Laserfiche WebLink
Caution- Be careful when"kneading"the screen Sudden screen slippage can pinch hands between the screen <br /> and the probe rod To prevent screen slippage, have an assistant hold onto the prepack during the <br /> ' "kneading"operation <br /> 4 Add additional five-foot prepacks to obtain the desired screened interval O-nngs can be installed <br /> between the prepack sections if desired <br /> 5 With the assistance of a second person,attach five- <br /> foot sections of 1 0-inch Schedule 40 PVC Riser <br /> to the top of the screen assembly O-nngsarc re- Plastic Plug <br /> ' quired at each nser point to prevent groundwater, (13227) <br /> located above the desired monitoring interval, <br /> from seeping into the well Continue to add nser 1 Nn Sch 40 PVC <br /> ' sections until the assembly reaches the bottom of Riser Pipe <br /> (12873) <br /> the probe rods (Fig 5 7) At least one foot (0 3 <br /> m)of riser should extend past the top probe rod <br /> Place the plastic plug into the top nser Duct tape <br /> may be used to help keep the plug in the nser <br /> 6 It is now time to pull up the probe rods from around <br /> ' the well screen and riser Reposition the probe <br /> unit so that the Rod Grip Puller can be attached to <br /> the rod string <br /> 7 Retract the rod string the total length of all the <br /> screens plus an additional 3 feet (I m) While <br /> pulling the rods, observe whether the top PVC 1 0-in x 2 5-in OD <br /> riser stays in place or moves up with the rods Prepack Screen <br /> (11678) <br /> a) If the nser stays in place,stable formation con- <br /> ditions are present Continue retracting the rods <br /> to the depth specified above Go to Section 4 4 k <br /> b) If the nser moves up with the probe rods,have <br /> a second person hold it in place while pulling up 1 0-in x 2 5 in OD <br /> the rods An additional section of PVC nser may Prepack screen <br /> ' be helpful Once the probe rods have cleared the (11679) <br /> �4ti <br /> lower section of screen, the screen and nser as- <br /> sembly should stop rising with the rods Con- <br /> tinue retracting to the depth specified above Go <br /> to Section 5 4 <br /> �v <br /> c) if the risers continue to move up with the probe = PVC Bottom Plug <br /> rods and cannot be held in place by hand, sand (12881) <br /> heave has most likely caused the screen to bind to Expendable Point <br /> the inside of the rods Extension rods are now 3 6-in OD <br /> required (Refer to Figure 5 8 for an illustration (AT3215) <br /> of extension rod accessories) <br /> FIGURES T <br /> Prepack Assembly Inside Probe Rods <br /> 0 <br /> Standard Operating Procedure Page 14 1 0-in x 2 5-in OD Prepack Screen Monitoring Well <br />