This looks familiar - we had to have our original cast iron sewer pipes replaced last year. The house is on a slab foundation, so the only options were to dig down through the flooring and foundation from the front of the house to the back, or 100 feet of tunnels under the house to remove/replace everything from underneath. We chose the second approach and had 6-8 foot piles of dirt around our house for a week. Totally worth it in the end, though.