Pressumeter test

[killswitchengage]

Hello
i would like ask you about computing bearing capacity for shallow foundations using the Pressumeter Test .No need to say that we conduct the test for initial soil conditions, but usually the exact same soil is wetted upon unloading . This could have a great deal of effect on comprehensibility and softening of the soil especially if the soil was initially dry ( i.e clays) , so is it reasonable to say that the bearing capacity will decrease afterwards ?

What about the case of removing an important amount of overburden pressure for ex in clayey soils ? i assume this will release the stresses above the clay and subsequent softening will occur ,so that the limit pressure will change somehow am i right ?

 

[BigHarvey]

I encourage you to read the pressuremeter rules by Menard (notice D60, exists in englsh). There is no such thing as a decrease of bearing capacity upon unloading, but you can have a bad quality borehole but this can be determined in analyzing the test data. In the rules you will find the coefficient for reloading moduli : for clay you can multiply the initial value by a factor of 2 (3 in silts and 4 in sands and gravels)

 

[killswitchengage]

Thanks you kind sir
But i was thinking that softening of OC clays and opening of fissures can alter the structure of the soil ( bare in mind i am talking about 12 m of soil getting removed ).
Could you please answer the first question ?