Browsing by Author "Sanjay Kumar Shukla"

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A simple method for estimating poisson's ratio of geosynthetics at zero strain
(2009) Sanjay Kumar Shukla; Nagaratnam Sivakugan; Sitaram Mahto
A theoretical expression for the Poisson's ratio of geosynthetics as a function of axial normal strain may be very useful, particularly during the initial design stage of some geosynthetic-related projects. This technical note examines the suitability of such an expression suggested by Giroud 2004 (Geotext. Geomembr., Vol. 22, No. 4, pp. 297-305) in detail, and suggests a simple approach to estimate the appropriate values of the Poisson's ratio of the geosynthetics at zero strain (v0), which are required for use of this expression. A chart is presented for this purpose, which can be used by knowing the experimental value of the Poisson's ratio of a geosynthetic at any one nonzero strain. The suggested procedure and proposed chart can equally be applied for estimating v0 of other similar materials. Based on the limited experimental results presented in this note, the Giroud's expression is recommended for use with v0=0.57 for the high density polyethylene (HDPE) geomembranes and v0=1.75 for the nonwoven geotextiles, assuming that these values will not differ significantly for other similar geosynthetics, because v0 is dependent only on the nature of material. Copyright © 2009 by ASTM International.
A simplified extension of the conventional theory of arching in soils
(Maney Publishing, 2009) Sanjay Kumar Shukla; Gaurav; Nagaratnam Sivakugan
A general formulation is presented for the analysis of arching in soils as an extension of the conventional shear plane approach, in which the slip surfaces within the soil mass are considered as vertical planes. Such an assumption results in a low estimate of the design load on the yielding buried structure because of a considerable separation between the assumed vertical slip surfaces and the actual curved slip surfaces. The arching theory presented in this paper overcomes this limitation of the conventional theory by assuming inclined slip surfaces close to the actual slip surfaces. Based on this concept, an analytical expression for the vertical stress on the yielding structure is derived; a special case of this general expression reduces to the conventional expression. The variation of the vertical stress on the yielding structure with depth has been presented graphically along with a comparison with the conventional vertical shear plane approach. It is observed that the amount of arching increases with increase in the ratio of depth to width of the yielding structure as reported in the literature. J. Ross Publishing, Inc. © 2009
A time-dependent expression for modulus of subgrade reaction of saturated cohesive foundation soils
(Maney Publishing, 2008) Sanjay Kumar Shukla
This paper presents an analytical derivation of a time-dependent expression for the modulus of subgrade reaction of the saturated cohesive foundation soil considering the primary consolidation aspect. The newly developed expression involves parameters that can be determined by conducting one-dimensional laboratory consolidation test on the undisturbed soil specimens. An experimental verification of the analytical expression is presented to observe its accuracy. A parametric study is also presented to point out the care required while selecting the parameters used in the expression. J. Ross Publishing, Inc. © 2008
Analytical expression for dynamic active earth pressure from c-Φ soil backfill with surcharge
(Maney Publishing, 2011) Sanjay Kumar Shukla; Muhammad Zahid
In this paper, an analytical expression is derived for the total dynamic active force from the c-Φ soil backfill with surcharge under seismic loading conditions. The special cases of this new expression result in the expressions given by earlier researchers for different field situations of soil backfills with and without seismic loadings. A graphical presentation is made to recognize the importance of angle of shearing resistance and cohesion of the soil backfill, surcharge and direction of vertical seismic loadings. As expected, this shows that the total dynamic active force decreases with an increase in the angle of shearing resistance of the soil backfill. Also, for any value of angle of shearing resistance, the presence of cohesion in the backfill decreases the active force, however, the surcharge load increases the active force significantly whether the seismic load acts or not. A numerical example is presented to illustrate the steps for calculation of total dynamic active force. J. Ross Publishing, Inc. © 2011
Analytical expression for factor of safety of an anchored rock slope against plane failure
(Maney Publishing, 2011) Sanjay Kumar Shukla; Md Monir Hossain
This paper presents a generalized analytical expression for the factor of safety of an anchored rock slope against plane failure, incorporating most of the practically occurring destabilizing forces. Some of the special cases of this general expression based on possible field situations have been presented in similar forms in the literature. The analysis of the new expression shows that the factor of safety of the rock slope against plane failure increases nonlinearly with an increase in angle of shearing resistance of the joint material, whereas an increase in its cohesion results in a linear increase. For determining a critical factor of safety, the direction of the inertial seismic force should be considered vertically downward. Since the values of shear strength parameters of the joint material, surcharge, water pressure and the stabilizing force govern the factor of safety significantly, it is essentially required to consider their realistic values based on the actual field conditions in the stability analysis. J. Ross Publishing, Inc. © 2011
Discussion of "Effect of rheological behaviour of geosynthetics on settlement response" by Kousik Deb, Sarvesh Chandra, and Prabir Kumar Basudhar
(Maney Publishing, 2009) Sanjay Kumar Shukla
[No abstract available]