一、问题的提出在研究水工建筑物的受力状态时,混凝土的自由体积变形具有重要意义。可举例说明如下: 假定有两个混凝土试件,其中一个是自由的,另一个是两端硬性嵌固的,如图1。当其它因素不变,仅温度变化量都等于△T时, 自由试件的总应变为ε_0=α△T,而嵌固试件的总应变为ε_m=0。在这种情况下,前者相当于自由体积变形的试件,后者则 First, the problem raised in the study of hydraulic structures under stress, the free volume of concrete deformation is of great significance. It can be illustrated as follows: Assume that there are two concrete specimens, one of which is free and the other is rigidly embedded at both ends, as shown in Figure 1. When the other factors are not changed and only the temperature variation is equal to ΔT, the total strain of the free specimen is ε_0=αΔT, and the total strain of the embedded specimen is ε_m=0. In this case, the former is equivalent to a free volume deformed test piece, and the latter is