Evaluation of hydraulic properties of unsaturated soils considering bulk density

(1)提出了一种测定土壤容重的方法。因此，考虑孔隙率的影响，可以得到全饱和度范围内的土壤水分特征曲线。(2)建立了粉砂土壤水分特征曲线的新模型。可以用来描述粉砂的空隙比、饱和度和基质吸力特性。发现收缩极限处的基质吸力与初始萎缩点有关。(4)提出了一种估算非饱和土渗透性的实验方法。它是原有瞬时剖面法的改进型，能测量多种土体的渗透性。新方法的特点是水分分布的非定常条件和水分分布的线性近似。(5)试件的体积变化对测量结果有影响，因此我们用考虑体积密度的持水曲线对试件的体积进行了修正。通过室内试验研究了压实能与孔压之间的关系，该方法可以测量非饱和土体体积变化较大的导水率。然后，吸力的行为可以用相互作用粒子之间的距离来解释。

(1) Method of measuring the bulk density of soils was developed during the phychrometer method. Therefore, soil water characteristic curves could be obtained considering void ratio over the full range of degree of saturation.(2) A new model of soil water characteristic curve could be formulated for silty sand. It can be presented the behavior of void ratio, saturation and matric suction of silty sand. And we got that it is applicable to other silts.(3) It was found that Matric suction in the shrinkage limit was concerned with the initial wilty point.(4) An experiment method has been developed to estimate the permeability of unsaturated soils. It is an improved type of the original instantaneous profile method, and is able to measure the permeability of many kinds of soils. The new method is characterized by the unsteady condition of water profile and linear approximation of moisture distribution.(5) Volume change of the specimen affects the measured, therefore, we corrected the volume of the specimen by the water retention curves considering bulk density. This proposed method could measure the hydraulic conductivity of unsaturated soils taking account of the considerable volume change.(6) The relationship between compaction energy and pore water pressure is investigated through laboratory testing. And then, the behavior of suction could be explained by the distance between interacting particles.