Study On Engineering Property Of Cretaceous System And Tertiary Red Beds In Hunan Province

There are a lot of red, maroon or claret politic siltstone and mudstone deposited in continental facies at late-cretaceous System and tertiary in Hunan province. The foundation is called "Red beds foundation" in engineering field. Due to its formation condition, Red beds with special engineering property is typical very slip stratum. For example, there is many landslide happened frequently at rainy season; highway subgrade filled with it easily takes place differential settlement resulting in dehiscence; during the period of constructing railroad and highway, excavating slope body and land-fill embankment in the region induce frequently disaster of collapse or slip in major scope, which influence engineering construction seriously; even there is karst at some area, etc.. To know deeply the engineering property of Red beds is precondition of using it effectively, so it is significant to research its property systematically in depth.Firstly, based on analysing and referring a lot of literatures at home and abroad, the thesis concludes its formation condition and study actuality for its engineering property. Then, some representative samples are tested with a series of trials such as physical and mechanical test, rheology test, permeability test and so on. Combining the test result, we make theoretical analysis and study to some engneering property such as the bearing capacity of Red beds, travel mechanism of landslide, n. rheology property and the property used in way-construction, and get some results as follows:(1) The study shows that its clay mineral is mainly kaolinite, montmorillonite or illite and contains some minerals such as feldspar, mica, etc. Red beds having crumbling property in soaking can be divided to C, B or A Red beds by it. And each kind of minerals has little different and regular change in order that the characteristic of Red beds is different and variable regularly.(2) The study shows that it is rational to adopt six-divided method to zone the weathered rock of Red beds, especially combining the wave velocity contrast and the weathering coefficient. It is firstly suggested that based on practical experience in investigation, we estimate accurately its physical mechanic property and bearing capacity of foundation further combining load test and dynamic sounding or standard penetration test. It correct that we apply mechanically criterion mechanically or depend on experience unilaterally in the past.(3) Systemic study firstly the travel mechanism of landslide of Red beds deposited in continental facies at late-cretaceous System and tertiary in Hunan province. Red beds...