Study On Road Cutting Slope And Embankment Stability Of Red-beds In Mid-Yunnan Province

Based on extensive geological investigation and analysis, deformation and failure mechanism and stability analysis of road cut slope in red beds are studied systematically and thoroughly in this paper. The author uses geological investigation, theoretic and numerical analysis to assist his research. Methods oriented by the typical projects of the red bed road cut slopes involved in the highway from Anning to Chuxiong in middle of Yunnan Province. The mechanic parameters of rock mass in red bed are simultaneously studied by using large numbers of laboratory test and field test. By the experiments through the soil work, Studying the red bed soft rock engineering function used to the embankment filler. The stability and setlement of the embankment have been analyzing,There by some factors that influence the stability and the setlement of the embankment have been got.The main results of this paper can be summed up as follows:(1) Studied the distribute and geology environment characteristic of red bed in middle of Yunnan Province, The strata of red bed in middle of Yunnan Province region are Cretaceous and Jurassic,the Cretaceous is distributing extensively, Rock mainly for the mudstone and the mudstone quality rock, secondly is sandstone, presenting by the layer form thin to middling and thick with each other, the part clips the marlite. The geologic conformation development, geologic conformation region and its influence region take the rock fell to pieces, the side slope stability became bad and break by large-scale. Rock airslake is very intensity, Performance for separate and trough figure, The rock unload consuming in the hard rock, The groundwater type mainly is the cranny water and lax hole water.(2) Studied the engineering geology characteristic of the red bed in middle of Yunnan Province, Include the characteristic of rock group, material constitute, conformation, airslake and water rock effect. the mainly soil mineral in red beds are illite/sericite, there is a small amount of kaolinite and chlorite, the micro-structure as irregular grains and irregular flakes stacked polymer,the mudstone mineral composition and microstructure of the decided its has strong hydrophilic, permeable weak and softening easily with water, argillation, plastic deformation and easy to collapse and other features;The red bed in the middle of YunNan is alternate for the soft rock and hard rock, in existence by alternating layers, the layer combines weak.had influenced by the regional structure,the layer has great torsion, fold and high angle fault with argillized phenomenon. The ability of red bed soft rock stick up to airslake is weak,has obvious differential airslake and the speed of disaggregation in mudstone is quick. the soft rock strength lowers and argillized seam is very lowe under the satisfied water condition.(3) Has systematic and general researched the red layer rock include the sandstone, powder sandstone and mire quality powder sandstone, the powder sand quality mire the rock and mire rock did single stalk compression the strength in appearance and transform experiment and under three stalk conditions strength with transform experiment, analyzed the strength characteristic of red layer and transform characteristic,got the Indicator of cohesive strength and frictional angle.Experiment discovered a transforming of the red layer soft rock the regulation is contented to elasticity-plasticity constitutive relation,can gived the constitutive relation and mohr-coulomb yielding function by elasticity-plasticity. The red layer structure noodles includes weak mezzanine, open a little fill and shut to match to have no fill structure noodles of fill, thin layer fill, thick layer carried on system to shear strength has experimented. Obtained the strength of the different type red layer structure noodles and transform parameter, Also studied water strength and the influence for transforming is to the structure noodles. Studied red layer soft rock and it weak mezzanine of the creep characteristic, Had clear understanding of long term strength and deformation of red layer and its weak mezzanine.(4) By the experimentation, studied the capability of red bed soft rock ground mixture as embankmen filler,Its mainly includes the characteristic of series design, hit close-grained, distortion and creep etc of red bed filling. Controling the characteristic of red bed soft rock ground mixture to anticipate embankment filler.(5) Bases the characteristic of geological engineering and rocks structure, Classed the quality classification of sturctural plane and polyhedron of red bed slope. Considering the relationship between the dip of bedding plane and the dip of slope, the dip red bed slope divided into five subgroupsand eleven kinds of damage type: consequent bedding rock slope, countertendency bedding slope and oblique crossing bedding slope. First, the deformation and failure mode consists of three types among consequent bedding rock slope:bedding sliding, sliding and fracturing, bending and fracturing. Secondly, the deformation and failure modes of coutertendency bedding slope are bending-toppling-sliding and slipe along the joint surface. Thirdly the failure modes of oblique crossing bedding slope consist of three types:ladder consequent bedding sliding, ladder consequent joint sliding, and wedge sliding. Fourthly the failure modes of caping layer slip along the interface and circular slide surface.(6) The author selected the typical slope engineering, Analysis the stability of the consequent bedding rock slope and countertendency bedding slope by the method such as Geology analogy, Limited-equilibrium Method, FLAC3D Fast Lagrangian Analysis for Continuum and shear strength reduction FEM method. the formula used to calculate stability factor of wedge failure with different friction angles on two structure planes using limit equilibrium method. Also discussed the reinforce method for differ failure style.(7) The character of settlement, lateral displacement, stability of embankment at different phases of construction have been studied. And also analyzed the rule of its with the variety regulation of time. Studied the settlement regulation influenced by the lateral displacement.