用孔隙分布曲线预测压实黄土非饱和渗透曲线及其适用范围的探讨  

Prediction of unsaturated permeability curve of compaction loess with pore-size distribution curve and its application scope

作　　者：李燕 李同录[1,2] 侯晓坤[3] 李华 张杰 LI Yan;LI Tong-lu;HOU Xiao-kun;LI Hua;ZHANG Jie(School of Geology Engineering and Surveying,Chang'an University,Xi'an,Shaanxi 710054,China;Observation and Research Station of Water Cycle and Geological Environment for the Chinese Loess Plateau,Ministry of Education,Zhengning,Gansu 745399,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;School of Equipment Management and Support,Armed Police Force Engineering University,Xi'an,Shaanxi 710086,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]黄土高原水循环与地质环境教育部野外科学观测研究站,甘肃正宁745399 [3]中国科学院地质与地球物理研究所,北京100029 [4]武警工程大学装备管理与保障学院,陕西西安710086

出　　处：《岩土力学》2021年第9期2395-2404,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41790442,No.41772278)。

摘　　要：土体非饱和渗透曲线受其孔隙分布的控制,因此可以用孔隙分布曲线预测渗透曲线。为了探讨这一方法对压实黄土的适用范围,制备了3组不同干密度的压实黄土样,通过压汞试验测得土样的孔隙分布(pore-size distribution,简称PSD)曲线,用课题组设计的小型土柱设备测定了其非饱和渗透曲线。利用PSD曲线预测渗透曲线,并与实测数据进行对比。结果表明:压实黄土的渗透曲线可分为由毛细水主导的低基质吸力阶段和由吸附水主导的高基质吸力阶段。在低吸力段,3组土样的渗透曲线差异较大,而在高吸力段3组土样的渗透曲线重合,表明高吸力段的渗透性和干密度无关。此外,3组土样的预测结果和实测数据在低吸力段吻合较好,在高吸力段预测结果小于实测结果。从PSD曲线的预测原理可见,该方法适合毛细水不适合吸附水。为此对高吸力段渗透曲线提出了修正方法,修正后的曲线可描述全基质吸力范围内的渗透曲线。The unsaturated permeability curve is governed by the pore-size distribution curve, which can be used to predict the permeability curve. In order to investigate the applicability of this method for compacted loess, three groups of compacted loess samples with different dry densities were prepared. The pore-size distribution(PSD) curves of soil samples were measured using mercury injection porosimeter test. The unsaturated permeability curves of soil samples were measured by small soil column equipment designed by our research group. Then the PSD curves were used to predict the permeability curves and compared with the measured data from soil column test. The results show that the permeability curves of compacted loess can be divided into a low matric suction stage dominated by capillary water, and a high matric suction stage dominated by adsorbed water. In the low suction stage, the permeability curves of the three soil samples differ greatly. While in the high suction section, the permeability curves of the three soil samples coincide, indicating that the permeability of the high suction section has nothing to do with the density of soil. In addition, the predicted results of three groups of soil samples are in good agreement with the measured data in the low suction section, but the predicted results in the high suction section are smaller than the measured results. It can be seen from the principle of the prediction method that this method is suitable for capillary water but not for adsorbed water. Therefore, a modified method is proposed for the prediction of permeability curve in the high suction section, and the modified method can describe the permeability curve in the whole matric suction range.

关 键 词：压实黄土 瞬态剖面法 孔隙分布曲线 非饱和渗透曲线 预测方法 

分 类 号：TU411[建筑科学—岩土工程]