## 6 Conclusions
\begin{tabular}{l l} \(A_{e}\) & area of triangular finite element \(e\) (m\({}^{2}\)); \\ A\({}_{bound}\) & boundary condition matrix for all boundary edges of finite elements; \\ A\({}_{equil}\) & equilibrium matrix of all finite elements; \\ A\({}_{discont}\) & discontinuity equilibrium matrix of all discontinuities for all finite elements; \\ A\({}_{yield}\) & yield matrix for all nodes of finite elements; \\ B\({}_{bound}\) & coefficient vector of all boundary edges of finite elements; \\ B\({}_{equil}\) & load vector of all finite element equilibriums; \\ B\({}_{equil}\) & coefficient vector of yield conditions for all finite elements; \\ C\({}^{T}\) & equilibrium matrix for all block elements; \\ F\({}^{T}\) & global external force vector for all block elements; \\ L\({}_{j}\) & length of interface \(L_{j}\) between rigid block element \(B_{j}\) and finite elements (m); \\ N\({}_{k}\) & normal force of the interface k between two adjacent block elements in the \(n_{k}\) direction; \\ N\({}_{j}\) & normal force in the \(n_{j}\) direction of rigid block element \(B_{j}\) applied on the interface \(L_{j}\) \\  & between rigid block element and finite elements; \\ Q\({}_{b}\) & force vector at the boundary surfaces of block elements; \\ Q & global internal force vector for all block elements; \\ V\({}_{k}\) & shear force in the \(s_{k}\) direction of the interface k between the two adjacent block elements; \\ V\({}_{j}\) & shear force in the \(s_{j}\) direction of rigid block element \(B_{j}\) applied on the interface \(L_{j}\) \\  & between rigid block element and finite elements; \\ \(b_{i}\) & shape function coefficients of the linear triangular finite element \((i=i,j,k)\); \\ \(c_{c}\) & cohesion of initial and final strength reduction, respectively (Pa); \\ \(c_{e}\) & cohesion of the rock bridge at nodes of eth finite element; \\ \(c_{i}\) & shape function coefficients of the linear triangular finite element \((i=i,j,k)\); \\ \(c_{k}\) & cohesion of the \(k\)th interface (Pa); \\ \(f_{xi}\) & \(x\) component of force acting on the center of block element \(i\); \\ \(f_{yi}\) & \(y\) component of force acting on the center of block element \(i\); \\ \(l_{i}\) & length of the interface between finite element \(E_{i}\) and the rigid block element \(B_{j}\) (m); \\ \(l_{k}\) & length of the interface \(k\) (m); \\ \(m_{i}\) & number of interfaces in block element \(i\); \\ \(n_{B}\) & number of all block elements; \\ \(n_{b}\) & surfaces number on known boundary; \\ \(n_{d}\) & number of finite element stress discontinuities in the rock bridges; \\ \(n_{e}\) & number of all triangular finite elements in rock bridges; \\ \(n_{j}\) & interface number between the rock blocks and finite elements in the entire rock slope; \\ \(n_{j}^{e}\) & number of triangular finite elements on interface \(L_{j}\); \\ \(n_{k}\) & number of all interfaces in all rock block elements; \\ \(n_{n}\) & number of nodes of all finite elements; \\ \(p\) & number of sides of interior polygon for linearizing Mohr-Coulomb yield function; \\ \(\alpha_{k}\) & inclination angle of \(n_{k}\)-axis with respect to \(x\)-axis measured anticlockwise (\({}^{\circ}\)); \\ \(\varphi_{p}\) & friction angles of initial and final strength reduction, respectively (\({}^{\circ}\)); \\ \(\varphi_{e}\) & friction angle of the rock bridge at \(i\)th node of finite element (\({}^{\circ}\)); \\ \(\varphi_{k}\) & friction angle of the kth interface (\({}^{\circ}\)); \\ \(\gamma_{e}\) & unit weight of finite element (N/m\({}^{3}\)); \\ \(\lambda\) & load multiplier of rock mass; \\ \(\lambda_{m}\) & strength reserve coefficient; \\ \(\theta_{d}\) & inclination angle of the discontinuity d measured anticlockwise with respect to \(x\)-axis (\({}^{\circ}\)); \\ \(\theta_{j}\) & inclination angle of the interface \(L_{j}\) measured anticlockwise with respect to \(x\)-axis (\({}^{\circ}\)); \\ \(\sigma\) & stress vector of all nodes for all finite elements; \\ \(\sigma^{j}\) & stress vector of nodes of finite elements on the interface \(L_{j}\); \\ \(\sigma^{d}_{ni}\) & normal stress acting on the node i of the discontinuity d between two adjacent finite elements, (\(i=1,2,3,4\)); \\ \end{tabular}