BLASTING EFFECT ANALYSIS ON THE NANJUNG TUNNEL STABILITY

• Main Author: Jasipto, Alio
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47018
• Institution: Institut Teknologi Bandung

Analytical research to predict blasting vibrations as a control, so that the stability of tunnel excavation is maintained has often been carried out. The equation obtained from the vibration prediction is widely used to estimate the standart vibration in blasting plan, but it is not always continued in numerical analysis. However, if this prediction can be used as an input parameter in a numerical model, many other parameters can be predicted as well as the safety factor and total displacement. Blasting vibration measurements have been made at several points around the tunnel using two minimate units. The cross section for data analysis and processing was chosen at STA 30-32 tunnel two which became the pre-model and stage 1 model, this was based on the use of explosives in this event. In addition, the model was verified to be a stage 2 model by modeling on blasting another day . Overall numerical models are made close to the field conditions both the geometry of the model and its input parameters. Pre-model results explain that peak particle velocity (PPV) on the surface will be lower when the density and modulus of young material is higher. The results of the PPV model 1 that uses 2% damping ratio are not much different from the actual PPV. PPV modeling is 2.43 mm/s produced from 6.8 kg explosives which is equivalent to 0.06 MPa blastload. The results of verification of the model 2, the difference between the actual PPV model and 0.57 mm / s and 1.17 mm / s. Tunnel stability in stable conditions based on the results of safety factors that are greater than 1 and total displacement are still allowed according to strain level diagram Sakurai, 1983.