The headrace of Shin-Aimoto Hydro-Electric Power Station is 10.8km long pressure tunnel, some part of which is tunneled by TBM method. Making the most use of perfect circurarity of the section, post-tensioned prestressed concrete is adopted for lining concrete beneath two small vallies where the overburden is not sufficient. Cost and period of construction for this part of the lining are saved. This report includes design and construction of prestressed concrete lining of pressure tunnel.
Properties of concrete with a new type accelerator that was made from Alunite and Gypsum were investigated. As the result of the test, the efficiency of this new accelerator for high-early strength of concrete was confirmed. To apply the accelerator to the practical test in execution of R. C. and S. R. C. construction work was also investigated, and it was found that this accelerator brought the removal of forms at early ages and shortening of term of works.