测定土壤饱和渗透系数的试验方法与结果优化

Test Method for the Determination of Soil Saturated Permeability Coefficients and the Optimization of Results

土的渗透系数是一个极其重要的水文地质参数,它反映了土壤和岩层的透水性能,是地下水计算中一个不可缺少的指标,但土的渗透试验受诸多因素的影响,如土的物理性质、试验环境、试验场所、人为操作等。为了较为客观、准确地获取包气带浅层土壤饱和渗透系数,本文概述了Guelph渗透仪法野外渗透试验和室内变水头渗透试验测定土壤饱和渗透系数的原理与方法,并通过统计学中的置信区间对试验数据进行了优化处理。结果表明:野外试验测得的土壤饱和渗透系数较室内试验大,但误差在一个数量级内;室内试验测得的土壤饱和渗透系数与《工程地质手册》(第三版)给出的土壤饱和渗透系数参考值接近;Guelph渗透仪用于野外测定土壤饱和渗透系数的可靠性较高。

Hydraulic conductivity is one of the most important hydrogeological parameters, for it reflects the permeability of soil and rock, which is an indispensable index in the calculation of groundwater. Soil permeability test is affected by many factors, such as soil physical properties, test environment, test site, manual operation and so on. For the purpose of obtaining soil saturated permeability coefficients in the shallow soil of unsaturated zone accurately and objectively,this paper discusses the principle and method of Guelph permeameter test and the indoor varying-head permeability test,and also optimizes the test data by constructing confidence intervals. The results show that values of saturated permeability coefficients in field test are higher than those in laboratory test, but the inaccuracies are within one order of magnitude, and that the measured values in laboratory test are closer to those given by Manual of Engineering Geolo- gy （Third Edition）. The study indicates that Guelph permeameter used for the determination of soil saturat- ed permeability coefficient in field is of high reliability.