天然砂砾料的级配特性及包线设计方法

Gradation characteristics and envelope curve design method for natural sandy gravel

依据料场勘探砂砾料粒径-质量百分数的级配曲线图,采用粒径外包法确定设计包线的方法,由于样本数量的限制,难以合理反映砂砾料的实际级配范围,导致部分满足工程要求的填筑级配被判定为不合格,影响大坝的填筑质量评定。为此,结合阿尔塔什等3座高坝工程的筑坝料,论证了Weibull模型反映砂砾料上凸型、S型或反S型以及分形模型级配特性的适应性,得到阿尔塔什、大石峡和大石门的料场砂砾料级配分别为S型和上凸型两种不同分布类型;首次提出采用粒径规一外包法,即利用最大粒径对级配规一化技术,确定砂砾料级配包线的方法,可以弥补由于现场勘探资料样本不足,导致设计包线不能客观反映料场级配分布规律的缺点。研究成果可直接用于砂砾料的级配设计,也可用于确定不同类型土体级配的包络线,具有较强的应用价值。

Due to the limitation of the number of samples, the particle-size envelope method for directly determining the sand-gravel design line according to the gradation curve of exploration stockyard is difficult to reasonably reflect the actual gradation range of the sand-gravel materials in the material field, resulting in some of the filling gradations being unqualified, so that it will affect the assessment of dam filling quality. For this reason, based on the construction materials of Aertash, Dashixia and Dashimen, the suitability of the Weibull model to reflect the convex, S-shaped, or inverted S-shaped gravel materials and the gradation characteristics of the fractal model is demonstrated. The gradation of gravel materials in the stockyard of the Aertash, Dashixia and Dashimen is divided into two different types: S-type and convex-type. For the first time, the method of using the maximal particle size to standardize the gradation to determine the grading of the material yard is proposed. It can make up for the shortcomings that the grading package cannot objectively reflect the gradation range of the yard due to insufficient exploration data. The research results can be directly used for the gradation design of gravel materials, and can also be used to determine the envelope of different types of soil gradations, which shows a strong application value.