Sensitivity Analysis Of Mechanical Parameters In Soil Cavern Excavation

Due to complexity of caverns engineering, it is impossible to get rid of the experience ofthe surrounding rock engineering classification method in engineering design, but the simplerformation conditions of soil cavern was able to apply more scientific and detailed stabilityanalysis method for cavern design provides theoretical support. This paper studies theinfluence law of mechanics parameters in surrounding soil to cavern surrounding soil stability,so that it can be more precise application of cavern engineering design, mainly in thefollowing aspects content.1Using engineering of Yellow River National Geological Museum for the researchbackground, based finite difference method, by applying FLAC3Dsoftware, for theunderground excavation in the process, create computing model, taking into account the valueof the time-space effects, and to determine cavern radius, elastic modulus, internal frictionangle, cohesion are the influencing factors in numerical calculation model of cavern stability.2Excavation of the whole process by simulating different sizes cavern, basis for judgingthe size of the plastic zone in surrounding soil, radius of cavern limit excavation for2.5m innone support case. As the cavern excavation radius increases, gradually increasing the scopeof the plastic zone in surrounding soil, process of stress redistribution reach steady stateincreased, horizontal direction stress in the surrounding soil is not a cavern radius affect,vertical direction stress with cavern radius decreases, horizontal displacement and verticaldisplacement increases with the cavern radius, and the sensitivity to changes in the amount ofchange for the different levels of the cavern radius unchanged.3By simulating the elastic modulus, internal friction angle, cohesion rule change whenthe excavation process. As the elastic modulus increases, the horizontal direction stress didnot produce a significant change in surrounding soil, vertical direction stress gradually increases, horizontal displacement and vertical displacement gradually decreases, and whenthe amount of change on the modulus of elasticity of the lower level changes is more sensitive.As the internal friction angle increases, the horizontal direction stress did not produce asignificant change in surrounding soil, vertical direction stress gradually increases, horizontaldisplacement and vertical displacement gradually decreases, and stress keep consistent insensitivity to different level changes of internal friction angle, but the displacement amount ofchange when the internal friction angle of the lower level change is more sensitive. As thecohesion increases, the horizontal direction stress did not produce a significant change insurrounding soil, vertical direction stress gradually increases, horizontal displacement andvertical displacement gradually decreases, And the vertical direction of the stress and thehorizontal displacement and the vertical displacement in the cavern foot and wall position fordifferent levels of the cohesion of the change when sensitivity unchanged, The horizontaldisplacement in the cavern roof position when the vertical displacement as a lower level andto the cohesion is more sensitive to changes.4According sensitivity analysis methods in systems analysis, make sensitivity analysisto affect the degree of elastic modulus, internal friction angle, cohesion in surrounding soil,through different parameter sensitivity factor comparison, determine stress, displacement insurrounding soil sorted from largest to smallest sensitivity of influencing factors: cohesion,internal friction angle, elastic modulus in engineering of Yellow River National GeologicalMuseum.