Inzhenernaya Geologiya Vol. XIII, No. 6/2018
VLADISLAV A. VASENIN
Vasenin V.A., 2018. Evaluation of disturbed parameters of the natural structure of the laboratory samples of clay deposits during engineering and geological surveys in Saint Petersburg territory and nearest areas. Inzhenernaya Geologiya, Vol. XIII, No. 6, pp. 48-65, https://doi.org/10.25296/1993-5056-2018-13-6-48-65.
In Russian technical standards there are no criteria for the natural structure disturbance degree of laboratory samples of coherent dispersed soils. At the same time, such soils are widely represented in various regions of the country, in particular, in St. Petersburg. The paper discusses various criteria for estimating the degree of natural structure disturbance of laboratory samples, and also considers various methods for restoring the strength of samples. The main attention is paid to the evaluation of the degree of violation of the natural structure of laboratory samples when performing odometric tests. The statistical results of such an assessment are given for more than 3,000 oedometer tests of quaternary soils of different genesis based on deformation criteria. The quality assessment of laboratory samples was evaluated at 130 sites performing engineering and geological surveys (by various organizations) in St. Petersburg from 2003 and 2018. According to the results of statistical analysis, it was shown that the quality of samples by the criterion of the relative change in the porosity coefficient at the effective household stress corresponds to “poor” or “very poor” (according to the scale proposed by Т. Lunne and others). The main causes of the violation of the natural structure of the samples (sampling without primers, violation of sampling and storage rules, as well as transportation of samples) are described. Based on the results of a statistical analysis of the deformation parameters of laboratory soil samples during the implementation of complex geological survey in St. Petersburg, it was concluded that it is impossible to use the test results of these samples for performing geotechnical calculations using modern models of soil mechanics without special correction procedures.
1. Vasenin V.A., 2018. Evaluation of clay deposits physical properties changed regularities in Saint-Petersburg territory and their communication with overconsolidation mechanisms. Geotechnics, № 3, pp. 70–86. (in Russian)
2. Golli A.V., Tikhomirova L.K., 1979. Sampler. Author's certificate of the USSR for invention. № 881196 v. G 01 N 1/04. (in Russian)
3. Golli A.V., Tikhomirova L.K., Shashkin A.G., 1990. Sampler. Author's certificate of the USSR for invention. № 1612228 v. G 01 N 1/04. (in Russian)
4. Golli A.V., Lisyuk M.B., Shulyatiev O.A., 1986. Sampler. Author's certificate of the USSR for invention. № 1259133 v. G 01 N 1/04. (in Russian)
5. Andersen A., Kolstad P., 1979. The NGI 54-mm samplers for undisturbed sampling of clays and representative sampling of coarser materials. Proceedings of the International Conference on Soil Sampling, Singapore.
6. Baligh M.M., 1985. The strain path method. Journal of Geotechnical Engineering, Vol. 111, No. 9, pp. 1108–1136.
7. Baligh M.M., Azzouz A.S., Chin C.T., 1987. Disturbances due to ideal tube sampling. Journal of Geotechnical Engineering, Vol. 113,
No. 7, pp. 739–757.
8. Bjerrum L., 1973. Problems of soil mechanics and construction on soft clays. Proceedings of the 8th ICSMFE, Moscow, Vol. 3,
9. Henkel D.J., 1960. The Relationships between the Effective Stresses and Water Content in Saturated Clays, Geotechnique, No. 10,
10. Lacasse S, Berre T, 1988. Triaxial testing methods for soils. In: Donaghe RT, Chaney RC, Silver ML (eds). Advanced triaxial testing of soil and rock, ASTM STP 977. ASTM, Philadelphia, PA, pp. 264–289.
11. Ladd C.C., Lambe T.W., 1963. The Strength of Undisturbed Clay Determined From Undrained Tests. Symposium on Laboratory Shear Testing of Soils, ASTM STP 361, pp. 342–371.
12. Ladd C.C, Foot R., 1974. New design procedure for stability of soft clays. ASCE Journal of Geotechnical Engineering, Vol. 117, No. 4, pp. 540–615.
13. Ladd C.C., Don J. DeGroot, 2003. Recommended Practice for Soft Ground Site Characterization: Arthur Casagrande Lecture. 12th Panamerican Conference on Soil Mechanics and Geotechnical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA, pp. 1–55.
14. Leonards G.A., 1976. Estimating consolidation settlements of shallow foundation on overconsolidation clay. TRB, Special report, 163.
15. Lunne T., Berre T., Strandvik S., 1997. Sample disturbance effect in soft low plasticity Norwegian clay. Proceedings of the Conference on Recent Developments in Soil Mechanics, Rio-de-Janeiro, 1997, pp. 81–102.
16. Lunne T., Berre T.V., Strandvik S., 1998. Sample disturbance effects in deep water soil investigations. Offshore Site Investigation and Foundation Behaviour 'New Frontiers: Proceedings of an International Conference, 22–24 September, London, UK, pp. 81–102.
17. Nakase A., Kusakabe A., Nomura H., 1985. A method for correcting undrained shear strength for sample disturbance. Soils and foundation, Vol. 25, No. 1, pp. 52–64.
18. Santagata M.C., Germaine J.T., 2002. Sampling disturbance effects in normally consolidated clays. Journal of Geotechnical and Geoenvironmental Engineering, Vol. 128, No. 12, pp. 997–1006.
19. Schmertmann J.N., 1955. The undisturbed consolidation behavior of clay. Transactions of ASCE, pp. 1201–1227.
20. Scofield A.N., Wroth C.P., 1968. Critical state soil mechanics. London: McGraw-Hill.
21. Siddique A., 1990. A numerical and experimental study of sampling disturbance. Thesis diss.
22. Simons N., Menzies B. Matthews M., 2002. A short course in geotechnical site investigation. London: Thomas Telford.
23. Shogaki T., 1994. Effects of samples on strength and consolidation parameter of soft clay. Soil and foundation, Vol. 34, No. 3,
24. Shogaki T., 1996. A method for correcting consolidation parameters for sample disturbance using volumetric strain. Soils and Foundations, Vol 36, No. 3, pp. 123–131.
25. Terzaghi K., Peck R.B. Mesri G., 1996. Soil Mechanics in Engineering Practice. John Wiley and Sons, New York.
VLADISLAV A. VASENIN
Design Institute Georekonstrukciya LLC, Saint Petersburg, Russia, firstname.lastname@example.org
Address: Bld. 4, Оffice 414, Izmailovsky Ave, 190005, Saint Petersburg, Russia