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A cut and fill is a procedure at construction sites to level slopes and create cuttings, canals, and embankments by removing earth from one point and using it as a fill in another. Techniques for this procedure have several distinct benefits, the most attractive of which are the time and cost savings the process offers. Transporting fill material to a construction site is time consuming and can add significantly to the overall project expense. The environmental footprint of any project is also minimized as there are no off-site, secondary excavations involved. Cut and fill operations on large sites featuring complex topography are generally carried out according to plans calculated by specialized software applications.
Suitably flat construction sites are very rare indeed; in most cases, some removal or supplementation of material will be necessary to level sites. This is particularly true of projects planned for sloping sites and in the construction of roads, railways, and canals. Sloping sites often require extensive local excavation and filling to gain the level ground needed for floor layouts, gardens, access, and parking areas. Railway, canal, and road routes require less local intervention but cover extended routes. The cost of supplementation of material from off-site sources is often cost prohibitive in both cases, however. The practice of using material removed from one area of a site to meet fill requirements in others represent significant savings and forms the core of cut and fill theory.
In the case of building construction on sloping sites, the material cut away from the slope at the building's footprint area is used to fill the gradient below that area. These fills are typically compacted and contained by retaining walls. In the case of railway and road construction, material is often cut away on slopes to maintain gradients and level carriage ways. This material is then typically used to form embankments along the cut areas which then form barriers for adjacent bodies of water or marshy areas and may also serve to mitigate air pollution due to the dispersal effect of the “valleys” they form. The cut material is also often used to cover rocks and tree stumps along the route and to stabilize the slope above the track or road.
Calculating cut and fill balances can be tricky, and especially on large site with complex slope profiles. Software applications such as Quantm and DynaRoad are then employed to create accurate maps of the topography and calculate the optimum cut and fill process. These programs can be used to calculate any excess fill requirements in advance and add considerably to the accuracy of preconstruction planning and cost analysis. This process also serves to minimize a project's total environmental signature because little or no additional, off-site excavation is required.