Research On Stability Of River Overburden In The Dam Foundation

In the western mountains,overburden are widely distributed in the valleys,thatmore than 30m thick.Because of its large thickness and poor mechanicalproperties,the overburden threatened the stability and safety of the hydroelectric dam.The Duobu Power Station is located in the main stream of Niyang River,it`srockfill Dam,27 meters high.At the project area,the riverbed with the thickness ofmore than 180 meters overburden, mainly composed of sandy gravel,with loosestructure and poor mechanical properties.Settlement and seepage characteristics of thefoundation is the important issues of the engineering construction.This paper takes advantage of the construction of Duobu Power Station,based onthe collection of background geological data,in-situ test and laboratory test,analysisthe basic feature of overburden.Using various methods to evaluate the overburdenissues such as compression settlement and seepage deformation,giving correspondingoperating measure suggestion and simulating the measure for check.Throughstudy,the main results as follows:⑴According to exploration data,determined the distribution of overburden,anddivided it into five different layers,defined the physical and mechanical parameters ofeach layer.⑵The use of conventional and numerical simulation methods,evaluated stabilityproblems may exist, such as capacity,settlement,liquefaction,seepage deformation andleakage.⑶Using ANSYS APDL software module,wrote the corresponding program.Inthe compression settlement analysis,realized Duncan-zhang model and simulation.Inseepage analysis,determined saturation line within the dam and exit point of the downstream dam face,completed seepage simulation of homogeneous dam andoverburden.⑷For seepage deformation,the initial development of horizontal imperviousblanket and curtain grouting are two seepage control measures,through simulation toverify the effectiveness of two measures,made treatment suggestion.