Abstract
As a solid energy source, CH(4) hydrate will inevitably break down physically as the result of geological movement or exploitation. Here, the molecular dynamics method was employed to simulate the uniaxial-deformation behavior of structure I (sI type) CH(4) hydrate under stress. The stress increases regardless of whether the hydrate is stretched or squeezed, and other physical parameters also changed, such as hydrate cage numbers, order parameters, and the number of water molecules. A noticeable difference is observed between the two systems. Upon stretching, the stress immediately recovers to 0 GPa once the hydrate is completely stretched apart. During the squeeze process, the stress is ultimately not zero since solid and liquid are always in contact. When the hydrate is stretched apart, about 5% of water molecules change from solid to liquid, about 7.8% of CH(4) molecules lose their shelter and become free due to the disintegration of water cages. While in the squeezing process, large cages (5(12)6(2)) are crushed more easily than small cages (5(12)); in the end, about 93.5% of large cages and 73% of small cages are crushed, and approximately 87.5% CH(4) is released from the cages. In mining CH(4) hydrates, caution must be exercised, as if the hydrates break as a result of stress, a large release of CH(4) may pose a security risk.