| Expressway construction will meet soft rock materials which will be used to fill embankment in EN-SHI area of Hu-bei province. The soft rock materials have such characteristics as the soft property, the low strength and the bad stability. The engineering characteristics of soft rock material in EN-SHI area are studied after investigating in site and testing indoor, analyzing with theory and observing after construction, the HONG-GUAN expressway is typical. The main work includes followings:1. This paper analysis the basic properties of soft rocks in EN-Shi area, include the chemical and particle composition, gradation characteristic, broken characteristic, character of surface, non-isotropic and non-continual characteristic, size effect, etc. After the test of compaction, CBR, the snapping back module, compressive strength, The variation law of the maximum density of Soft Rock Filling Materials has been obtained when its effect factors as the coarse aggregate contents, the maximum grain sizes, compactive efforts, replace method, etc. shear tests for soft rock material are performed. The effect law between cohesion of the material with coarse aggregate contents, water contents and the maximum density are studied. The dilatancy of soft rock filling material under different confining pressure also studied.2. It is shows from dynamic finite element analysis of soft rock filling materials subgrade under traffic load that deformation of soft rock filling materials roadbed are sensitive to traffic loads, when the load increases, the plastic deformation, vibration displacement, velocity and acceleration increase significantly; strictly control overloading is conducive to reducing road settlement. Speed can not be ignored, when speed is greater, the deformation is smaller. With the increase of soft rock filling materials density, the settlement deformation of subgrade becomes small, which means vertical displacement weight, the maximum horizontal displacement components, the largest displacement and the maximum vertical displacement components slope become small.3. GM(2,1) model of sedimentation forecast was set up based on Grey theory .Anisochronous displacement was changed to isochronous serial with Lagrange function. Higher Order weakening operator are introduced into it to weaker the original data in the hope of lowering the sensitivity of outer factors and solving it convenience. The estimation model is set up .Then the Overhauls model is introduced to be used as a combination amendment, and the optimal combination model of subgrade settlement prediction is established. This model is used and the result shows that the predictive value square deviation (variance) is smallest. The model improved accurate and stable of predictive value, which is better than a single Grey prediction model and Verhulst model.4. According to the nonlinear of strength of soft rock filling materials ,the slope stability analysis method of soft rock filling Materials embankment is established. The method does not require bar division, through analysis of the overall slope of the potential changes to solve the problem. safety factor can be directly solved and the results are accurate, which doesn't need numerical analysis and iterative calculation.5. Considered stability, anti-erosion, economic and other factors, this paper, using a comprehensive multi-attribute decision-making law, optimizes the cross section design plan of Soft Rock Filling Materials subgrade in order to select the most economic and stability method. It's a simple and feasible method, which can reduce the impact of subjective factors and provide a more rational basis for determining a reasonable cross-section form.6. In the foundation of the information investigation engineer investigation, through the typical test section experiment in HONG-GUAN highway, this paper has raised some construction technologies such as the construction machinery choice and the combination, the scene spreads paving and the leveling-up, the construction compaction craft and so on.
|
PDF Full Text Request