Test 2 [KB] Flashcards
What are test pits ? 3
1.Test pits are holes are used in site investigation engineering to expose subsurface soil and rock layers for examination and testing.
2.They are typically dug manually or with a backhoe.
3.Test pits provide a direct visual inspection of soil and rock layers, allowing for the identification of soil types, rock types, and any other features such as water table and soil structure.
Briefly summarize the advantages of test pits. (2)
- They are relatively inexpensive [1] and quick to excavate [2], making them a cost-effective option.
What are test pits safety issues in 5 points?
- Test pits can be unstable and may collapse, especially if they are dug in loose soil or at a steep angle.
- Test pits can be hazardous in weather conditions such as heavy rain because it reduces friction between soil particles.
- These possible collapses can pose a danger to workers and equipment.
- Make sure test pits can always quickly and easily be escaped.
- Also, digging such pits may inadvertently damage underground utilities such as water or gas lines, electrical cables, or sewers. Always consult with the city when digging test pits in urban areas.
Why can’t a site investigation be conducted entirely through examination of photographs/maps?(3)
1.Photographs and maps can provide information about the surface features of a site, such as topography, vegetation, and man-made structures.
2.Geologic maps, survey maps, mining records, and hydrological maps can provide information about the subsurface soil, rock layers, and water content.
3.However, the subsurface soil, rock layers, and water content may have changed over time and may be highly variable, even in a small area.
How can the complementary information to photographs/maps be obtained? 2
1.Complementary information may be obtained by visiting the site, visually examining, and interacting with local residents and specialists.
2.Then, by bringing equipment to the site, you can dig exploratory test pits and trenches, logging of rock outcrops, statistics on jointing, index testing in-situ, reconnaissance by helicopter or light airplane, and seismic or electromagnetic geophysical traverses.
What is pore pressure?
Pore pressure refers to the pressure exerted by fluids (such as water or air) that occupy the spaces, or pores, within a rock or soil.
In a rock and soil context, pore pressure is an important factor that can affect the stability and behavior of geological formations.
What is a creep test of rocks?
The creep test is a laboratory test used to measure the deformation behavior of a material over time when subjected to a constant load or stress.
The test is typically performed on a small sample of the material, such as a cylindrical core or a soil specimen, and involves applying a constant load or stress to the sample and measuring the resulting strain or deformation over a period of hours or days.
