| Bedding slope is a common type of slopes, especially in the red layer of the southwest region, such bedding interbedded sandstone and mudstone slope formed by a distributed more widely. Generally, this type of slope excavation cut feet once more likely instability. Syria in the construction of railway station Gulin station slope is typical of this type of interbedded sandstone and mudstone type slope. During the construction process, embankment slope side produced a more significant deformation, the final formation of the landslide instability, seriously affect the project safety. This paper Gulin station landslide for the study, in a large number of geological survey, based on the identification of the structural features of the original slope analyzes the causes of the landslide mechanism, and the state of landslide stability analysis, and proposed reinforcement of the next pre-disaster measures. The main results are as follows:(1) Gulin station bedding slope of conglomerate composed of slope excavation revealed Jurassic system Shaximiao (J2S) purple mudstone, gray, brick red sandstone, the slope was outside the dump along the sand-shale interbedded structure. Among them, the sandstone thickness is generally1-2m, widespread shale thickness of20-40cm. Moderate degree of weathering sandstone Overall, the structure is more complete. Weathered mudstone relatively strong compared to the broken rock, fractured joints.(2) When grading excavation slope, slope deformation occurs more obvious, which increases the total displacement of slope excavation progression and increases levels of excavation, slope deformation occurs mainly in the upper part of the slope excavation geotechnical body, showing deformation within the slope descending to the surface, the forward edge of the rear edge of decreasing distribution, interbedded sandstone and mudstone interbedded with the weathered sandstone and mudstone in the upper part of the junction strongly weathered slope deformation The most dramatic, maximum up to10cm. Rock produced produce bedding slip along mudstone and sandstone level, and at the trailing edge forming a crack. Under heavy rain effect, directly formed slippery surface, and finally to the slope slippage occurs crack damage.(3) Numerical analysis of the slope deformation analysis showed that:a very significant deformation occurred in storm conditions, slope, very large amount of deformation in the upper part of the slope strongly weathered sandstone and mudstone interbedded top, deformation is most intense, the magnitude of maximum70cm, descending the slope from top to bottom throughout the deformation, deformation of interbedded sandstone and mudstone of the entire range of highly weathered reach30-70cm, rock shear displacement occurred after the formation of cracks along the shear layer, these cracks top-slicing under gradually through, may be directly formed slip bands, eventually ripping style sliding slope damage occurred, consistent with the deformation characteristics of the site investigation survey.(4) The use of plastic limit analysis method for slope stability along the sandstone and mudstone layers were evaluated. Combined with interbedded sandstone and mudstone bedding slope failure modes (slip-fracturing) to establish a sliding mechanism field of plastic limit analysis, and calculate the external power and loss of power and the "energy factor" on the slip mechanism, stability calculation method has been bedded sandstone and mudstone slope, has been highly critical slope excavation Gulin station is15m understanding.(5) According to the characteristics common bedding sand shale slope and common bedding rock cutting support measures proposed to avoid softening shale, sand excavation toe avoid exposing-mud interface, try to set up deep in the sandstone rock stable, undisturbed the proposed support among mudstone. |
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