Behaviour of small groups of granular columns in clay

Hope, David (1988). Behaviour of small groups of granular columns in clay. University of Birmingham. Ph.D.

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Abstract

The results of a laboratory investigation into the behaviour of small groups of up to five granular columns, in soft clay, loaded by various foundation configurations under rapid undrained conditions is presented. Columns with a constant layer length to diameter ratio in both floating and end-bearing conditions are considered. Electronic instrumentation was developed to record boundary stresses and displacements and radiographic techniques were employed to measure internal displacements and strains in the columns and clay.

Extensive use of interactive mainframe and mini computers was made in collecting, storing and processing the laboratory data.

The improvement in bearing capacity and reduction in settlement was found to be strongly dependent on the relative column and clay areas in contact with a foundation. The column end-bearing condition was also a contributory factor.

The mechanism of column and clay deformation was observed as being dependent on the boundary conditions. Column yield occurred as a general shear failure or a local shear failure depending on the relative sizes of the clay and column areas.

Laboratory results showed that direct analogy with conventional piles or pile groups cannot be made. An empirical relationship for estimating the improvement in bearing capacity and settlement is proposed.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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