基于上限有限元法的节理岩质边坡稳定性分析

发布时间：2019-04-15 21:07

【摘要】：上限原理有限元法不仅可以得到边坡的安全系数,还可以给出临界滑动面,且摆脱了极限平衡法假设条件过多、过于刚性的缺点,具有更严谨的理论基础,因此拥有更广阔的应用前景。但是,对于岩质边坡,由于其存在大量的节理面,造成应力不连续,这给直接运用传统的数值计算方法带来了困难。其实,每组的节理面均表示在某一特定的方位上边坡的材料特性比较差,只需在处理这些特定方位时,采用相应的软弱节理面的材料特征即可,这样便可有效地化解节理面难以模拟的缺陷。因此,基于传统的上限有限元法,采用四边形单元,通过对单元建立积分意义上的协调方程的弱形式,来得到可以调整单元内部速度场的线性化的协调方程,从而可以克服插值速度场为非线性的缺点。对于任意应力点,从空间方位出发,将方位进行离散,建立并推导出了基于方位离散线性化的上限有限元法,该方法在考虑含多组节理面的岩质边坡计算上有着更好的优势。两个算例结果表明:该方法与传统的上限有限元法一样,可以稳定地从极限解的上方收敛,满足上限性质,且对于含多组节理面的岩质边坡同样有很好的收敛性。
[Abstract]:The finite element method of the upper bound principle can not only obtain the safety factor of the slope, but also give the critical sliding surface, and get rid of the shortcomings of too many hypotheses and too rigid conditions of the limit equilibrium method, so it has a more rigorous theoretical foundation. Therefore, it has a wider application prospect. However, for rock slopes, due to the existence of a large number of joint surfaces, the stress is discontinuous, which makes it difficult to use the traditional numerical calculation method directly. In fact, the joint surface of each group indicates that the material characteristics of the slope on a particular azimuth are relatively poor, and only the material characteristics of the corresponding soft and weak nodal surfaces are used in dealing with these particular orientations. In this way, the defects of the joint surface which are difficult to simulate can be effectively solved. Therefore, based on the traditional upper limit finite element method, the quadrilateral element is used to establish the weak form of the coordination equation in the sense of integral to obtain the linearized coordination equation which can adjust the internal velocity field of the element. Thus, we can overcome the disadvantage that the interpolation velocity field is nonlinear. The upper limit finite element method based on azimuth discrete linearization is established and derived for arbitrary stress points. This method has better advantages in the calculation of rock slopes with multi-joint surfaces. The results of two numerical examples show that, like the traditional upper bound finite element method, the proposed method can converge stably from the top of the limit solution and satisfy the upper bound property, and it also has good convergence for rock slopes with multi-group joint surfaces.
【作者单位】：武汉市市政建设集团有限公司;武汉市市政路桥有限公司;重庆交通大学;
【分类号】：U416.14

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