Technical Manual: Conduits through Embankment Dams (FEMA 484)

Conduits through Embankment Dams183 CIPP liner being positioned for installation ..........................329184 The hydrostatic inversion method is being used for CIPP liner installation into an existing conduit .................................329185 The calibration hose of this pulled-in-place CIPP developed “fins.” These fins were considered to have an insignificant effect on hydrauliccapacity for this particular conduit application and were not removed ..... 330186 Excavator removing the intake structure for an existing outlet works ..... 334187 Cofferdam constructed around the construction area for a new outlet works ......................................................... 337188 During the removal of this outlet works conduit a flood occurred. No stream diversion or cofferdam was used at this site ....................338189 A very large surface void appeared directly above a test microtunnelinginstallation when the operator stopped advancement of the machine butbriefly allowed the slurry pump to continue to circulate the drilling mud.The void appeared in backfill surrounding some test instruments, some ofwhich appeared to support the adjacent soils . . . . . . . ..................340190 Hydraulic fracture of embankment levee during HDD installation is visible in this photograph. The drilling mud, which was dyed pink, sothat such fractures could be observed, followed an interface along a clayseam.......................................................... 343191 Drilling a grout hole from the interior of a conduit . . ..................347192 Injection of urethane grout to stop leakage...........................349193 Determine the cause of the damage to determine the proper repair method .......................................................349194 Evaluate the extent of the damage..................................351195 A repair being made using epoxy-bonded replacement concrete. The use of epoxy resin ensures a strong, durable bond between the old concreteand the replacement concrete .....................................353196 An example of resin injection equipment used for small repair projects. Components are pumped independently and mixed at the nozzle forinjection....................................................... 355197 Abandonment of a conduit by injection of cement grout through holes drilled from the surface of the embankment dam to depths of up to 60 feet........................................................... 357198 An auger is being used to drill within an embankment dam . . . .......... 359199 Grout is delivered to the site and is pumped into the conduit being abandoned..................................................... 362200 Grout being delivered to the pumping truck .........................362xxiv