- This tool is for evaluating bottom stability of braced cut in sand due to hydraulic gradients, as shown in the figure above.
- The depth of the sand layer below the excavation is assumed very large (L
_{3}→∞). - The maximum exit gradient for steeted excavations in sand with L
_{3}→∞ is evaluated by Harr's method (1962). - All the input parameters should be positive.
- For "nan", "0" or "inf" displayed in Results, please check your input parameters.
- The safety factor against piping Fs can be obtained by this tool.
- If Fs is given to estimate the dimension of the excavation, users can try to input different parameters to see the "Fs" in results. The desired dimension corresponds to the caluclated "Fs" same as the given Fs.

**Modulus for Harr's method**

m =

**Maximum exit gradient**

i_{exit(max)}=

**Factor of safety against piping**

F_{s}=