This study investigates the effect of free water on the mechanical properties and blast resistance of concrete. For this purpose, comparative experiments on saturated and normal concretes subjected to quasi-static compression, cyclic loading-unloading, quasi-static splitting, and dynamic compression are conducted. Thereafter, contact explosion tests are performed on saturated and normal concrete slabs. The results show that free water reduces the blast resistance of concrete slabs. This is primarily because free water alters the mechanical properties of concrete, including its compressive strength, tensile strength, damage evolution rate, and strain rate effect. Therefore, the material parameters of saturated concrete differed from those of normal concrete. It is unreasonable to employ the material parameters of normal concrete for simulating the cracks and damage modes in hydraulic concrete structures subjected to underwater explosions. Then, the material parameters of Holmquist-Johnson-Cook constitutive model for the saturated and normal concrete slabs are determined based on experimental data, respectively. Finally, the numerical simulation of concrete slabs subjected to contact explosions was carried out. The results show that the numerical predictions and the test data both for the saturated and normal concrete slabs subjected to contact explosions were in good agreement.

这项研究调查了游离水对混凝土力学性能和抗爆炸性的影响。为此，对饱和混凝土和普通混凝土进行准静态压缩，循环装卸，准静态劈裂和动态压缩进行了对比实验。此后，对饱和混凝土板和普通混凝土板进行接触爆炸测试。结果表明，游离水降低了混凝土板的抗爆炸性。这主要是因为游离水会改变混凝土的机械性能，包括其抗压强度，抗张强度，损伤演化率和应变率效应。因此，饱和混凝土的材料参数不同于普通混凝土。利用普通混凝土的材料参数来模拟遭受水下爆炸的水工混凝土结构的裂缝和破坏模式是不合理的。然后，分别基于实验数据确定了饱和混凝土板和普通混凝土板的Holmquist-Johnson-Cook本构模型的材料参数。最后，进行了混凝土板接触爆炸的数值模拟。结果表明，饱和混凝土板和普通混凝土板接触爆炸的数值预测和试验数据吻合良好。分别根据实验数据确定了饱和混凝土板和普通混凝土板的Holmquist-Johnson-Cook本构模型的材料参数。最后，进行了混凝土板接触爆炸的数值模拟。结果表明，饱和混凝土板和普通混凝土板接触爆炸的数值预测和试验数据吻合良好。分别根据实验数据确定了饱和混凝土板和普通混凝土板的Holmquist-Johnson-Cook本构模型的材料参数。最后，进行了混凝土板接触爆炸的数值模拟。结果表明，饱和混凝土板和普通混凝土板接触爆炸的数值预测和试验数据吻合良好。