开挖及动荷载作用下边坡响应的DDA方法研究

对适用于分析边坡在开挖及动荷载作用下的响应情况的不连续变形分析(DDA)方法进行研究。首先,利用基于生死单元的DDA方法模拟边坡的开挖过程,并分析边坡的开挖变形,通过与有限元法计算结果对比,证明该方法的正确性;其次,为克服传统的DDA方法不考虑介质中产生的散射波在边界的反射问题,实现基于黏性边界理论的地震波输入方法;此外,在DDA方法中引入自由场边界,通过实例分析表明在利用DDA方法进行动力分析时,模型两侧施加自由场边界的模拟效果要优于两侧施加黏性边界的模拟效果。将改进的DDA方法运用于边坡工程的动力响应分析,通过与经典有限元法的对比,证明了改进DDA方法的正确性。

RESEARCH ON DDA METHOD FOR RESPONSE OF SLOPES UNDER EXCAVATION AND DYNAMIC LOAD

Discontinuous deformation analysis(DDA) method is improved to analyze the response of slopes under excavation and dynamic load.Firstly,the process of slope excavation is simulated using the DDA method based on element birth and death,and the deformation of slope is analyzed.The results are compared to those of finite element method.It is indicated that the DDA method is effective in slope simulation.Secondly,the input way of seismic wave is carried out based on viscous boundary theory.It is better than the traditional DDA method because the traditional DDA method does not consider the reflection of scattered waves at boundaries,which are generated in the media.In addition,the free-field boundary is introduced into the DDA method.Case study shows that DDA model with free-field boundaries at both sides is better than that with viscous boundaries.Finally,the improved DDA method is used to analyze the response of slopes under dynamic load.By comparing the results with those of finite element method,the accuracy of the improved DDA method is proven.