Three-dimensional upper bound analysis for collapse stability of cavern roofs in composite strata under a generalized nonlinear failure criterion
Qianlong Zhu,Chao Cao,Yuliang Lin,Xiaojing Li,Ye Ma,Rongning Deng
Abstract
In composite rock-soil strata, cavern excavation often induces roof collapse. To address this issue, a generalized nonlinear failure criterion capable of describing the mechanical behavior of both soil and rock is adopted. Using the upper bound limit analysis method, three-dimensional stability analysis models for cavern roofs are established, considering both rectangular and elliptical cross-sections. The total energy dissipation rate of the collapsing block is formulated, thus identifying the potential failure zone of the cavern roof. Based on this energy dissipation rate equation, a set of quantitative stability evaluation indicators for the cavern roof is derived, and stability charts for the roof factor of safety F and supporting pressure p/ra under various parameters are established. The proposed method is validated through engineering case studies, numerical simulations and quantitative comparisons with previously published research. The results indicate that the parameters of the rock and soil mass, as well as vertical seismic forces, significantly affect the stability of the cavern roof. Under identical stability number N, the required supporting pressure for rectangular cavern roofs is greater than that for circular ones, suggesting a higher susceptibility to failure in rectangular configurations.
Key Words
Qianlong Zhu, Yuliang Lin, Ye Ma, Rongning Deng: School of Civil Engineering, Central South University, Changsha 410075, China; National Engineering Research Center of High Speed Railway Construction Technology,Changsha 410075, China Chao Cao, Xiaojing Li: China Construction Fifth Engineering Bureau Co. Ltd., Changsha, 410019, China
Address
Qianlong Zhu, Yuliang Lin, Ye Ma, Rongning Deng — School of Civil Engineering, Central South University, Changsha 410075, China; National Engineering Research Center of High Speed Railway Construction Technology,Changsha 410075, China
Chao Cao, Xiaojing Li — China Construction Fifth Engineering Bureau Co. Ltd., Changsha, 410019, China
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