A utility conduit and related methods of assembling lengths of utility conduit with a mechanical spline connector. The utility conduit includes opposed male and female ends, wherein the male end is slidably insertable into the female end of adjacent conduits. The female end includes one or more circumferential sealing channels into which a seal member is positionable and an internal spline groove that is circumferentially defined inside the conduit. The female end includes a wall bore through a conduit wall that intersects with the internal spline groove. The male end includes an exterior spline groove on an exterior of the conduit. A spline can be inserted through the wall bore and into a space cooperatively defined by the internal spline groove and the external spline groove. The spline is inserted such that the spline occupies the space cooperatively defined by the internal spline groove and the external spline groove.