Excavation stability of foundation pit in karst area based on hydro-machine-damage coupling
Aiming at the rock instability caused by hydro(H)-machine(M)-damage(D)coupling during,the construction process of foundation pit engineering in karst area,the stress-seepage-damage coupling model and algorithm based on Hoek-Brown strength criterion were established.Firstly,according to the damage theory,the H-B strength criterion was modified by introducing damage factor,and the governing equations of stress field and seepage field and permeability evolution equa-tion were given to realize the complete coupling of stress,seepage and damage.Then,a solution algorithm for the model was provided,and the results of triaxial laboratory tests and simulation calculations of limestone were compared,which showed good fitting and verified the accuracy of the model.Fi-nally,the model was used for the excavation stability analysis of the foundation pit project of the Suoyuwan South Station of Dalian Metro,and the surface settlement and underground continuous wall deformation under the coupling and non-cou-pling conditions were calculated respectively.The calculation results show that the deformation value considering the cou-pling is significantly greater than the uncoupling,and it is closer to the field monitoring value.At the same time,in or-der to determine the minimum thickness of the anti-outburst layer of the surrounding rock,the distribution characteristics of the damage area at 2 m,4 m,6 m and 8 m of the anti-out-burst layer were calculated respectively,which has certain significance for the risk prediction during actual construction.
karst areaexcavation of foundation pitsstabili-tyhydro-machine-damage coupling model
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