Deep foundation pit support

Deep Foundation Pit Support

DEEP foundation pit support involves a range of techniques used to reinforce the sides of deep excavation sites. Under certain geological conditions, the soil around the sides of an excavation can become unstable, leading to caving and other structural supports. To avoid such a situation, it is common practice to use lateral support to reinforce the sides of the pit.

One form of deep foundation pit support is the installation of ground anchors, steel cables or bars which are drilled into the soil or rock surrounding the excavation. These can then be preloaded with a compression force to further strengthen the support. The anchors are installed as a series of parallel lines, arranged in rows and columns. This method is suitable for a variety of soil and rock conditions and it is also possible to use a combination of different anchor types to enhance the efficiency of the process.

Since the 1950s, bored pile walls have also been used to provide deep foundation pit support. These walls are constructed using an August Frisch boring machine which drills a series of hollow piles into the ground up to a depth of 15 to 30 metres. These piles are then filled either with concrete or soil, depending on the particular application. The wall is built up using interlinked segments, creating a continuous barrier around the excavation.

More recently, there has been an increased focus on the use of diaphragm walls to provide deep foundation pit support. These walls, which are also known as cut-off walls, are constructed using a series of vertical panel elements which are connected by horizontal ties and grouted into the excavation. In addition to providing a stable base for the excavation, these walls can also be used to contain the groundwater so that it cannot interfere with the construction process.

Finally, there are a variety of other techniques which can be used to conform deep foundation pit support, depending on the particular project requirements. These include the use of prefabricated steel barriers, soil nails, shotcrete and grout columns. The choice of support system will also be influenced by a number of factors, including the soil and rock type, ground movement, and the range of structural loads which will be placed on the walls. By considering all of these elements, engineers can ensure that the most appropriate support system is selected for any particular excavation job.