岩土工程稳定性分析RFPA强度折减法

RFPA STRENGTH REDUCTION METHOD FOR STABILITY ANALYSIS OF GEOTECHNICAL ENGINEERING

将强度折减法的基本原理引入到岩石破裂过程分析RFPA方法中,建立RFPA-SRM岩土工程稳定性强度折减分析方法。该方法以有限元方法作为应力分析工具,不仅满足静力平衡、应变相容,且充分考虑材料的细观非均匀特性,并秉承RFPA方法的破坏过程分析优势,能够反映岩土结构随强度劣化而呈现出渐进破坏诱致失稳的演化过程。以岩土工程中的边坡为例,阐述RFPA-SRM方法在边坡稳定性分析中的应用。利用RFPA-SRM方法进行边坡稳定性分析时,不需对滑动面做任何预先假定,对复杂地质地貌的边坡稳定性分析是实用的;同时以基元的破坏次数统计作为边坡的失稳判据,不仅可直观地得到坡体的滑移破坏面,还可求得安全系数,为边坡的稳定性研究提供一种新的便捷、有效方法。特别是RFPA-SRM对边坡破裂过程的模拟对于理解边坡的破坏形成机制具有重要意义,更有利于从边坡失稳的源头入手指导边坡防护设计。最后对RFPA-SRM方法在一连拱分叉隧道安全设计中的应用进行探讨,得到该隧道结构的安全系数及潜在破坏模式,表明RFPA-SRM方法同样适合其他岩土结构稳定分析。

The fundamental principle of strength reduction is adopted in RFPA（rock failure process analysis） code; and a RFPA based numerical code RFPA-SRM （strength reduction method） is developed for rock and soil engineerings. In this code, the finite element method is employed to obtain the stress fields. RFPA-SRM not only satisfies the global equilibrium, strain consistent and nonlinear constitutive relationship of rock and soil materials, but also can consider the heterogeneous characteristics of materials at mesoscopic level. The advantages of RFPA method in failure process analysis to reproduce the damage-induced failure process due to the strength degradation of rock and soil structures is an important feature in RFPA-SRM code. Practical applicability of the proposed technique to complicated cases is demonstrated. The failure criterion of slope failure is employed by assuming that the counts of failed elements with reduction steps reach to maximum values. As the proposed method is used to conduct the stability analysis of slope, the failure surface of slope as well as the safety factor can be achieved directly without any assumption on the failure surface. RFPA-SRM provides a powerfully alternative and effective approach for the stability analysis of slope. Especially the fracture process obtained with RFPA-SRM is significantly meaningful for the investigation of failure mechanism of slope, which is beneficial to fundamentally guide the in-situ design of slope. Finally, the stability analysis is conduced on a divaricately multi-arch tunnel. The safety factors and failure surface of the tunnel are numerically obtained, which show that RFPA-SRM is suitable for stability analysis of rock and soil structures.