土壤水分特征曲线测定过程中土壤收缩特性研究  

Study on soil shrinkage characteristics during soil water characteristic curve measurement

作　　者：邢旭光[1,2] 赵文刚[1,2] 马孝义[1,2,3] 张云龙[3] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100 [3]西北农林科技大学机械与电子工程学院,陕西杨陵712100

出　　处：《水利学报》2015年第10期1181-1188,共8页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(51279167);"十二五"国家科技支撑基金项目(2012BAD08B01);水利部公益性行业专项项目(201301016)

摘　　要：为探求不同土壤水分特征曲线拟合模型的适宜性以及离心机法测定过程中的土壤收缩特性，选取云南黏壤土（KM）、辽宁砂壤土（SY）、新疆砂壤土（KL）和山东壤土（LY），分别对土壤水分特征曲线进行测定并拟合，而后对测定过程中土壤的收缩度及其收缩特性进行分析。结果表明，对于KM、SY、KL和LY：（1）当吸力从0增至7000cm时，土壤含水率逐渐减小，且减小速率呈现“降低-增加-降低”趋势；（2）各土壤水分特征曲线经验模型均表现出良好的模拟效果，适宜模型分别为VG—M（m，n）、LND—M、VG—M（1—1／n，n）和VG—B（m，n），其中VG模型可作为最优模型同时对4种土壤进行土壤水分特征曲线拟合；（3）在土壤水分特征曲线测定过程中，土壤有效收缩度与吸力满足对数函数关系（R2=0．82～0．97），4种土壤收缩量表现为SY〉KM〉LY〉KL，且容重增加了0．19～0．46g／cm3；（4）基于土壤收缩特征值可将土壤收缩过程大致分为伪饱和段、结构段和超正常段，且对于4种土壤，3个收缩段均可以用直线模型描述，但各收缩段的吸力范同存在差异。Clay loam soil from Yunnan （KM）, sandy loam soil from Liaoning （SY） and Xinjiang （KI,）, and loam soil from Shandong （LY） were selected for analyzing the characteristics of soil shrinkage during soil water characteristic curve measurement in order to explore the suitability of fitting models for soil water characteristic＇, curve, and the changes of soil shrinkage. In this paper, soil water characteristic curves of the four soil types were measured by centrifuge method and were fitted by RETC software. The results showed that as for KM, SY, KL and LY soils, firstly, soil moisture content gradually decreased with soil suction increasing from 0 to 7000 em. And the rate of soil water reduction decreased, and then increased, and then decreased again. Secondly, all fitting models presented in RETC software were of high accuracy for the simulation of soil water characteristic curves, and the appropriate fitting models for KM, SY, KL and LY soils were VG-M（m, n）, LND-M, VG-M（I-1/n, n） and VG-B（m, n）, respectively. And VG model could be considered as the optimal model for simulation of soil water characteristic curves of the four soils. Thirdly, a logarithmic function was found between degree of effective soil shrinkage and soil suc- tion during soil water characteristic curve measurement. The soil shrinkage was ranked in the order of SY 〉 KM 〉 LY 〉 KL, and the bulk density of the four soils increased by 0.19 - 0.46 g/cm3. Fourthly, soil shrink- age process could be roughly divided into pseudo-saturated stage, structural stage and super-normal stage. And as for KM, SY, KL and LY soils, the three stages could be described by linear function, but the ranzes of soil suetion corresponding to three soil shrinkage stages were different.

关 键 词：土壤水分特征曲线 土壤收缩 容重 模型 

分 类 号：S152.7[农业科学—土壤学]