The Use of Lime for Drainage of Cohesive Soils Built into Hydraulic Engineering Embankments

Abstract

This paper examines whether lime can be used for the drainage of cohesive soils built into hydraulic engineering embankments. It is a common practice, as early as the planning stage, to seek to reduce costs and accelerate work while maintaining the quality of work. Although lime stabilisation is not currently a widely used solution in the hydraulic engineering sector, it can play an important role in the future. Lime stabilisation can be considered an optimal solution as it shortens the embankment construction by eliminating the need to replace the soil when it is over-wet. This paper investigates whether it is possible to apply lime treatment in the forming of hydraulic engineering embankments as well as analyses the efficiency of mechanical soil drainage and compares it against chemical drainage (lime stabilisation) based on the example of the construction of the Szalejów Górny dry flood control reservoir located in south-western Poland. It presents the results of geotechnical investigations carried out during the construction phase and compares them with cases reported in the literature. The observation of the construction process reveals a high efficiency and effectiveness of quicklime (CaO) as a stabiliser in the soil used for reservoir dams. Adoption of this technology made it possible to achieve significantly higher embankment formation rates (max. approx. 14,000 m3/week) than when mechanical drainage was used (max. approx. 11,000 m3/week). It was also noted that the lime stabilisation process was significantly independent of unfavourable weather conditions, resulting in frequent high weekly efficiencies. Geotechnical tests on samples of the lime-stabilised soil built into the dam body confirmed the possibility of obtaining favourable strength parameters, particularly with regard to the angle of internal friction, cohesion and degree of plasticity. Therefore, it can be expected that lime will be used more widely in the formation of hydraulic engineering embankments and that soil stabilisation technology will be applied more frequently.