Cross Passages Ground Treatment for Melbourne Metro Tunnel Project-Video

Video Transcription

Video Summary

Maynard treated five poor-ground cross-passages on Melbourne’s nine-kilometre Metro tunnel project before the TBMs arrived. At depths of about 30 metres, overlapping jet-grout columns and rock grouting created stable, low-permeability ground. Installation was challenging in a confined urban environment, including beneath a low-clearance bridge and near live utilities and rail infrastructure. Extensive trials, real-time monitoring, staged grouting adjustments, and verification testing confirmed the treatment met design requirements. Excavation revealed a homogeneous grout mass, and cross-passages were opened without additional internal grouting. Structural movements remained controlled, and the project was completed on time and within budget.

Keywords

Melbourne Metro tunnel

cross-passage grouting

jet-grout columns

ground treatment

tunnel excavation