Risk assessment and modelling for underground cavern construction project

Abstract

Many cost-time models available today are based on previous underground construction projects where the models originated from. This is unfavourable for Singapore as her geological

conditions differ from these countries. As such, a cost-time model catered to Singapore’s geological condition was constructed. This includes the use of Kriging interpolation and average advance rate method to construct the cost and time model respectively with available field data. Kriging interpolation was used as it approximates the estimation error and estimate of the variable together, thus, resulting in better predictions. However, the average advance rate method was adapted from a study done by Paraskevopoulou and Benardos (2013). Both models used different methods to construct as the data available was not sufficient to adopt the same methodology. Although the cost and time models were constructed differently, it has shown that the model was effective to a certain extent. It was noticed that the model worked well in the equivalent geological condition of RMR range 61-80 with cross-sectional areas between 170- 180m2. Similarly, it has also highlighted that with more field data, the model could be heightened. The eventual cost-time model consists of a graph with the predicted excavation costs and a table with the predicted excavation costs and advance rate. With the values obtained from this cost-time model, it can be used as the inputs for DAT in the project conceptualisation phase for future underground cavern construction projects in Singapore.