There are many different types of foundation excavations performed during the construction of a project. For example, soil may be excavated from the cut or borrow area and then used as ﬁll . Another example is the excavation of a shear key or buttress that will be used to stabilize a slope or landslide. Other examples of excavations are as follows:
- Footing Excavations. This type of service involves measuring the dimension of geotechnical elements (such as the depth and width of footings) to make sure that they conform to the requirements of the construction plans. This service is often performed at the same time as the ﬁeld observation to conﬁrm bearing conditions.
- Excavation of Piers. As with the foundation excavations , the geotechnical engineer may be required to conﬁrm embedment depths and bearing conditions for piers. above Figure presents typical steps in the construction of a drilled pier.Open Excavations. An open excavation is deﬁned as an excavation that hasstable and unsupported side slopes. below Table 6.16 presents a discussion of the general factors that control the excavation stability, and other Table lists factors that control the stability of excavation slopes in some problem soils.
- Braced Excavations. A braced excavation is deﬁned as an excavation where the sides are supported by retaining structures. below Figure shows common types of retaining systems and braced excavations.
Since most building sites start out as raw land, the ﬁrst step in site construction work usually involves the grading of the site. Grading is deﬁned as any operation consisting of excavation, ﬁlling, or a combination thereof
Easements. The ﬁrst step in the grading operation is to determine the location of any on-site utilities and easements. The on-site utilities and easements often need protection so that they are not damaged during the grading operation
Clearing, Brushing, and Grubbing. Clearing, brushing, and grubbing are deﬁned as the removal of vegetation (grass, brush, trees, and similar plant types) by mechanical means. It is important that this debris be removed from the site and not accidentally placed within the structural ﬁll mass.