STABILITY ANALYSIS OF PILLARS IN CONSIDERATION OF RHEOLOGICAL BEHAVIOUR OF ROCK
摘要
The mined-out area of a gypsum mine is right un-demeath civil constructions of a township, threatening the safety ofthe latter. To evaluate the long-term stability of the mined-out area,a visco-elastic plastic finite element analysis is carried out,combinedwith in situ measurements. The visco-elastic plastic coeffcients havebeen determined through laboratory rock creep tests. Noticing the lim-itations of conventional element failure criteria,the authors proposeda new method to evaluate the stability of the element, i. e., by a si-multaneous control of the energy density and strain of the element.Computation showed that at stable state,one third of the pillars arein the visco-plastic state,the rest of the pillars, the roof and floorare still in the visco-elastic state. The stress concentration coefficientat the boundary of pillars and roof is 2. 3,and the maximum verti-cal stress on the pillars is 11. 8 MPa. Data measured on site are con-sistent with the computation results,indicating that the proposed ca