Air-filled porosity,
plastic limit, and soil strength
The geotechnical characterization tests included: (i) particle-size distribution (ABNT, 1984a); (ii) specific gravity of soil solids (ABNT, 1984d); (iii) liquid limit (ABNT, 1984b); and (iv)
plastic limit (ABNT, 1984c).
Therefore, as the absence of related investigation, the unified strength theory is adopted for
plastic limit load analysis of the shaft lining, which takes the effects of intermediate principal stress and SD effect of material on the material strength into account [7-9], and can be used to analyze the
plastic limit of the shaft lining which is verified by a case study.
In recent years, demand from downstream industries is driven mainly by government regulations like the
Plastic Limit Order and No Plastics Order.
Plastic limit and compaction characteristics of finegrained soils, Proceedings of the ICE-Ground Improvement 9(1): 17-22.
The associated laboratory tests were performed following the procedures outlined by the Technical Specifications of INVIAS (Colombian National Institute of Roads): INV E-125-07 (corresponding to ASTM D 4318-00) to determine liquid limit, INV E-126-07 (corresponding to ASTM D 4318-00) to determine
plastic limit, and INV E-122-07 (corresponding to ASTM D 2216-98) to determine water content.
The PI is the difference between the liquid limit and the
plastic limit of the soil and is a convenient representation of its plasticity characteristics.
The variations of liquid limit and
plastic limit with varying percentages of fly ash are shown in Figures 1 and 2.
The
plastic limit and plasticity index of the soil samples was obtained using ASTM D4318-10 as the basis of the study.
Thus, the Ishlinsky model describes the effect caused by reduction of the
plastic limit under repeated load by a force acting in the opposite direction before the
plastic limit is reached (the Bauschinger effect).
The
plastic limit and plasticity index were significantly high and the optimum moisture content was below
plastic limit [6,7].