Study On Deformation Characteristics And Stability Of High Embankment Filled By Coarse Grained Soils On Sloping Ground

High embankment has become to a common structural style of roads in mountainous areas due to the complex topography conditions. In order to avoid geologic disasters resulting from excessive deformation or unstable landslide of the high filled foundations, it is urgent to study the related technical problems existing in design and construction of the high embankment. Therefore, depending on the practical projects, this dissertation carried out studies mainly about deformation and strength characteristics of the coarse grained soils, calculation method for settlement of the high filled body and stability of the high slopes and steep slants, deformation control of the high embankment and complete set of technique for slope stabilization. And these studies have very important theoretical and practical values.Depending on the practical projects, engineering characteristics and constitutive model of the coarse grained soils, deformation characteristics and stability of the high embankment filled by coarse grains soils as well as treatment method of the stability were all systemically studied. And the studies of the deformation characteristics and stability of the high embankment filled by coarse grained soils on sloping ground were especially focused on. Therefore, the studies of this dissertation provide scientific references for reasonable design of the high embankment and useful guides for engineering practice. Furthermore, the studies also contribute to further development of science of the coarse grained soil mechanics.The main contents and results of this dissertation include:Depending on the practical projects, large-sized triaxial tests were carried out in lab in order to study the compression and shear characteristics of the coarse grained soils. According to the test results, firstly, water has important influence to the compression and shear characteristics of massive grain soils. Secondly, the pattern of stress-strain curve is mainly weak strain-softening or strain-hardening style. And the patterns were determined by the around confining press. Finally, the coarse grained soils possess characteristics of shearing expand and shearing compression. And the shearing strength has nonlinear characteristics and varies with the strain level.The nonlinear constitutive model of coarse grained soils considering effects of characteristics of shearing expand, characteristics of strain softening and strain level was created by modifying the Naylor's K-G model. The modified model describes the strain hardening and softening phases using sectional-function. The deduced shearing modulus Gt and volume change modulus Kt are functions of variables of stress state, stress ratio and incremental ratio of stress. And the modulus can also reflect the characteristics of shearing expand and strain softening. Validity and reliability of the modified model were verified by numerical modeling and test study.According to the numerical modeling and analysis using the modified K-G model, deformation rules of the high embankment on sloping ground with different filled heights and slope ratios, as well as effecting rules of slope gradient, cover thickness of foundation and strength parameter to the deformation of the high embankment on sloping ground were obtained.Practical calculation method of compression deformation of the high embankment step filled by coarse grained soils was discussed. Then, considering the consolidation pressure resulted from the soil compacting in the earlier stage, the simplified calculation method for settlement of the high embankment was put forward. And the method was verified by carrying out field compacting test and settlement monitoring of roadbeds.Stability of the high embankment filled by coarse grained soils was studied using limiting equilibrium method. Thus, effecting rules of the different filled heights and slope ratios to the stability of high embankment slope on plane foundations as well as effecting rules of slope gradient, cover thickness of foundation, toe blocks and retaining wall to the high embankment on sloping ground were all obtained.Via the numerical modeling and analysis for restriction technique of lateral deformation of the toe blocks, toe retaining wall, etc., actual effects and influencing factors of the restriction technique were obtained.