平面闭合方形空沟主动隔振效果简化计算模型

Simplified Calculation Model for Active Isolation Effect of Planar Closed Square Open Trenches

空沟隔振是一种常见的减小人工振动的隔振方法,它可以有效地减小屏蔽区内的地面振动。介绍了基于位移变量的三维格子法理论,通过对比隔振现场测试结果,验证了方法的可靠性。基于前述计算理论,分析了影响平面闭合方形空沟隔振效果的几个主要因素:空沟宽度、深度和位置等。分析表明:空沟深度与位置是影响其隔振效果的主要因素;空沟位置不同,其深度的影响会有所差别;土体泊松比越大,对空沟隔振越不利。提出了影响因子的概念,建立了空沟隔振效果的简化计算模型。在此模型中,上述几个主要因素对空沟隔振效果的影响被分别表示为几个不同的影响因子,它们的乘积就是空沟隔振效果。根据格子法的计算结果,给出了各个影响因子的计算公式,并进行了算例验证。

Open trenches are widely utilized for reducing artificial vibration in geotechnlcal engineering. Ground vibrations can be efficiently eliminated in screening zone by them. The three dimensional grid method based displacements variables was presented and validated through comparing vibration isolating results obtained by grid method with them by field test. Based on the theory mentioned above, several main key factors having influence on the isolation effect, including the width , the depth and the location of a planar closed square open trench, were analyzed. The results show that the depth and location are main factors having impact on the isolation effect, the influence of the depth varies with the changing of the location and larger Poisson＇s ratio of the soil induces adverse effects to the isolation effect. A new simplified calculation model was proposed for evaluating the isolation effect of open trenches. In the model, the influences of the foregoing factors are denoted as several influence factors respectively. The product of these influence factors represents the isolation effect. All equations of influence factors on the basis of the results from the grid method calculation results were given in details. The model has been tested by an example.