Operating instructions for the Liebherr LR 1350 crawler crane.
Full description
HYDROGEOLOGY LECTURE NOTES
-
Plot h/h 0 and time on semi-log paper (h/h 0 on vertical arithmetic axis; time on horizontal log axis) Connect points with a best-fit curving line Match the data curve to the closest curve on the type curve graph and determine the value of α for that curve Keeping the curves matched, determine the time value (t) on the field data curve that coincides with W = = 1 (on the type curve graph). Solve for T using the following equation
T=
rc2 t
(Equation 9-5)
where
-
rc = radius of the well casing [L] t = time value that corresponds to W = = 1 [t] Solve for S using the following equation
S=
rc2 α rs2
(Equation 9-6)
where rc = radius of the well casing [L] rs = radius of the well screen [L] α = value associated with matched curve from the graph This method will give you a transmissivity and a storativity.
Hvorslev Method - Plot h/h 0 and time on semi-log paper (h/h 0 on vertical log axis; time on horizontal arithmetic axis) - Connect points with a best-fit straight line - Determine the value of T o from the graph (defined as the time where h/h 0 = 0.37) - Plug into the following equation:
L r 2 ln r K= 2LTo
(Equation 9-7)
where r = radius of the borehole L = length of the screened interval Note that this method gives you the hydraulic conductivity , not the transmissivity.
Potential Problems with Slug Tests When using a single well to evaluate the hydraulic parameters in an aquifer, the well loss and the influence of the sand pack and screened screened interval become significant. significant. When performing a multi-well multi-well aquifer test with a pumping well and a single observation well, the drawdown response in the observation well reflects the transmissivity and storativity storativity of the part of the aquifer aquifer between the two wells. In effect, we are measuring the properties of the aquifer in between the two wells. However, when using a piezometer to run a slug test, there is a possibility that the conductivity of the sand pack around the well screen may be so much different in conductivity than the formation that we are actually measuring the conductivity of the filter pack rather than the formation itself. Multi-well tests are always a more more accurate representation of the aquifer; however, however, single well tests are sometimes our only choice.
