PSI - Issue 6

L.N. Kondratieva et al. / Procedia Structural Integrity 6 (2017) 101–108 L.N. Kondratieva, V.M. Popov,P.Ye. Medvedsky/ StructuralIntegrity Procedia00 (2017) 000 – 000

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Fig. 4. Isofields of soil shearing stresses in sheet pile corset of different dep th: а – without corset; b – ℎ ℎ = 5 m; c – ℎ ℎ = 10 m; d – ℎ ℎ = 30 m Analyzing the calculation results we may conclude that where corset is placed at depths over 10 m - maximum shearing stress value is being considerably decreased causing shearing stresses to "spread" lengthwise the pile sheeting. It is possible also to point out that deep corset is causing the shearing stresses to grow both along its internal and external sides. Placement of sheet pile corset is causing horizontal stresses to be limited and to be transferred towards the corset. Where corset depth is relatively small (at 300 kPait is amounting to 5m - i.e. it is corresponding to the width of applied load 0.5 b ; at 500 kPa this depth is 10m) it is expected that horizontal stresses occurring below the corset will influence settlement (i.e. decrease it).Where corset has larger depth it is expected that all horizontal stresses will be "re-directed" (in condition of absolutely stiff confining element). Thus, settlement lowering effect (which could be caused by horizontal stresses impact underneath the sheet piling) will not take place. Shearing stresses may cause minor soil movement in the bottom part of the corset. We managed to verify the calculation methodology by correlating the results of clay soil stress-strain distribution in sheet pile corset with results of laboratory testing of sandy soil enclosed in cylindrical steel envelope Ledenev, V.V. and Savinov,Ya.V. (2002). Analysis of investigation results gave satisfactory produced good agreement. In order to verify correctness of the invented methodology we compared the results of settlement calculations with results of geotechnical monitoring of residential 8-storeyed house with address as follows: Saint Petersburg, Shkapin Street, 13 which was constructed with the use of pile sheeting along the contour which was removed upon completion of construction works. In order to perform calculation using Plaxis 3D software Brinkgreve, R. B. J., Engin, E., Swolfs,W. M. (2013)we developed the model of foundation with footing, inter alia, with earth footing enclosed in sheet pile corset (Fig. 5).

Fig. 5. 3-D model

We investigated zones of distribution of soil body plastic points with and without corset (Fig. 6). а)