The stress,strain as well as resistivity of coal during uniaxial compression process were tested based on self-built real-time testing system of loaded coal resistivity.Furthermore,the coal resistivity regularity and ...The stress,strain as well as resistivity of coal during uniaxial compression process were tested based on self-built real-time testing system of loaded coal resistivity.Furthermore,the coal resistivity regularity and mechanism were analyzed at different stages of complete stress-strain process,which includes the two kinds of coal body with typical conductive characteristics.The results indicate that coal resistivity with different conductive characteristics has different change rules in complete stress-strain process.It is mainly represented at the densification and flexibility phases before dilatation occurs.The variation of resistivity can be divided into two kinds,named down and up.Dilatation of coal samples occurred between 66%σ_(max) and 87%σ_(max).Because of dilatation,coal resistivity involves sudden change.The overall representation is shifting from reducing into improving or from slow improving into accelerated improving.Thus,coal resistivity always shows an increasing tendency at the plastic stage.After peak stress,coal body enters into failure stage.The expanding and communicating of macro fracture causes further improvement of coal resistivity.The maximum value of resistivity rangeability named λ reached 3.49.Through making real-time monitoring on coal resistivity,variation rules of resistivity can be deemed as precursory information so as to reflect the dilatation and sudden change before coal body reaches buckling failure,which can provide a new technological means for forecasting the dynamic disaster of coal petrography.展开更多
To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argilla...To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argillaceous siltstone and brown mudstone) were performed by using an MTS-815.02 tri-axial rock mechanics test system, with which the stress-strain curves according to the seepage variation were obtained. Based on the experimental results and by employing Hooke's law, the formulation of the coefficient of strain-dependent permeability was presented and introduced to establish a coupling model. In addition, the mathematical expression and the incremental formulation for coupling model were advanced, in which five parameters that can be respectively determined by using the experimental results were included. The calculated results show that the proposed coupling model is capable of simulating the stress-strain relationship with considering the seepage-stress coupling in the nonlinear elastic stage of two kinds of soft rock.展开更多
基金supported by the Research Project of Chinese Ministry of Education of China(No.113031A)the Basic Scientific Research Business Expenses of Central University of China (Nos.3142015001 and 3142015020)the New Century Talent Supporting Project by Education Ministry of China(No. NCET-11-0837)
文摘The stress,strain as well as resistivity of coal during uniaxial compression process were tested based on self-built real-time testing system of loaded coal resistivity.Furthermore,the coal resistivity regularity and mechanism were analyzed at different stages of complete stress-strain process,which includes the two kinds of coal body with typical conductive characteristics.The results indicate that coal resistivity with different conductive characteristics has different change rules in complete stress-strain process.It is mainly represented at the densification and flexibility phases before dilatation occurs.The variation of resistivity can be divided into two kinds,named down and up.Dilatation of coal samples occurred between 66%σ_(max) and 87%σ_(max).Because of dilatation,coal resistivity involves sudden change.The overall representation is shifting from reducing into improving or from slow improving into accelerated improving.Thus,coal resistivity always shows an increasing tendency at the plastic stage.After peak stress,coal body enters into failure stage.The expanding and communicating of macro fracture causes further improvement of coal resistivity.The maximum value of resistivity rangeability named λ reached 3.49.Through making real-time monitoring on coal resistivity,variation rules of resistivity can be deemed as precursory information so as to reflect the dilatation and sudden change before coal body reaches buckling failure,which can provide a new technological means for forecasting the dynamic disaster of coal petrography.
基金Projects(50378069, 50639090) supported by the National Natural Science Foundation of ChinaProject(50639090) supported by the Joint Fund of Yalong River Hydropower Development, China
文摘To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argillaceous siltstone and brown mudstone) were performed by using an MTS-815.02 tri-axial rock mechanics test system, with which the stress-strain curves according to the seepage variation were obtained. Based on the experimental results and by employing Hooke's law, the formulation of the coefficient of strain-dependent permeability was presented and introduced to establish a coupling model. In addition, the mathematical expression and the incremental formulation for coupling model were advanced, in which five parameters that can be respectively determined by using the experimental results were included. The calculated results show that the proposed coupling model is capable of simulating the stress-strain relationship with considering the seepage-stress coupling in the nonlinear elastic stage of two kinds of soft rock.
