Safety Evaluation of Penstock Laid on Downstream Surface of Dam and Its Expansion Pipe

Finite element method and analytic method are used to safety evaluation of a penstock laid on downstream surface of dam and its expansion pipe on the following issues: (i) Concrete cracking zone, maximum crack width and stress in liner and bars are calculated and analyzed with allowable value; (ii) Relative displacement at both sides of the joint between dam and power station, and stress of expansion pipe are calculated and analyzed with allowable value. The conclusion show that the scheme of penstock layout design and structural design is reasonable for steel playing high strength role, that the penstock structure has safe bearing capacity, and that the expansion pipe scheme can meet the design requirements of compatible structure displacement and requirements of strength.