§1.問題的提出在洛口工程中,用到大量的混凝土。混凝土用大小不同的石子,按一定比例混合,再浇入水泥而成。石子按直径不同可分为四級 8—12,4—8,2—4,1—2 (单位为厘米)到底石子按什么比例来配合才能使水泥用量最少?并且又滿足抗压性、抗渗性、和抗冻性的要求呢?这是有很大經济意义的現实問題。况且,到目前为止,石子級配的最优方案问 §1. PROBLEM PROBLEM In the Lokou project, a large amount of concrete is used. Concrete with different sizes of stones, according to a certain percentage of mixed, and then poured into the cement. According to the diameter of different stones can be divided into four 8-12,4-8,2-4,1-2 (in units of centimeters) in the end what proportion of stones to cooperate in order to minimize the amount of cement? And also to meet the pressure resistance, resistance Permeability, and frost resistance requirements? This is a real economic problem of great significance. Moreover, so far, the gravel optimal solution asked