Kamila Międlarz, Jakub Konkol and Lech Bałachowski
1.1 Aim of research
This research is focused on effective angle of internal friction and compares the results for the Vistula Marshlands muds and peats with similar softsoils. Effective shear strength parameters of the deltaic soils near Gdańsk are measured in drained and undrained triaxial compression tests and estimated with the Norwegian Institute of Technology (NTH) method using the Cone Penetration Tests (CPTU) sounding. The observed dilative-contractive soil behaviour is discussed taking into account the CPTU classification chart
Wei Wang, Na Li, Fang Zhang, Aizhao Zhou and Snow Chi
IREEN: The effect of freezing-thawing cycles on performance of fly ash stabilized expansive soil subbases. Geotechnical Special Publication, 211: 697(2011).
13. J. J. GUO, W. WANG, X. N. WANG: Improved hyperbolic model for harden/soften stress-strain curve of Yangtze River soil. The Electronic Journal of Geotechnical Engineering, 17(L): 1675(2012).
14. W. WANG, X. J. SONG, H. LING, T. H. LU, G. W. ZHOU: Composite exponential-hyperbolic model for stress-strain curve of seashore softsoil. Chinese Journal of Geotechnical Engineering, 32
5. Z. Lechowicz, A. Szymański, Deformations and stability of embankments on organic soils [in Polish], Wydawnictwo SGGW, Warszawa 2002.
6. H.P. Neher, M. Wehnert, P.G. Bonnier, An evaluation of softsoil models based on trial embankments, Plaxis B.V., Delft, The Netherlands.
7. Z. Wiłun, Outlines of geotechnics [in Polish], Wydawnictwa Komunikacji i Łacznosci, Warszawa 2003.
8. D.M. Wood, Soil behaviour and critical state soil mechanics, Cambridge University Press 1990.
Road embankments, especially their slopes’ surfaces, must fulfil all the requirements concerning the exploitation criteria after the completion of construction works. This is very important while constructing or modernizing the embankments, based on the substrate including low-strength soils as well as in simple ground conditions (most convenient). The last dozen or so years of intensive construction of transport infrastructure have shown how big is the problem of ensuring the required volumes of qualified soil material for the construction of road embankments or the modernization of railway embankments. The depleting deposits of natural and easily accessible soils for the construction of embankments result in the need to use anthropogenic soils, for example, in the form of aggregates from the recycling of construction waste and other locally available waste materials, usually in the form of slag and ashes from the combined heat and power plants. In such cases, there’s a need to treat transportation earth structures individually in the scope of designing and quality control, because there are no applicable standard provisions in this scope.
This work indicates some of these important contemporary problems of transport engineering, occurring in newly built and modernized road objects, such as the stability of road embankments based on a low-strength substrate, use of anthropogenic soils and materials originating from the recycling of concrete surfaces for the construction of road embankments.
Some important modern problems of the transport engineering, which occur in the newly built and modernised road objects, have been indicated in the work. A discussion was conducted regarding the methods of assessing the stability of slopes of the road embankments, the obtained stability margins and the interpretation of obtained results in the specific cases of foundations of the road earth structures. Presented observations result from analysing the stability assessments of slopes of the road embankments, which was conducted on many communication objects, characterised by high variability of foundation conditions.
5. Chen Wensu. The settlement of softsoil creep numerical simulation. Tianjin: Tianjin Univesity, 2004.
6. Mimura, M., Jeon, B.G. Numerical assessment for the behavior of the Pleistocene marine foundations due to completion of the 1st phase island of Kansai international airport. Soils and Foundations, 2011, 51(6):1115-1128.
7. Mimura, M., Jeon, B.G. Interactive Behavior of the Pleistocene ReclaimedFoun-dations due to the Completion of the adjacent Reclamatio. Annuals of Disas. Prev. Res. Inst., Kyoto Univ., No.54B, 2011
-1688, The Netherlands, 2006.
9. S. N. MALARVIZHI, K. ILAMPARUTHI, Comparative Study on the Behavior of Encased stone column and Conventional Stone Column, Soils and Foundations, 47 , 5, 875-885, 2007.
10. S. MURUGESAN, K. RAJAGOPAL, Model Tests on Geosynthetic Encased Stone Columns, Geosynthetic International, 14 , 6, 346-354, 2007.
11. J. GNIEL, A. BOUAZZA, Improvement of SoftSoils Using Geogrid Encased Stone Columns, Geotextile and Geomembrane, 27 , 3, 167-175, 2009.
12. C. S. WU, Y. S. HONG, Laboratory
Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.
The seismic analysis carried out assuming foundation to be perfectly rigid and bonded to the soil underneath is far from truth and therefore, the soil-structure interaction effect on the dynamic behavior of the bridge pier should be considered. The assessment of soil-structure effect on the design force generated has been estimated using Force based, Capacity Spectrum and Direct Displacement based methods considering fixed and flexible foundations. For this purpose a single cantilever bridge pier of constant diameter with varying heights has been considered for the analysis in different type of soils and earthquake zones. The study has revealed that soil-Structure Interaction index is negative in some cases, especially in soft soil, implying base shear demand being greater than that of fixed base contrary to the traditional views.
. SR EN ISO 10318:2006: “Geosynthetics. Terms and conditions“ (in Romanian).
. W. VOSKAMP, P. RISSEEUW: “Method to Establish the Maximum Allowable Load under Working Conditions of Polyester Reinforcing Fabrics”, în SoftSoil Stabilization using Geosynthetics, Edited by Koerner, Reprinted from Geotextiles and Geomembranes, Vol. 6, Nos 1 - 3, Elsevier Applied Science, Essex, England, 1988, p. 173 - 184.
. SR EN ISO 10319:2008: “Geosynthetics. Wide strip tensile test“(in Romanian