CIVILKITengineering tools Open the tool

hydraulics / hydrostatics

Where does hydrostatic wall thrust act?

A vertical wall beside still water sees a pressure that grows linearly with depth. That simple diagram gives a useful first load, but it does not describe every water action on a structure.

Draw the pressure triangle first.

At the free surface, gauge pressure is zero. At depth H, the pressure is γH. Integrating the triangular distribution gives a resultant force per metre of wall of γH²/2, with its line of action at H/3 above the base.

Per metre and total force are different.

Hydraulic and retaining-wall calculations often begin with a unit slice of wall. The CivilKit screen reports that line load, then multiplies it by the entered wall length so the total force and base moment remain explicit.

What still needs judgement

  • Different water levels, drainage, seepage, pore pressure, uplift, and rapid drawdown.
  • Waves, current, impact, turbulence, gates, valves, sloshing, and transient loads.
  • Wall stiffness, joints, crack control, anchorage, sliding, overturning, bearing, buoyancy, and foundation response.

The U.S. Army Corps of Engineers uses the same depth-times-specific-weight relationship and conventional triangular water-pressure distribution in its sheet-pile wall manual.