GEOE 413 Lecture Notes - Lecture 21: Free Surface, Backhoe, Demobilization

• School: Queen's University
• Department: Geological Engineering Courses
• Course: GEOE 413
• Professor: Mark S Diederichs

Document Summary

Excavation methods: manual hand excavation, mechanical cutters, rippers and road headers, drilling and blasting, tunnel boring machines, slurry, earth pressure balance, hard rock. Huge steel bar with pointy bits of steel. It gets turned and hit into the rock. Used so you can put dynamite in. Runs on air with an oil line to keep lubricated. Greater level of movement than regular backhoe. If rock is a bit harder it can be fitted with a hoe ram: jackhammer on steroids. Lower over break than blasting creating a smoother profile. Simultaneous mucking and breaking possible in large openings. Lower cost requirements for the tunnel equipment at the beginning of the project. Flexibility to install additional support measures, rock bolts, dowels, steel ribs if required. Higher rock strength or abrasiveness directly increases tool wear and costs. Where existing weakness planes are absent, excavation can be difficult. Sinkhole in ottawa happened because of this. Key to determine where any bottle necks are.