The Engineering Geological Features Of Red Rock And Analysis Of The Stability Of Engineering Slope In Western Hunan

Red sandstone formation in the northeast of Yuan-Ma basin in western Hunan was deposited in turn by soft and hard rock and taken to be the secondary depressed area of the primary subsidence zone in Cathaysian structural system, which had been formed during the period of the Cretaceous to early Tertiary. Due to the special mechanical properties of the soft rock layer, such as low strength, weak resistance to weathering, soften by water and collapse after losing water, bad stability in excavating, and from the characteristics of that results the phenomenon of landslide or collapse in cutting slope and embankment slope when slope excavating or after excavating. So, it is necessary to research the stability of red sandstone engineering slope.We focus on the engineering slope of the red sandstone in the construction of Chang-Ji highway. Field investigation and indoors analysis, numerical simulation are used to analyze the engineering geological characteristics of red sandstone, the classification of red sandstone and the stability of engineering slope, and reached the following conclusions:(1) The shear strength reduces with the water content increases, cohesion first increase and then reduce with water content increase, and the angle of internal friction gradually decrease with the increasing of water content in the weak interlayer of western Hunan red sandstone.(2) The range of red sandstone slope is divided into three types with different mass structure , they are nearly horizontal slope , tilt-like and layered overlying accumulation, and have different types of slope stability discriminate model(3) Pull and slide is the main failure model of red sandstone engineering slope in western Hunan, and the accuracy is verified using limit equilibrium method and display finite difference method.The research results have a certain theoretical significance and practical value of red sandstone areas of research projects from the slope of a certain effect on the future of engineering practice is also of great guiding significance.