双对数平面内砂岩颗粒料孔隙比-应力曲线变化规律

Test Analysis of The e-pCurves of Sandstone Particles under Double Logarithmic Plane

为探究灰白砂岩颗粒料在侧限压缩情形下孔隙比—应力（e-p）曲线变化规律及其数学表达,设置砂泥配比、干密度及含水率三因素共11种方案,得到各方案下砂岩颗粒料的e-p曲线,并将e-p曲线与双对数坐标指数模型曲线进行对比,评价模型理论e-p曲线与砂岩颗粒料试验曲线吻合程度。试验结果及模型分析表明,不同砂泥配比时,双对数坐标指数模型颗粒料e-p曲线变化趋势与试验曲线一致;不同干密度时,当轴向应力处于0~0.8MPa时,该模型曲线与试验曲线吻合程度较高;不同含水率作用下砂岩颗粒料试验e-p曲线呈相互穿插形态,当应力处于0.4~1.6 MPa且含水率高于6%时,模型孔隙比理论值大于试验值。可见基于标准砂不同初始孔隙比建立的双对数坐标指数模型对不同干密度砂岩颗粒料e-p曲线数学表述吻合度较高,与不同砂泥配比及初始含水率的e-p曲线吻合度较低。

In order to explore the change rule and mathematical expression of the e-p curves, the gray sandstone particles are used in the situation of lateral confined compression test. The three factors including 11 kinds of solutions are adopted in the tests, and they are the proportion of sandstone mudstone particles, the dry density and the moisture content. Thus, the test curves of e-p are obtained under the influence of one of those factors. Then those test e-p curves are compared to the theoretical curves originated from exponential model in double logarithmic coordinate. In turn, the degree between those test e-p curves and those theoretical e-p curves is to be evaluated through this way. The test results and the analysis of exponential model indicate that the change trend of those theoretical e-p curves are in keeping with those test e- p curves just changing different the proportion of sandstone and mudstone particles in tests. When the axial stress is in the range of 0-0.8 MPa, the degree of those theoretical e-p curves and those test e-p curves is high just changing different dry density of sandstone particles. For sandstone particles, some of the test e-p curves of different moisture content present the shape of intersection. And all of the void ratio originated from exponential model is greater than the experimental value while the axial stress is in the range of 0.4-1.6 MPa and the moisture content is exceeded 6%. Therefore, according to different initial void ratio of standard sand, the exponential model in double logarithmic coordinate is listed. And it is conformed to the test e-p curves in sandstone particles within different dry density. Further, the degree of different moisture content and the proportion of sandstone mudstone particles is inferior compared with the effect of the dry density for sandstone particles.