The mechanical behaviors of soil exposed to monotonic and cyclic pneumatic loading are investigated through laboratory testing. The fracture morphology, air pressure, and earth pressure (EP) were monitored and analyzed. In monotonic pneumatic fracturing, pressure of air is the crucial factor that determines the length and number of fractures. In cyclic pneumatic fracturing, the number and propagation of fractures is greater than that under the monotonic loading, as well as the disturbance zone of the pressurized air to the soil. It is found that high-frequency injection maintains higher air pressure inside the soil, coupled with the cyclic loading, the fatigue fracturing effect is much better than that under monotonic loading. The patterns of fractures subjected to monotonic and cyclic loading are presented. It is concluded that the higher the injection frequency and air pressure, the larger the number and propagation range of fractures.

通过实验室测试研究了暴露于单调和循环气动载荷的土壤的力学行为。对裂缝形态、气压和土压力（EP）进行监测和分析。在单调气力压裂中，空气压力是决定裂缝长度和数量的关键因素。在循环气力压裂中，裂缝的数量和扩展大于单调加载下的裂缝数量和扩展，以及压缩空气对土壤的扰动区。研究发现，高频注入使土体内保持较高的气压，再加上循环加载，疲劳压裂效果明显优于单调加载。呈现了受单调和循环载荷作用的裂缝模式。