岩质边坡开挖过程动态仿真分析的块体单元法

BLOCK ELEMENT METHOD FOR DYNAMICALLY SIMULATING EXCAVATION PROCESS OF ROCK SLOPE

岩质边坡开挖过程的静态仿真分析方法在计算精度和速度上均存在不足,无法适应边坡动态设计的需要。基于动态仿真的思路,提出岩质边坡开挖过程动态仿真分析的块体单元法。首先,提出三维岩石块体系统识别的切割算法,通过逐条或逐组加入结构面或开挖面切割块体,以及平面删除后的块体合并,实现开挖过程中块体系统的动态识别,提高块体系统识别的计算效率。然后,提出动态开挖过程中的开挖荷载计算方法,从而建立岩质边坡开挖过程动态仿真分析的块体单元法,避免在开挖前的块体系统中预置开挖面而导致人为引入不连续面问题和设置刚度问题。最后,通过简单算例及工程应用,对所提的动态仿真分析方法的计算精度和速度进行验证。结果表明,所提的动态仿真分析方法的计算效率明显优于传统的静态仿真分析方法。

The computational accuracy and efficiency of the conventional simulation method cannot meet the need of information design of rock slope.Based on the new idea of ＂dynamic simulation＂,the block element method is proposed to dynamically simulate the excavation process of rock slope.Firstly,the ＂cutting algorithm＂ is put forward to identify the block system,in which the new discontinuity or excavation is introduced into the model by cutting the current block system,and the deletion of discontinuity is implemented by block mergence.So the variable block system during excavation can be identified dynamically,and the efficiency of the identification algorithm is improved.After that,the calculation of the excavation load during the dynamic simulation is discussed in detail and implemented in the block element method,in which those problems caused by the artificial pre-imbedded planes and their stiffness in modeling the excavation procedure are totally avoided.Finally,the newly proposed method is verified to be accurate and efficient by a simple numerical example and an engineering example.