桥基高边坡稳定的二维、三维有限元对比分析

Comparative Analysis of Stability of High-Steep Slope under Bridge Load with 2D and 3D Finite Element

研究目的:目前桥基高边坡分析主要基于二维平面问题处理,忽视其空间效应。无论是高边坡还是桥台基础等都是三维实体,二维分析的结果推广到实际应用中往往存在一定误差。相对三维领域,二维条件下各种边坡理论发展较为成熟,工程上简便实用,二维分析仍是值得考虑的一种方式。在二维和三维2种状态下,对荷载作用下的高边坡岩体力学行为特征和规律进行对比分析,研究结果可为桥基高边坡设计及稳定性评价提供参考。研究结论:二维和三维条件下,桥基高边坡岩体力学行为特征大致相同,二维计算的应力、位移普遍偏大,这种现象在桥梁基底附近尤为明显;同等条件下二维所计算的坡面稳定性较三维偏于保守;相对三维,二维计算的误差并不恒定,误差大小随荷载强度、桥基位置、坡度、桥基尺寸等各因素变化而变化。

Research purposes： Now the 2D analysis is the common method for stability evaluation of high -steep slope under bridge load now, but it ignores the spatial effect. As the high - steep slope or bridge foundation is 3D solid, if the 2D analysis results are used for them, there is a certain error in the real application. Compared with 3D, the 2D theory on slope is relatively mature, with feature of easy application in the engineering, so it is still the main method considered for the slope analysis. The comparative analyses of mechanical behaviors and regulation of rock mass of high - steep slope under load are made with 2D and 3D in detail. The results can be as the reference to the design of high - steep slope under bridge load and its stability evaluation. Research conclusions ：The mechanical behavior of rock mass of high -steep slope under bridge load obtained by 2D analysis is the approximately same as that by 3D analysis. The values of stress and displacement obtained by 2D analysis are generally bigger than that by 3D, especially this phenomenon is obvious near the bridge foundation. Compared with 3D analysis, 2D results of slope stability is relatively conservative under the same condition. The error between 2D and 3D is not constant and it changes with the changes of load intensity, bridge foundation position, gradient, bridge foundation size etc.