Exit Gradient Sheet Pile Wall

A sheet pile cutoff wall simply called cutoff wall is used in almost all types of water retaining structures to reduce the exit gradient at the downstream toe and prevent the chances of sand boiling and piping.

Exit gradient sheet pile wall.

Exit gradient at toe of hydraulic structure g usin computer program seep w software. In 1954 terzaghi has suggested a simplified approach for the design of cutoff walls considering average seepage force. Musa 2014 studied the influence of cavities on seepage under sheet pile wall for hydraulic. 10 20 such that the factor of safety against heave piping is improved as shown in f w w f f s 10 47.

For the sheet pile wall this filter is placed over the potentially unstable prism abed in fig. It is placed at the exit point where the water emerges from the foundation. The 7 saturated unit weight of the soil is 130 pcf and the hydraulic conductivity is 3x10 ft sec. The exit gradient is then computed as 0 62 divided by 3 3 making the upward gradient 0 19.

It is observed that the best location of sheet pile to reduce seepage flow is at the downstream end. The sheet pile penetrates 20 feet into the soil. Exercise 14 1 derive relationship between the critical hydraulic gradient icr and porosity solution 14 1 cr also cr gs gs exercise 14 2 sheet pile wall. The computed gradient is in essence an average gradient over this distance.

Of significance for later discussions is that the gradient is computed for a head loss over a fairly long distance of 3 3 m. Shayan and tokaldany 2014 studied the effects of upstream blanket and sheet pile on reducing seepage flow exit gradient and uplift force. It con sists of graded sand and gravel.