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桩承式加筋路堤的现场试验及数值分析 总被引：4，自引：0，他引：4
对一桩体面积置换率为8.7 %的低置换率桩承式加筋路堤进行了现场试验及三维有限元分析。现场主要进行了桩、土荷载分担,孔压、沉降及侧向水平变形等内容的观测。将观测数据与常规设计方法及三维有限元分析结果进行了对比研究,在此基础上对设计方法的适用性进行了分析。研究结果表明,路堤填土的土拱效应造成荷载向桩体转移,这种荷载转移大幅度减小了在软土层中产生的超孔隙水压力。当填土高度大于2.5 m时,土拱效应的应力折减系数可用Russell和Pierpoint或Hewlett和Randolph提出的土拱效应分析方法进行计算,其结果与三维有限元分析也较相符,但在路堤高度较小时,只有Russell和Pierpoint方法与实测结果相接近。路堤施工过程中,实测的水平变形与沉降之比仅为0.2左右,这表明采用桩承式加筋路堤不仅可减小沉降,而且可减小水平向的变形,提高路堤的稳定性。 相似文献
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为研究桩承式加筋地基作用机制及影响加筋效果的因素,设计天然软土地基、土工格栅加筋地基、桩承式地基、桩承式加筋地基4组模型试验,通过对试验结果的对比,分析阐述桩承式加筋地基的作用机制。同时,将三维数值模拟的结果与试验结果进行对比验证,在此基础上采用三维流固耦合的数值模型研究影响桩承式加筋地基处理效果的因素。研究结果表明,4组试验中,桩承式加筋地基加载板的沉降量最小,承载力最大;桩承式加筋地基的桩土应力比大于同样荷载条件下的桩承式地基;随着桩间距的增大,桩承式加筋地基表面沉降逐渐增大,桩土应力比逐渐减小;随着格栅模量的增加,桩承式加筋地基表面沉降逐渐减小,桩土应力比逐渐增大。 相似文献
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Reinforcement and Arching Effect of Geogrid-Reinforced and Pile-Supported Embankment on Marine Soft Ground 总被引：1，自引：0，他引：1
The effectiveness of constructing a geogrid-reinforced and pile supported embankment on soft ground to reduce differential settlement has been studied by pilot scale field tests and numerical analysis. Three-by-three pile groups with varying pile spacing were driven into a layer of soft ground, and a layer of geogrid was used as reinforcement over each pile group. Further, a 2-D numerical analysis has been conducted using the computer program FLAC 2D. The mechanisms of load transfer can be considered as a combination of embankment soil arching, geogrid tension, and stress transfer due to the difference in stiffness between pile and soft ground. Based on the pilot scale field tests and results of numerical analysis, we find that the geosynthetic reinforcement slightly interferes with soil arching, and helps reduce differential settlement of the soft ground. Also, the most effective load transfer and vertical stress reduction at the midspan between piles occurs when the pile cap spacing index D/b (D: pile cap spacing, b: diameter of pile) is 3.0. 相似文献
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土工格栅低温下蠕变特性试验研究 总被引：5，自引：1，他引：4
土工格栅蠕变特性是影响土工格栅加筋结构长期工作性能的重要因素。通过室内蠕变试验,对土工格栅的低温蠕变特性进行了试验研究,结果表明,塑料土工格栅在低温下蠕变特性与常温下明显不同,20 ℃常温状态下1 000 h后,当伸长率接近14 %时且60 % Pmax（Pmax为断裂强度）下,变形仍没有稳定迹象,而在同等荷载下-20 ℃低温状态时,仅100余小时,变形就趋于稳定,且伸长率不足2.5 %。结果表明塑料土工格栅蠕变性能受温度影响很大,并且温度越低蠕变值越小。 相似文献
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The effectiveness of constructing a geogrid-reinforced and pile supported embankment on soft ground to reduce differential settlement has been studied by pilot scale field tests and numerical analysis. Three-by-three pile groups with varying pile spacing were driven into a layer of soft ground, and a layer of geogrid was used as reinforcement over each pile group. Further, a 2-D numerical analysis has been conducted using the computer program FLAC 2D. The mechanisms of load transfer can be considered as a combination of embankment soil arching, geogrid tension, and stress transfer due to the difference in stiffness between pile and soft ground. Based on the pilot scale field tests and results of numerical analysis, we find that the geosynthetic reinforcement slightly interferes with soil arching, and helps reduce differential settlement of the soft ground. Also, the most effective load transfer and vertical stress reduction at the midspan between piles occurs when the pile cap spacing index D/b (D: pile cap spacing, b: diameter of pile) is 3.0. 相似文献
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