THE CONSOLIDATION OF PEAT

ONE-DIMENSIONAL CONSOLIDATION THEORIES HAVE BEEN DEVELOPED FOR AMORPHOUS GRANULAR PEAT AND FIBROUS PEAT. THE THEORIES TAKE ACCOUNT OF FINITE STRAIN, A DECREASING PERMEABILITY AND COMPRESSIBILITY, AND SECONDARY COMPRESSION TIME EFFECTS. THE DIFFERENT PHYSICAL MECHANISMS INVOLVED IN THE SECONDARY COMPRESSION OF THESE TWO EXTREME TYPES OF PEAT ARE DISCUSSED AND ARE SHOWN TO LEAD TO SIMILAR NON-LINEAR RHEOLOGICAL MODELS, ALTHOUGH IT IS ARGUED THAT THEIR EFFECTIVE STRESS-STRAIN-TIME EQUATIONS ARE FUNDAMENTALLY DIFFERENT. A REVIEW IS MADE OF PUBLISHED EXPERIMENTAL DATA AND THIS SHOWS THE THEORIES TO BE IN ESSENTIAL AGREEMENT WITH THE MAIN REPORTED FINDINGS. AN IMPORTANT FEATURE OF THE THEORIES IS THAT THEY TEND TO SUBSTANTIATE THE PRIMARY H SQUARED SCALING LAW. A REASONABLE ENGINEERING ASSESSMENT OF THE FIELD BEHAVIOUR MAY THEREFORE BE MADE BY EXTRAPOLATING THE LABORATORY SECONDARY COMPRESSION TAIL AND SCALING THE PRIMARY CURVE ACCORDING TO H SQUARED. DEPARTURES FROM THIS SIMPLE SCALING LAW ARE ATTRIBUTED TO THE TESTING OF UNREPRESENTATIVE SAMPLES OR TO THE LATERAL FLOW OF PORE WATER AT THE FIELD SCALE. A TECHNIQUE IS SUGGESTED FOR OBTAINING THE BASIC PARAMENTERS OF THE THEORIES FROM SETTLEMENT RECORDS, AND THE RESULTS OF AN EXPERIMENTAL INVESTIGATION ARE GIVEN TO SHOW THE ADEQUACY OF THIS PROCEDURE. TEST RESULTS ON AMORPHOUS GRANULAR AND FIBROUS PEAT ARE GIVEN AND SHOW VERY CLOSE AGREEMENT WITH THE THEORETICAL PREDICTIONS OF SETTLEMENT AND DISSIPATION OF PORE PRESSURE (A).