50 C 17 19 DECEMBER 2015, Pune, Maharashtra, India Venue ...igs/ldh/files/igc 2015 pune... · pull out capacity of screw pile due to ineffective electric field in the soil mass available

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INDIAN GEOTECHNICAL CONFERENCE

17th – 19th DECEMBER 2015, Pune, Maharashtra, India

Venue: College of Engineering (Estd. 1854), Pune, India

STUDY OF ELECTRO KINETIC STRENGTHENING OF CLAY ADJACENT TO

SCREW PILE TO IMPROVE ITS LOAD CAPACITY

T. V. Visanth1, V.P. Reethi2

ABSTRACT

Screw pile foundation system consists of helix plate shaped steel bearing plate attached to the central

shaft, which have been used for construction purpose over 150 years. It can be used to resist both uplift

and compression loads. The central shaft provides resistance to axial load via skin friction and transfers

axial load to the helix plates while the helix plates serve as individual bearing elements to support a load.

Screw piles are becoming a more common structural foundation in everyday construction sites, but really

shine where there are problems in terms of poor foundation material or remote locations with limited

access. They are extensively used in the construction of transmission tower foundations, pipe lines and

braced excavations. Since their applications take the advantage of its pullout capacity, various

investigations have done on the same, which have shown that the load capacity of screw pile depends on

the shear strength of soil surrounded. Here, the objective of project is to investigate the potential of

electro kinetic treatment through screw pile to stabilize the clayey soil surrounded and to increase its pull

out capacity. The use of electro kinetic treatment is a new methodology as a viable in situ soil remediation

and treatment method. The principles of electro kinetic treatment method involve applying a low direct

current or a low potential gradient to electrodes inserted in the low permeable soils that cannot readily

drained. Complex mechanisms in electro kinetics such as electro osmosis, electro migration and

electrophoresis cause the transportation of charged species across the soil. Electro kinetic phenomenon is

an emerging process delivers the cationic stabilizing agents to the soil particles by introducing them at the

appropriate electrode for stabilizing the soils having low shear strength, high compressibility and low

bearing capacity.

In this experimental study, electro kinetic process was carried out in a steel tank covered inside by

glass plate in order not to affect the electro kinetic process. The test tank size was 40cm x 70cm x 50cm,

1T.V.Visanth, Civ il Engineering, P.G.Student, Thrissur, Kerala , [email protected]

2V.P.Reethi, Civil Engineering, Asst.Professor, Thrissur, Kerala, [email protected]

T.V.Visanth &V.P. Reethi

in which clayey soil was filled by 73% water content and 1.8 g/cc bulk density in order to simulate the

site conditions. A screw pile was fabricated as 30mm dia. helix plate welded to 10mm dia. central shaft,

which was screwed in to the soil. Electro kinetic treatment was carried out through screw piles by adding

potassium hydroxide stabilizer through oppositely charged electrode using 30V capacity D.C. supply

along with ammeter. Pull out tests were carried out with the pulley arrangement of steel tank. The tests

were conducted by varying the parameters such as voltage gradient of DC supply and spacing of

electrodes. The effect of electro kinetic treatment was evaluated by comparing the results of the pull out

and vane shear tests performed on the untreated and treated soil. The experiments result that increase in

voltage gradient causes increase in ion transfer flow which will strengthen the soil around the screw pile

and improve the pull out capacity. The increase in spacing of electrodes decreases the improvement in the

pull out capacity of screw pile due to ineffective electric field in the soil mass available between

electrodes.

Keywords: Electro kinetics, Electro osmosis, Electro chemical stabilization, Screw piles

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STUDY OF ELECTROKINETIC STRENGTHENING OF CLAY ADJUSCENT TO SCREW PILE TO IMPROVE ITS LOAD CAPACITY

Author 1 T.V.Visanth, P.G. student, IES College of Engineering, Thrissur, [email protected]

Author 2 V.P. Reethi, Asst.Professor, IES College of Engineering, Thrissur, [email protected]

ABSTRACT: Screw pile foundation system consists of helix plate shaped steel bearing plate attached to the central shaft, which are becoming a more common structural foundation in everyday construction sites, but really shine where there are problems in terms of poor foundation material or remote locations with limited access. Here, the objective of project is to investigate the potential of electro kinetic treatment through screw pile as appropriate electrode to stabilize the clayey soil surrounded and to increase its pull out capacity. In this experimental study, electro kinetic process was carried out in a steel tank of size was 40cm x 70cm x 50cm, in which clayey soil was filled. A screw pile was fabricated as 30mm dia. helix plate welded to 10mm dia. central shaft, which was screwe d in to the soil. Electro kinetic treatment was carried out through screw piles by adding potassium hydroxide stabilizer by varying the parameters such as voltage gradient of DC supply and spacing of electrodes. The experiments result that increase in voltage gradient will strengthen the soil around the screw pile and the increase in spacing of electrodes decreases the improvement in the pull out capacity of screw pile.

INTRODUCTION

Screw piles are helical anchors consist of a steel centre solid shaft or pipe and one or more steel helical plates welded near the toe of pipe and sometimes at intervals along the shaft. While the availability of labour popularized other foundation types for a while, the simplicity and effectiveness of screw pile techniques are creating demand. Screw piles have been used widely in engineering applications to provide structural stability against axial compression, uplift tension, overturning moment and lateral forces. Screw piles are becoming a more common structural foundation in everyday construction sites, but really shine where there are problems in terms of poor foundation material and or remote locations with limited access.

Screw pile usage has extended from lighthouses to rail, telecommunications, roads, and numerous other industries where fast installation is required, or building work takes place close to existing structures. Most industries use screw pile foundations due to the cost efficiencies and the reduced environmental impact. Screwing the foundations in the ground means that there is less soil displacement and so much soil does not need to be transported from the site, saving on

transportation costs and reducing the carbon footprint of the project. The main benefits of screw pile foundations include: shorter project times, ease of installation, ease of access, reduction of the carbon footprint, ease of removal when the foundations are no longer required, reduced risk to the workforce, and reduced costs. Soil stabilization is the process of stabilizing the soil to improve the engineering properties of soil enough to allow field construction to take place. Stabilization includes compaction, pre consolidation, provision of drainage and many other such processes. A cementing material or a chemical can be added to a natural soil for the purpose of stabilization.

Electro kinetic stabilization is another process of stabilizing the soil by reducing the water content, improving the cementing process between the particles by various processes like electro osmosis, electrophoresis and electro migration. Electro kinetics is defined as the transport of charge, action of charged particles, and effects of applied electric potentials on formation and fluid transport in porous media. It is an emerging technique which uses direct current (DC) or a low electric potential difference to an array of electrodes placed in the soil. Electro kinetic treatment


has been known in geotechnical engineering for over six decades, yet, the technique is rarely used. Electro kinetic treatment is an effective soil improvement technique used in many geotechnical field projects, such as slope stabilization, shear strength improvement, electrochemical hardening, fine-grained soils stabilization, consolidation and dewatering.

Here a study of electro kinetic strengthening of clay adjacent to screw pile by electro kinetic treatment through the pile, was conducted. Both the screw pile installation method and electrochemical process are not soil disturbing processes and since current can pass through the steel screw piles, electro kinetic stabilization process through screw piles will be a good method. And load carrying capacity of screw pile mainly depends on soil surrounded the pile which can be effectively stabilized by electro kinetic treatment.

LITERATURE REVIEW

Andina S and Leonids P (2010), describe the system of helical piles and its behavior in compression. Latvian building code, Canadian building engineer calculation, A.B.Chance method and Finite element method were used for the determination of helical pile load bearing capcity. The construction methods of screw pile foundations have been compared and the advantages and disadvantages have been described. From the study the conclusions obtained are larger the diameter of helical plate, higher its capacity and increasing the embedment depth, a higher load bearing capacity of the screw pile will be obtained. Abdulla.W.S and Al-Abadi.A.M,(2010), made a study on Cationic –electro kinetic improvement of an expansive soil, in which enhanced electro osmosis with injection of saline solutions were studied. Treatments were done with calcium chloride and potassium hydroxide and the improvements of the soil were studied. The potassium ions greatly improve soil shear strength due to the ion fixation of clay minerals. The swell potential of the soil reduced from 3-14% and the friction angle is increased by 12

0, which increases the soil bearing capacity by

increasing bearing capacity factor, Nγ. Narasimha, Rao et al. (1993) made an attempt to arrive at the capacities of helical screw piles based on the measured shear strength. A cylindrical failure surface between the top and bottom helical plates are assumed in this study and the effect of spacing of helical plates on uplift capacity is considered. With the help of experimental studies done with screw piles made of 13.8mm diameter mild steel shafts to which mild steel plates of 33mm diameter were welded done in a cylindrical tank of diameter

350mm and height 500mm filled with marine clay, pull out capacities of screw piles were calculated.

Test tank of 400mm x 700mm x 500mm can be used in order to reduce the side effects for the load test of screw piles of 13mm dia., 500mm height with helical plate of 33mm. KOH is a strong electrolyte which can be used as the stabilizing agent for electro kinetic process since potassium ions effectively enter the clay structure. EK process through screw pile as anode during electro osmosis EK process with screw pile as cathode during chemical stabilization will increase the shear strength parameters of soil around the screw pile and thus increase its pull out capacity.

MATERIALS USED

Soil

The base soil selected for the study was clayey soil and it was collected from a construction site at Kadavanthra, Ernamkulam, from a depth of 3 to 6 meters from the ground level. Air dried soil samples were used in this particular study. Fig.1 shows the image of collected soil sample.

Fig 1 Clayey soil from Kadavanthra

In accordance with Indian Standard procedures, all the basic properties of soil were found out. Atterberg’s limits for the soil were determined by using test procedures according to IS 2720 (Part -5) 1985, from which plastic limit, and shrinkage limit of the base soil are found to be 34% and 12% respectively. The plasticity index of the soil which is the difference between liquid limit and plastic limit is 42%.Grain size analysis was carried out as per IS 2720 (Part 4) – 1985, to determine the percentage of different particles in the clayey soil. It states that the soil contains approximately 26% of sand particles, 46% silt and 28% clay particles. The specific gravity of soil was found to be 2.62 on average of three test trials. The maximum dry density (MDD) of soil was found as 13.65 kN/m³ and optimum moisture content (OMC) was found as 29%.

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Table 1. Basic properties of soil

Property Obtained

values Specific Gravity 2.62 Natural water content (%) Atterberg limits

73

Liquid limit (%) 76

Plastic limit (%) 34

Shrinkage limit (%) 12 Plasticity index (%) Grain size distribution

42

Clay (%) 28 Silt (%) 46 Sand (%) Compaction characteristics

26

Maximum Dry density (kN/m3) 13.65

Optimum moisture content (%) 29 Soil classification as per IS 2720

MH

Potassium Hydroxide Potassium hydroxide which can be used as stabilizing chemical was purchased locally as pellets. Solution can be prepared by adding them in correct proportion to distilled water.

Model Screw Pile

Screw piles are modeled according to the scaling law proposed by Mazurkiewicz (1968) which reported that the minimum pile length/pile diameter ratio (L/D) of 10:1 is a good ratio for model pile tests. Model steel piles are made of mild steel having 10mm shaft diameter to which mild steel plates of 30mm is welded and (Fig 3.2) having 500mm length was used in this study.

Fig 2 Fabricated screw pile

Model Test Tank The test tank made of steel with dimensions 70cm x 40cm x 50cm was used for the study considering the lateral dimensions of failure pattern of screw pile during loading. The inside of tank was covered by 4mm thick glass in order not to effect the electro kinetic treatment. The tank set up also had special arrangement of pulleys to conduct the pull out tests. With the help of rope screw pile can be pulled out through these pulleys. Sufficient drainage holes were also given for the tank for draining the water accumulated near the cathode during electro osmosis procedure.

RESULTS AND DISCUSSIONS Pull out tests were conducted to find the effect of both the electro osmosis and electro chemical stabilization phases of treatment on the improvement of pull out capacity. Tests were started with 10V treatment through the screw pile installed at a depth of 15cm and electrode spaced at 25cm as a part of whole treatment program.

Fig.3 The variation of pull out capacity of screw pile after electro osmosis and electro chemical stabilization process

Fig.3 includes the results which showed that both the electro osmotic and electro chemical stabilization process will help to increase the improvement of pile pull out load capacity. The reduction in water content and stabilization of soil around the screw pile are the causes of pile pull out capacity improvement.


Results of EK Treatment through Screw pile

Varying the Voltage Gradient

Pull Out Test Results

The pull out tests were conducted on screw pile by varying the voltage gradient as 10V, 15V, 20V and 30V. The embedment depth, electrode spacing and concentration of chemical used were kept constant as 5, 25cm and 1 mol. respectively. Fig.4 shows the variation of pull out capacity of screw pile by varying the voltage gradient and it states that with increase in voltage gradient applied during the process, the improvement in uplift capacity also increases.

Fig.4 Variation of uplift load with deformation of screw pile with varying the voltage gradient applied during electro chemical treatment As per IS 2911-1985 part 4, safe uplift load can be taken as the two third of load that make vertical displacement of 12 mm. Fig.5 shows the variation of the safe uplift load for the screw pile after EK treatment with different voltage gradient. Results showed that the safe uplift capacity of screw pile goes on increasing with the voltage gradient applied, but not that much considerable at higher voltages of 20V and 30V. When the voltage gradient increases, there will be more amount of ion migration between the electrodes. The improvement in safe uplift load at higher voltages was found to be not much differed from the improved value at 15V voltage gradient. This is because of return movement of water during electro chemical stabilization which will reduce the improvement of shear strength around the soil which in turn affects the pull out capacity.

` Fig.5 Variation of safe uplift load for different voltage gradient applied

Applied voltage of 15V can be taken as the optimum voltage gradient that can be applied for further tests which gives an improvement of 103% in the pull out capacity of screw pile.

Variation of Current During EK Treatment

As the voltage gradient applied for the electro kinetic treatment goes on increasing the current passing also increases. Fig.6 and Fig.7 shows the variation of current during electro osmosis and electro chemical stabilization respectively. During the process of electro osmosis the current values goes on decreasing and during electro chemical stabilization the current goes on increasing.

Fig.6. Variation of current with time during electro osmosis for various voltage gradient

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Fig.7. Variation of current with time during electro chemical stabilization for different voltage gradient

Resistance of soil increased during electro osmosis by the water transfer towards the cathode and loss of ionic strength of soil due to migration of ions near the electrodes and so current decreases. During the electro chemical stabilization the resistance of soil decreased with time due to the distribution of stabilizing ions into the soil and they migrate easily which causes the passage of current and hence current decreases.

Variation of Cumulative Water Drained after Electro

Osmosis

During the electro osmosis phase of treatment, water will drained through the steel pipe with drained holes which is provided as cathode. For the first 90 minutes of electro osmosis, the amount of water drained was observed with time.

Fig.8. Variation of cumulative drained water with time for different voltage gradient applied during electro osmosis

Results showed that the cumulative water drained by the electro osmosis process was found to be increased with increase in voltage gradient applied between the electrodes. It was because of the fact that higher the voltage gradient there will be more electric field within the soil which cause the water transfer more effectively and drain more water. Fig.8 shows the variation of cumulative water drained during electro osmosis with varying the voltage gradient. Water Content Variation throughout the Process of Electro

Kinetic Treatment

The water content of the soil near the screw pile was determined by oven dry method throughout the test after both the electro osmosis and electro chemical stabilization. It was done in order to find the effect of water content on the shear strength of soil and so the increase in pull out capacity of soil. Test results show that the water content of soil near the screw pile decreases after the electro osmosis process and increases after the electro chemical stabilization. Fig.9 shows the variation of water content of the soil near the screw pile throughout the electro kinetic treatment.

Fig.9. Variation of water content with time throughout the electro kinetic process During electro osmosis, screw pile act as anode and water transferred to the cathode which decreases the water content near the pile. During electro chemical stabilization due to reverse polarizing screw pile act as cathode in order to attract the stabilizing ions which also cause the reverse movement of water towards the pile which increases the water content.


Variation in Vane Shear Strength of Soil near Screw Pile

after Treatment

The vane shear test of soil near the screw pile after the whole process of electro kinetic stabilization were carried out in order to find the increase in shear strength of soil. Fig.10 shows the values of vane shear strength for different voltage gradient applied during the treatment. Results showed that the shear strength of soil was found to be increased with increase in voltage gradient applied during electro kinetic treatment.

Fig.10. Variation of vane shear strength with the voltage gradient of electro kinetic treatment The vane shear strength of soil near the screw pile goes on increasing with the increase in voltage gradient applied during electro kinetic treatment because increase in voltage gradient decreases the water content near the screw pile. And the increase in voltage gradient also helps to distribute more stabilizing agents near the screw pile. So it is because of the increased effect of whole electro kinetic process with the increase in voltage gradient enhances the soil strength.

Results of EK Treatment through Screw pile

Varying the Spacing of Electrodes

Pull Out Test Results

Electro kinetic treatments through screw pile were done by varying the spacing of electrodes to find its effect on improvement of pull out capacity of screw pile. Electro kinetic treatment with 15V voltage gradient, 1M potassium hydroxide was done using the screw pile installed at embedment ratio 5, by changing the spacing as 25cm, 35cm and 45cm. Fig.11 shows the test results which show the variation of pullout capacity of screw

pile with the increase in spacing of electrodes. It states that with increase in the spacing of electrodes, the improvement in pull out capacity of screw pile goes on decreasing.

Fig.11. Variation of uplift load with deformation of screw pile for different spacing of electrodes during electro kinetic process

Fig.12. Variation of safe uplift load with the spacing of electrodes Fig.12 shows the variation of safe uplift load with the increase in the spacing of electrodes. The percentage increase in improvement goes on decreasing with the increase in spacing of electrodes. For the EK treatment at 45cm electrode spacing the safe uplift load increased to 19.69N from 16.15N of untreated soil which shows only 22 % increase. The reason behind this is, with increase in the spacing between the electrodes, the volume of soil between the electrode increases which reduce the electric field effect in soil. So effects of all

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treatment get reduced. Hence the improvement in shear strength of soil around screw pile reduces with increase in spacing of electrodes. The percentage improvement in pull out capacity of the screw pile was reduced from 103% to 22% when the spacing of electrodes increases from 25cm to 45cm. Variation of Current d uring EK Treatment

The variations of current with time were studied throughout the electro kinetic treatment. Fig.13 and Fig.14 shows the variation of current during electro osmosis and electro chemical stabilization respectively. With increase in spacing of electrodes the initial current of the process decreases and this current value goes on decreasing with time during electro osmosis. During the electro chemical stabilization the current value goes on increasing.

Fig.13. Variation of current with time during electro osmosis for different spacing of electrodes With increase in spacing of electrodes the current at start of the process decreases because of the increased path for current flow. As mentioned earlier this current value goes on decreases with time during electro osmosis because of the water transfer towards the cathode which make uneven distribution of water which adversely affect the current flow. During electro osmosis, the charged ions within the soil became concentrated near the electrodes which cause the loss of ionic strength of soil which increases the resistance of soil. During electro chemical stabilization the stabilizing ions distribute in the soil which decrease the resistance of soil with time.

Fig.14. Variation of current with time for different electrode spacing during electro chemical stabilization

Variation of Cumulative Drained Water during Electro

Osmosis

Fig.15 shows the variation of cumulative water drained after the electro osmosis with time for treatments with different electrode spacing. It shows that the amount of cumulative water drained decreases with increase in electrode spacing.

Fig.15. Variation of cumulative water drained with time for different spacing of electrodes in electro kinetic treatment Increase in spacing between the electrodes cause reduced effective electric field between the electrodes. The ion movement between the electrodes gets reduced and also the water transfer to cathode gets reduced. The


less current flow with increased electrode spacing decrease the water drained from cathode. Variation of Water Content throughout Electro Kinetic

Treatment

The water content near the screw pile was determined by oven dry method. Fig.16 shows the variation in water content of soil near the screw pile. It was found to be decreased after electro osmosis and then increased after electro chemical stabilization.

Fig.16. Variation of water content with time for different electrode spacing throughout the electro kinetic treatment During electro osmosis the water is transferred from screw pile to cathode and hence the water content near the screw pile gets reduced. The increase in electrode spacing cause the lack of effective current flow between the electrodes which resulted in reduced water transfer. So the reduction in water content is not much for the treatments with higher electrode spacing. During electro chemical stabilization the reverse movement of water by the reverse polarization of electrodes cause the increase in water content near the screw pile whose rate also affected by the electrode spacing as explained above. Variation of Vane Shear Strength near Screw Pile

after Treatment

Fig.17 shows the variation of vane shear strength of soil near the screw pile after the whole electro kinetic treatment. It shows that the vane shear strength of soil near the screw pile decreases with increase in spacing of electrodes. The vane shear strength values result as

5.09, 3.51 and 2.98 N/cm2 for 25cm, 35cm and 45cm

spacing respectively.

Fig.17.Variation of vane shear strength with different electrode spacing

During the electro osmosis the electric field get less effective for higher electrode spacing which causes the reduction in shear strength attained by the water content reduction. During electro chemical stabilization, the increased spacing of electrodes cause the effective stabilizing ion transfer to the screw pile which also affect the increase in vane shear strength. So the electrode spacing increment inversely affects the stabilization of soil and so improvement in shear strength gets reduced.

CONCLUSIONS

Screw piles are steel screws used for foundation through which electro kinetic treatment can be effectively carried out in order to stabilize the soil around it and which increase its pull out capacity. In this experimental study electro kinetic treatment was done using screw pile through two phases of electro osmosis and electro chemical stabilization, to improve the pull out capacity of screw pile. The focus of the study is to evaluate the efficiency of EK treatment by increasing the soil strength and so the screw pile pull out capacity. The variation in the improvement of load capacity of pile was studied by varying the EK parameters as voltage gradient applied and spacing of electrodes. The following conclusions were made from the study.

The optimum voltage gradient that can be applied for the treatment was taken as 15V since it gives 103% improvement for the screw pile pull out capacity and it is equalent to general in situ range of 60V/m for EK

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treatment. Application of higher voltage can cause the increased return movement of water to screw pile which adversely affects the improvement in pull out capacity of screw pile.

103% improvement reveals the fact that two screw piles in untreated soil can be replaced by electro kinetically treated single screw pile.

As the voltage gradient applied for the EK treatment increases, the cumulative water drained out from cathode increases during electro osmosis.

The vane shear strength of soil after whole EK treatment increases with increase in voltage gradient applied for it.

As the spacing of electrodes at EK treatment increases the improvement of pull out capacity decreases. The increase in spacing of electrodes means the increase in soil volume between the electrodes which cause the reduction of effective electric field in soil.

As the spacing of electrodes increases the cumulative water drained decreases during electro osmosis and the amount of distributing stabilizing ions decreases during electro chemical stabilization.

The vane shear strength of soil near the screw pile decreases with increase in spacing of electrodes used during EK treatment.

REFERENCE

Narasimha Rao.S and Prasad.Y.V.S.N,(1993). “Estimation of uplift capacity of helical anchors in clays”,J.Geotechnical engineering.,ASCE,119, 352-357. Abdulla.W.S and Al-Abadi.A.M, (2010). “Cationic –electrokinetic improvement of an expansive soil”, J.Applied clay science(47), 343-350. IS 2911(Part 4)-1985: Code of Practice for Design and Construction of Pile Foundations Micic,S. et.al .(2002). “Bearing capacity enhancement of skirted foundation element by electrokinetics” Proceedings of The Twelfth International Offshore and Polar Engineering Conference, 685 – 692.

Thakur, L. S. et.al. (2011). “Strengthening silty soil using electro kinetic grouting”, Proceedings of Indian Geotechnical Conference,441-444. Ajitha Bhaskar.,and Chandran, M. L., (2011), “Perfomance of steel piles in dry sea sand on axial load”,Indian Geotechnical Conference, December 15-17,Kochi, 219 – 221. Narasimha, R. S., and Yenumula,V. S. N., (1996), “Lateral capacity of helical piles in clays”, Journal of Geotechnical Engineering, ASCE, Vol. 122, No. 11, 938-941. Narasimha, R. S. et al., (2006), “Studies on pullout capacity of anchors in marine clays for mooring systems”, Applied Ocean Research ,Vol. 28, 103–111. Tjandra,D. et.al. (2007). “Improving marine clays with electro kinetics method”, Civil Engineering Dimension, 9(2) , 98-102. Tran,T.T. et.al. (2013). “Improvement of expansive soil by electro-kinetic method”, Journal of Southeast Asian Applied Geology.5(1), 50-59. Andina S and Leonids P (2010). “Helical pile behaviour and load transfer mechanism in different soils”, The 10

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international Conference,Lithuania,1174-1180. Daniel R.L and Jean G.S.(1984). “Tests on model tension piles”, J. Geotech. Engrg.,110, 1735-1748. Zhemin S. et.al (2007). “Comparison of electro kinetic soil remediation methods using one fixed anode and approaching anodes”, J. Environmental Pollution (150),193-199. IS 2720 (Part 4)-1985: Indian Standards of Methods of Test for Soils- Grain size analysis IS 2720(Part 5)-1985: Indian Standards of Methods of Test for Soils- Grain size analysis Determination of liquid and plastic limit IS 2720(Part 30)-1980: Indian Standards of Methods of Test for Soils- Laboratory vane shear test


Kristen M.T and David C.S,(2007). “Predicting the axial capacity of screw Piles installed in canadian soils”, j.OttawaGeo,1608-1615. Samudra ,J .(2004). “Stabilising volume change characteristics of expansive soils using electro kinetics: A laboratory based investigation” Australian Geo mechanics, 39(4), 33-46. Srirama, R.A. et al., (2007), “Pullout behavior of granular pile-anchors in expansive clay beds in situ’’, Journal of Geotechnical and Geo environmental Engineering, ASCE, Vol. 133, 531-538. Stalin,V.K et.al.(2009). “Decontamination of clay using Electro kinetic phenomena”, Indian Geotechnical Conference, 276-279. Thakur L.S et.al (2013). “Effect of grout concentration & voltage gradient on electrokinetic grouting”, Proceedings of Indian Geotechnical Conference , 1-6.

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50 C 17 19 DECEMBER 2015, Pune, Maharashtra, India Venue ...igs/ldh/files/igc 2015 pune... · pull out capacity of screw pile due to ineffective electric field in the soil mass available