数学解析法在界限含水率试验中的判别式研究

大量工程实践证明，由于受诸多因素的影响，采用液塑限联合测定法时，双对数坐标系上最高点A，中间点B，最低点C三点完全在一条线上的情况很少见，大部分情况是不在一条直线上。对于三点不在一条直线上的情况，《土工试验方法标准》的规定是先确定锥入深度2 mm在直线AC和AB上的含水率，然后确定两者之间的差值，如果差值小于2%，则不需重做试验，反之则需重做试验。这种做法步骤复杂，速度较慢。对此，通过数学解析法推导出判别式，可以不求取锥入深度2 mm在两直线上的含水率的情况下，快速判定是否需重做试验。

Discriminant Study of Mathematical Analytic Method in Boundary Moisture Content Test

A large number of engineering practice shows that, as the liquid-plastic limit combined method was used, on log-log coordinates, the corrdinate system of three points, including the highest point A, the intermediate point B, and the lowest pint C, being together in a line, is rare due to the influence of many factors, but not in a line in most cases. In a case of the three points not in a line, the specified in the Standard for Soil Test Method is as follows, determine the moisture content on the Line AC and the Line AB in case of 2 mm penetration at first, then find out the difference therebetween; if the difference is less than 2%, it is not required to repeat the test, otherwise, the test should be done again. This method is complex and slow, then the discriminant is deducted hereto by means of mathematical analysis to decide whether to repeat the test quickly on the condition of not solving the moisture content on the two lines at 2 mm of the depth of penetration.