非饱和土双应力变量广义土水特征曲线模型验证

发布时间：2018-03-07 11:52

本文选题：土壤　切入点：模型　出处：《农业工程学报》2017年06期 　论文类型：期刊论文

【摘要】：利用基于轴平移技术的Geo-Expert高级型应力相关土-水特征曲线压力板仪研究不同覆土压力(0、40、100、200 k Pa)对南阳膨胀土土水特征曲线(soil-water characteristic curve,SWCC)的影响;并对提出的考虑土体变形及多孔隙分布形态的双应力变量广义SWCC表征方程进行如下试验验证:1)不同覆土压力下微多孔隙分布形态的南阳膨胀土侧限固结试验及脱湿试验SWCC验证;2)零净法向应力状态双孔隙尺度硅藻土双峰SWCC试验验证;3)不同净围压状态下单孔隙尺度韩国残积土SWCC试验验证;4)多应力路径下法国Bapaume黄土,不同初始干密度下日本Edosaki砂土在脱湿-吸湿过程SWCC试验验证;并比较分析新方程与van Genuchten方程及Fredlund等方程的差异性。结果表明:1)覆土压力会显著改变膨胀土结构及孔隙通道,进而改变SWCC边界效应区、过渡区形态;也改变了双重孔隙尺度土壤的进气值;第1个波峰SWCC进气值均在1 k Pa左右;相比于零覆土压力试样,40、100、200 k Pa覆土压力试样第2个波峰SWCC进气值分别高4.74、17.58、67.23 k Pa;2)未考虑净法向应力影响的单应力状态多峰SWCC、考虑侧限双应力状态多峰SWCC、各向同性净法向应力单峰SWCC、不同脱湿-吸湿路径SWCC及不同初始干密度的SWCC试验拟合曲线均表明,双应力广义SWCC具有包容复杂影响因素的能力;3)新方程能够利用至少3个土-水数据即可拟合出具有较高的精度的整条SWCC。研究为定量描述土壤的持水、渗透及强度特性提供参考。
[Abstract]:The influence of different overlying earth pressures on soil-water characteristic curved-water characteristic curve of Nanyang expansive soil was studied by using Geo-Expert advanced stress-related soil-water characteristic curve pressure plate based on axial translation technique. The generalized SWCC equation with double stress variables considering soil deformation and pore distribution was tested as follows: 1) the lateral consolidation test and dewatering of Nanyang expansive soil with micropore distribution under different overlying pressure were carried out. Wet test SWCC verification (No.2) double pore scale diatomite bimodal SWCC test verification of zero net normal stress state) issuance of orders under different net confining pressure states SWCC test of Korean residual soil with pore size verifies that (4) France Bapaume loess under multi-stress paths. Under different initial dry densities, the Edosaki sand in Japan was verified by SWCC test in the process of desiccation-moisture absorption, and the differences between the new equation and van Genuchten equation and Fredlund equation were compared and analyzed. The results show that the overlying earth pressure can significantly change the structure and pore channel of expansive soil. Then the shape of SWCC boundary effect zone, transition zone and the inlet value of double pore scale soil were changed. The first peak of SWCC air intake value was about 1 KPA. Compared with the zero overlying soil pressure specimen, the SWCC inlet value of the second peak of the second wave peak of the zero overlying earth pressure specimen is 4.74 ~ 17.58.67.23k Pao _ 2, respectively.) the multi-peak SWCCs without net normal stress effect are considered, and the multi-peak SWCCs with the lateral limit double stress state are considered, and the isotropic net SWCCs are taken into account. The fitting curves of normal stress single peak SWCC, SWCC with different desiccant and moisture absorption paths and different initial dry densities are obtained. The new equation can use at least three soil-water data to fit the whole SWCC with high accuracy. The study provides a reference for the quantitative description of soil water retention, permeability and strength characteristics.
【作者单位】：西南大学工程技术学院;College
【基金】：国家自然科学基金项目资助(11572262,41602354) 中央高校基本科研业务费专项资金资助(XDJK2016D016,XDJK2016B006)
【分类号】：TU43

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