SOIL MECHANICS
Assignment 1 – Ground Investigation
All structures start in the ground and have foundations of some sort. It is important therefore to know what the ground is like beneath the structure you are going to build so that you can design suitable foundations. Any project will have a site investigation including intrusive ground investigation. There are many different tests that can be carried out to give all sorts of data. What ones need to be carried out depend on the structure. For instance, a 10 story building will likely need ground investigation to a very deep depth as the load it will be implying will have a great effect deep down and pile foundations may be needed. A small road however will probably not need any investigations deeper than about 4m and these will only be to check that the ground is not complete putty under the topsoil. A desk study is needed to determine what types of testing need to be done, for instance, if a map is produced revealing an old coal mine in the area where you plan on building a house, then you will need to perform deep tests to ensure that there is not a mine tunnel underneath your structure that could fail and compromise it. I will look at the most common types –
• Trial Pitting
• Boreholes
• penetration tests
All the data an falls into either two categories; factual, being information like a particular soils density or water content, or interpretive, which is not black and white information but more commonly predictions as to how soil will react in different circumstances.
Trial pitting
It is the easiest form of investigation. It is simply digging a hole in the ground and having a look at what comes out. It does not necessarily have to be by machine, it can be by hand, however it is quicker and a lot easier to use a machine! As material is dug out it is recorded by an engineer the type of soils that come out, usually at every meter, but more frequently if the stratum changes more frequently. As...