Drilling and Blasting Techniques in Tunnel Construction
Overbreak Definition and Consequences
Overbreak is an undesirable effect produced when the volume of rock excavated due to blasting is larger than the theoretical volume. It can be expressed as the ratio of the difference between the actual cross-section (Sa) and the theoretical one (St): (Sa – St) / St. The over-profile or extra-profile can also be defined as the ratio of the difference between the theoretical and real areas of the cross-sections to the perimeter of the tunnel, excluding the floor:
Read MoreUnderstanding Material Types, Properties, and History
What Are Materials?
A material is any substance used for the construction of an object. Raw materials are resources obtained from nature to be used in subsequent production processes.
Evolution of Material Use
Technology and progress are strongly related to the number and types of materials utilized. Each new historical stage incorporated new materials, some serving to define an era, such as the Stone Age, Bronze Age, and Iron Age. Primitive humans used materials like stone, wood, and clay.
Material
Read MoreGeosphere Dynamics: Geological Processes & Volcanic Hazards
Geosphere Dynamics and Processes
External Geological Processes
These processes occur on the most superficial layer of the lithosphere. External agents like atmospheric gases, water, ice, and wind drive geological processes such as:
- Weathering: The physical or chemical alteration of rocks.
- Erosion: The movement of weathered materials to lower areas.
- Transport: The carrying of eroded materials.
- Sedimentation: The settling of transported materials, which can eventually transform into sedimentary rocks.
Internal
Read MoreGothic Architecture: Cathedrals, Monasteries, and Innovations
Gothic Architecture: Cathedrals and Monasteries
In the mid-12th century, Romanesque buildings began to be replaced by large and slender European churches in cities. These Gothic cathedrals were financed by nobles and abbots of the great monastic orders. The groups involved in building these cathedrals were linked to the new social group: the bourgeoisie. The Gothic building style appeared around 1140, coinciding with the construction of monasteries, reflecting the influence of monastic life and thought
Read MoreGeological Processes and Landform Evolution
Geological Processes
External Geological Processes
Weathering
Weathering is the disintegration of rocks due to external agents. It alters geological fractures and minerals. There are two main types:
- Gelifraction (Frost Wedging): Water expands upon freezing, widening cracks within rocks.
- Thermoclastia: Rock rupture due to intense sunlight exposure.
- Decompression: Expansion and fracturing of rocks formed at great depth.
Chemical Weathering
Chemical weathering is the disintegration of rocks due to chemical
Read MoreWater Resource Uses and Sustainable Management Strategies
Water Resource Base
Urban Uses
Civil, commercial, or public use. An increase in these water uses can be an indicator of an increased population or improved quality of life. The quantity of water used for purposes such as domestic needs (e.g., bathrooms) represents a significant part of consumer demand.
Industrial Uses
In this case, water demand is generated by different industrial processes: as a raw material, as a refrigerant, as a waste receiver, for transporting materials, and as a cleaning agent.
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