基于有限元应力积分剩余推力等安全系数法的岩体边坡稳定分析研究

发布时间：2018-07-10 17:07

本文选题：岩体边坡 + 有限元法　；参考：《太原理工大学》2015年硕士论文

【摘要】：边坡中常常因为地质成因和构造影响产生节理、裂隙、断层或软弱夹层等不稳定结构面，这些结构面的存在会对边坡的稳定性产生重大影响。若这些不稳定结构面相互连接，贯通岩体边坡，将会导致滑坡、倾倒等重大工程事故。这些事故一旦发生，其所导致的后果是难以预计的。若要处理这些软弱结构面，所需要花费的工程费用十分庞大且难以彻底清除。因此对岩体边坡抗滑稳定性能的核算分析是一项重要而普遍的工程问题。边坡抗滑稳定性分析这一课题自提出至今研究者们创造了诸多的验算方法，并且经过实际工程的验证形成了一套完整而成熟的理论体系。但是，由于多种因素对岩体边坡稳定性都有不可忽略的影响，且各原理在分析的过程中均不能将这些因素完全考虑。现行岩体边坡稳定性分析的理论有其各自的优缺点，时至今日仍没有形成统一的规范和客观准确的评价方法。因此，有必要对边坡稳定问题进行更深入的探讨。本文探讨了岩体边坡稳定分析中的传统有限元应力代数和计算方法中存在的不足，提出了考虑滑裂面方向夹角因素的有限元应力积分剩余推力法，并对使用两种方法计算得到的安全系数进行了对比分析。对不完全贯通软弱夹层岩体边坡的最终破裂面进行了搜索，试图寻找到安全系数最小的滑裂面即最危险滑裂面。具体研究内容如下： (1)提出了考虑软弱夹层夹角影响的有限元应力积分分析计算方法的原理及求解思路，本文称其为有限元应力积分剩余推力等安全系数法。传统有限元应力代数和法所求得的安全系数仅仅是各滑裂面上抗滑力与滑动力代数和相加后的比值，没有考虑到各滑裂面间方向夹角对安全系数的影响，其所得结果的下滑破坏面与工程实际破坏情况有较大偏差。本文提出的方法将充分考虑方向夹角的影响，在等安全系数的前提下，材料所发挥的粘聚力和摩擦系数为ci/k，fi/k。求出各滑裂面上的滑动力和抗滑力，二者之差所得结果若为正值则视为该滑裂面上的剩余滑动力，反之则称其为剩余抗滑力。计算各滑裂面上所得的剩余滑动力（抗滑力）在主抗滑面方向上的平衡条件，即可求得整个滑裂面上的安全系数k。 (2)将所提出的有限元应力积分剩余推力等安全系数法的算法用FORTRAN语言进行编写，，用方便、高效、快捷的计算机语言来解决复杂的计算过程，同时也为该方法的运用及推广开阔了前景。 (3)使用算例对两种方法所求得的安全系数进行对比分析，阐明在加入滑裂面间夹角因素的有限元应力积分剩余推力分析法求得的安全系数是客观确定的，而传统有限元应力代数和法有不确定性和简化性。同时，最小安全系数破裂面方向有悖于工程常识现象。 (4)在实际工程中，岩体边坡中的软弱结构面往往是不完全贯通的。岩体最终破坏时的滑裂面走向成为本文研究的重要课题。本文通过对一个含有两条软弱夹层的不完全贯通岩体边坡进行分析研究。通过改变滑裂面的初始破裂点位置和滑裂面与水平方向间的倾角，模拟计算确定边坡的最危险破裂面，运用本文提出的有限元剩余推力法作为求解安全系数的方法。将所求的安全系数进行比较分析后选定安全系数最小的滑裂面即为最危险滑裂面。 (5)加入滑裂面间夹角影响因素的有限元应力积分剩余推力等安全系数分析法，不仅继承了有限元应力代数和法能直接求出安全系数的优点，而且比传统的应力代数和法计算求得的安全系数更贴近工程客观实际，使用起来更加可靠。基于此方法对非贯通软弱夹层的岩体边坡最终破裂面的搜索也符合工程实际。因此对该方法的研究于岩体边坡稳定性的发展有极大的促进作用。
[Abstract]:In the slope, unstable structures, such as joints, cracks, faults or weak intercalation, are often caused by geological causes and tectonic influences. The existence of these structures will have a great influence on the stability of the slope. If these unstable structures are connected to each other and through the rock slope, it will lead to landslides, dumping and other major engineering accidents. In order to deal with these weak structural surfaces, the cost of engineering is very large and difficult to eliminate thoroughly. Therefore, it is an important and universal engineering problem to calculate and analyze the anti sliding stability of rock slope.
The stability analysis of slope stability has created a lot of checking methods since it has been proposed, and a complete and mature theoretical system has been formed through the verification of practical engineering. However, many factors have not negligible effect on the stability of rock slope, and all the principles can not be used in the process of analysis. These factors are fully considered. The existing theory of rock slope stability analysis has its own advantages and disadvantages, and there is still no unified standard and objective and accurate evaluation method today. Therefore, it is necessary to further discuss the problem of slope stability.
In this paper, the shortcomings of the traditional finite element stress algebra and calculation method in the rock slope stability analysis are discussed. The finite element stress integration residual thrust method, which considers the angle factor of the sliding surface, is put forward, and the comparison analysis is made for the safety coefficient calculated by the two methods. The final fracture surface of the slope was searched to find the most dangerous slip surface, namely the most dangerous slip surface.
(1) the principle and solution of the finite element stress integral analysis and calculation method considering the influence of the weak sandwich angle are put forward. In this paper, it is called the safety factor method of the finite element stress integral residual thrust and so on. The safety coefficient obtained by the traditional finite element stress algebra and method is only the anti slip force and the sliding force algebra and the addition of the sliding force on the sliding surface. The ratio has not taken into account the effect of the angle between the direction of the sliding crack on the safety factor, and there is a great deviation between the failure surface of the result and the actual damage of the engineering. The method proposed in this paper will take full consideration of the influence of the direction angle. Under the condition of equal safety factor, the cohesion and friction coefficient of the material are ci/k, fi/k. The sliding force and anti slip force on each slip surface are obtained. The result of the difference between the two is considered as the residual sliding force on the sliding surface, and conversely, it is called the residual anti slip force. The calculation of the balance condition of the residual sliding force (anti slip force) on the main anti sliding surface in each slip surface can be used to obtain the safety factor K. on the whole sliding surface.
(2) the algorithm of safety coefficient method, such as the finite element stress integration residual thrust and so on, is written in FORTRAN language. It is convenient, efficient and fast computer language to solve the complicated calculation process. At the same time, it also broadens the prospect for the application and popularization of the method.
(3) by comparison and analysis of the safety coefficient obtained by the two methods, the safety coefficient obtained by the finite element stress integral residual thrust analysis method is determined objectively, while the traditional finite element stress algebra and method are uncertain and simplified. At the same time, the minimum safety factor fracture surface is also analyzed. It is contrary to the common sense of engineering.
(4) in actual engineering, the weak structural surface in the rock slope is often not completely connected. The strike of the sliding surface in the final failure of the rock mass is an important subject in this paper. In this paper, the slope of an incomplete penetrating rock mass containing two weak interbeds is analyzed and studied. The position of the initial fracture point of the sliding surface is changed. The dip angle between the sliding surface and the horizontal direction is simulated to determine the most dangerous fracture surface of the slope. The method of the finite element residual thrust method proposed in this paper is used as a method to solve the safety factor. The minimum safety factor is selected as the most dangerous slip surface after the comparison and analysis of the safety coefficient.
(5) the safety factor analysis method, such as the finite element stress integral residual thrust and so on, not only inherits the advantages of the finite element stress algebra and the method that can directly calculate the safety factor, but also is more close to the objective reality than the traditional stress algebra and the method calculated by the traditional stress algebra and method, and is more reliable in use. The method of searching the final fracture surface of rock slope with non penetrating and weak interlayer conforms to the engineering practice. Therefore, the study of this method has a great effect on the development of rock slope stability.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU457

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