Dissertation > Industrial Technology > Mining Engineering > Mine the pressure and support > Theory of rock pressure > Rock mechanical properties

Study on Rheological Propertiesof Jinchua No.2 Minging District in Air and Saturated States

Author LiNa
Tutor CaoPing
School Central South University
Course Underground Space Science and Engineering
Keywords rock in deep level high in-situ stress rheology saturation non-linear visco-elastic-plastic models
Type Master's thesis
Year 2011
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With the rapid economic growth, people demand more and more resource, but in fact our shallow level resources have been facing a crisis, while the deep resources are there is a big potential, so a large number of mining engineering has already turned to the depth level. Rock engineering in depth level own its special features-high original stress, rheological property of rock is more evident with special complex environment. Long-term immersion coupled with well-developed deep water, the nature of rock is more unstable, which accelerate the destruction of surrounding rock, causing big damage to people and property.Therefore, research works to the properties of rock under deep water become very necessary. Long-term experiments have respectively been conducted to analyse the deep rock’s mechanical and rheological properties in the natural state and water-saturated state, which was collected from JinChuan NO.2 district. And then the rheology constitutive model of rock is proposed, undering analysis of macroscopic mechanical properties of water on rock properties and rheological effects. The main research works are as follows:(1) Standard test blocks are processed from the deep Earth rocks, collected from JinChuan NO.2 district. Meanwhile, experiments on the physical properties of the rocks are measured.(2)Both conventional uniaxial compression test and shear test are conducted on RYL-600 testing machine. This article analyzes the deformation of rock samples, strength characteristics and failure law and the compressive strength of specimens, deformation modulus and poisson ratio variation law,obtains a variety of basic mechanical parameters of rock samples for the creep test which will provide a basis for numerical calculation.(3) Creep experiments have been conducted by adopting multi-step incremental cycling loading and unloading method and using rock samples collected in Jinchuan No.2 mining area in air and saturated states. According to the experimental creep curve, data of experiments had been processed according to instant elastic strain, visco-elastic-plastic strain, instant plastic stain and visco-plastic stain, respectively. Deformation feature of visco-elastic-plastic rock in depth level have been derived.(4)A new nonlinear viscoplastic body is proposed, which is in series connecting with generalized Kelvin model, we can construct a new seven-component nonlinear viscoelastoplastic rheological model of rock. The model effectively describes the mechanics characteristics of Jinchuan No.2 district. The model parameters are identified successfully through the damped least square method according to the creep test curves.

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