Abstract: An expansion device for breaking solid materials, including at least one hose element having an inner expansion chamber with a non-circular cross section before pressurization or having an inner pressuring means and/or a reinforcement arranged on the outside of the inner expansion chamber which has a non-circular cross section before pressurization. The inner pressuring means is arranged around the inner expansion chamber and the reinforcement is arranged around the inner pressuring means. Optionally an outer layer is arranged around the reinforcement, having at least one “directional-breaking-force amending” material portion which is arranged outside the reinforcement. The at least one hose element has a coupling connection on a first end of the hose element, and optionally a second coupling connection on a second end of the hose element.