The long and short of it is no, to both of your questions.
Is there an ad network which provide ads not blocked by ad blockers?
No, at least not a reliable long-term one. As advertising networks appear, soon enough people see the adverts and report them so they would get blocked. You would be fighting a war of attrition with your users ad-blockers that probably wouldn't reflect well on you, and you'd have to keep switching ad providers which limits your choice and you'd probably not get enough clicks from one before it was blocked to meet their payout threshold.
Is there a tool that nevertheless circumvent the issue so that my ads are shown?
If there were tools to circumvent the blockers, the use of such software wouldn't be as popular as it clearly is. Your best chance of getting your adverts displayed is to get onto the white-lists maintained by owners of the ad-blocking software, and hope your users keep the default settings (which allow non-intrusive ads). Or, providing a sense of community and regular user base who trust you not to bombard them with crap. Some users actually do disable ad-blocking if they like a site, and it asks them nicely.
The last time I checked, the most used ad-blocking software was AdBlock Plus. They provide details on their pages of how to submit your site for consideration to be white-listed. Doing so you must meet their criteria of what they consider "not intrusive".