IMHE OpenIR  > 山地灾害与地表过程重点实验室
粘性泥石流堆积物自然固结特性研究
Alternative TitleStudy on Characteristics of Natural Consolidation of Viscous Debris Flow Deposition
Language中文
陈舜
Thesis Advisor王道杰
2014
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name硕士
Degree Discipline环境工程
Keyword粘性泥石流堆积物 自然固结 孔隙水压力 体积含水量 降雨侵蚀
Abstract泥石流自然固结是泥石流堆积的重要组成部分,在泥石流灾害危险性评估时应考虑固结带来的危害。泥石流堆积后,在重力等作用下,孔隙水压力消散,堆积物发生失水固结。在不同堆积边界条件及不同堆积深度下,堆积物具有不同的固结特性,直接影响其固结度。 本论文基于太沙基饱和土一维固结理论,修正得到粘性泥石流堆积物固结方程,可用于固结过程中孔隙水压力消散分析与计算。以蒋家沟粘性泥石流体为研究对象,开展了堆积固结水槽实验,重点研究了在不同透水条件及不同堆积深度的孔隙水压力与体积含水量变化规律。固结后继续进行人工降雨实验,研究了降雨侵蚀对堆积物固结的影响。对泥石流堆积体自然固结特性的研究,为研究泥石流砾石土成因与结构特性提供一定的科学参考。 (1)根据太沙基一维固结理论,修正相关参数得到粘性泥石流堆积物固结方程。 (2)通过不同透水性床沙条件下泥石流堆积固结水槽实验,得到孔隙水压力消散、体积含水量变化具有不同的特性。 堆积固结初期,堆积物保持短暂的高孔隙水压力,该阶段堆积物极不稳定,易发生重启。两种透水床沙边界条件下,孔隙水压力分布都与深度成正比例关系,孔隙水压力消散速率在不同深度下相同,深度只决定孔隙水压力分布,不影响孔隙水压力消散的速率。 透水床沙边界条件下,体积含水量分布同样与深度呈正相关性,减少速率在不同深度下也相同。而在不透水床沙边界条件下,体积含水量分布与深度成正比例关系,减少速率却随深度增加而加大。说明透水床沙条件下排水固结更快,边界床沙渗透性对失水固结具有重要影响。 (3)人工降雨实验时,孔隙水压力的恢复与消散路径是不重合的,固结后土体结构和性质都发生了改变。体积含水量变化具有滞后于降雨的特性,同时降雨侵蚀泥石流堆积物,使其表层粗化现象非常明显,产沙过程满足方程。
Other AbstractDebris flow deposits consolidate under their own weight is an important part of the accumulation of debris flow,and the damage of consolidation should be taken into account in disaster evaluation. The pore water pressure dissipated after post depositional consolidation. Different boundary conditions and stacking depth affects their consolidation characteristics which refer to how quickly they consolidate (dissipate pore fluid pressure and compact) and magnitude of consolidation. We established the equations in terms of diffusion of excess fluid pressure and vertical displacement of debris flow deposits consolidation driven by gravity based on Terzaghi one-dimensional consolidation of saturated soil theory. A tank experiment of gravity-driven consolidation was carried out for viscous debris flow deposits in Jiangjia Gully. It focused on the changes of pore water pressures and volumetric water content,under different drainage conditions and vertical depth. Then an artificial rainfall experiment was carried out with the purpose of studying how rainfall effected the consolidation of debris flow depositions. This research provided a scientific reference values through satisfactorily understanding the formation and structural properties of debris flow gravelly soil. The following main conclusions were obtained: (1) We established the equations in terms of diffusion of excess fluid pressure and vertical displacement of debris flow deposits consolidation driven by gravity based on Terzaghi one-dimensional consolidation of saturated soil theory. (2) Though different permeable bed conditions which viscous debris flow deposited on,the results of trench experiment showed that the dissipation of pore water pressure and changes of volumetric water content exhibited various characteristics. They persisted high pore fluid pressure in earlier period of consolidation which was very likely to occurring remobilization. Distribution of pore water pressure and volumetric water content were proportional to the depth of accumulation ,but the dissipation rate were independent to the depth,under the same boundary conditions. It was faster and greater magnitude of consolidation under permeable basal bed condition than impermeable one. (3) Rainfall had a significant impact on the consolidation of viscous debris flow deposits. The paths between restoration and dissipation of pore water pressure was not coincident when artificial rainfall experiment was conducted,and volumetric water content still changed when rainfall was end. The surface was roughened obviously.
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/8019
Collection山地灾害与地表过程重点实验室
Recommended Citation
GB/T 7714
陈舜. 粘性泥石流堆积物自然固结特性研究[D]. 北京. 中国科学院研究生院,2014.
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