Analysis On The Suitability Of Building Bituminous Core Dam On Soft And Hard Ibterbedded Rock Masses For A Reservoir In Yunnan Province

The core wall dam which made of bitulith is a kind of dam type that was widely used in water conservancy and hydropower engineering construction.A reservoir in Yunnan will be built on layered rock masses with layers of hard rock and soft rock of different thickness,as a control water conservancy project on Chuyi river in Maguo river basin.It is the first case to build bituminous concrete core wall dam on layered rock mass with soft and hard phases as dam foundation in Yunnan province where local seismic intensity in the Ⅷ region.This paper from engineering characteristics.analyzes and evaluates the applicability of layered rock mass as the foundation of asphalt concrete core dam based on the of dam foundation rock mass.On the bases of in-depth investigation and study about analysis of Hydro-geologic conditions and the geological background and characteristics of rock dam site area,dividing into two major categories of sandstone and mudstone according to rock type and intensity of the rock dam site area,and dividing the boundaries of the hard and soft rock hard rock and soft rock according to the relevant specification,The boundaries can be sured with saturated uniaxial compressive strength(Rb),namely when Rb>30 Mpa for hard rock;When Rb is 30 MPa,it is soft rock.In the research and analysis of the engineering characteristics of rock mass,the types of structure and combination characteristics of rock mass can be summarized.according to the field investigation,.According to the classification index,we can determine the relation between reservoir dam foundation rock mass quality classification scheme in accordance,with the quality of dam foundation rock mass are classified by the analysis of mudstone softening properties against dam in the selection of rock mechanics parameters,The deformation modulus of the dam site area on the weakly weathered sandstone is 3.5 GPa,the deformation modulus of weak weathering sandstone is 5 GPa,but due to the softening characteristics of mudstone has adverse influence on dam foundation,It is finite that the modulus of foundation rock mass deformation is weakening according to the analysis of argillaceous rock dam Therefore,the deformation modulus of the dam foundation with the rock mass in weakly weathered zone～aeolian zone belt can meet the requirements.The results of rock structure classification and engineering quality classification show that the rock structure of dam site is favorable to the anti-sliding stability of dam foundation,and the shear strength of the rock body of dam foundation can also meet the requirement of no shear failure under reservoir pressure,in the analysis of anti-sliding stability of dam foundation.In the stability analysis of engineering slope,the polar projection analysis shows that most of the building slope forms unstable slope after excavation,but it is stable after treatment,which proves that the treatment measures are correct and feasible.This paper expound the suitability of soft and hard interlayer rock mass as the foundation of asphalt concrete core wall dam from the study of the engineering characteristics of dam foundation rock mass are studied from many aspects,and draws a conclusions.that the dam foundation rock mass of a reservoir in Yunnan province is suitable for the construction of asphalt concrete core wall dam.