Try to block out the cave with cube the cave walls then simply model another stalactits and move them so they look attached. And if you are going for real look of the cave you should go into Zbrush for good nice details it will be very helpful. Unless you are good @ modeling high res models into maya but as far as i can see you are not ... so just block out the cave get the shape in the picture and then go into Zbrush for detailing ... that's how i would do that

Good luck