岩土破裂过程分析RFPA离心加载法
Centrifugal loading method of RFPA for the failure process analysis of rock and soil structure
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摘要: 将离心加载算法引入到岩石破裂过程分析RFPA系统中,形成了RFPA离心加载法(RFPA-Centrifuge)。RFPA-Centrifuge的应力分析采用有限元基本算法,满足静力平衡、应变相容及岩土体的非线性应力–应变关系;秉承了RFPA系统的破坏分析功能,并且同样考虑材料细观非均匀的影响,对边坡等难点问题进行分析时,不需对滑动面或破坏区域做任何预先假定。通过对垂直土坡离心物理试验、倾斜的土坡、含两组平行节理岩质边坡和不同截面形状隧道的数值试验,证明该法可以直观、逼真地获得岩土结构的破坏区域或滑移破坏面,同时求得安全储备系数,分析结果与物理的试验和有限元强度折减法均比较一致。RFPA-Centrifuge不仅回避了强度折减法中有关力学参数复杂的折减规则,还克服了强度折减法难以用物理试验进行相互验证的不足,因而是一种极具前景的岩土工程稳定性分析方法。Abstract: The fundamental principle of centrifugal tests usually applied in geotechnical engineering was introduced into rock failure process analysis(RFPA) system,so RFPA–Centrifuge was proposed.Stress analysis of RFPA-Centrifuge adopted the FEM basic arithmetic,so it was satisfied for the force equilibrium,strain consistency and nonlinear constitutive relation of rock and soil materials.RFPA-Centrifuge took the analytical function of RFPA for failure,also took into account the heterogeneous characteristics of materials at micro-and macro-scopical levels.As the proposed method was used to conduct the stability analysis of slopes of tunnel engineering which was the difficult point of geotechnical engineering,failure surface as well as the safety factor could be achieved directly without any artificial assumption on the failure surface.Based on the numerical simulation of centrifugal tests on vertical soil slopes,declining soil slopes,rock slopes with two group joints and tunnels with different shapes of sections.It was proved that RFPA-Centrifuge might obtain the failure area or slip face intuitively and realistically,and at the same time,the safety factor could be obtained.The results were close to those of physical tests and strength-reduction method with FEM.The present method could not only slide over the complex reduction rules about mechanical parameters in strength-reduction method with FEM,but also tide over the scarcity of evidence to be difficult to validate with physical tests in strength-reduction method with FEM.Therefore it is a valid numerical method for slopes in geotechnical engineering.