International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Vol...
Upcoming SlideShare
Loading in...5
×

Effects of surcharge loads on liquefaction parameters of pond ash improved w

422

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
422
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
22
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Transcript of "Effects of surcharge loads on liquefaction parameters of pond ash improved w"

  1. 1. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 225 EFFECTS OF SURCHARGE LOADS ON LIQUEFACTION PARAMETERS OF POND ASH IMPROVED WITH STONE-SAND COLUMNS H.P. Singh1 1 Department of Civil Engineering, NERIST, Itanagar, Arunachal Pradesh, India, ABSTRACT Huge quantities of coal ash produced from thermal power plants are very fine, non-plastic and of low unit weight and are loosely disposed into lagoons or ponds covering an area of several square kilometres. These ashes in ponds, called pond ash are having low load carrying capacity and poor settlement characteristics. This material in their saturated condition may be susceptible to liquefaction during earthquakes. On the other hand the performance of such materials can substantially be improved by applying soil reinforcement techniques and their liquefaction potential can be reduced. Keeping this in view and in order to rehabilitate the abandoned ash ponds, it is therefore necessary to evaluate the liquefaction resistance and settlement susceptibility of pond ash In the present study, a number of tests were performed on a small Vibration (Shake) Table imparting harmonic excitation of 0.3g amplitude under the frequency of 5 Hz to pond ash samples prepared at relative densities of 20% without and with stone-sand columns at 4d c/c spacing, where d is diameter of stone-sand columns. Tests were also conducted on improved pond with various surcharge loads. The liquefaction parameters of pond ash such as maximum excess pore water pressure (Umax), maximum excess pore water pressure built up time (t1), Maximum pore water pressure stay time (t2), complete excess pore pressure dissipation time (t3) were measured with the help of glass tube piezometer and stop watch. The liquefaction resistance of pond ash was evaluated in terms of maximum pore water pressure ratio (rumax = Umax/σv’) for all the tests. It was observed that the liquefaction resistance of pond ash increases with the inclusion of stone-sand columns. It was also observed that the liquefaction resistance of pond ash further increases when various surcharge loads are applied on the samples of pond ash improved with stone-sand columns Thus there is a significant increase in liquefaction resistance of pond ash due to surcharge loads. Key Words: Harmonic Excitation, Liquefaction Parameters, Pond ash, Stone-Sand Column, Surcharge Loads, INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND TECHNOLOGY (IJCIET) ISSN 0976 – 6308 (Print) ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), pp. 225-235 © IAEME: www.iaeme.com/ijciet.asp Journal Impact Factor (2013): 5.3277 (Calculated by GISI) www.jifactor.com IJCIET © IAEME
  2. 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 226 1. INTRODUCTION A major source of electrical energy in India is thermal power, which is being generated by burning of low-grade coal of high ash content. The current production of ash in India is over 100 million tons per year out of which a very small percentage (3 to 5%) is being used for various applications such as brick making, cement manufacture, soil stabilization, etc. Disposal of the remaining quantity of ash has created a major problem of availability of land. In many thermal power plants ash deposit is spread over a large area usually for a height of 10 to 30 m. Toth et al.[1] studied the use of fly ash as a structural fill and found that the physical behavior of fly ash is similar to that of silt. Sridharan et al.[2] investigated the geotechnical characterization of various ash ponds in India and reported that pond ashes in general possess low unit weight, good frictional properties, low compressibility and low Permeability and they are well suited for their use as a structural fill. Choudhary and Verma [3] used the soil reinforcement technique to improve the TISCO pond ash and found that there is significant increase in the CBR value of pond ash due to inclusion of reinforcement and pond ash can be used as a pavement subgrade. Singh et al. [4] also observed that these materials are very fine, loose and non-plastic similar to fine sand and may be vulnerable to liquefaction during earthquakes. They described the procedure of determining the liquefaction resistance of pond ash based on shake-table tests. Zand et al. [5] gave the procedure of evaluating liquefaction potential of the impounded fly ash using cyclic triaxial tests and found that fly ash is susceptible to liquefaction during earthquakes. A challenging task is to improve these areas for further construction of civil engineering structures like buildings, roads etc. Therefore, it is essential to study the liquefaction behaviour of pond ash and an appropriate ground improvement technique to improve its liquefaction strength. Gandhi and Dey [6] studied the improvement of fly ash by blasting techniques and found that fly ash is densified to great extent in deeper depths. Boominathan and Hari [7] used the soil reinforcement technique with randomly distributed fibres and mesh element and concluded that addition of fibres/mesh elements increases significantly the liquefaction resistance of fly ash at low relative density. Singh et al.[8] used the stone-sand columns to improve the liquefaction resistance of pond ash using one dimensional shake table and found that there is significant increase in liquefaction resistance of pond ash when improved with stone-sand columns at 3d c/c spacing of the columns(where d is diameter of stone-sand column). However, the studies on liquefaction behaviour of pond ash improved with stone-sand column under various surcharge loads are rarely available in the literature. This paper is an extension of Singh et al. [8] and it exclusively deals with effects of surcharge loads on various liquefaction parameters of pond ash. A number of vibration table studies for liquefaction are reported in the literature e.g. Florin and Ivanov [9], Finn [10], DeAlba et al. [11], and Gupta [12]. However, these studies deal with sands. The present study has significance, as the pond ash covers a large area, near thermal power plants in India. In this study, tests have been conducted on a small shake table imparting one-dimensional horizontal harmonic excitations to the pond ash samples improved with Stone-sand columns at columns spacing of 4d c/c without and with different surcharge loads. The effects of surcharge loads on liquefaction parameters of improved pond ash have been investigated in the present study. 2. PROPERTIES OF POND ASH The pond ash used in the tests was collected from the site of Anpara-D thermal power plant, Anpara, Uttar Pradesh, India. The index properties of the fly ash are given in Table 1. Further, the grain size distribution curve of pond ash is shown in Fig. 1.
  3. 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 227 Table 1: Properties of Anpara Pond ash S. No. Properties Value 1 Specific Gravity (G) 2.31 2 % Optimum Moisture Content (OMC) 22 3 Grain Size Distribution (a) % of Particles Coarser than 4.75 mm 2 (b) % of Particles ( 4.75 mm ~ 0.075mm) 64 (c) % of fines (finer than 0.075mm) 34 4 Plasticity Index (PI) Non-Plastic 5 Maximum Void Ratio (emax) 1.31 6 Minimum Void Ratio (emin) 0.54 Fig. 1: Grain size distribution curve of pond ash 3. EXPERIMENTAL SET UP The tests were performed on a simple but indigenously fabricated vibration table. The test bin is a watertight tank 1.05 m long, 0.60 m wide and 0.60 m high in which sample of fly ash was prepared. The details of the experimental set up are described below. The tank is mounted on a horizontal shake table. The sides of the tank consist of a rigid mild steel frame with 5 mm thick steel panels. The shake table consists of a rigid platform, which rests on four wheels supported on four knife-edges. This is driven in horizontal direction by a 3 H.P. A.C. motor through crank mechanism for changing rotary motion into translatory motion. The crank mechanism consists of a device for changing the amplitude of motion through two eccentric shafts. By changing the relative position of two shafts, the amplitude can be fixed as desired. The equipment has facility to change the frequency of dynamic load using the pulleys of different diameters on the driving shafts. The pore pressure measurements were performed with the help of glass tubes piezometer. These were attached to the tank set up with rubber tubes. At the mouth of rubber tubes, G.I (galvanized iron) pipes were connected, which go up to the center of tank i.e. the locations of points for measuring pore water pressure. At the outlet of these G.I. pipes, porous stone wrapped with filter papers were placed. A Schematic diagram of test set up is shown in Figure 2. The shaking table can produce one-dimensional harmonic excitation of varying amplitude (0.05 to 1g) and frequency up to 10 Hz. The measurement of the pore water pressure was conducted
  4. 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 228 at three different depths in the shake table tank. The locations of measuring points from base of the tank are: Bottom Point (B): 40 mm Middle Point (M): 125 mm Top Point (T): 200 mm The total effective depth of the tank is 600 mm and the ash samples are filled for a height of 500 mm from the bottom of tank. Fig. 2: Liquefaction table used in the study 4. EXPERIMENTAL PROCEDURE 4.1 Preparation of Samples All the tests were performed keeping the relative density of pond ash as 20 %. By trial the following sequential procedure has been evolved for preparing the submerged sample of pond ash to achieve the relative density to 20 %: a) 175 liter of water was filled in the tank, which is sufficient to submerge the points where piezometers are connected. It ensures the removal of air bubbles from G.I. pipes, rubber tubes and piezometer tubes. b) About 350 kg of pond ash was dropped through funnel keeping the tip of the funnel at a height of 25 cm above water surface. c) The water with pond ash was left for 12 hours so that all the fines and coarse particles settle properly in the tank. This procedure ensured the full saturation of the pond ash sample. d) The surplus water on the top of the saturated pond ash sample was then carefully removed and its weight was measured. e) The height of the saturated pond ash sample in the tank was measured and the volume of the space occupied by the sample in the tank was evaluated using plan dimensions of the tank. f) Total weight of the pond ash plus the net amount of water divided by the volume of sample obtained in step (e) gives the saturated unit weight of pond ash. Using this saturated unit weight (γsat) and with the known value of specific gravity (G), the value of void ratio (e) can be obtained using the following equation:
  5. 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 229 wsat e eG γγ + + = 1 (1) Where γw is the unit weight of water. g) Using the values of maximum voids ratio (emax) and minimum voids ratio (emin), Table 1, the relative density (R.D.) can be found from the following equation: minmax max .. ee ee DR − − = (2) This procedure gave the relative density as 20 % h) For the preparation of the pond ash sample with stone-sand columns, the mild steel hollow open- ended pipes (750 mm long and 50 mm dia) were inserted at the desired locations. The bottom ends of the pipes were plugged with detachable wooden cones while inserting in the tank. These pipes were filled with the mixture of stone chips (10 mm down size) and fine sand, in proportion of 2:1 by weight and mixed thoroughly in a mixer, in five layers. Each layer was given 25 blows of the 2.5 kg rammer dropped from a height of 450 mm. After each layer was compacted, the pipe was withdrawn by the same amount. Thus finally whole pipe was withdrawn. The center-to-center spacing between pipes was kept as 4d. Further, it was observed that the inclusion of stone-sand columns increases the submerged unit weight of pond ash sample by 24 % . Fig. 3: Location of stone-sand columns in the shake table tank (dimensions are in mm) 200 200 200 200200200 1050 600 15 Stone–Sand Columns φφφφ= 50
  6. 6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 230 4.2 Test Procedure As per IS: 1893[13], the site from where the pond ash was procured falls under seismic zone III and the expected peak ground acceleration at the site is 0.16g. The predominant frequencies in many past earthquakes in alluvial deposits have been observed to be of the order of 2 to 5 cycles per second. Therefore, to be on the conservative side, the tests were performed at an acceleration of 0.3g and at a frequency of 5 Hz. Before imparting the shaking, the values of static pore water pressures in all the three piezometer were recorded. Then shaking was imparted for 60 seconds. The pore water pressures were recorded at the interval of 10 seconds till these get completely dissipated. This procedure was adopted in studying the liquefaction behavior of pond ash, pond ash with stone-sand columns and Pond ash improved with stone-sand columns under various surcharge loads. The tests were conducted for following four cases:. (a) Pond Ash with Stone-Sand Columns @4d c/c spacing with total 15 columns. (b) Pond Ash with Stone-Sand Columns @4d c/c spacing with total 15 columns under the surcharge loads of 2.77kN/m2 . (c) Pond Ash with Stone-Sand Columns @4d c/c spacing with total 15 columns under the surcharge loads of 7.62kN/m2 . (d) PondAsh withStone-Sand Columns @4d c/cspacing with total 15 columns under the surcharge loads of 12kN/m2. Where d is the diameter of the stone columns. These spacing of stone-sand columns were selected keeping in view the spacing of actual stone columns used in the field. In each test, variation in excess pore water pressure with time was recorded using three piezometer tubes and stopwatch. Since the actual earthquake duration normally does not exceed 60 seconds, the results in this paper have been presented for shaking of 60 seconds. 5. TEST RESULTS The test results for above four cases are shown in Figs. 4 (a-d), respectively. In these figures, variation in excess pore water pressure with time is shown at the location of all the three points in the tank. The general trend of results is similar in all the four cases. The pore water pressure rises significantly even after the shaking was stopped. This is attributed to the fact that it takes some time in pond ash to develop pore water pressure after shaking starts and rise of pore water pressure continues quite some time under free vibration even when shaking is stopped. In second stage, the pore water pressure remained constant for some brief duration before dissipation starts, this time lag is attributed to free vibration phase of shaking, which ultimately converts in deceleration. Finally, dissipation led pore-water pressure to zero, which occurred after more than an hour. Thus dissipation of pore water pressure took very long time in pond ash as compared to time taken in sands. It was due to the fact that the pond ash contained significant amount of fine particles (34 %). It can be observed that in all the four cases, the pore water pressure is the maximum at bottom point and minimum at top point. This behavior was expected, as the effective overburden pressure is the maximum in bottom and decreased upward. However, the maximum value of pore water pressure ratio rumax (defined later) was almost the same at all the three points. Also in all four cases the maximum pore water pressure first reached at bottom point and then proceeds upwards.
  7. 7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 231 Fig. 4 (a): Pond ash with stone-sand columns @4d c/c spacing with total 15 columns Fig. 4(b): Pond ash with stone-sand columns under the surcharge loads of 2.77kN/m2
  8. 8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 232 Fig. 4(c): Pond ash with stone-sand columns under the surcharge loads of 7.62kN/m2 Fig. 4(c): Pond Ash with Stone-Sand Columns under the surcharge loads of 12 kN/m2
  9. 9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 233 Table 2: Values of Excess Pore Water Pressures of Improved Pond Ash at Different Surcharge Loads Surcharge Loads (kN/m2 ) U60 (kN/m2 ) ru60 Umax (kN/m2 ) rumax Effective over burden Pressure,σ'0, (kN/m2 ) 0 0.70 (B) 0.25 (M) 0.70 (T) 0.19 (B) 0.08 (M) 0.089 (T) 2.01(B) 1.46(M) 1.31(T) 0.55 (B) 0.48 (M) 0.53 (T) σ'v (B) = 3.62 σ'v (M) = 3.04 σ'v (T ) = 2.47 2.77 0.41 (B) 0.24 (M) 0.22 (T) 0.064 (B) 0.041(M) 0.042 (T) 2.20 (B) 1.72 (M) 1.49 (T) 0.34 (B) 0.30 (M) 0.28 (T) σ'v (B) = 6.39 σ'v (M) = 5.81 σ'v (T) = 5.24 7.62 0.32 (B) 0.22 (M) 0.21 (T) 0.028 (B) 0.021(M) 0.021 (T) 1.95 (B) 1.51(M) 1.33 (T) 0.173 (B) 0.142(M) 0.132 (T) σ'v (B )=11.24 σ'v (M) =10.66 σ'v (T) = 10.09 12.00 0.25 (B) 0.20 (M) 0.18 (T) 0.016 (B) 0.013(M) 0.012 (T) 1.79 (B) 1.49 (M) 1.26 (T) 0.115 (B) 0.099(M) 0.087 (T) σ'v (B) = 15.62 σ'v (M) =15.04 σ’v (T) = 14.47 Table 3: Values of Time Parameters (t1, t2 and t3) for Improved Pond Ash at Different Surcharge Loads Surcharge Loads (kN/m2 ) t1 (s) t2 (s) t3 (s) B M T B M T B M T 0 340 550 620 90 120 180 4970 4730 4520 2.77 370 560 620 90 120 180 3900 3680 3560 7.62 420 580 630 110 130 190 2710 2530 2420 12.00 450 620 660 120 150 200 2490 2290 2200 6. EFFECTS OF SURCHARGE LOADS It was observed that decrease in rumax value was not significant when the pond ash was strengthened with stone-sand columns at 4d c/c spacing. Therefore, the effect of surcharge loads on liquefaction parameters of pond ash improved with stone-sand columns at 4d c/c spacing has been investigated. The values of rise in pore water at all the three points (Bottom – B, Middle –M, Top – T) for all the four cases have been presented in Table 2. Here U represents the pore water pressure at the end of shaking while Umax represents the maximum pore water pressure before dissipation starts. From Table 2, it can be observed that Umax for bottom point is greater than that of middle point and so on. The last column of Table 2 represents the effective overburden pressure at the three points in the tank, which has been used in computation of maximum pore water pressure ratio rumax defined as follows: rumax= Umax / σv’ (.3) The variations of excess pore water pressure with respect to time have been presented in Fig. 4(a-d) for improved pond ash without and with three surcharge loads i.e. 2.77 kN/m2 , 7.62 kN/m2 and 12.00 kN/m2 . Further the liquefaction parameters were computed from the plots of Fig. 4(a-d)
  10. 10. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 234 and are given in Tables 2 and Table 3. The level of acceleration and exciting frequency considered were the same as in case of improved pond ash without surcharge loads (i.e. 0.3 g and 5 Hz). The interpretation of tests results are discussed in the following sections. 6.1 Variation of rumax with Surcharge It can be observed from Table 2 that the value of rumax decreases when the surcharge loads are applied on the pond ash. At higher value of surcharge load, the magnitude of developed maximum pore water pressure decreases (Gupta 1977 also observed the same trend for sand) and there is substantial reduction in rumax corresponding to largest surcharge load. e.g. the value of rumax at bottom point for zero surcharge loads is 0.55. When the surcharge load is increased from 0 to 2.77, 7.62 and 12 kN/m2 the values of rumax decreases from 0.55 to 0.34, 0.17 and 0.11 respectively. Similarly for middle and top points also the same decreasing trend of rumax is observed with respect to surcharge loads. Since the decrease in maximum pore water pressure ratio indicates an increase in liquefaction resistance, thus the liquefaction resistance of pond ash improved with stone-sand columns (at 4d c/c spacing), is improved due to placement of surcharge loads. The similar observation was made by Gupta (1977), though with respect to sand. This may be because of the fact that the status of vibration of pond ash changes as it is no free field motion and the effective overburden pressure within the pond ash sample increases due to application of surcharge loads. This is why the value of rumax decreases significantly due to surcharge loads. 6.2 Variation of Time Parameters with Surcharge It is observed from Table 3 that there is a change in the values of time parameters (t1, t2 and t3) due to surcharge loads. The maximum pore water pressure built up time (t1) and the maximum pore water pressure stay time (t2) increase whereas pore water pressure dissipation time (t3) decreases. The similar trend was found by Gupta (1977) with sand. This is attributed to the fact that surcharge load increases the effective overburden pressure at all the three points within the pond ash and test sample becomes more stiff which inhibits the development of excess pore water pressure during shaking and exhibits the dissipation of pore water pressure when shaking is stopped. That is why the built up time (t1) increases and dissipation time (t3) decreases when surcharge loads are applied over the test sample. Although there is a marginal increase in maximum pore pressure stay time (t2) but its effect will not be significant when the maximum pore water pressure ratio (rumax) is less than 0.5 7. CONCLUSIONS There is a significant effect of surcharge loads on the liquefaction behaviour of pond ash improved with stone-sand columns installed at 4d c/c spacing. The value of maximum pore water pressure ratio decreases when the surcharge loads are applied on the pond ash. At higher value of surcharge load, the value of maximum pore water pressure ratio decreases and there is substantial reduction in rumax corresponding to largest surcharge load. e.g. the value of rumax at bottom point for zero surcharge loads is 0.55. When the surcharge load is increased from 0 to 2.77, 7.62 and 12 kN/m2 the values of rumax decreases from 0.55 to 0.34, 0.17 and 0.11 respectively.There is a change in the values of time parameters (t1, t2 and t3) due to surcharge loads. The maximum pore water pressure built up time (t1) and the maximum pore water pressure stay time (t2) increase whereas pore water pressure dissipation time (t3) decreases. The effect of increase in maximum pore water pressure stay time (t2) will be negligible for the value of rumax less than 0.5 and hence liquefaction resistance of improved pond ash increases due to application of surcharge loads.
  11. 11. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME 235 8. ACKNOWLEDGEMENT Author is thankful to Prof. D.K. Pal, Prof. Swami Saran and Dr. B.K. Maheshwari of Earthquake Engineering Department, IIT Roorkee, for their valuable supports, encouragement and guidance for conducting the tests in the Soil Dynamics Laboratory. The help and support extended by Sri Subodh Jain, Laboratory Assistant in preparing the test set up is gratefully acknowledged. REFERENCES [1] P.S. Toth, H.T Chan and Cragg, Coal ash as structural fill with special reference to Ontario experience.CanadianGeotechnicalJournal, 25, 1978, 694-704. [2] A. Sridharan, N.S. Pandian and C. Rajshekher, Geotechnical characterization of pond ash. Proc. of the Symposium on fly ash Utilization, I.I.Sc Bangalore, 1997, 43-58. [3] A.K. Choudhary and B.P. Verma, Behavior of reinforced fly ash subgrade, Journal of Institution of Engineers (I); 86, 2005, 19-21. [4] H.P. Singh, B.K.Maheshwari, S. Saran and D.K Paul, Evaluation of liquefaction potential of pond ash, Proc. of 14th World Conference on Earthquake Engineering, Beijing, China, October 12-17, paper no. 04-02-0031, 2008 [5] B. Zand, T. Wei, P. J. Amaya, W.E. Wolfe and T. Butalia, Evaluation of liquefaction potential of impounded fly ash, World of Coal Ash (WOCA), Covington, Kentucky, May 7- 10, 2007. [6] S.R. Gandhi and A.K. Dey, Liquefaction analysis of pond ash. Proc. Of the Fifteenth Int. Conf. On solid waste Technology and Management, Philadelphia, 1, 1999, 4D. [7] A. Boominathan, and S. Hari, Liquefaction strength of fly ash reinforced with randomly distributed fibers, Journal of Soil Dynamics and Earthquake Engineering, 22, 2002, 1027- 1033. [8] H.P. Singh, B.K. Maheshwari, S. Saran and D.K. Paul, Improvement in liquefaction resistance of pond (fly) ash using stone-sand columns, International Journal of Geotechnical Engineering; 4(1), 2010, 23-30. [9] V.A. Florin and P.A. Ivanov, Liquefaction of saturated sandy soils, Proc. of Fifth Int. Conf. on Soil Mechanics and Foundation Engineering, Paris, 1, 1961, 107-111. [10] W.D.L. Finn, Soil-dynamics-liquefaction of sands. Proc. of First Int. Conf. On Microzanation, Seattle (USA), 1, 1972, 87-111. [11] P. DeAlba, H.B. Seed, and C.K. Chan, Sand liquefaction in large-scale simple shear tests. Journal of Geotechnical Engineering Division, ASCE, 102:GT9, 1976, 909-927. [12] M.K. Gupta, Liquefaction of Sands during Earthquakes, doctoral dissertation, University of Roorkee, Roorkee, India, 1977 [13] IS: 1893– Part 1, Criteria for Earthquake Resistant Design of Structures: General Provisions and Buildings, Bureau of Indian Standards, New Delhi, 2002. [14] Machhindra S.Purkar and Sunil Y. Kute, “Numerical Modeling of Reinforced Soil Segmental Wall Under Surcharge Loading”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 1, 2013, pp. 1 - 15, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. [15] Manish H. Sharma and Dr. C.H. Solanki, “Liquefaction Hazard Mapping”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 1, 2013, pp. 52 - 70, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.

×