Abstract:
Excavation of pits, trenches for foundations of civil buildings and industrial structures
in saturated clayey soils often leads to soil structural change and great decrease in the soil strength
and deformation characteristics. In some cases, an artificial sand base is used as a method for
construction on saturated clayey soils. However, technology violations and unsuitable material
used during construction can be the reason for excess settlement of the erected facilities. The study
includes a real example of an emergency situation at gantry crane railways with three hundred
meters in length in the town of Tobolsk. The artificial base was made using local sand with
specific properties such as subsidence and frost heaving, which were not taken into account in the
design process. The observed excess non-uniform base deformations were up to 240 mm. The base
properties of the silty sand were analyzed in a laboratory study. Two tests were carried out to
simulate possible impact on the artificial sand base. They showed that the values of the initial
compaction factor Kcom of sand base were found in the range of 0.87-0.92. So, the base subsidence
was about 12% of the actual base deformation and the total base settlement under the total
operation loading made about 19%.
