Tensile Force of Geogrids Embedded in Pile-Supported Reinforced Embankment(Title of the paper with font Times New Roman, size 16pt, single space, centered)
Yunmin Chen, Xuecheng Bian, Xiaowei Ye(First + Middle (initial) + Last name, font Times New Roman, size 10pt, single space, left justified)
Department of Civil Engineering,Zhejiang University, Hangzhou 310058, China(Affiliation: Department, Institute, Address, Country,font Times New Roman, size 8pt, single space, left justified)
; ; (Emails of all authors:font Times New Roman, size 8pt, single space, left justified)
Abstract:The geogrid reinforced piles are widely employed in construction of high-speed railway embankment to prevent the failure or excessive settlement of the embankment over soft or even stiff soils. Many methods for computation of the tensile force of the geogrid are available, while seldom of them have been effectively validated due to the difficulty in measurement of the geogrid stress. In this paper, a full-scale high-speed railway embankment model is established for assessment of the tensile force of the geogrid embedded in the reinforced cushion. Water bags are distributed around the pile caps to model the subsoil and the settlement of the subsoil is modeled by the vertical deformation of the water bags. The tensile force of the geogrid induced by the spreading force of the embankment and that caused by the vertical loads applied on the geogrid are separately measured by two types of optical fiber sensing approaches.(The page margins: top (3cm), bottom (2.5cm), left (2.4cm) and right (2.4cm). The abstract: 200~300 words, font Times New Roman, size 10pt, single space, justified. Please delete the format descriptions in red when you complete writing your paper.)
Keywords:Piled embankment; Geogrid; Tensile force; Fiber Bragg grating(3~5 keywords, font Times New Roman, size 10pt, single space, justified)
Introduction(The first level title: font Times New Roman, bold, size 12pt, single space (before: 30pt, after: 16pt), justified)
High-speed railway has achieved great development in China in recent years. The strength, stiffness and stability of the embankment are greatly required for high-speed railway. The requirement of post-construction settlement of high-speed railway is much stricter than that of highway [1]. The geogrid-reinforced piled embankment has the merits of rapid construction, small and controllable deformations, and global stability [2,3]. Such construction technique has been increasingly employed to address the challenges posted by construction of high-speed railways over soft or even stiff soils in China [5-8].
High-speed railway has achieved great development in China in recent years. The strength, stiffness and stability of the embankment are greatly required for high-speed railway. The requirement of post-construction settlement of high-speed railway is much stricter than that of highway. (The main body: font Times New Roman, size 10pt, single space, justified. The text-indent is 1.5ch since the second paragraph.)
Establishment of Full-Scale Test Model
For a column inclusion improved soft subsoil, the improvement area ratio used to describe the relative improvement of the soft layer by the columns. Their definitions are illustrated in Fig.1 and can be expressed as follows:
(1)
(2)
whereA = the total cross-sectional area of the zone improved by a single column, Ac =the cross-sectional area of a column, H=thickness of the soft clayey deposit, and HL=length of columns.
Fig. 1 Definition of and
Compression of Column Improved Soft Layers(The second level title: font Times New Roman, bold, italic, size 10pt, single space (before: 24pt, after: 12pt), justified)
The most common methods using a unit cell model and the final compression of the end bearing column improved clayey subsoil can be calculated by two different approaches, namelythe equilibrium method and the composite modulus method.Equilibrium method.
Table 1 Parameters adopted for settlement predictions
Depth(m) / Soil strata / Cc / e0 / t(kN/m3) / OCR0.01.5 / Surface soil / 0.85 / 1.50 / 16.0 / 5.0
1.54.0 / Softclay / 2.00 / 3.10 / 13.4 / 2.4
4.06.0 / 2.00 / 2.81 / 14.0 / 1.7
6.08.0 / 1.34 / 2.58 / 14.1 / 1.4
8.09.5 / 1.00 / 2.49 / 14.3 / 1.2
9.511.2 / Stiff clay / 0.35 / 1.10 / 18.0 / 1.2
Conclusions
The methods for calculating the consolidation settlement of both end bearing and floating column improved soft clayey deposit under embankment load are presented. In the case of floating column improvement, the method has been applied to a case history in Saga, Japan.The methods for calculating the consolidation settlement of both end bearing and floating column improved soft clayey deposit under embankment load are presented.
Acknowledgements
The work described in this paper was supported by the National Science Foundation of China (Grant no. 51308493).
References(The references should be cited in the text using the reference numbers and written in accordance with the flowing format)
[1] Abosh, H., Ichmoto, E.,Enoki, M., Harada,K. (1979). The composer - A method to improve characteristics of soft clay by inclusion of large diameter sand columns. Proceedings of International Conference on Soil Reinforcement: Reinforced Earth and Other Techniques, Paris, vol. 1, pp. 211-216.
[2] Taylor,D.W. (1948). Fundamentals of Soil Mechanics. John Wiley & Sons Inc, New York.
[3]Chai,J.C.,Miura,N. (1999). Investigation on some factors affecting vertical drain behavior. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 125(3): 216-226.