Pre-disintegrated soft rock embankment structure based on spatial function zones and design method thereof

A design method of the pre-disintegrated soft rock embankment structure based on spatial function zones, comprising:

• S1, performing field sampling at a pre-disintegrated soft rock embankment and preparing a sample by a stratified sample compression method;
• S2, conducting a static triaxial test on the sample in step S1 under test conditions of different confining pressures to obtain a cohesive force c and an internal friction angle 4 of pre-disintegrated soft rock-soil mass, and obtaining a strength envelope formula for pre-disintegrated soft rock by processing static triaxial test data;
• S3, conducting a dynamic triaxial test on the sample in step S1 with different stress ratios, compaction degrees, and confining pressures to obtain a permanent axial deformation and a dynamic rebound modulus of embankment soil mass under action of a dynamic load, and establishing a prediction model for a dynamic rebound modulus of embankment soil mass and a prediction model for a permanent strain of a subgrade under the action of the dynamic stress;
• S4, establishing a two-dimensional finite element numerical model of the pre-disintegrated soft rock embankment through finite element software, with consideration of the action of the dynamic stress and with an X-axis representing a longitudinal length of the subgrade and a Y-axis representing a height of the subgrade, meshing the two-dimensional finite element numerical model, and exporting coordinates of each node in the two-dimensional finite element numerical model and a vertical stress σ1qj a lateral stress σ3qj and a dynamic stress corresponding to each node;
• S5, conducting a static triaxial creep test on the sample prepared in step S1 with different stress ratios and compaction degrees to obtain a permanent axial deformation of the embankment soil mass under action of a static stress, and establishing a prediction model for a permanent strain of a subgrade under the action of the static stress;
• S6, establishing a two-dimensional finite element numerical model of the pre-disintegrated soft rock embankment by using the finite element software without consideration of the action of the dynamic stress, obtaining distribution rules of depths and shear failure ratios of a subgrade workspace, and dividing an embankment structure into an embankment shear control zone, an embankment settlement control zone, and an embankment shear-settlement control zone;
• wherein the embankment shear control zone is a zone in which a shear failure ratio is greater than a predetermined value;
• the embankment settlement control zone is a filled zone right below a top surface of an embankment;
• and the embankment shear-settlement control zone is an intersection of the embankment shear control zone and the embankment settlement control zone;
• and
• S7, based on divided spatial function zones, obtaining parameter design values of different zones by inversion, and carrying out a modified mixing ratio design for pre-disintegrated soft rock.