Maintaining the shape of holes

摘要

In order to maintain the shape of a hole, such as a grave, dug in the ground, an inflatable bag is lowered into the hole and then inflated to a low pressure so as substantially to fill the hole, thus maintaining the sides of the hole against subsidence and also largely preventing water seeping into the hole. A protective cover is then placed over the hole and means are provided for anchoring this cover to the bag itself, which is wedged against the sides of the hole.