Page - 505 - in Book of Full Papers - Symposium Hydro Engineering

deep cement soil mixing is one of the most suitable methods to overcome this problem. The sole purpose of deep cement soil mixing is to improve shear strength of soil by in situ mixing the soil with cement grout. Keywords: Wonogiri Dam, reservoir, ground improvement, deep cement soil mixing 1) Model Tes Hidraulik Bangunan Pelimpah Bendungan Cipanundan, Jawa Barat, Indonesia 1. BACKGROUND The Wonogiri Multipurpose Dam was constructed at Upper Solo River basin in 1978-1981. Since impoundment of Wonogiri reservoir on December 29, 1980, the reservoir has been rapidly filled with sediments. The quantity of sedimentation reached 65% of the dead storage on 2013 that mostly from Keduang River as Bengawan Solo’s tributary. To mitigate sediment problem in the Wonogiri reservoir, the Master Plan and the Feasibility Study on countermeasures for sedimentation in the Wonogiri Multipurpose dam reservoir were carried out from 2004 to 2007 by JICA for detail design and supporting report by Nippon Koei Co, Ltd and Yachiyo Engineering Co., Ltd until 2010. 1.1. The Location The Project is located in Wonogiri Regency of Central Java Province in the central region of Java Island approximate 600 km east of the Indonesian Capital city Jakarta. Figure 1. Indonesian Map, Source: Nippon Koei Report 505