| 摘要 |
<p>Method and apparatus for extracting blocks of stone material by means of tubular expansion devices operated at high fluid pressures. The devices are introduced at ambient pressure into cylindrical bores formed in the material to be excavated, in the region of the desired parting planes of the block from the rock. The pressure is then increased up to 100-500 bar so as to obtain parting of the block. Each expansion device consists of a tube of plastic material with a high modulus of elasticity provided at its opposite ends with metal sealing members which are axially bored and connected to one another by a metal rod housed inside the tube. <IMAGE></p> |
