| According to the engineering problems such as rockfall, collapse, instability andetc in the weathered rock cut slope, and relying on the construction project ofexpressway from the border between Inner Mongolia and Hebei to Chengde City inDaguang Highway, the numerical simulation of stability was analyzed for the activeflexible retaining system in rock cut slope with FLAC3D. The stability mechanism ofslope reinforcement with the system was deeply studied to determine the optimumretaining scheme and apply in practice.1) By consulting the relative documents and information, the classification andthe mechanical mechanism of active flexible retaining system were introduced indetail. According to the protection function and the component types, the activeflexible retaining systems are divided into different types, which can adapt todifferent field situations and engineering protection objectives. Its action principle isthe core of "local bearing, overall effect".2) Through the field investigation in the experimental road section, four sloperetaining schemes (not protection, simple enclosure protection, reinforcementenclosure protection, active retaining protection) and three analysis conditions (slopeis overall stable, slope surface is stable with retaining protection, the local slopestrength is reduced) were determined. According to the results of indoor tests, fieldinvestigation and the relative information, the FLAC3D analysis model andparameters of the slope were determined. According to the research purpose, themechanical responses with the FLAC3D numerical simulation analysis weredetermined such as slope safety coefficient and unbalance force, displacement andstress to put forward the design flow of flexible retaining system with the FLAC3Dnumerical simulation.3) The loading laws of flexible retaining system were studied by the simulationon the system itself. The results indicate that the stresses of anchor, horizontalsupporting rope and longitudinal supporting rope decrease to an order of magnitude inturn, and the stress of steel wire net is minimum. The steel wire nets can disperse andreduce the anchor stresses, and the supporting rope can disperse the stresses of steelwire net.4) According to the FLAC3D numerical simulation on the slope in the selected experimental road section with four flexible retaining schemes under three conditions,the stability and the displacements of the slope as well as the variation and thedistribution laws of stresses in the retaining system were studied. The results indicatethat, compared with the scheme one, the slope safety coefficients of the scheme two,the scheme three and the scheme four increase in turn, and the scheme four increasesmost obviously. The maximum displacements of slope are reduced by29.3%,30.1%and48.6%, and the maximum displacements of local dangerous rock are reduced by18.5%,21.0%and81.8%, respectively. All the reduce extent of stress on themonitoring points in the slope with the scheme two and the scheme three are within1%, but all the monitoring points in the scheme four decrease significantly(33.3%~30.9%). Compared with the scheme two, the maximum axial tensions ofanchor under the three conditions for the scheme three and the scheme four arereduced by5.0%and17.0%on average, and the tensile stresses of steel wire net arereduced by9.9%and23.4%on average, respectively. According to the above laws,the protective effect of the scheme four is best, the scheme two and the scheme threetake the second place. Then the scheme four was selected to apply into experimentalroad sections as the best retaining scheme.In short, the above researches can provide a guide for the design scheme offlexible retaining system of rock cut slope in the experimental section of thesupporting project as well as a reference for the similar engineering. |
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