舟山某地区砂土的液化机理及加固研究

发布时间：2018-01-19 14:20

本文关键词： 饱和液化土振动台试验碎石桩超静孔隙水压力　出处：《浙江海洋大学》2017年硕士论文　论文类型：学位论文

【摘要】：饱和砂土在地震的振动作用下极易发生液化,从而产生土层喷砂冒水、地基不均匀沉降及地面开裂等现象,这些都将可能带来大量人员伤害和财产损失。同时,由于土体构成的复杂性,且具有很强的区域性特征,不同区域的砂土在地震作用下液化机理也将可能呈现不同的特征。因此,围绕区域砂土开展液化机理分析以及考虑加固措施将对区域安全具有重要的价值和意义。本文针对舟山某地区饱和砂土开展了其液化机理和加固的相关试验研究。在振动条件下,本文开展了未加固砂土模型、桩距分别为3倍、4倍以及5倍桩径的碎石桩加固振动模型试验。观察比较了各个模型的宏观现象,详细采集了各个模型的超静孔隙水压力和加速度等数据,并结合相关软件分析、归纳总结了其中的变化规律和机理。研究表明:(1)从宏观现象这方面来看,未加固砂土与加固砂土的液化现象具有明显的不同。对于未加固砂土振动模型,孔隙水一开始从土体表面裂缝渗出,并伴有土体隆起现象;而对于碎石桩加固的砂土振动模型,孔隙水一开始是从碎石桩内部涌出,土体表面没有明显隆起。可见,碎石桩在其中起到了有效的排水减压消散作用。(2)不论是未加固还是不同桩距加固的砂土振动模型,其超静孔隙水压力都是随土体深度的增加而不断增大。对于同样深度的土层,不同模型的超静孔隙水压力峰值是相近的。(3)相比其他未加固和加固模型,桩距为3倍直径的加固振动模型具有最优的抗液化效果,即开始液化的时间有明显的延迟。本文的研究工作,将为舟山该区域的饱和砂土地基抗液化处理提供有用的参考依据,具有一定的工程应用价值。
[Abstract]:Saturated sand is prone to liquefaction under earthquake vibration, resulting in sand blasting, uneven settlement of the foundation and ground cracking, which may bring a large number of human damage and property losses at the same time. Because of the complexity of soil composition and strong regional characteristics, the liquefaction mechanism of sand in different regions may also show different characteristics. Analysis of liquefaction mechanism around regional sand and consideration of reinforcement measures will be of great value and significance to regional safety. In this paper, the liquefaction mechanism and reinforcement of saturated sand in a certain area of Zhoushan are studied. Under vibrating conditions. In this paper, the vibration model tests of gravel piles with 3 times and 5 times diameter of piles are carried out, and the macroscopic phenomena of each model are observed and compared. The data of excess pore water pressure and acceleration of each model are collected in detail, and combined with the analysis of relevant software, the variation law and mechanism are summarized and summarized. The research shows that: 1) from this aspect of macroscopic phenomenon. The liquefaction phenomenon of unreinforced sand is obviously different from that of reinforced sand. For the vibration model of unreinforced sand, pore water seeps out from the surface of soil and is accompanied by the uplift of soil. However, for the vibration model of sand and soil strengthened by gravel pile, pore water is gushing out from the inside of gravel pile at the beginning, and the soil surface is not obviously raised. Gravel piles play an effective role in drainage decompression dissipation. 2) the sand vibration model is not reinforced or reinforced with different pile-spacing. The excess pore water pressure increases with the increase of soil depth. For the same depth soil layer, the peak value of excess pore water pressure of different models is similar to that of other models without reinforcement and reinforcement. The reinforcement vibration model with 3 times diameter of pile spacing has the best anti-liquefaction effect, that is, the time of starting liquefaction is obviously delayed. It will provide a useful reference for anti-liquefaction treatment of saturated sand foundation in Zhoushan area, and has certain engineering application value.
【学位授予单位】：浙江海洋大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU441;TU472

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