Research On Slope Failure Mechanism And Prevention Countermeasures Of G1002Electric Tower In Jinping Hydropower Station

During August29th and30th,2012, it was heavy rain around the construction area of Jinping hydropower station, causing lots of geological disasters. In which, the slope of G1002electric tower in the left bank of Jinping hydropower station down-slid partially, making D leg of the tower exposed and bringing a serious threat to the security of the electric-tower and entire transmission line. On the basis of detailed field investigation and engineering geological conditions of the landslide, it is partitioned and its forming conditions is analyzed, the process of landslide occurrence is reconstructed and formation mechanism of the landslide is discussed in this paper. What’s more, the stability of the residual body of the landslide is calculated using limit equilibrium method. This paper also studies the stability and failure characteristics and mechanism of the landslide residual body. On the basis of the above research, two kinds of landslide treatment measures are put forward. It is expected that it can provide some experience and references to electrical tower siting in mountain gorge areas by analyzing this typical example. There are some important contents and achievements:1. According to the detailed site exploration and deformation characteristics of the landslide, its detailed characteristics is introduced. The landslide is also partitioned and the characteristics of each region is described.2. This paper summarizes the formation conditions of the landslide by analyzing its engineering geological and hydrogeological conditions. And it is concluded that steep topography, favorable rock and slope structures, scouring of the toe of slope by the mountain torrents and continuous heavy rain are key factors of triggering the landslide.3. This paper reconstructs the down-sliding process of the landslide according to its engineering geological conditions and deformation characteristics. And it can be divided into three stages:the first stage was that the slope was saturated because of heavy rain, the second stage was that the toe of the slope was scoured by the mountain torrents and a small range of slump was formed in the leading edge of the slope, the third stage was that the slope finally failed because of the continuous scouring by the flood. Based on this, it is concluded some inspirations of electrical tower siting.4. This paper also calculates the stability of the residual body of the landslide in the deformation and fracture zone to provide the basis of the design of countermeasures. The result shows that it is unstable and needed to be treated.5. It is simulated of the stability and failure mechanism of the residual body under natural and raining conditions using FLAC-3D. It shows that it is stable and has almost no displacement in natural condition, but it is unstable in raining condition, the biggest displacement occurs in the leading edge and penetrating shear zone appears in the deep of it.6. On the basis of the above research, two kinds of landslide treatment measures are put forward combining with its topography and traffic. The first one is lattice frame anchor frame beam; the second one is anti-sliding pile and crack filling. Considering its traffic, difficulty of construction and engineering disturbance, the second measure is recommended.