Dear tq,
Sure, anytime you use geophysical techniques that are noninvasive, you have
uncertainty that you are modeling the proper geometry. Refraction,
reflection, surface waves & nondestructive testing all have this
shortcoming. I guess you have to ask something about the rockfill and its
nature - what is the max boulder size. In SF, I don't think you'll see the
boulders (based on my experiences with SF in Triassic/Piedmont interface in
residuum from diabase near Dulles Airport outside of Washington D.C.)
because of the large area of ground investigated. Same with SASW (based on
my experiences with vitrified masses in South Carolina). You would only
obtain an overall Vs profile that you could relate to mass density and depth.
Respectfully,
Paul
At 08:12 AM 10/28/99 +0800, Rusli wrote:
>John Wayne,
>
>Through experiences, the present of boulders may give rise to the hidden
>layer in interpreting the S waves thus resulting in false calculation of
>density.
>Remember Acaustic impendance effects.
>
>tq
>
>> -----Original Message-----
>> From: Paul Mayne [SMTP:[log in to unmask]]
>> Sent: Wednesday, October 27, 1999 7:21 PM
>> To: Ron Benary; >> Subject: Re: dynamic compaction - heavy tamping
>>
>> Yes Ron,
>>
>> This has been handled previously in rockfills using shear wave
>> velocity measurements (see Hansbo, 1981, X ICSMFE; Mayne & Jones,
>> ASCE JGE Oct. 1983). The easiest methods for Vs would include
>> spectral analysis of surface waves (SASW) and seismic refraction (SF),
>> although a few benchmark areas with either downhole and/or crosshole
>> would be beneficial. P.S. GDS now offers a commercial package for
>> SASW measurements.
>>
>> Sincerely,
>>
>> Paul W. Mayne
>>
>> At 12:12 AM 10/27/99 +0200, Ron Benary wrote:
>> >>>>
>>
>> dear collegues
>>
>> we design a dynamic compaction (heavy tamping) of a 10 m' rock
>> fill, mainly composed of soft rocks excaveted materials.
>>
>> we are looking for approval methods to define the difference in
>> density between the intial and final stage of compaction.
>>
>> SPT, CPT, etc. are not valid methods since the fill contain
>> stones and hard materials which false the results and damage the test
>> equipments.
>>
>> Is anybody have a good advise.
>>
>> thanks in advance
>>
>> ron
>>
>>
>> <<<<
>>
>
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