Important Considerations

We have a lot of experience using the Wildcat, and we have a lot of conversation with others who use the Wildcat, and from that we realize that one feature of the system needs to be emphasized.

Fluid injection into the annulus between cone path and sounding rod keeps the soils from squeezing in onto the rods where they would cause energy-robbing friction during driving. If a portion of the hammer's energy is robbed by friction, the blow-counts will indicate soils being stronger than they are, which is an unconservative situation. Therefore, always inject polymer slurry fluid so that the hole remains visibly filled with slurry during testing. This practice gives better data, and it also allows easier extraction of the sounding rods at the end of your test.

If the sounding rods are clogged with soil, all the pumping in the world will not fill the hole with slurry. At the end of each day's testing, while any trapped soil is still moist, check and clean your rods to make sure that slurry will circulate through them when they are next used.

In the past, when we used cellulose to make slurry, its longer dissolving time was frustrating, which led some users to give up on slurry injection and test dry. Now that we distribute fast dissolving polymer slurry, the frustration is gone and there is no legitimate reason to not test with fluid injection.

The constant pounding on sounding rods eventually fractures the male thread end of some sounding rods. We have begun a reclaiming process to renovate such broken rods. If you break a rod, don't throw it away, call us at 800-383-2624 and we will arrange to buy that broken rod back from you, and we will pay for you to ship it back to us. When we have an inventory of renovated sounding rods, you will have a choice between buying new replacement rods, or the renovated and lower price rods.

The Stork hammer-lifter works exceptionally well, and any Wildcat owner should seriously consider buying one. It takes almost all the work out of dynamic cone testing, and as a consequence one person can use it to get a great amount of data, and that person feels normal at day's end. With the Stork you will not get short depth tests because the tester ran out of energy. Recently, we tested 15 feet of very stiff to hard glacial till at two locations in a half day.

We have been studying the correlation between CBR and Wildcat dynamic cone resistances by Wildcat cone testing locations where we also have tested BEARING RATIO OF SOILS IN PLACE by ASTM D 4429-84 . We believe that a close approximation of in-place CBR values are 0.170 times dynamic cone resistance in Kg/cm². We suggest that if you use that correlation, keep in mind that in-place CBR's will change with moisture and compaction variations.