Analysis of a geotextile-reinforced embankment constructed on peat

1984 ◽  
Vol 21 (3) ◽  
pp. 563-576 ◽  
Author(s):  
R. K. Rowe ◽  
M. D. Maclean ◽  
K. L. Soderman

This paper describes a finite element analysis of two instrumented sections of a geotextile-reinforced embankment constructed on peat. The results from the analysis provide very encouraging agreement with the field observations for both instrumented sections at the endof the two major stages of construction. It is shown that the drained strength parameters c′ = 1.8 kPa, [Formula: see text] determined from simple shear apparatus provided the best agreement between predicted and observed behaviour. Analyses were also performed using both the field vane strength and the drained shear parameters (c′ = 0, [Formula: see text]) determined from triaxial tests, and the implications of these analyses are discussed. The geotextile–fill interface strength properties are also presented and it is suggested that, in this embankment, interface slip was not a factor affecting embankment performance.The analysis indicates that the major effect of the high modulus geotextile (Geolon 1250) used in the deepest section of the deposit was to reduce lateral movements, although it may have slightly reduced vertical movements as well. It is concluded that even a very high modulus geotextile will not prevent large consolidation settlements of embankments on peat. Key words: embankment, muskeg, peat, geotextile, settlement, analysis, finite element, shear strength, soil reinforcement.

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yong Fu ◽  
Jun Hu ◽  
Jia Liu ◽  
Shengbin Hu ◽  
Yunhui Yuan ◽  
...  

The technology of artificial horizontal freezing method is increasingly being used in the soil reinforcement of urban underground projects such as shield-driven tunnelling. Compared with the freezing process, the thawing process is more complicated, and the thawing behavior of artificial frozen soil surrounding shield-driven tunnels has not been well investigated in both the academic and industrial domains. This study, therefore, aims to investigate the natural thawing heat transfer behavior of artificial horizontal frozen soil in shield-driven tunnelling using a three-dimensional finite element method. The finite element modelling is based on the horizontal freezing reinforcement project of Chating Station to Jiqingmen Station Tunnel in the Nanjing Metro Line 2. Validation between finite element results and site measured results is firstly conducted. The natural thawing temperature field contours as well as the radial and longitudinal distributions of natural thawing temperature in the frozen soil surrounding the tunnel are then explicitly examined. Furthermore, sensitivity analysis of influencing factors such as the thermal conductivity, latent heat of phase change, ambient temperature inside tunnel, freezing time, and original ground temperature is carried out. The results and findings of this study may enrich the current limited database and enable a better understanding of natural thawing heat transfer behavior of artificial frozen soil in shield-driven tunnelling.


1990 ◽  
Vol 27 (2) ◽  
pp. 224-232 ◽  
Author(s):  
R. J. Chalaturnyk ◽  
J. D. Scott ◽  
D. H. K. Chan ◽  
E. A. Richards

Nonlinear finite element analyses were performed on a nonreinforced embankment and a polymeric reinforced embankment, with 1:1 side slopes, constructed on competent foundations. The nonreinforced and reinforced embankment analyses are compared to examine the influence of polymeric reinforcement within a soil slope. It is shown that significant reductions in the shearing, horizontal, and vertical strains within the slope occur because of the presence of the reinforcement.The finite element analysis of the reinforced embankment construction gives the magnitude and distribution of load within the reinforcement. For all embankment heights, the maximum reinforcement load did not occur in the lowest reinforcing layer but in the reinforcing layer placed 0.4H above the foundation, where H is the height of the slope. The displacement patterns and surface deformations of the nonreinforced and reinforced slopes are compared to show the marked reduction in slope movements resulting from the presence of the reinforcement.The location and shape of potential shear surfaces within the homogeneous reinforced slope are examined. The position of the maximum load in each reinforcing layer within the reinforced slope indicates that, for the example studied, a circular-shaped slip surface represents a probable failure mechanism within the slope. Key words: soil reinforcement, geotextiles, finite element, slope stability, geogrids, limit equilibrium, reinforced slope.


2000 ◽  
Vol 37 (6) ◽  
pp. 1209-1226 ◽  
Author(s):  
D T Bergado ◽  
C Teerawattanasuk ◽  
S Youwai ◽  
P Voottipruex

A full-scale test embankment was constructed on soft Bangkok clay using hexagonal wire mesh as reinforcement. This paper attempts to simulate the behavior of the full-scale test embankment using the finite element program PLAXIS. The agreement between the finite element results and the field data is quite good. The important considerations for simulating the behavior of the reinforced wall embankment were the method of applying the embankment loading during the construction process, the variation of soil permeability during the consolidation process, and the selection of the appropriate model and properties at the interface between the soil and reinforcement. The increased reinforcement stiffness tends to increase the reinforcement tension and increase the embankment forward rotation. The reinforcement tensions increased with the compression of the underlying soft foundation. The appropriate interface properties between the backfill soil and the hexagonal wire mesh reinforcement corresponding to the interaction mechanism at working stress conditions were dominated by the direct shear mechanism. The direct shear interaction coefficient of 0.9 was used.Key words: soil reinforcement, hexagonal wire mesh, finite element analysis, field embankment.


1973 ◽  
Vol 10 (2) ◽  
pp. 129-144 ◽  
Author(s):  
N. A. Skermer

A simple trapezoidal element is presented for use in the analysis of thin core rockfill dams with nonlinear soil parameters. Handling of nonlinear soil parameters and allowance for the intermediate principal stress in plane strain problems are discussed. The analysis of El Infiernillo rockfill dam using trapezoids in the core and transitions, and variable Young's modulus and Poisson's ratio, reveals the transfer of stress that takes place around the core. Comparisons of strain observations at El Infiernillo Dam with results from the analysis are good, except in zones of compacted rockfill. It appears that the actual stiffness of compacted granular fills may be seriously underestimated, if soil parameters are based on data obtained from triaxial tests on normally consolidated samples. A fundamental understanding of soil deformation behavior would lead to an improvement in the finite element analysis of soil structure.


Author(s):  
Thomas D. White ◽  
A. Samy Noureldin ◽  
Dwayne Harris ◽  
John E. Haddock

Subsurface drainage is important for long-term pavement performance. Rational procedures to analyze and evaluate the design, reliability, and effectiveness of subsurface drainage systems are needed in order for their use to be recommended with confidence. Three pavement subdrainage test sections were constructed in 1995 on the eastbound driving lane of I-469 in Indiana, at the northern junction with I-69, between Stations 150+05 and 173+40. Presented are the original laboratory characterization and mechanistic evaluation for permanent deformation and stability of the test sections employing finite element analysis. Triaxial tests were conducted on all pavement layers of the sections. Falling weight deflectome-ter evaluations in 1995 and 1998 are also presented. Such measurements are not available after 1998 because compliance with Indiana Department of Transportation safety regulations is required at that location. Finite element analyses were conducted by using laboratory-measured material properties to predict pavement response to falling weight deflec-tometer loads, compare predicted and measured deflections, examine layer shear stability for shear stress and strength, and predict rutting. Long-term pavement performance indicators up until 2007 (including international roughness index and ground penetration radar), after 12 years of heavy truck traffic, are also presented. Finite element analysis predicted very well the deflections measured by the falling weight deflectometer and accumulated rutting of the three test sections. Comparisons of shear stresses and strengths indicated that the sections were stable. All long-term evaluations indicated that all drainage layers in the study sections have performed their function adequately and protected the subgrade.


Author(s):  
Th. Zisis ◽  
A. Kordolemis ◽  
A. E. Giannakopoulos

Functionally graded materials (FGMs) are composite materials that exhibit a microstructure that varies locally in order to achieve a specific type of local material properties distribution. In recent years, FGMs appear to be more interesting in engineering application since they present an enhanced performance against deformation, fracture, and fatigue. The purpose of the present work is to present evidence of the excellent strength properties of a new graded composite that is inspired by the human teeth. The outer surface of the teeth exhibits high surface strength while it is brittle and wear resistant, whereas the inner part is softer and flexible. The specific variation in Young’s modulus along the thickness of the presented composite is of particular interest in our case. The present work presents a finite element analysis and an experimental verification of an actual composite with elastic modulus that follows approximately the theoretical distribution observed in the teeth.


1994 ◽  
Vol 31 (2) ◽  
pp. 145-150
Author(s):  
C.B. Crawford ◽  
H. Jitno ◽  
P.M. Byrne

The discrepancy between calculated consolidation settlements and measured settlements under a 3.8 m high section of an earth embankment is investigated in this paper. A conventional one-dimensional analysis underestimated the observed settlement by 40%. A two-dimensional finite-element analysis was carried out to assess the effects of lateral spreading on vertical movements, and the results were in close agreement with the measured values. Key words : case history, consolidation, finite element analysis, settlement.


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