Experimental Study On Structural Property And Stress-strain Relationship Of Granite Residual Soil

Granite residual soil is widely distributed in South China. Because of the lack of the deepresearch about the physical and mechanical properties of granite residual soil, there appearmany problems during the practice of geotechnical engineering on granite residual soil area.Through stress-path controlled triaxial tests on the high-quality granite residual soilundisturbed soil and disturbed soil from the pit of a construction site in shenzhen, the researchfocus on the stress-strain behavior and the structural impact of granite residual soil. The maincontents and results include:1. By conventional triaxial consolidation undrained and consolidated drained test onGranite residual soil undisturbed sample and remolded sample,here comes the followingunderstandings, after the comparison among the tests: Granite residual soil undisturbed soilshowed strong structural, its structural properties makes it stronger than remolded, As the testconfining pressure increasing, the structural impact weakening, the strength and deformationcharacteristics of the Granite residual soil undisturbed sample and remolded sample arebecoming more and more consistent.2. From the results of isotropic consolidation test of Granite residual soil undisturbedsample and remolded sample, it shows that the Granite residual soil is a kind of anisotropicsoil, the vertical compression performance is much better than the horizontal direction, andthe existence of structural reinforced this anisotropy.3. Under same confining pressure, the Granite residual soil remodeling sample equal ptriaxial test peak is higher than normal triaxial consolidated undrained test. This indicates thatremodeling sample has the over-consolidated clay Properties after isotropic consolidation test,which enhanced the strength of equal P situation.4. Strength index comparison between equal P triaxial test and conventionalconsolidation undrained test: Cohesion indicators dropped significantly, the angle of internalfriction has been greatly improved. This shows that under equal P path, Granite residual soilundisturbed sample’ structure is disrupted, leading to sharp decline of its cohesion.5. Stress-strain curves for triaxial shear test on Granite residual soil undisturbed sampleis mostly a strain softening one, and the damage from the test is the rupture surface kind.Stress-strain curves for triaxial shear test on Granite residual soil remodeling sample is mostlya strain hardening one, and the damage from the test is a drum type.6. according to the consolidated undrained test of Granite residual soil undisturbedsample and remolded sample: the nonlinear model stress-strain expression of Nanjing water ASTRI, demonstrates the Strength and strain softening properties properly; ModifiedCambridge model and Duncan-Chang model demonstrates Stress-strain properties of thegranite residual soil remolded sample properly.