土工格栅控制液化土体流动变形的试验研究

发布时间：2018-03-30 16:41

本文选题：土工格栅　切入点：液化变形　出处：《岩土工程学报》2017年10期

【摘要】：液化导致的土体大变形以及侧向流动是地震引起建筑物破坏的主要原因。采用土工格栅作为主要加固材料,开展建筑物荷载作用下液化场地流动变形的振动台试验研究,考虑水平层状土工格栅、包裹状土工格栅和土工格栅+无纺布联合处理等3种加固方案对结果的影响,从超孔隙水压力发展、建筑物沉降量以及格栅应变特性等分析加固方案对液化变形的处理效果。试验表明:采用上述3种加固方案所得的相同埋深处超孔隙水压力峰值基本相等,表明土工格栅的加入基本不能改变地基的液化状态,而后期超孔隙水压力在土工格栅+无纺布联合加固方案下消散速度最快。与其它两种加固方案相比,土工格栅+无纺布联合加固方案下建筑物沉降量最小,相比未加固工况沉降量减少24%,土工格栅中间位置的应变峰值小于边缘位置的应变峰值。采用土工格栅+无纺布联合加固时,具有较大表面积的无纺布对该覆盖区域液化土体有较好的约束作用,限制了砂土颗粒的竖向移动。此外,砂土颗粒对无纺布的作用力将由土工格栅承担,这种作用力将有利于土工格栅与砂土之间的摩擦效应,进一步限制液化砂土的流动变形。
[Abstract]:The large deformation and lateral flow of soil caused by liquefaction are the main causes of building failure caused by earthquake. Using geogrid as the main reinforcement material, the shaking table test study on the flow deformation of liquefaction site under the action of building load is carried out. Considering the effect of horizontal layered geogrid, encapsulated geogrid and geogrid non-woven treatment on the results, the development of superpore water pressure is considered. The settlement of buildings and the strain characteristics of grille are analyzed to deal with the liquefaction deformation. The experimental results show that the peak value of excess pore water pressure at the same buried depth obtained by the above three reinforcement schemes is basically equal. The results show that the addition of geogrid can not change the liquefaction state of the foundation basically, but the excess pore water pressure dissipates the fastest under the geogrid non-woven joint reinforcement scheme at the later stage, compared with the other two reinforcement schemes. Under the combined reinforcement scheme of geogrid non-woven fabric, the settlement of buildings is minimum. Compared with the unreinforced condition, the settlement is reduced by 24%, and the strain peak in the middle position of the geogrid is smaller than that in the edge position. When the geogrid is combined with non-woven fabric, the strain peak of the geogrid is smaller than that at the edge. The non-woven fabric with large surface area has a good constraint on the liquefaction soil in the covering area, which limits the vertical movement of sand particles. In addition, the force of sand particles on the non-woven fabric will be borne by the geogrid. This force will benefit the friction effect between the geogrid and the sand, and further limit the flow deformation of the liquefaction sand.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学土木与交通学院;上海申元岩土工程有限公司;
【基金】：国家自然科学基金面上项目(51379067,51679072) 重点国际合作研究项目(5141001028) 教育部创新团队发展计划(IRT_15R17) 河海大学中央高校基本科研业务费项目(2015B17314)
【分类号】：TU43

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