Deflection of Prototype Geosynthetic-Reinforced Working Platforms over Soft Subgrade

Abstract

Large-scale experiments were conducted on working platforms of crushed rock (breaker run stone or Grade 2 gravel) overlying a simulated soft subgrade to mimic conditions during highway construction where a working platform is used to limit total deflections because of construction traffic. Tests were conducted with and without geosynthetic reinforcement to evaluate how deflection of the working platform is affected by the presence of reinforcement, type of reinforcement, and thickness of the working platform. Four different geosynthetics were used: geogrid, woven geotextile, nonwoven geotextile, and drainage composite. Reinforced working platforms deformed at a slower rate, and, in most cases, deformation of geosynthetic-reinforced working platforms nearly ceased after approximately 200 loading cycles. Total deflections at 1,000 cycles were smaller by a factor of approximately two for reinforced working platforms relative to unreinforced working platforms, and smaller deflections were associated when less extensible geosynthetics were used for reinforcement. The thickness of a geosynthetic-reinforced working platform needed to meet a target deflection diminished approximately linearly with increasing logarithm of the interaction modulus, a measure of in situ extensibility measured in a pullout box. The reduction in working platform thickness attained with reinforcement was also larger when the target total deflection was smaller.

Laboratory Assessment of Coir Geotextile Mats Under Wheel Load Conditions for Low-Volume Roads (LVRs)

“…The behaviors of natural coir mats to reinforce the pavement section were studied by [5]. The polymeric geotextile studies were also noticed by [6] Perkins (1999) and Kim et al 2006 [7]. The coir geotextile mats are utilized for various applications with soil like reinforcement, drainage, filtration, separation, slope protection, interface in civil engineering aspects.…”

Pilot-scale load tests of a combined multilayered geocell and rubber-reinforced foundation

“…geocell) have been widely utilised in geotechnical engineering applications for, for example, road construction layers, stable embankments, slope and earth stabilisation and construction of footings over soft soil (e.g. Collin et al 1996;Perkins and Ismeik 1997;Raymond 2002;Hufenus et al 2006;Kim et al 2006;El Sawwaf 2007;Alamshahi and Hataf 2009;Bathurst et al 2009;Moghaddas Tafreshi and Dawson 2010a;Boushehrian et al 2011;Madhavi Latha 2011;Moghaddas Tafreshi et al 2011;Leshchinsky and Ling 2013). An important possible use of such reinforcements would be to improve the bearing capacity and settlement of footings.…”

Evaluation of the use of alternative materials in pavement foundation layers

“…Therefore, after completing field testing, Cells 128 and 228 were removed. While Kim et al (2006) stated that issues caused by the lack of separation of subgrade layers from LSSB would not be expected to be significant during construction because of the short term, this study showed that such an issue could arise during construction [Figure 5.5(a)].…”

“…Geotextiles are divided into two types: (1) woven and (2) nonwoven. While woven geotextiles are generally used for reinforcement [not as effective as geogrids due to lack of interlocking between the grids and aggregates (Kim et al 2006)] and separation, nonwoven geotextiles have less reinforcement capability and are generally used for separation and drainage (Edil et al 2005).…”