The influence of the choice of strain modulus value on foundation settlement

• Autorzy: Jastrzębska M. , Łupieżowiec M.
• Języki publikacji: EN

Abstrakty

EN

The paper aims at presenting the influence of strain moduli chosen at the stage of designing on the values of foundation settlement. The settlement forecasting prevailing now is still based on the readings of the primary and secondary values of soil deformation moduli from standard PN- 81/B-03020 as the values dependent on soil state and the type or origin. Such an approach is contradictory to the discovery of a strong nonlinearity of strain characteristics in the range of small strains (10(-5)-10(-3)) and does not take into consideration an increase in the modulus with the depth (with increasing mean effective stress). Therefore, for the needs of this paper, Young's modulus E has been determined for silt, based on precise triaxial tests with a local measurement of strains, and also a numerical FEM analysis has been carried out using the Z_Soil v. 2007. The analysis carried out for small foundations (2.0 m × 2.0 m footing, 400 kPa load, and 0.5 m × 0.5 m footing, 600 kPa load) and for a large foundation (40.0 m × 40.0 m raft, 200 kPa load) has shown a clear reduction of settlement, even threefold, assuming a variable value of the modulus E. This reduction is especially visible for large foundations.

Słowa kluczowe

EN

foundation settlement; strain modulus

PL

osiadanie fundamentu; moduł odkształcenia

• Wydawca: De Gruyter
• Czasopismo: Studia Geotechnica et Mechanica
• Rocznik: 2011
• Tom: Vol. 33, nr 2
• Strony: 31--39
• Opis fizyczny: Bibliogr. 9 poz.

Twórcy

autor

Jastrzębska M.

autor

Łupieżowiec M.

• Silesian University of Technology, Gliwice,

Bibliografia

• [1] BURLAND J.B., "Small is beautiful" – the stiffness of soils at small strains, 9th Bjerrum Memorial Lecture, Canadian Geotechnical Journal, 1989, Vol. 26, 499–516.
• [2] JASTRZĘBSKA M., Calibration and verification of one-surface elasto-plastic soil model of strongly non-linear anisotropic strengthening (in Polish), PhD Thesis, Silesian University of Technology, Gliwice, 2002.
• [3] JASTRZĘBSKA M., Investigations of the behaviour of cohesive soils subject to cyclic loads in the area of small deformations (in Polish), DSc Monograph, Silesian University of Technology Publishers, Gliwice, March 2010.
• [4] JASTRZĘBSKA M., ŁUPIEŻOWIEC M., Foundations settlements taking into account the variability of strain moduli (in Polish), 56th National Conference of KILiW PAN and KN PZiTB, Kielce–Krynica, September 2010, 145–152.
• [5] KRIEGEL H.J., WEISNER H.H., Problems of stress–strain conditions in subsoil, Proceedings of 8th Int. Conf. on Soil Mechanics and Foundation Engineering, 1973, Vol. 1, No. 3, 133–141.
• [6] KUWANO J., KATAGIRI M., Recent state of laboratory stress–strain tests on geomaterials in Japan, [in:] Advanced Laboratory Stress–Strain Testing of Geomaterials, A.A. Balkema Publishers, Tokyo, 2001, 47–52.
• [7] ŁUPIEŻOWIEC M., Analysis of large-size structures foundation taking into account a strong variability of soil stiffness in the area of small strains (in Polish), Scientific Papers of Cracow University of Technology, Environmental Engineering series, Cracow, 2010.
• [8] MAIR R.J., Development in geotechnical engineering research: application to tunnels and deep excavations, Proceedings of the Institution of Civil Engineers, Unwin Memorial Lecture 1992, Civil Engineering, 1993, Vol. 93, 27–41.
• [9] ZIMMERMANN TH., TRUTY A., URBAŃSKI A., PODLEŚ K., Z_Soil.PC 2007 3D user manual, Theory, Tutorials and Benchmarks, Data Preparation, Elmepress International & Zace Services Ltd, Switzerland, 2007.