砂砾石土的管涌临界渗透坡降预测方法  

A method of predicting critical gradient for piping of sand and gravel soils

作　　者：吴梦喜[1,2] 高桂云 杨家修[4] 湛正刚 WU Meng-xi;GAO Gui-yun;YANG Jia-xiu;ZHAN Zheng-gang(Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;The Institute of Crustal Dynamics,China Seismological Bureau,Beijing 100085,China;Powerchina Guiyang Engineering Corporation Limited,Guiyang,Guizhou 550081,China)

机构地区：[1]中国科学院力学研究所,北京100190 [2]中国科学院大学,北京100049 [3]中国地震局地壳应力研究所,北京100085 [4]中国电建集团贵阳勘测设计研究院有限公司,贵州贵阳550081

出　　处：《岩土力学》2019年第3期861-870,共10页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划课题(No.2013CB035903);国家科技支撑计划课题(No.2014BAB03B04);华能科技项目(No.NHKJ15-H13)~~

摘　　要：内部结构不稳定的砂砾石土在渗流作用下可能发生细颗粒移动流失现象,从而降低砂砾石土地基的承载力。确定坝基砂砾石土的管涌临界渗透坡降,是砂砾石地基上堤坝设计和防渗安全分析的重要内容。基于砂砾石土在渗流作用下单个颗粒或颗粒群的力平衡理论,推导了砂砾石土发生管涌的临界坡降的预测公式。基于文献中64组垂直向上的砂砾石土管涌试验,采用Kenney-Lau稳定性判别方法结合Kezdi粒径比法分析了土体的内部稳定性,表明该方法是利用颗粒级配曲线判别砂砾石土内部稳定性的有效方法。通过对41组发生管涌的砂砾石土的临界渗透坡降的预测与试验结果比较,表明渗流作用下砂砾石土内部颗粒所受到的渗透力与颗粒表面积成正比的假定合理。提出的基于颗粒群启动模式假定的公式计算值,比文献中其他方法更接近于试验结果。Fine particles in an internally unstable sand and gravel soil may be washed out under seepage, thus the bearing capacity of a dam foundation with those sand and gravel soil layers reduces. The determination of critical piping permeability gradient of gravel soil on dam foundation is an important step in dam design and seepage prevention safety analysis. In this paper, the prediction of the critical vertical upward hydraulic gradient of piping in sand and gravel soils were developed based on the force balance theory of a single particle or a group of particle under seepage. Based on 64 groups of vertical upward piping tests of gravel soils in literatures,Kenney-Lau stability criterion method and Kezdi particle size ratio method were used to analyze the internal stability of gravel soils.The results show that the proposed method is an effective method to access the internal stability of gravel soils using particle gradation curve. By comparing the predictions of critical permeability gradient with the experimental results of 41 groups of sand-gravel soils, it is a reasonable assumption that the permeability of particles in sand-gravel soils under seepage is proportional to the surface area of particles.

关 键 词：管涌 内部稳定性 砂砾石土 临界渗透坡降 

分 类 号：TV698.233[水利工程—水利水电工程]