空沟对冲击荷载隔离的现场试验与数值模拟

发布时间：2018-01-08 06:17

本文关键词：空沟对冲击荷载隔离的现场试验与数值模拟　出处：《岩土力学》2014年S1期 　论文类型：期刊论文

【摘要】：在场地开挖了一条空沟,以落锤式弯沉仪(falling weight deflectometer,简写为FWD)的荷载模拟冲击荷载,通过FWD自带的传感器测得空沟后一定范围内的竖向位移。通过室内试验,获取试验场地的岩土参数,采用非线性动力有限元软件ABAQUS建立二维模型(将远处单元定义为无限单元来模拟吸收边界,从而避免振动波的来回反射)。以空沟中心线的现场测试数据为依据,校核有限元模型。通过分析不同工况模拟的竖向位移,研究得出空沟-荷载间距、沟深、沟宽等对隔振效果的影响。结果表明,(1)空沟-荷载间距越小,隔振效果越好,但实际隔振工程中,为避免振动对空沟侧壁的稳定性的影响,空沟与振源不宜太近,因此可以不计空沟-荷载间距对隔振效果的影响;(2)就提高隔振效果而言,增大沟深比增大沟宽更有效,而相同的隔振效果,窄-深沟的挖方量远小于宽-浅沟;(3)在对冲击荷载进行隔振设计时,对于一般的民用和工业建筑,综合隔振效果、开挖和支护费用等因素,采用宽度为0.5~1.0 m,深度为2.0~2.5 m的空沟较为合理,与某工程实例进行比对,验证结论的合理性。
[Abstract]:An empty ditch was excavated in the site to simulate the impact load of the falling weight deflector (FWD). The vertical displacement in a certain range after the empty ditch is measured by FWD sensor. The geotechnical parameters of the test site are obtained by indoor test. The nonlinear dynamic finite element software ABAQUS is used to establish a two-dimensional model (the distant element is defined as an infinite element to simulate the absorbing boundary). In order to avoid the back and forth reflection of the vibration wave, based on the field test data of the hollow groove center line, the finite element model is checked. Through the analysis of the vertical displacement simulated under different working conditions, the gap between the gully and the load and the depth of the ditch are obtained. The results show that the smaller the gap between gully and load, the better the isolation effect, but in order to avoid the influence of vibration on the stability of side wall in actual isolation engineering. The gap should not be too close to the vibration source, so the effect of gap between gully and load on vibration isolation can be ignored. (2) as far as the isolation effect is concerned, it is more effective to increase the depth of the trench than to increase the width of the trench, and the amount of dredging in the narrow-deep ditch is much smaller than that in the broad-shallow ditch for the same isolation effect; 3) for general civil and industrial buildings, the width of vibration isolation effect, excavation and support cost is 0.5 ~ 1.0 m. The hollow ditch with a depth of 2.0 ~ 2.5 m is reasonable, and compared with an engineering example, the rationality of the conclusion is verified.
【作者单位】：郑州大学交通运输工程系;宁波大学土木工程系;
【基金】：国家自然科学基金资助(No.51008286,No.51278467)
【分类号】：TU435
【正文快照】： 1引言爆破、交通、重工业厂房等形式的人工振动,对周边的居民、工作人员及建筑物本身会产生很大的影响,通常采用连续屏障,如空沟、填充沟、混凝土墙和非连续屏障。用单排或多排柱腔、桩进行隔振,对于土质较好的地层,连续屏障是优先选择,其隔振效果要好于非连续屏障。国内外众

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