Stability analysis of layered cutting slope soil nailing support structure based on strength reduction method

The rock mass structure of jointed rock slope dominates the slope deformation and stability.To assure the safety of the layered rock slope,the analysis method combined the rock mechanics theory,nonlinear finite element analysis and strength reduction factor method is proposed to analyze the stability of the jointed rock slope by using soil nailing structure.In the nonlinear finite element modeling for jointed rock slope with dense joints,assuming the joints distribute evenly in the rock,dense distribution jointed rock material model is established based on continuum mechanics theory.The improved safety factor calculation method for jointed rock slope stability using strength reduction method is proposed.It is suggested to calculate the internal forces of rock slope excavation and after supporting by using given rock mass strength parameters.Then the nonlinear finite element analysis is performed for the constructed rock with the slope rock mass strength parameter decreases gradually.Safty coefficient is obtained till the limit state of rock slope is achieved.The stability of the soil nailing support structure for DK409+989.4~DK410+020 of Yuhuai Railway at right side of Meijiang River is performed by using strength reduction method.The result shows that the safety coefficient of jointed rock slope is 2.3,which indicates that the rock slope is in stable state.The potential failure surface for the soil nailing slope is consistent with the measured maximum tensile stress for the soil nailing,which is also the interface between the elastic zone and the plastic zone.