The Engineering Properties As Road Packing Of Incohesive Earth And Rock Mixture Of Red Clastic Rock And Their Parameter Prediction

The earth and rock mixture are widely used in the project construction, because of their good compacting effect, strong perviousness, large compression density, high shear strength, low settlement deformation, high bearing power etc. In the past, the compaction method was adopted to study the compaction density, or large triaxial test was used to study the strength parameters and deformation parameters. However, as for the earth and rock mixture in the past study, the correlations between the main physical index and strength parameters, deformation parameters and settlement deformations were few studied and used in the actual projects. The earth and rock mixture samples studied in this paper, which are got from certain road earth-bank filling element of Yu-Qian highway, behave with dark aubergine and incohesive. The controlling factors selected in this paper studies include the different density, different gravel(P5) and different maximal grain size, because they are gained easily and have large effect on the strength and deformation properties of the project. And many important results have been obtained through the systematic and deep research. The contents are discussed as follows: 1. Elaborating the present research situations on the earth and rock mixture; 2. Getting shear strength index and stress-strain relation of the earth and rock mixture through the large triaxial test with the same mix proportion and different confining pressure; 3. Adopting multi-stage loading pattern in one test sample, carrying out multiple large-scale triaxial tests with different density, different content of grain size and different maximal particle diameter, and getting the strength index and stress-strain relation of the earth and rock mixture; 4. Building the correlations between the strength index of the earth and rock with density and gradation based on the above results, carrying out the FEM numerical modeling, and studying the effect of these factors on the earth bank stability and deformation; 5. Classifying the road property of the earth and rock mixture based on the above correlations; 6. Building the primary forecast models and precise models of the earth and rock mixture, based on density and gradation index; 7. Checking and approving the primary forecast models and precise forecast models. Through the above study, this paper comes to the main conclusions that: â‘ The strength properties of earth and rock mixture depend on the interaction of coarse size and fine size and have the typical characteristics that strength index of the earth and rock mixture increase and the deformation decrease with the increase of density. â‘¡The meshed force decrease and internal friction angle increase with the increase of coarse size content(P5), and taking into account the earth-bank settlement deformation, the coarse size content from 65% to 70% is classified as the best content. â‘¢When the maximal grain size is over 50mm, the shear strength decrease rapidly, and the earth-bank settlement value increase; theoretically, it is best that the grain size is low 50mm, however the part of earth and rock mixture that the grain size over 50 millimeters is not possible to be discarded in actual project. So we should be more discreet, controlling especially the degree of compaction. â‘£Finally, the parameter forecast models are built in this paper, based on the above three index which can be got in the actual projects. The primary forecast models with above 57% precision are used wider. And the precise forecast models with above 93.2% precision are used less narrow.