考虑饱和渗透系数的宽级配土渗流侵蚀过程室内试验研究  

Laboratory experimental study on seepage erosion in wide-graded soils considering saturated permeability coefficient

作　　者：明华军[1,2] 陈西 卢晓春[2,3] 田旭灿 魏康旭 MING Huajun;CHEN Xi;LU Xiaochun;TIAN Xucan;WEI Kangxu(Hubei Key Laboratory of Disaster Prevention and Mitigation(China Three Gorges University),Yichang 443002,Hubei,China;College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,Hubei,China;Hubei Key Laboratory of Hydropower Engineering Construction and Management,Yichang 443002,Hubei,China)

机构地区：[1]防灾减灾湖北省重点实验室(三峡大学),湖北宜昌443002 [2]三峡大学水利与环境学院,湖北宜昌443002 [3]水电工程施工与管理湖北省重点实验室,湖北宜昌443002

出　　处：《水利水电技术（中英文）》2023年第7期183-192,共10页Water Resources and Hydropower Engineering

基　　金：防灾减灾湖北省重点实验室(三峡大学)开放基金项目(2022KJZ10);国家自然科学基金项目(51609126)。

摘　　要：【目的】宽级配土是堤防的主要填料,其在水力梯度作用下会发生内部侵蚀直至管涌破坏。渗流侵蚀过程会改变土体性质,进而影响饱和渗透系数。依据饱和渗透系数演变规律,探究土体渗流侵蚀过程,有助于工程安全性评价与渗透破坏预测防治。【方法】采用自制渗流侵蚀试验仪,通过逐级升高渗透水压力,开展土体侵蚀过程试验,测量饱和渗透系数和细颗粒流失量,探究级配与干密度对渗流侵蚀过程的影响。【结果】结果显示:依据饱和渗透系数演变规律,渗流侵蚀过程可分为侵蚀前期阶段、侵蚀发展阶段和侵蚀破坏阶段,从而定义了渗蚀发展临界水力梯度和渗蚀破坏临界水力梯度;宽级配土的渗蚀发展临界水力梯度与渗蚀破坏临界水力梯度均随级配参数D 15/d 85增加而减小;当细颗粒含量处于欠填状态时,渗蚀发展临界水力梯度随细颗粒含量增加而减小,渗蚀破坏临界水力梯度随细颗粒含量增加近似线性增大;当细颗粒含量处于满填状态时,两种临界水力梯度与累积细颗粒流失率均随着干密度增加而增大。【结论】可见,由于渗透侵蚀造成的饱和渗透系数变化显著地受土体级配与密实状态的影响。[Objective]Wide-graded soil is a good filling material for embankment,however,the process of seepage erosion by piping is caused by the hydraulic gradient between the river and the seepage points,which threaten the stability of river embankments.During the process of seepage erosion,saturated permeability coefficient increases as a result of both the fine particles loss and the steepened hydraulic gradient.Saturated permeability coefficient is used to investigate the process of seepage erosion in this paper,which helps to evaluate the safety of related engineering.[Methods]In this paper,a series of laboratory experiments on seepage erosion are conducted with a self-made apparatus to measure saturated permeability coefficients and loss amounts of fine particles.During these experiments,the particle erosion in soils with different dry densities,fine particle contents,and grading parameters D 15/d 85 are investigated.Based on the result of the experiments,the critical hydraulic gradient of seepage erosion development i ini and the critical hydraulic gradient of seepage failure i f are defined corresponding to the process of seepage erosion.[Results]The result show that these two critical hydraulic gradients decrease with increasing grading parameters D 15/d 85.Moreover,the experiments reveal that the fine particle content has a significant impact on the process of seepage erosion and two critical hydraulic gradients.If the soil is in the underfilled state because of the fine particle content,i ini decreases and i f increases with increasing fine particle content.And both two critical hydraulic gradients and loss amounts of fine particles increase with increasing dry densities if it is in the filled state.[Conclusion]Therefore,because of seepage erosion,saturated permeability coefficients of wide-graded soils are significantly influenced by the particle size distribution and the dry density of the soil.

关 键 词：宽级配土 饱和渗透系数 渗流侵蚀 细颗粒含量 级配参数 临界水力梯度 

分 类 号：TV871.4[水利工程—水利水电工程]