【摘要】 结合有限单元法,使用隐式锚杆单元来模拟端锚式锚杆,推导杆体和预应力对模型的附加刚度贡献,并对锚杆的端锚力也给予恰当模拟。隐式锚杆单元隐含在岩体单元中,极大地简化有限元模型划分。但锚杆应力计算值与工程实测值相比往往偏大,考虑到锚杆对岩体的局部影响效应因素,进一步分析锚杆与岩体的相互作用,导出岩体在弹塑性状态下变形与锚杆力间的解析关系式。结果显示,当岩体进入塑性、变形较大时,用推导公式对锚杆变形、应力进行修正是非常必要的。最后的算例分析表明,隐式锚杆能较好地模拟支护效果,用修正方法算得的锚杆力与实测值较为接近。为更加精确地模拟锚杆的支护效果提供一些有益的方法。更多还原

【Abstract】 Combined with the 3D FEM,the end-anchored bolts are simulated by implicit bolt element. The stiffness contribution of bolt and prestress is deduced,and the strength of anchor end is also simulated. The implicit bolt elements are combined in the elements of rock mass,so the mesh generation is extremely simplified. However,the calculated stress of bolt is always greater than the measured value. This paper analyzes the interaction of rock bolt and rock mass,and presents the analytical expression of elastoplastic deformation of rock mass and bolt stress. The results indicate that it is essential to revise the bolt stress by using the formulas when rock mass is in plastic state. Finally,a case study indicates that the implicit bolt element can simulate well the supporting effect. And the calculated results agree with the observed ones. This paper offers some beneficial methods for more accurately simulating the support effect of bolts.更多还原