Applications of various shotcrete types in mine tunnels: a case study

Shotcrete is widely used in mines and tunnels as a reinforcement material. It is also the most expensive element of supporting systems. This study is performed to reduce expenses of shotcrete by keeping the quality in acceptable limits. Site specific investigation is performed at Mine Company called Cayeli Bakir. This company is at the North - East of Turkey producing copper and zinc. Firstly literature review is done and data are collected for investigation. The effect of particle size distribution on uniaxial compressive strength is investigated. The effect of superplasticizers/water, superplasticizers/cement, water/cement and fine aggregate /coarse aggregate ratio on uniaxial compressive strength of shotcrete is determine through literature data and some mix compositions are suggested to be tried. The operational restrictions on site changed these suggestions and revised mix compositions are sampled for investigations. The reasons of change in mix compositions are discussed and an algorithm for this type of studies is presented through experiences. The results of site investigations showed that slump and particle size distribution has an important effect on uniaxial compressive strength, but this idea should be supported more site data.