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Subsidence In��estigation Quiros-Martir�ez Residence-Zephyrhills,Florida SD1I Project Number�3023547 ----- SDII utilizes a unique method to track and document circulation of drilling fluid. The Glossar defines the t�;;rms used to note the condition of circulation,and the SPT boring logs(Appendix C present the relevant data for each borehole. We track two conditions: flu�d return to the surface from the bor�;hole and loss of fluid from the borehole into surrounding strata. If the drill bit becomes clogged or if the clay content of the drilling fluid is hi increase the I7uid viscosity and prevent the pumps from circulating the liquid, circulation may be gh enough to reduced or e liminated. Loss of drilling fluid movement for these reasons does not suggest the presence of cavities or other sinkhole-related phenomena because the volume of drilling fluid in the system does not change. SDII's boring logs state the initial flow of drilling fluid through the system and t.fien track any reductions in flow in order to separate loss of return of the mud to the surface from within the borehole from loss of the fluid from the borehole into the surrounding strata. If the drillinF; fluid flows out of the borehole into the surrounding strata, drilling flwd is lost. This is knowii as a loss of drilling fluid circulation and the rate at which the fluid flows out of the borehole into the surrounding strata can be used to understand the nature of the permeable zone into which th�e liquid flows. If the permeable zone is a cavity or contains large pores, loss of fluid circulation is rapid. lf the fluid is lost from the borehole slowly, it is probably moving into sand or other mate:rials that are permeable but not characterized by pore spaces large enough to take rapid movem,ent of a viscous fluid. The terms used to document losses of circulation are defined in the Glossary, and the data are presented on the boring logs Appendix C). At the beginr�ing of each use of the split spoon, the drill string will be placed in the borehole and allowed to rest on the bottom of the hole for a few seconds, lf the drill string sinks or drops under its own weigirt, a "weight-of-rod" (WOR) event occurs, and WOR-strength materials have been encountered. After sufficient time is provided with the spoon resting in the hole, the weight of the hammer i s added to the static load. Again, the rod, spoon, and hammer may sink or drop to cause a wei;�;ht-of-hammer" (WOH) event. WOR and WOH events may reflect voids, disturbed material, or s.�oft soils. The longer the drill string the more weight is piaced on the soils and the less meaningful is the WOR or WOH event as a diagnostic toot. The rapidity of the decline during a WOR or WOH event assists in understanding the nature of the material Ulrough which the drill string passes. As a result, SDIl utilizes a unique method for describing W'OR or WOH events. For example, a rapid WOR or WOH event is more likely to reflect penetr��tion of a void (or extremely weak strata) than is a slow downward movement of the drill string. The terms used to denote the rapidity of movement of the drill string during a WOR or WO:H event are defined in the Glossary, and the borehole-specific data are presented in the right hand column of each SPT boring log(Appendix C). ASTM Meth�>d D 1586 governs the SPT process. Dynamic Co�ae Penetrometer Test The dynamic cone penetrometer (DCPT) is a hand-held penetrometer that operates in a fashion similar to the SPT. The cone point is seated 2 inches into the undisturbed bottom of the auger