水下浇筑混凝土的主要问题是水泥和砂被水冲走以及水掺入混凝土内增大了它的水灰比。然而,大多数人认为:在浇筑过程中,如果导管的底端始终埋在混凝土中,新浇的混凝土就会在先浇的混凝土的底部流动,这样前者就得到后者的保护,见图1。我们的试验却表明:从导管流出的混凝土能呈现不同的流态,暴露于水中的混凝土比预计的要多。 The main problems with pouring concrete underwater are that the cement and sand are washed away by the water and the incorporation of water into the concrete increases its water-cement ratio. However, most people think that if the bottom end of the pipe is always buried in the concrete during pouring, the fresh concrete will flow on the bottom of the poured concrete so that the former is protected by the latter, as shown in Figure 1 . Our experiments show that concrete flowing out of the duct can exhibit different fluid regimes, with more concrete exposed than expected.