAILS AS PER VES (VEC) METHOD

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