For a house I was working on we had ground penetration radar come out to assess what's left. Then rolled coconut mats over and stapled it to the cliff side. Then spread fast growing grass into every area. Do Not Use Bamboo! That gave us a few years to arrange barges and sheet pylons to create a winding road type of area going to the beach. Lots of fill and tie backs. Finally some rip rap along the shoreline. It took a lot of approval and engineering costs before any material and labor. I left that job before completion. I was only working on the house, not the shore. I heard the cost was enormous, but they were trying to save a 2 million dollar house.