Load-transfer platform behaviour in embankments supported on semi-rigid columns: implications of the ground reaction curve

Abstract

Post-construction data from an instrumented geosynthetic reinforced column supported embankment (GRCSE) on drilled displacement columns in Melbourne, Australia, show the time-dependent development of arching over the 2 year monitoring period and a strong relationship between the development of arching stresses and subsoil settlement. A ground reaction curve is adopted to describe the development of arching stresses and good agreement is found for the period observed thus far. Predictions of arching stresses and load-transfer platform behaviour are presented for the remaining design life. Four phases of arching stress development (initial, maximum, load-recovery, and creep strain phases) are shown to describe the time-dependent, and subsoil-dependent, development of arching stresses that can be expected to occur in many field embankments. Of the four phases, the load-recovery phase is the most important with respect to load-transfer platform design, as it predicts the breakdown of arching stresses in the long term due to increasing subsoil settlement. This has important implications in assessing the appropriate design stress for the geosynthetic reinforcement layers, but also the deformation of the load-transfer platform in the long term.

Membrane effect of geosynthetic reinforcement subjected to localized sinkholes

“…In such an structure where subsoil may have voids or sinkholes, membrane effect often occurs along with soil arching (e.g., Giroud 1981;Kinney and Connor 1987;Giroud et al 1990;Wang et al 1996;Han and Gabr 2002;Rogbeck et al 2003;Briançon and Villard 2008;Abusharar et al 2009;Lu and Miao 2015;Feng and Lu 2015;Huckert et al 2016;King et al 2017). During a subsiding process, geosynthetic interacts with overlying soil: subsided soil deflects geosynthetic and is also prevented from sinking by the deflected geosynthetic at the same time.…”

Geosynthetic reinforced column supported embankments and the role of ground improvement installation effects

“…1. These zones broadly resemble the subsurface conditions encountered in the Melbourne site (described in further detail below, see also King et al 2016King et al , 2017aKing 2017): zone A -fill, zone B -Coode Island Silt, and zone C -Fishermens Bend Silt. The cylindrical cavity expansion solutions developed by describe the excess pwp and displacement field for the soil mass surrounding a driven pile are derived in the Supplementary Data section.…”

“…The geological profile is complex and highly variable, with the Coode Island Silt varying from 7 m to 15 m along the length of the embankment; the underlying stiff to very stiff clays of the Fishermens Bend Silt unit form the founding unit for the columns. A detailed description of the subsurface conditions is presented in King et al (2016King et al ( , 2017a. The North Dynon embankment is a widened embankment and comprises a lower and upper level LTP with a gabion wall around the periphery of the embankment.…”

“…This paper presents post-construction survey data as well as inclinometer, piezometer, and tiltmeter data. Additional earth pressure cell (EPC) and strain gauge data have been presented in a complimentary paper where the localized LTP behaviour was examined (King et al 2017a). A similar embankment cross section through area No.…”

Nghiên cứu độ lún hệ cọc đất xi măng kết hợp lưới địa kỹ thuật cường độ cao trên mô hình thực nghiệm

“…Nhờ khả năng chịu kéo lớn, đặc biệt với loại lưới địa kỹ thuật cường độ chịu kéo cao, khi trải trên đỉnh cọc tạo thành lớp truyền tải mềm, làm gia tăng tải trọng truyền vào cọc, giảm một phần tải trọng truyền xuống đất yếu giữa các cọc nhờ đó giảm được độ lún lệch giữa cọc với phần đất xung quanh (Xing và các cộng sự (2014) [2], Smith và các cộng sự (2004) [3], J. Han và J. Huang (2005) [4], Chai và các cộng sự (2017) [5], King và các cộng sự (2017) [6]). Ở Việt Nam, các nghiên cứu liên quan độ lún hệ GPRS bằng thực nghiệm còn rất hạn chế, chủ yếu là các nghiên cứu bằng phương pháp số (Nguyễn Thị Loan (2016) [7], Nguyễn Minh Tâm (2015) [8], Nguyễn Quốc Dũng (2012) [9], Phạm Anh Tuấn (2015) [10]).…”