水位波动下滑带土的渗透-固结变形特征试验  

Seepage-Consolidation Deformation Characters of Sliding-Zone Soils under Water Level Fluctuation

作　　者：李岚星 胡新丽[1] 黄悦庭 张海燕 李亚博 Li Lanxing;Hu Xinli;Huang Yueting;Zhang Haiyan;Li Yabo(Faculty of Engineering,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学工程学院,湖北武汉430074

出　　处：《地球科学》2024年第12期4690-4700,共11页Earth Science

基　　金：国家自然科学基金重点国际(地区)合作研究项目(No.42020104006)。

摘　　要：三峡库区水位波动期间,滑坡岩土体的渗流-应力耦合特性关乎到滑坡的稳定性.开展了一维渗透试验,通过分析马家沟滑坡滑带土的渗流速度和水力坡降的关系,得到了渗透压加卸载过程的渗流特征;同时开展稳态和周期性渗透压下的三轴固结试验,分别分析了围压、渗透压幅值和加载过程对渗透系数和体积应变的影响.研究结果表明:(1)渗透压加载至一个阈值前,滑带土中的渗流满足达西定律,超过该阈值渗流呈现非线性,卸载时渗流符合达西定律;(2)稳态渗透压作用下,滑带土的渗透系数与围压的对数呈线性关系,滑带土的瞬时模量影响系数随着渗透压增大呈现显著的指数下降的趋势;(3)动态渗透压作用下,滑带土的渗透系数随波动次数呈指数下降,且各周期内均出现回弹效应,整体上先膨胀再压缩,累积变形回弹的时间节点与渗透系数衰减速率的阈值一致.During the water level fluctuation period of the Three Gorges reservoir area,the seepage stress coupling characteristics of the geotechnical body in the landslide have a great influence on the stability of the landslide.In this paper,a one-dimensional seepage test was conducted on the sliding-zone soil of Majiagou landslide.It tested the relationship between the seepage velocity of the soil and the hydraulic gradient and found the seepage characteristics of the seepage pressure p loading and unloading process.It also performed triaxial consolidation tests under steady-state and cyclical p and analyzed the effects of the confining pressureσ3,the amplitude of the p,and the loading process on the permeability coefficient k and the volume strain.The following conclusions were drawn.(1)During the loading process,the seepage flow in the soil conforms to Darcy's law when the p was less than a certain threshold value,and the seepage flow shows nonlinearity when the p exceeds the threshold.The seepage flow conforms to Darcy's law when the p was unloaded.(2)When under a steady p,the k of soil is linear to the logarithm of theσ3.Its instantaneous modulus influence coefficient decreases exponentially when the p increases.(3)When under a cyclical p,the k of soil decreased exponentially as the number of fluctuations increases.And a rebound effect of expansion and then compression appears in the specimens in each cycle.The rebound of accumulated deformation occurs at a certain time point,which is almost consistent with the threshold value in the fitting function of the k and the number of cycles under the same conditions.

关 键 词：滑带土 水位波动 固结变形 渗透特性 周期性渗透压 工程地质 

分 类 号：P642.3[天文地球—工程地质学]