Soil test in rainy season

[NewbieInSE]

Hello Engineers,

Does the SPT data taken from boreholes in the rainy season, provide good results? I mean, does rain affect the test? What about the soil samples taken from shallow depth. I think SPT data above the usual Water Table may not be correct as these layers become wet in the rainy season.

 

[Ron]

Fundamentally, for an SPT, the location of the water table, whether wet season or dry, is irrelevant to the test. It is not irrelevant to the overall data evaluation but does not affect the test results.

 

[NewbieInSE]

Thanks, Ron.

So fundamentally wet or dry condition doesn't matter whether the soil is clayey or sandy, right?

 

[Ron]

Yes, it matters in the data evaluation, it just doesn't matter for the test itself. The test is done the same way without regard to the water table or the in situ moisture content.

 

[phamENG]

Newbie - yes, it matters, but in the end the geotech will be able to give you a good result. They can account for the presence of ground water in the soil column and still determine the relevant properties of the soil, allowable bearing pressure, settlement predictions, etc.

Or are you trying to interpret a boring with un-adjusted blow counts without the help of a geotech and want to know how ground water elevation impacts that interpretation?

 

[NewbieInSE]

Thanks phamENG,

are you trying to interpret a boring with un-adjusted blow counts without the help of a geotech and want to know how ground water elevation impacts that interpretation?

No, i was thinking whether site condition (wet or dry) might affect SPT value, shallow footing bearing capacity etc.? I think after adjustment of overburden and water table and energy etc., the result will be identical (provide same Soil Bearing Capacity etc.).