Study of engineering geology and analysis of rock slope stability in karstic areas

Design and construction of engineering structures in karstic areas can face numerous problems due to the dimensions and geometry of karstic structures and existence of unpredictable locations and cavities. Therefore, comprehensive investigations may help to avoid hazardous areas, plan preventively and take effective and corrective course of actions. In this study, due to the karstic conditions of the foundation of the Khorramabad's artificial waterfall, different methods were used to evaluate the engineering geological features of the karst and analyze the rock slope stability. These methods include determination of the physical, mechanical, hydraulic and solubility properties of the rock samples obtained from the boreholes drilled in the rock slope. In addition, karst geomorphology and rock engineering classification were studied for karst development and engineering judgement. To determine and analyze possible landslides in the rock slope, Dips, Roclab, Rockplane, Swedge and Slide softwares were used in static state and in contact with surface water flow. According to the results, the region is a young karst in terms of karst maturity and the solubility velocity constant of the limestone is 6.99×10-5 m / s. Also, possible slips detected in the rock slope are of plate, wedge and mass types, whose long-term stability will be provided by anchors and shotcrete. However, due to the stabilization costs, environmental problems causing by cement injection in karstic dissolved cavities and increase in landslides risk causing by surface water flow, it was recommended that preventive planning be considered for the construction of the waterfall at the proposed site.