Excavation support or earth retaining structures are required where excavation is deep and required slope canít be provided.
Generally to construct a structure either above or below the ground, excavation of soil is necessary in the ground. According to our requests it may be shallow or deep. But when deep cuts are made in soil, there is a chance of collapsing excavated areas due to low stability. To prevent this we need some temporary excavation supports. The failure of soil cut arises when the limit of excavation exceeds its safe height limit.
Types of Excavation supports: There are two most common adopted methods of providing excavation supports:
ē Soldier pile and lagging
ē Soil nailing
1. Soldier Pile and Lagging: These are nothing but I-sections which consists web between two flanges. They are drilled into the ground around the periphery to the slightly below point of the required excavation depth. Weak concrete is used for grouting of piles. Struts are connecting member which connect the one side cut wall to another cut wall horizontally.
2. Soil Nailing Method of Excavation Support: soil nailing is another technique of protecting excavated ground. It is an economical and rapid process. First shallow cut is excavated and then the cut is coated with shotcrete. It is more effective and easier if it is done with subsequent layers of installation. It is mainly used for rail or road embankments, tunnel excavations etc.
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