Mechanism And Controlling Techniques Of Landslide In Cataclastic Rock Mass Of Shuangda Road In Beijing

The landslide in cataclastic rock mass is formed and developed under complex geologicalenvironmental conditions.This kind of landslide widely exists in many different areas. At present,there are few researches on this kind of landslide; it often gets the wrong conclusions when usingcurrent research methods. So studies on this kind of landslide have important theoretical valueand practical engineering instruction. It has also important reference values for the cutting slopein cataclastic rock mass.This paper takes the example of Shuangdalu landslide in Beijing. which is a representativeof the landslide in cataclastic rock mass. In order to analyze the basic characteristics, formingand developing condition, hazard mechanism, a comprehensive and multi-method study isadopted, including in-site exploration, in-site monitoring, outdoor and indoor tests, numericalsimulation, theoretical analysis method, etc. Through the indoor and outdoor experiments,numerical simulation and analogous analysis of engineering experience and mechanicalparameters back analysis method, the mechanics parameters and stability analysis method of thelandslide in cataclastic rock mass are selected. On this basis, a whole set of mechanicalparameter selection and the stability assessment system suitable for cataclastic rock mass is setup in this paper. At last, the theoretical design of anchorage system and vegetation protectiontechnique on cataclastic rock mass are studied.The Shuangdalu landslide is a hidden landslide along bedding, occurred in shale,argillaceous dolomite and inter-bedded fault zone. This landslide is characterized by threesections model--sliding-tension-extrusion (cracking-shearing). In this paper, by usingengineering geology analysis principle, the forming and developing mechanisms of thecataclastic rock mass and inter-bedded fault zone are studied. It reveals that the slippery slopestructure is the material basis for landslide origin, and the formula of sphere of influence ofunloading is deduced, the affected areas of inter-beded fault zone is calculated, at the same time,the numerical results show that excavation unloading causes the inter-bedded fault zonedestruction and stress concentration, This shows that the excavation unloading is the directcause of landslide deformation. On this basis, the transformation criterion of failure mode in thecataclastic rock cutting slope and landslide are summarized. Cracks and deep displacementdistribution law indicate that the landslide is at the early stage of the overall slip. The"anti-sliding layer"is extremely important in the deformation control and stability of thelandslide, which is also the key factor for the stability assessment of landslide and for thedevelopment of control methods. The segmented validation parameter selection method based on steady-state is proposed. On this basis, the potential slip surface of the anti-sliding sectionand its connection method is calculated by the numerical calculation and limit equilibriummethods. The type of failure modes and stability analysis method of landslide and cutting slopein cataclastic rock mass are proposed. The calculation method based on the strength reductionof the residual thrust is proposed by comparative analysis of traditional methods.Slope surface compression effaced by anchor and the lattice frame anchor structure is veryobvious. Prestressed anchors play a role of the"body stress"in the depth of the slope, and the"body stress"in the slope decay quickly, on this basis, the concept of"equivalent anchoringwall"is proposed. The notices of anchor section segment design and construction are proposed.Prestressed anchor design method by load - structure model is proposed to make up the shortfallof prestressed anchor effect considered by existing norms. Based on the Winkle elasticfoundation beam theory, it is proposed that vertical and horizontal beam load distribution ratiocan be considered according to the radio of the underside width, at the same time, a new designmethod is given. The assessment method based on the monitoring the controlling effect theanchor and the lattice frame anchor structure is proposed. Vegetation slope protection technologyis developed which is suitable for the cataclastic rock and considering the slope surface stabilityproblems and ecological requirements.