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Study and Application of the Equivalent Parameters of Full-Length Anchored Rock Masses in DDARF
(1 Shandong Provincial Key Laboratory of Appraisal and Retrofitting for Building Structures, Shandong Jianzhu University, Ji'nan 250101;2 Geotechnical and Structural Engineering Research Center, Shandong University, Ji'nan 250061;3 Shandong Urban Construction Vocational College, Ji'nan 250103)
Abstract In the discontinuous deformation analysis of rock failure (DDARF), it is assumed that the rock mass is reinforced by end-anchored bolts. The study of the rock masses reinforced by full-length anchored bolts is still in its early stages. In light of the equivalent anchoring effect, and considering the variation of mechanical parameters of the rock mass supported by full-length anchored bolts, a method was proposed to perform an anchoring-effect analysis of full-length anchored bolts in DDARF. Based on construction of the Yimeng power station project, and using FLAC software, this paper analyzed the plastic zone of surrounding rocks under three conditions of excavation: no support; support with improved equivalent mechanic parameters; and rock mass support with full-length anchored bolts. Furthermore, the crack development of the rock masses was analyzed by DDARF. The results show that: 1) in FLAC analysis, fewer plastic zones occurred in surrounding rocks under conditions of support with improved equivalent mechanic parameters and those reinforced with full-length anchored bolts compared with excavation with no support, and the calculation results under the conditions of 1.18 times cohesive force and full-length anchoring are matched especially well; and 2) in DDARF analysis, the cracks in the surrounding rocks using anchors with improved mechanic parameters and full-length anchoring are controlled more effectively compared to those in rock masses with no support, with roughly the same development scale and number of cracks. Thus, using the improved equivalent mechanic parameters for anchored rock masses to simulate the full-length anchoring effect in DDARF can not only reduce the complexity of the calculation but also improve its accuracy.
Abstract：
In the discontinuous deformation analysis of rock failure (DDARF), it is assumed that the rock mass is reinforced by end-anchored bolts. The study of the rock masses reinforced by full-length anchored bolts is still in its early stages. In light of the equivalent anchoring effect, and considering the variation of mechanical parameters of the rock mass supported by full-length anchored bolts, a method was proposed to perform an anchoring-effect analysis of full-length anchored bolts in DDARF. Based on construction of the Yimeng power station project, and using FLAC software, this paper analyzed the plastic zone of surrounding rocks under three conditions of excavation: no support; support with improved equivalent mechanic parameters; and rock mass support with full-length anchored bolts. Furthermore, the crack development of the rock masses was analyzed by DDARF. The results show that: 1) in FLAC analysis, fewer plastic zones occurred in surrounding rocks under conditions of support with improved equivalent mechanic parameters and those reinforced with full-length anchored bolts compared with excavation with no support, and the calculation results under the conditions of 1.18 times cohesive force and full-length anchoring are matched especially well; and 2) in DDARF analysis, the cracks in the surrounding rocks using anchors with improved mechanic parameters and full-length anchoring are controlled more effectively compared to those in rock masses with no support, with roughly the same development scale and number of cracks. Thus, using the improved equivalent mechanic parameters for anchored rock masses to simulate the full-length anchoring effect in DDARF can not only reduce the complexity of the calculation but also improve its accuracy.
2015, Vol. 52 