We have published many posts about pile foundation. Of those posts, under-reamed pile foundation related posts have received thousands of visitors per month. We have published different aspects of pile testing, driving, boring and damaging to the same. In this post we will learn the fact when a driven pile is required to be redriven.
We have some posts and will publish many posts regarding drilling of piles in different type of soils. Now we will focus on plastic clay. It is very easy to think that a driven pile displaces soil and takes its own volume in the soil. But in case of bored pile the soils are removed or wash out to be occupied by a pile.
The problem arises in driving through a plastic clay deposit that is in saturated condition. The plastic clay soil displaced by a driven piles results some kind of heaving action. This phenomenon is usually found in previously described saturated plastic clay. The heaving action may displace ground, lifting existing structures surrounding it. If a pile is previously driven near a heave forming pile it comes lift out.
As this pile is heaved out the bearing capacity of pile is required. That is end bearing of pile reduced and if this plastic clay remains in significant depth along the pile length, the skin resistance of pile assumed during capacity calculation also reduced.