Loess Structural Model And The Flooding Of Loess Channel Deformation Test And Numerical Analysis

The structural characteristics, its effecting factors and its effect on mechanicalproperty of unsaturated loess are studied in this paper based on the lateral confinedcompression and inundation tests of both the intact and the artificial structural loessspecimens, and on the triaxial tests under the conditions of ordinary shear compression,iso-stress ratio, collapsible deformation under different stress levels, iso-suction andtotally disturbed-saturated specimen. On the basis of analyzing the suction-water contentcurves measured in intact loess and the electron photo scanned on intact loess specimensbefore and after their inundation in triaxial test condition, the collapsibility mechanismand the relation between micro-structure and collapsibility of loess are also studied.In consideration of the above mentioned tests and also the stable state principle aswell as the state porous ratio of totally disturbed clay specimens, the yield function and thedamage function of unsaturated loess are established based on the conception that theinversal deformation is induced by the two mechanisms of slips and crush of the soilintegration and damage principal. And then a structural constitutive model of unsaturatedstructural loess is obtained. By using the calculating program drawn up on account of thismodel the results of lateral confined compression and inundation tests, and the triaxialinundation tests in different stress levels are examined and analyzed. The coincidence isobtained between the tested and calculated results.In order to study the regulation of deformation and failure of canal in the collapsibleloess and to verify the correctness and reasonability of the structural model suggested, themodeling tests of deformation, suction change and inundating process of the canal areconducted on the centrifugal machine, which discovers the types, the mechanism and theeffecting factors of the canal slope failure in the process of its inundation. The calculatedsuction change, deformation change history and inundation surface change with time ofinundation of two canal model schemes are also closed to that of tested when the single-phase pore fluid assumption, the structural model of loess and the FEM program of planestrain consolidation are used. This shows that the proposed method and model arereasonable and feasible in practical use and provide a hopeful prospect for evaluating thedeformation of loess canal and earth engineering of loess under the coupling action ofloading and inundating.