Analysis of Cylindrical Cavity Expansion with Linear Softening and Large Strain Behavior Based on Extended SMP Criterion   Dongxue Hao PhD candidate, State Key Lab. of Coastal and Offshore Eng., Dalian Univ. of Technol.; Inst. of Geotech. Eng., School of Civil and Hydraul. Eng., Dalian Univ. of Technol., Dalian, China haodongxue@yahoo.cn Maotian Luan Professor, State Key Lab. of Coastal and Offshore Eng., Dalian Univ. of Technol.; Inst. of Geotech. Eng., School of Civil and Hydraul. Eng., Dalian Univ. of Technol., Dalian, China mtluan@dlut.edu.cn Rong Chen PhD candidate, State Key Lab. Of Coastal and Offshore Eng. Dalian Univ. of Technol.; Inst. of Geotech. Eng., School of Civil and Hydraul. Eng., Dalian Univ. of Technol., Dalian, China rongchen@yahoo.cn
			ABSTRACT

The extended spatial mobilization plane theory (SMP) is adopted in consideration of the effect of intermediate principal stress on soil shear strength. Damage softening parameter, taken as degradation grads of material mechanics capacity, is introduced to depict the soils softening behavior after yielding. Rowe’s Stress-dilatancy equation in combination with cohesion degradation expression by damage softening parameter is rewritten. It can not only express soil dilation as a function of both friction angle and cohesion, but also describe trends from structure degradation. The problem is formulated in small strain in the elastic zone and large strain in the plastic zone. Based on the extended SMP criterion and stress-dilatancy relation, the governing equations of axisymmetric problem in the plane strain condition and the partial differential equations for the boundary-value problem of cavity expansion in frictional cohesive soils are established. Solutions of radial and hoop stresses and strains around an expanding cavity are obtained by recursive computations. The significance of consideration of the effect of intermediate principal stress is demonstrated by a comparative study between the present solution and current solution based on Mohr-Coulomb criterion. Also the influence of damage softening parameter, cohesion and friction angle is examined by a parametric study.

Keywords: Extended spatial mobilization plane theory; shear dilatancy; linear softening behavior; large strain

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