Optimization Design of Pillar Size in Roompillar Mining Method Considering Rheological Effects
A large number of pillars will be left to support the overlying strata when using roompillar mining method.Reasonable pillar size is the key to maintaining the stability of goaf.In order to study the rea-sonable pillar size of a phosphate rock,considering the rheological properties of the rock itself,the reason-able size range of the pillar is obtained by theoretical calculation.On this basis,a numerical model of goaf with corresponding size pillar is established.The Burgers constitutive model of the pillar is given,and the ex-cavation simulation with or without bolt support is carried out respectively,and the variation characteristics of the stress and displacement of the stope are analyzed.The results show that the larger the pillar size is,the better the stress of the roof and the pillar is,the lower the roof subsidence is,and the less obvious the creep effect is.The anchor bolt can improve the overall stiffness of the roof and inhibit the roof subsidence,and its supporting effect is obvious in the small pillar stope.The research results can provide some reference for the design of pillar size in roompillar stope.
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