ABSTRACT
In 2015 expansion of a uranium mine in South Kazakhstan required new infrastructure development. Local soils are represented by aggressive, saline water-saturated sediments (CBR < 0.5%) which are not able to provide a stable foundation for mobile drilling rigs, access roads and working platforms. Traditional technology required drainage, soil replacement and dyke construction. In order to determine a cost-effective and time saving alternative solution, practical research work on the bearing capacity of the foundation soils together with further Mechanical-Empirical (ME) design for the access road was carried out.
Installation of a polymer geogrid-stabilised granular layer over very poor ground made it possible to gain access to conduct static plate loading tests and obtain the actual bearing capacity of the soft soil. The use of this information together with an ME approach allowed an economic access road to be designed that was sufficient to support the heavy loads imposed from travelling or operating drilling equipment. In 2015, the first series of plate tests was performed and a trial road structure, consisting of two Mechanically-stabilised crushed Stone Layers (MSL), was constructed successfully. After this mechanically-stabilised road had been examined and found to be satisfactory in terms of bearing capacity and settlement, site development was continued in 2016 using this alternative approach. The project allowed a better understanding of MSL modelling and performance control methods over extremely soft soil and confirmed the effectiveness of stabilisation geogrid technology.
