Statistical Evaluation of Material Strength

通过对砂土和混凝土抗压强度统计数据库的组装，并应用分叉理论，研究了砂土和混凝土强度的统计变化规律，对混凝土进行了一系列圆柱形试件的压缩试验，获得了应力-应变曲线的集合。首先，将尺寸为0.5mm、1.0mm和2.5mm的无光泽珠粒用于聚集体以观察尺寸的影响。通过应用分叉理论，指出当尺寸较小时，分叉占主导地位，而当尺寸较大时，断裂占主导地位。其次，通过改变水灰比的26%、35%和62%来研究水灰比的影响，发现当水灰比较大时，分叉现象最为明显。由于目前的理论只适用于分叉模式是唯一的情况下，在试验过程中拍摄的照片和草图的标本，以确定分叉模式，并根据这些模式对这些曲线进行分类。以这种方式分类的曲线准确地遵循分叉理论;这评估了理论的有效性。

The statistical strength variation of sand and concrete is investigated through the assemblage of statistical data bank of their compressive strength and the application of the bifurcation theory to the data.For concrete, a series of compression tests are conducted on cylindrical specimens to obtain an ensemble of stress versus strain curves. First gless beads of the size of 0.5mm, 1.0mm, and 2.5mm were used for sggregates to observe the influence of the size. Through the application of the bifurcation theory, it has been noted that bifurcation is predominant when the size is small, whereas fracture is predominant when large. Next the influence of the water cement ratio was investigated by varying its values by 26%, 35%, and 62% to note that bifurcation is predominant when its value is large.For sand, a set of 50 triaxial compression tests were conducted on cylindrical Toyoura sand speciments to obtain an ensemble of stress versus strain curves. Since the present theory is applicable only for the case where the bifurcation mode is unique, the photos and sketches of the specimens were taken during the tests to identify the bifurcation modes, and those curves were categorized in view of these modes. The curves categorized in this manner accurately followed the bifurcation theory ; this assesses the validity of the theory.