In view of the 155m high large concrete socket of Jinping I high arch dam, No.1~12 slip bodies during socket construction and storage period are studied by searching the possible slip surfaces. Anti-slip safety factor Ks of slip bodies are evaluated by using 3D nonlinear finite element multi-grid method. The results show that the range of Ks during the socket construction is 1.711~2.328 and in storage period it is increased to 1.910~2.653 due to the thrust force at dam abutment. All the indexes are in a reasonable range, which indicates that the concrete socket has good anti-slip stability. During the whole casting process and operation period, the stability of socket and rock slope below the socket can be guaranteed. And also the stability of slip bodies can be improved, because dam construction and impoundment could give an additional support.
Arch dam is an important dam type used in deep valley for its reasonable structure and graceful somatotype. Ertan arch dam (240m), completed in 1999, is a land mark of arch dam construction in China [1], which shows that China has reached the international advanced level. Now, there are several high arch dams under-construction in China, e.g. Xiaowan (292m), Xiluodu (278m), Goupitan (233m), Laxiwa (250m), Dagangshan (210m) and Jinping I(305m) etc. Recently, the dam construction of Jinping I arch dam began, which is the highest arch dam under-construction all over the world. In the construction of high arch dam, many worldwide problems are met, and the research of these problems has important significance for engineering [1–5]. In high arch dam the requirement of foundation is reflected in stress, strain and degree of stability etc. In the situation of complicated foundation, the foundation needs reinforcement treatments when the stress strength and stability can not meet the requirement. Sometimes, concrete sockets are adopted in the construction of high arch dam [4, 6, 7]. The socket at bottom is called as bottom socket, which is used to adjust rock stress when the bottom rock is in poor geological condition and the dam abutment is in good geological condition, such as bottom socket of Lijiaxia arch dam [8, 9], bottom socket of Vaiont in Italy [10], etc. The socket at dam abutment is called as dam abutment socket, such as dam abutment socket in left bank of Jinping I arch dam. Large concrete socket can reduce the differential deformation of foundation, even the distribution of dam stress and avoid the cracking of dam. Safe running of Inguri arch dam and Lijiaxia arch dam has proved that large concrete socket is beneficial to the improvement of stability for arch dam. Jinping I hydroelectric power station is a first-class large-scale project, which is located across the Yalong River at the common boundary of Yanyuan County and Muli County, Liangshan Yi Autonomous Prefecture, Sichuan Province, P. R. China. This barrage is a doubled-arch dam with maximum height of 305m. The crest and foundation surface elevation are ▽1885m and ▽1580m, respectively.
