Wenger 72944 Dokumentacja Pobierz pdf (Strona 173)

Section 5 Formulation of Alternative Plans

EAA Storage Reservoirs Revised Draft PIR and EIS February 2006

5-19

FIGURE 5-6: TYPICAL RCC LEVEE SECTION

Currently, the total construction cost estimates are within approximately 7% for

both the earthen and RCC embankments. Design assumptions and

requirements have been refined based upon the results of a project recently

constructed and operated by the SFWMD. The objectives of this project, called

“Temporary Test Embankment Cell Construction,” were to: 1) obtain

performance data on the seepage potential at the reservoir site, 2) evaluate the

suitability of on-site materials for embankment construction and slope

protection, and, 3) determine the suitability of cap rock for chimney and drain

materials.

5.3.2.2 Cut-off Wall

Based on the preliminary evaluation of embankment stability and potential off-

site impacts, cut-off walls will be needed for the EAA reservoirs. The cut-off wall

would ensure that off-site impacts are within acceptable limits and that exit

gradients have adequate safety factors against potential piping failure. For

earthen embankments, it is estimated that a 35 feet cut off wall will be needed

along the east side (US-27), north and west sides (agricultural areas), and along

STA 3/4 side in the south. Along the Holey land area to the southwest, a 50-foot

deep cut-off wall is recommended. For the roller compacted concrete

embankment, a 50-foot deep cut-off wall is recommended along the entire

reservoir perimeter. The cut-off wall will be composed of soil-bentonite mix with

a minimum width of 3 feet. The cut-off wall evaluation is presented in details in

the Engineering Appendix.

1 2 ... 168 169 170 171 172 173 174 175 176 177 178 ... 385 386

Wenger 72944 Dokumentacja Strona 173