Centrifuge model tests on geotextile-reinforced slopes

Abstract

This paper addresses the static response of geotextile-reinforced slopes resting on a firm foundation to the self-weight loading imposed in a geotechnical centrifuge at pre-failure and at failure. A series of centrifuge tests were carried out on model geotextile-reinforced sand slopes with different types of reinforcement, spacing and slope inclination. A wrap-around technique was used to represent a flexible facing. In order to initiate failure in the reinforcement layers, the ratio of the length of the reinforcement to the height of the slope was maintained as 0.85. Reinforced slope models were subjected to varied g-levels (in steps of 5g from 10g onwards) up to a maximum target g-level of 75g or to collapse, whichever occurred first. A digital image analysis technique was employed to arrive at displacement vectors of markers glued to the reinforcement layers. The displacements were used to compute and analyse the strain distribution along the reinforcement layers, and to identify the peak strain distribution pre-failure and at failure. The development of a particular type of failure mechanism was found to depend upon the tensile strength-strain characteristics of a reinforcement layer. Maximum peak strain in the reinforcement layers was observed to occur at mid-height of the slope. With an increase in slope inclination from 2V:1H to 5V:1H, the magnitude of maximum peak strain was observed to increase, and its location was observed to move downwards from mid-height of the slope. Stability analysis of the reinforced slope models was found to be in good agreement with physically observed centrifuge test results.

Influence of Slope Height and Inclination on the Distribution of Reinforcement Loads within Reinforced Soil Slopes

“…However, it is observed that the reinforcement loads distribution is affected greatly by slope inclination. As the slope inclination increases, the location of the normalized maximum reinforcement load transfers gradually from the mid height to the bottom of the slopes, which agrees with the result of the test including two slope models with different inclinations (Viswanadham et al, 2007). Fig.5 shows the reinforcement loads distribution for the 13.5-m-high slopes with different slope inclinations.…”

“…However, the results of field and centrifuge tests by Abe et al (1989) and Zornberg et al (1998a) showed that the reinforcement loads in different reinforcement layers were not the same or similar, but very different. In addition, Viswanadham et al (2007) proposed that slope inclination affected the location of the maximum peak reinforcement load, which consequently impacts reinforcement loads distribution with slope height. Viswanadham's opinion was also supported by the results of several field tests and centrifuge model tests (e.g., Delmas et al, 1988;Fannin et al, 1990;Barrows et al, 1993;Sommers et al, 2009;Wang et al, 2011).…”

Experimental study on seismic deformation modes of reinforced-soil walls

“…Moreover, as noted by El-Emam and Bathurst (2007), the interaction between the reinforcement and the granular soil under very low confining pressures (the topmost reinforcement layer in these tests) can be expected to be less than the corresponding reinforcement layer located at a greater depth at prototype scale. Viswanadham and Mahajan (2007) commented that, to model reinforcement layers correctly, two similitude requirements have to be fulfilled: (1) scaling of tensile strength-strain behavior and (2) modeling of the bond between soil and geotextile.…”

“…Krishna and Latha (2007) built some of their 0.6 m high models with 34-37% relative density. Viswanadham and Mahajan (2007), in their study of the static response of reinforced slopes in a centrifuge, constructed their models with 55% relative density. Bathurst et al (2000) built their 3.6 m high full-scale models with 50% relative density.…”

Numerical Analysis on Deformation Behavior of Geosynthetic-Reinforced Slopes

“…Some valuable work associated with such analysis has been conducted by Jewell, 1982Jewell, , 1986Jewell, and 1991Milligan and Rochelle, 1984;Rowe and Soderman, 1985;Leshchinsky and Reinschmidt, 1985;Leshchinsky et al 1986;Hird, 1986;Chouery et al, 1989;Leshchinsky and Boedeker, 1989;Koerner, 1990;Low et al, 1990;Greenwood, 1990;Mandal and Labhane, 1991;Wright and Duncan, 1991;Greenwood and Zytynski 1993;Sabhahit et al, 1994;Leshchinsky et al 1995;Mandal and Joshi, 1996;Low and Tang, 1997;Palmeira et al, 1998;Shahgholi et al 2001. Centrifuge model tests have been conducted by Zornberg et al (1998Zornberg et al ( & 2003, Viswanadham and Mahajan (2007) to investigate the mechanical behaviour of reinforced slopes both at failure and in pre-failure states.…”