Acceptable Visual Tests

Visual analysis gathers qualitative information about the excavation site in general, the soil next to the excavation, the soil forming the sides of the open excavation, and soil samples from excavated material. It includes the following seven steps:

1. Observe excavated soil samples and soil in the sides of the excavation. Estimate the range of particle sizes and relative amounts of particle sizes. Soil primarily composed of fine-grained material is cohesive material. Soil composed primarily of coarse-grained sand or gravel is granular material.
2. Observe soil as it is excavated. Soil that remains in clumps when excavated is cohesive. Soil that breaks up easily and does not stay in clumps is granular.
3. Observe the side of the opened excavation and the surface area next to the excavation. Crack-like openings, such as tension cracks, could indicate fissured material. If chunks of soil spall off a vertical side, the soil could be fissured. Small spalls are evidence of moving ground and are indications of potentially hazardous situations.
4. Observe the area next to the excavation and the excavation itself for evidence of existing utility lines and other underground structures, and to identify previously disturbed soil.
5. Observe the opened side of the excavation to identify layered systems. Examine layered systems to identify if the layers slope toward the excavation. Estimate the degree of slope of the layers.
6. Observe the area next to the excavation and the sides of the opened excavation for evidence of surface water, water seeping from the sides of the excavation, or the location of the level of the water table.
7. Observe the area next to the excavation and the area within the excavation for sources of vibration that may affect the stability of the excavation face.

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