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题名	细颗粒含量对泥石流源区宽级配粗砾土渗流固结性质的影响
作者	吕立群
学位类别	硕士
答辩日期	2013
授予单位	中国科学院研究生院
授予地点	北京
导师	陈宁生
关键词	泥石流 粗砾土 渗流 固结
其他题名	Influence of fine particle content on Wide Grading Coarsed Grained Soils’ consolidation and seepage properties
学位专业	岩土工程
中文摘要	5-12汶川地震诱发了大量的崩塌、滑坡等次生山地灾害，如深溪沟泥石流源区小型浅层崩滑体，为震后灾区泥石流的暴发提供了丰富的松散固体物源。这些松散物源在重力和降雨渗透作用下，随着时间的发展会逐渐固结，如果起动这些物质形成泥石流需要更强的暴雨来激发。对于地处龙门山区的泥石流沟，在地震诱发崩塌滑坡产生巨量松散固体物质的情况下，研究松散堆积体渗流固结性质对该地区泥石流以后的发展趋势及泥石流规模有重要的研究意义。 通过颗粒粒度分析发现，深溪沟泥石流源区不同采样点的土体的粗颗粒（>0.075mm）部分，各个粒组分布都不相同，但各粒组之间所占的比例差别不大，然而细颗粒（<0.075mm）部分在不同采样点的粗砾土中所占比例却相差甚远，从4.92%变化到43.76%，且粘粒含量低，因此研究细颗粒对低粘粒含量粗砾土渗透系数、固结系数及固结变形量等力学参数的影响很有必要。 通过自行设计的渗透试验装置、GDS三轴仪及离心机进行了渗透试验和压缩固结试验和离心固结试验，发现细颗粒含量对低粘粒含量粗砾土的渗透系数和固结系数、压缩指数都有重要影响。细颗粒含量对固结前后土体的渗透系数的影响呈单调性，渗透系数都随细颗粒含量的增加而降低。细颗粒含量对土体的压缩指数的影响根据不同的饱和度呈现不同的规律，当饱和度较低时，压缩指数随细颗粒含量的增加而降低，当饱和度较高时，压缩指数随细颗粒含量的增加先降低后增加。土体的固结系数随着细颗粒含量的增加而减少，而且减小的幅度越来越小，细颗粒含量在0～10%之间时，固结系数降低明显，说明细颗粒含量特别少的土体的固结速率受细颗粒含量变化影响较大；当细颗粒含量大于10%时，土体固结速率受细颗粒含量影响逐渐减小，但减小的幅度较小。随着固结时间的延长，土体的沉降量增大，但是在离心机内，土体固结在最初的40min内便完成了总的沉降量的70%，这与自然状态下的泥石流源区土体固结有差别。 松散固体物源在重力和降雨渗透作用下固结作用逐渐加强，随着时间的发展，泥石流活动呈现输移控制型向松散固体物质控制型过渡。对于龙门山区的泥石流的发展趋势总体呈现活动强度下降趋势，可供形成山地灾害的松散固体物质来源总量呈下降趋势。
英文摘要	Wenchuan earthquake induced massive secondary disasters of collapses, landslides and debris flows, such as the small shallow landslides of the source of debris flow of Shenxigou ditch, providing rich source of loose solid for the outbreak of post-earthquake debris flow. This loose material will gradually consolidate under the gravity and rainfall infiltration effect along with the time development, which requires stronger rainfall to stimulate these substances to form debris flow. For Shenxigou ditch, the study of consolidation and seepage properties of the massive loose solid mass generated by the earthquake has important research significance for the trend of the debris flow development. Through study of particle size analysis, although the size distribution of coarse particle part (>0.075mm) of soil are not identical, little difference in size account for the proportion., the fine particles (<0.075mm) part in the proportion of the different coarse grained soil samples is far, from 4.92% to 43.76%.So it is necessary to research the effect of content of fine particle on penetration and the mechanical properties of consolidation deformation. Through the designed permeability test device, the GDS instrument and centrifuge for penetration test and consolidation test, we found that the content of fine particles of debris flow source has an important influence on coefficient of permeability, compression and consolidation. Influence of fine particle content of soil on the consolidation and permeability coefficient is monotone both before and after consolidation, and permeability coefficient decreases with the increase of fine particle content. Effect of fine particles of soil on compression index has different rules according to the different saturation. The compression index decreased with increasing of the content of the fine particles when the saturation degree is low compared with compression index first decreased and then increased when the saturation is high. The consolidation coefficient of soil decreased with the increasing content of the fine particles, and the extent of decreases is smaller. When fine particle content in 0 ~ 10% , the consolidation coefficient decreased significantly, indicating that the consolidation rate is influenced by the fine particle content obviously, but when the fine content greater than 10%, the consolidation rate influenced by the fine particle content gradually decreased. With the consolidation of the soil, the settlement of soil increased, but in the centrifuge, consolidation has completed 70% of a total settlement in the original 40min, which is different from the consolidation of nature state. Loose solid source consolidation gradually strengthen in the effect of gravity and rainfall infiltration, and along with the time development, stimulating these materials to form debris flow requires stronger rainfall. Debris flow activities present transport-controlled type transition to loose solid material-controlled type. For Shenxigou ditch, debris flow presents that the activity strength declines, loose solid material sources used for forming hazards of debris flow decrease, and the total volume of debris flow descends.
语种	英语
公开日期	2014-05-30
内容类型	学位论文
源URL	[http://ir.imde.ac.cn/handle/131551/6954]
专题	成都山地灾害与环境研究所_山地灾害与地表过程重点实验室
推荐引用方式 GB/T 7714	吕立群. 细颗粒含量对泥石流源区宽级配粗砾土渗流固结性质的影响[D]. 北京. 中国科学院研究生院. 2013.

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