Page 43 - Built Expressions - Online Construction Magazine - November 2014 Issue

Cover Feature This includes such applications as compacting the fll over a trench, compacting soil around a footing, or working in areas where large equipment might cause damage to adjacent structures or property. Manually operated compactors come in a number of different styles depending on the application. There are small steel-wheel rollers, vibratory plate compactors, and rammers. While these smaller compactors allow the Contractor to work in small areas, they require more time and effort to compact the material to the required density. The use of full-size equipment is generally preferred where possible. Earth compactors-are designed for diverse application in compacting soil, sand and breaking stone. Therefore these earth compactors are ideal for construction purposes and road tunnellingjournal.com projects since these works require compaction. Earth compactors are used for compaction of top layer of earth. Tunnelling Equipment Plate Compactors- are particularly suitable for application like Tunnels of less than a meter or so in diameter are typically compacting loose gravel and sand done using trenchless construction methods or horizontal on footpaths, sub-grade for concrete foors, trenches, column footings & directional drilling. for small repair works like pot-hole repairs. 7. Grader Equipment is embankments & providing blanket of less than a meter or so in diameter A grader is also known as a road grader, surface before spreading ballast and are typically done using trenchless a blade, a maintainer or a motor laying track. Graders are also used construction methods or horizontal grader. This is a construction machine to set native soil foundation pads to directional drilling. Tunnelling with a long blade used to create a fat fnish grade prior to the construction equipment has limiting disturbance surface. Graders can produce inclined of large buildings and for underground to the surrounding ground and surfaces, to give cant (camber) to mining. Capacities range from a blade producing a smooth tunnel wall. This roads. In some countries they are width of 2.50m to 7.30 m and engines signifcantly reduces the cost of lining used to produce drainage ditches with from 93–373 kW (125–500 hp). the tunnel and makes them suitable shallow V-shaped cross-sections on to use in heavy urbanized areas. The either side of highways. Graders are 8. Tunnelling Equipment major disadvantage is the upfront commonly used in the construction Tunnelling equipment is a machine cost. TBMs are expensive to construct and maintenance of dirt roads and used to excavate tunnels with a circular and can be diffcult to transport. gravel roads. In the construction of cross section through a variety of soil However, as modern tunnels become paved roads they are used to prepare and rock strata. There can bore through longer, the cost of tunnel boring the base course to create a wide fat hard rock, sand and almost anything machines versus drill and blast is surface for the asphalt to be placed in between. Tunnel diameters can actually less-this is because tunnelling on. Similarly, graders are used for range from a meter (done with micro- with TBMs is much more effcient and levelling the surface during earthwork TBMs) to almost 16 meters. Tunnels results in a shorter project period. Vol: 3 Issue: 11 November 2014 Built Expressions PG 43