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为了探讨非饱和黏土质砂的渗气规律,对常规三轴仪进行了改造,使其能够进行非饱和土渗气性量测,改进后的渗气装置具有构造简单、制样方便、试样均匀性好、加载系统稳定、可用量测的气压力梯度范围较大、提高了量测精度等优点,并解决了量测空气体积困难的问题和渗气试验气体从刚性壁和试样边缘流出的问题。使用该套仪器研究了不同干密度和不同含水率条件下气体流速与渗透系数随压力梯度变化的规律,分析了气体流速、渗气系数同含水率和干密度之间的依存关系,建立了渗气系数与含水率和干密度之间的函数关系。研究结果表明:试样在所研究的含水率、干密度范围,非饱和黏土质砂中气体流动可用达西定律描述。
In order to investigate the gas seepage regularity of unsaturated clay sand, the conventional triaxial instrument was modified to make it possible to measure the gas permeability of unsaturated soil. The improved gas seepage device has the advantages of simple structure, convenient sample preparation, Good uniformity, stable loading system, large range of available pressure gradient for measurement, improved measurement accuracy and the like, and solves the problems of difficult measurement of air volume and outgassing of test gases from rigid walls and sample edges The problem. The gas flow rate and permeability coefficient with the pressure gradient under different dry density and different water cut were studied by using the set of instruments. The dependence of gas flow rate, gas permeability coefficient and moisture content and dry density was analyzed, and the infiltration Gas coefficient as a function of moisture content and dry density. The results show that the gas flow in unsaturated clayey sands can be described by Darcy’s law in the range of moisture content and dry density studied.