一砂样的天然孔隙比e为0.688,最大孔隙比emax为0.805,最小孔隙比emin为0.645则该土样的相对密实度Dr=

以知箍筋Asv/S=0.805，采用双肢φ8（Asv=50.3mm2）箍筋，则箍筋间距宜取（）毫米。 A: 65 B: 125 C: 180 D: 200

A compressible fluid is flowing through a pipe with a constriction. The diameter of the narrow section is 1/2 the diameter of the wide section. The density of the fluid in the narrow section is 3/4 the density of the fluid in the wide section. If the velocity of the compressible fluid is 3.600 m/s in the narrow section, then what is the velocity of the fluid in the wide section? A: 0.675 m/s B: 0.805 m/s C: 0.250 m/s D: 0.333 m/s E: 0.500 m/s