Numerical Simulation Of The Damsite Zone Geostress Field And The Stability Of Surrounding Rockmass Of The Underground Cavern Group In Xiluodu Hydroelectric Power Station

Abstract: Xiluodu hydroelectric power station of Jinsha kiver is another planned giantproject only second to the Thre Gorges Project in China. The dimension of theundengound chambers located in the mountains in Permian Emei Mountain Basalt strataon the bank of Jinsha kiver is qute large in the world. As a whole, the rockmass qualityis qnde good. Bllt the discolltinuities such as interlayer shearng belts, illtrastfatal-shearing belts and joints randomly distributing in the strata, wosened the strellgth andlowered the quality of the rDCkmass. Additional1y the size of the opening section is so -lnye that the stress redistribution and adjustment around the caverns should be intensive.And the stress redistribution and adjustment may lead to violent stress concelltration,' Which, in tal may l7ad to failure of sorounding rockmass. When inierayer shearingbelts exist, the probabilop of surrounding roclanass failure would be inerased badly Thesurroundillg rockmass stability is associated with the fethee of initial geostress field too.So numerical simulation of the initial geostress field and the stabilop analysis ofundWund caverns is selected as the topic of this paPer Based oll careful fieldgeological investigaton of the basic geological conditions, the surrounding roCkmassstubo of undengound chambers is studied systematically in this paPer Then thegeostress field at the damsite zone is simulatCd and analyzed according to the dataobtained. At the same time, the stability of three main chambers among the undergroundcaverns on both banks is analyzed with 3D- o software and the differences b0tween themain chambers on both banks are discussed. At last, initial suPpOrt measure design forthe caverns is suggested.