Soft Soil

The manuscript deals with the experimental and 3-dimensional numerical studies carried on the soft clay bed reinforced with three different types of 3D-cellular confinement systems. The geogrid cells, commercial geocells and the bamboo cells are the three different types of 3D-cells used in the study. First, laboratory plate load tests were performed on the soft clay beds. Subsequently, numerical simulations were carried out to compliment the experimental findings. The numerical simulations were carried out in 3-dimensional framework using FLAC 3D by considering the actual honeycomb shape of the geocells. The foundation soil, infill soils and the cell materials were modeled with three different material models, namely, modified Cam-clay, Mohr Coulomb and the linear elastic models. The maximum bearing capacity was observed in the case of foundation bed reinforced with the bamboo cells due to its higher stiffness, higher tensile strength and the higher surface roughness values. Using the validated numerical model, the effect of tensile strength and the surface roughness of the geocell on the performance of the reinforced soft clay beds were quantified. The tensile strength of the geocell material found to have a more pronounced influence than the surface roughness. In addition, a hypothetical case of the prototype foundation on the soft clay has been analyzed and results of the model and prototype cases were found to be in accordance with each other.

This research aims to investigate; strength characteristics of artificial granular material for soft soil cement stabilization, design parameters of artificial granular column elements encased geogrid, and bearing capacity of artificial granular column soft soil reinforcement models. Artificial granular material consisting of triangular prisms, cubes and hexagon prisms of the same volume, made from cement stabilized soft soil using the trial mix method to represent strength equivalent design criteria of road sub-base layer. Artificial granular column elements test and soft soil reinforcement models test with geogrid-made granular column systems were carried out in each shape variation. Based on design criteria CBR value=20% for road sub-base layer, then cement stabilization is set at 12.5% which corresponded to the value of qu=400 kN/m 2 with cement water ratio w/c of 1.9. Sub-grade modulus column elements in various granular forms E=1.58-2.67 kN/m 2 with poisson  =0.29-0.33, granular hexagon prism shows higher capacity performance and design parameters. Soft soil reinforcement model with artificial granular columns-geogrid is significance improving bearing capacity of soft soil foundation systems with an increase ratio of 28.5-33; the granular hexagon prism shows capacity performance and design parameters higher than other granular types.

We examine the possible non-linear behaviour of potentially liquefiable layers at selected sites located within the expansion area of the town of Nafplion, East Peloponnese, Greece. Input motion is computed for three scenario earthquakes, selected on the basis of historical seismicity data, using a stochastic strong ground motion simulation technique, which takes into account the finite dimensions of the earthquake sources. Site-specific ground acceleration synthetics and soil profiles are then used to evaluate the liquefaction potential at the sites of interest. The activation scenario of the Iria fault, which is the closest one to Nafplion (M=6.4), is found to be the most hazardous in terms of liquefaction initiation. In this scenario almost all the examined sites exhibit liquefaction features at depths of 6–12 m. For scenario earthquakes at two more distant seismic sources (Epidaurus fault – M6.3; Xylokastro fault – M6.7) strong ground motion amplification phenomena by the shallo...

This research aims to investigate; strength characteristics of artificial granular
material for soft soil cement stabilization, design parameters of artificial granular
column elements encased geogrid, and bearing capacity of artificial granular column
soft soil reinforcement models. Artificial granular material consisting of triangular
prisms, cubes and hexagon prisms of the same volume, made from cement stabilized
soft soil using the trial mix method to represent strength equivalent design criteria of
road sub-base layer. Artificial granular column elements test and soft soil
reinforcement models test with geogrid-made granular column systems were carried
out in each shape variation. Based on design criteria CBR value=20% for road subbase
layer, then cement stabilization is set at 12.5% which corresponded to the value
of qu=400 kN/m2 with cement water ratio w/c of 1.9. Sub-grade modulus column
elements in various granular forms E=1.58-2.67 kN/m2 with poisson  =0.29-0.33,
granular hexagon prism shows higher capacity performance and design parameters.
Soft soil reinforcement model with artificial granular columns-geogrid is significance
improving bearing capacity of soft soil foundation systems with an increase ratio of
28.5-33; the granular hexagon prism shows capacity performance and design
parameters higher than other granular types.

Piled raft system proves to be more effective on such problematic soft soil conditions. It takes the high vertical load and used to bring the settlement, differential settlement and tilting of structure within the permissible limit. Piled raft system proves to be cost effective than the conventional pile foundation system. Piled raft foundation accounts for complex soil-structure interaction, which needs interaction between structural engineer and geotechnical engineer. Geo-foam application is introduced below the footing to enhance floating resistance. The performance behavior of piled raft foundation in clayey soil and layered soil is carried out using laboratory experimental and then verified by 2D PLAXIS. There is a significant relationship between the decrease in settlement of the piled raft due to hydrostatic uplift.

The effect of stiffness degradation on the lateral strength demands of inelastic single-degree-of-freedom systems subjected to soft soil records is investigated. The modified-Clough model is used to represent structures that exhibit significant stiffness ...

Among all the possible options to define the seismic input for structural analysis, natural recordings are emerging as the most attractive. Easily accessible waveform databases are available and evidence shows that only a relatively limited number of criteria has to be considered in selection and scaling to get an unbiased estimation of seismic demand. Like many codes worldwide, Eurocode 8