NO OF BORE HOLE
NO OF BORE HOLE
(OP)
hi
i have area bout 24000 square meter i want to ask about the
average number of bore hole to perpare soil report
the porpose of area mall 3 floor without basement
thanks for any comments
i have area bout 24000 square meter i want to ask about the
average number of bore hole to perpare soil report
the porpose of area mall 3 floor without basement
thanks for any comments






RE: NO OF BORE HOLE
If you run into any garbage fill areas, feel free to investigate further to better guestimate the limits of the bad strata.
Mike McCann
McCann Engineering
RE: NO OF BORE HOLE
Perhaps you will receive more responses if you were to pose your question at the Geotechnical Engineers Area found at the link below:
http://www.eng-tips.com/threadcategory.cfm?lev2=12
RE: NO OF BORE HOLE
RE: NO OF BORE HOLE
RE: NO OF BORE HOLE
RE: NO OF BORE HOLE
civilperson gives a reasonably good idea, say, for most cases. Not knowing the general site area geology, I might go an extra borehole or two to greater depths and concentrate most borings in the mall footprint with only a few in outlyer areas for parking.
I know of one where there would have been problems with borings not going over 14 m given that the site had 40 ft of dense sand and gravel (let's not quibble that 14m is 42+ ft). But, underneath, there was some 100 ft of soft to firm clay. For footings of a 3 storey mall, that should pose no problem as the dense sand and gravel would likely support the whole of the structure without any added stresses on the underlying soft clay. However, should you say raise grade at the mall so that people can enter, say the 2nd level of the mall at one side vs the 1st level on the other side, the added fill would surely stress the underlying soft clay and lead it into consolidation settlement - and differential settlements across the width of the mall.
FYI, I was involved in one site where the designer wanted piling to rock and we went to 70 m deep and beyond to find it! Almost all of our 30 borings at this site have been in excess of 40 m. All previous work at site was piling to rock in the order of 40m or so; so the 70m+ was a major piece of site information.
In the end, there is no hard rule (many organizations have guidelines), but you need to have enough boreholes to properly model your site with reasonable accuracy. You should be prepared to drill additional holes if, as was intimated earlier, you find "garbage" or very soft clays and you want to delineate the deposit and you should be prepared to deepen borings if you find unsatisfactory conditions within the depths investigated. Drilling, the choice of hole depths and number of borings should be a flexible activity to account for varying and unknown conditions - and your client should be kept fully in the loop as you might see your site costs skyrocket!