水位变化对多空沟屏障远场隔振效果的影响研究  

Research on the effect of the moving water table on passive isolation effectiveness using a multiple open trench barrier

作　　者：李建平[1,2] 张晓磊 冯世进[1,2] LI Jian-ping;ZHANG Xiao-lei;FENG Shi-jin(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土力学》2020年第9期3131-3138,3147,共9页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973计划)青年科学家项目(No.2014CB049101)。

摘　　要：受季节性降雨的影响,雨季和旱季存在明显的水位波动。为分析地下水位升降对多空沟隔振效果的影响,建立了上覆单相弹性层饱和地基中空沟有限元分析模型。模型中考虑了沟中水的作用,算例分析了等沟深和不等沟深多沟屏障、沟壁倾斜多沟屏障和连续起伏地形屏障在不同水位下的远场隔振效果。计算结果与相应单相弹性地基进行对比,结果表明:土体渗透性低时,多数水位下不利于多沟屏障隔振;沟深为0.3LR(LR为R波波长)的三沟屏障通常可获得较理想的隔振效果(75%隔振率),但屏障在隔振效果最差的共振水位(0.6LR)下,空沟须贯穿上覆干土层才可获得75%隔振率;递减沟深屏障可有效降低上覆土层共振的不利影响;沟深较浅时,沟壁倾角越大,多沟的隔振效果越好,但对较深多沟的影响小;连续起伏的地形景观可作为一种有效的绿色隔振屏障。Groundwater table might significantly fluctuate due to seasonal rainfall.In order to investigate the effect of the moving water table on the screening performance of multiple open trench barriers,a finite element model is developed to describe wave propagation in a layered ground,which is modeled as a dry layer resting on a saturated substratum.The effect of infiltrated water in trenches is considered in this model,and the vibration isolation efficiencies of multi-trench barriers with equal and unequal trench depth,multi-trench barriers with inclined trench wall and continuous undulating terrain barriers at different water levels are analyzed as comparable cases.Comparing with the corresponding single-phase elastic foundation,the numerical results show that a low permeability coefficient of the saturated substratum might have a significantly adverse effect on the vibration isolation efficiency for most of water tables.A triple trench barrier with a depth of 0.3LR(LR is Rayleigh wavelength)usually can achieve a satisfactory screening efficiency(i.e.75%reduction),while the depth should be at least 0.6LR at the critical water table,where the worst isolation efficiency occurs.A multiple trench barrier with decremental depth can effectively reduce the adverse effect of the resonance.The larger sloping sides are,the better isolation effect of a barrier is for the shallow trenches,while it is not important for deep ones.Moreover,a rolling terrain landscape can be an environment-friendly isolation measure,which would achieve a great vibration isolation efficiency.

关 键 词：地下水位 饱和地基 多空沟屏障 隔振效果 COMSOL软件 

分 类 号：TU470[建筑科学—结构工程]