Pure fighter with polearm master archetype, advice?

[Sossen]

My character currently looks like this, and yes my stats are over the top but another player got every stat above 15 with 4d6L:

Halforc Polearm Master 2

Str:18
Dex:16
Con:15
Int:12
Wis:15
Cha:8

Feats:Combat Reflexes, Power attack, Dodge

Excriminal trying to get away from his earlier life. He fights with a bardiche and wears a breastplate.

Essentially this is not a powergaming build: I want something that is appropriate to my character but also works in combat. My current idea is a tripbuild, utilizing defensive actions that protect the squishies but still dish out damage, as is appriopriate with a reach weapon. My feat progression looks something like this:

3:Weapon focus
4:Switch dodge for combat expertise, imp trip
5:weapon spec
6:greater trip

Tripbuilding like this makes sure that he is efficient up till this level, but at higher levels a lot of enemies will be immune to tripping. How do I proceed? Anything that should be switched out?

I have already gone over some ideas, like combat patrol, whirlwind attack etc, but those two seem underpowered when counting feat tree costs. Thoughts?

[Heaggles]

This is a fun arctype there is alot of tripping feats out there if you want to trip take a weapon with the trip trait that will help a little yes tripping gets hard at higher lvs but I have seen fighters do it all the way up to lv 20