Comparison Of The Effects Of Sample-preparing Methods On Tri-axial Test Results Of The Soils

Soil test is an important method in the study of soil mechanics, Soil test can provide reliable parameter for calculator, engineering design and construction and soil test is the premise and basis for the correct evaluation of essential properties of engineering. This text take advantage of the tri-axial consolidation un-drained and consolidation drained shear test results of natural medium sand, Nanning fine sand, Nantong silty sand, Nantong silt, which using strain controlling triaxial apparatus make further comparision, analysis and summary. Mainly discusses the effect of different sampling methods on static three axial test results.This text compares the characteristics of stress and strain relation, pore water pressure, effective stress path, instability line, critical state line of natural medium sand, Nantong silty sand, Nantong silt made by dry-sampling method and moist-sampling method in the tri-axial consolidation un-drained shear test. The characteristics of stress and strain relation, volumetric strain and effective stress ratio of natural medium sand, Nanning fine sand, Nantong silty sand, Nantong silt made by dry-sampling method and moist-sampling method in the tri-axial consolidation drained shear test were contrasted. The effective stress shear resistance indexes of natural medium sand, Nanning fine sand made by dry-sampling method and moist-sampling method and Nantong silt made by disturbed-sampling, dry-sampling method and moist-sampling method in the. tri-axial consolidation drained shear test were contrasted. The total and effective shear resistance indexes of Nantong silty sand made by dry-sampling method and moist-sampling method and Nantong silt made by disturbed-sampling, dry-sampling method and moist-sampling method in the tri-axial consolidation un-drained shear test were contrasted. Discusses the influence law of sample-preparing methods on the shear resistance indexes of different soils. Duncan-Zhang Model Parameters of natural medium sand, Nanning fine sand made by dry-sampling method and moist-sampling method in the tri-axial consolidation drained shear test and Nantong silty sand made by dry-sampling method and moist-sampling method in the tri-axial consolidation un-drained shear test were contrasted. In the end, mainly discusses the influences of different initial water content of moist-sampling on natural medium sand, Nanning fine sand, Nantong silt made by moist-sampling method in the tri-axial consolidation drained and un-drained shear test. By comparison and analysis, we can find that natural medium sand, Nanning fine sand, Nantong silty sand, Nantong silt made by dry-sampling method and moist-sampling method in the tri-axial consolidation un-drained and drained test were significantly different. In the tri-axial consolidation un-drained:In addition to medium sand, the dry-sampling method showed strain hardening, and moist-sampling method presented strain softening both loose and dense state. For loose state, moist-sampling method more in line with the general law. For dense state, dry-sampling method were in good agreement with the general rules. The study on instability and critical state line found that the characteristic of strain softening was easier exhibited for moist-sampling method than dry-sampling method. For loose state, the critical state line slope dry-sampling method and moist-sampling method were exactly the same. The loose samples prepared by moist-method present strain hardening and contractibility basically, and yet the dry-method samples present strain softening and dilatability. The dense samples prepared by dry-method show strain softening and dilatability, and yet the moist-method samples present strain hardening and contractibility. In general, the shear resistance indexes of different soils made by dry-sampling method are higher than moist-sampling method. Duncan-Zhang Model Parameters of different soils made by dry-method and moist-method can’t find obvious law and its law waiting to be found. In the tri-axial consolidation un-drained shear test, initial water content of moist-sampling method can influence test results. In the tri-axial consolidation drained shear test, initial water content of moist-sampling method can’t influence test results.