在水力学中,河流横截面积 F(厘米~2)、水与河流横截面土基接触的周边长度 L(厘米)的比值称为水力半径 R(厘米),即 R=(F/L)。我们通常把混凝土构件截面尺寸、暴露在大气的程度与其干缩的影响用水力半径倒数表示:(1/R)=(L/F)以 R=(1/R) R 的单位为(厘米/1)=厘米~(-1) In hydraulics, the ratio of the river’s cross-sectional area F (cm~2) to the perimeter L (cm) of the contact between the river and the cross-section of the river is called the hydraulic radius R (cm), ie, R = (F/L). . We usually express the cross-sectional dimensions of the concrete component, the degree of exposure to the atmosphere and the effect of its shrinkage on the radius of the hydraulic force: (1/R) = (L/F) in R = (1/R) R in units (cm/cm 1)=cm~(-1)