Civil Engineering - Water Supply Engineering - Discussion

Rock Hardness: Consolidated rocks are typically very hard and dense, making them resistant to the impact forces used in percussion drilling. This results in a very slow rate of penetration and increased wear on the drilling equipment.

Fragmentation Issues: The impact mechanism of percussion drilling tends to create small, fine fragments rather than larger, more manageable pieces. This can lead to difficulties in removing the debris from the borehole, further slowing down the drilling process.

Tool Wear and Damage: The repeated high-impact forces can cause significant wear and damage to the drilling tools, leading to frequent replacements and increased operational costs.

Energy Inefficiency: Percussion drilling requires a lot of energy to break through hard, consolidated rock formations. This makes it less efficient compared to other drilling methods like rotary drilling, which can apply continuous pressure and shear forces more effectively.

The percussion method of drilling the well hole is also known as the cable method of drilling.

It is ineffective in loose material because of the slumping and caving of the material around the drilling bit. This method is useful for cutting consolidated rocks from soft clay to the hardest rocks.

Percussion drilling is the most suitable method used for drilling boreholes in Hard soils or Soft rock strata.

So, the given answer is correct.

No, option D is not correct,

Percussion drilling is especially suitable for consolidated rocks, however it's unsuitable for the other 3 options. This question is taken from SK Garg Vol1 which CLEARLY mentions this. (will be at pg 145 or around that).

Ref books such as Gopal Ranjan, BC Punamia.

If it's asked "suitable" instead of "unsuitable", only then option D can be correct.

The answer is correct.

Percussion drilling is mainly suitable for consolidated and unconsolidated formations like sand, silt, clay, sandstone. But unsuitable for consolidated rocks.

The given answer is correct. It is suitable for unconsolidated and consolidated SILT SAND CLAY SANDSTONE. But not for consolidated rocks.

PERCUSSION.

Although the technique is slower than other drilling techniques, it is the only manual drilling technique that is able to drill through consolidated rock layers.

Please describe the solution.

Percussion drilling is suitable for unconsolidated and consolidated formations:; sand, silt, stiff clay, sandstone, laterite and gravel layers depth up to 25m Unsuitable for rocks.

Percussion drilling is suitable for unconsolidated and consolidated formations:; sand, silt, stiff clay, sandstone, laterite and gravel layers depth up to 25m Unsuitable for rocks.