LOW-COST ELECTRO-MECHANICAL PRESS FOR DETERMINING PRE-CONSOLIDATION PRESSURE

ABSTRACT

The pre-consolidation pressure is a soil parameter indicating the maximum load that can be supported without irreversible deformation. However, the commercially available equipment for such determination is very expensive, limiting studies on this subject. The objective of this study was to develop a low-cost press model for determining a soil pre-consolidation pressure. The press comprised an electric jack for lifting a soil sample against a fixed piston. A compression cell was built using Technyl®. The stability and smoothness of the applied loads were controlled using springs with different dimensions and strengths. The load and deformation data were obtained using an indicator connected to the load cell and a dial indicator, respectively. The equipment was tested by determining the pre-consolidation pressure in an Oxisol cultivated with cotton and under an area of native Cerrado. The pre-consolidation pressures for a soil water tension of 10 kPa were 50.8 kPa and 61.1 kPa for the soil under the native Cerrado and cotton crop, respectively, and the compressibility indexes were 0.71 and 0.37, respectively. The main advantages of this equipment are its low cost, ease of construction, and simplicity of operation. However, the equipment is non-automatic; thus, the data necessary for the construction of the compression curve must be collected by an operator.

KEYWORDS
uniaxial compression; soil compaction; consolidation test; soil load support capacity