A MECHANICAL MODEL OF A BOLT IN THE VICINITY OF A JOINT AND ITS NUMERICAL MANIFOLD METHOD (NMM) APPLICATION

This study presented a beam element model for bolts near the joints in jointed rock masses. The model is able to capture the characteristics of bolts near the joints, including tension, compression, bending, and shearing deformation and plastic hardening after yielding. After incorporating the model into the numerical manifold method, a numerical method for anchored jointed rock masses is proposed. Since bolts can be treated as physical meshes in the numerical manifold method, bolt elements are independent of manifold meshes in our method. Thus, the numerical preprocessing involved in bolts is significantly simplified, and the sophisticated simulation of large-scale bolts is also achieved. A good agreement between numerical results and the test data of a bolted joint plane was observed, demonstrating the effectiveness of the proposed model. Finally, the model is applied in the surrounding rock-supporting system in the underground powerhouse of the Shuibuya project. Numerical results show that the model can properly capture the features of the deformation of bolted rocks and the support effects.