循环载荷对压实雪冰抗压强度的影响研究

The effect of cyclic loading on the compressive strength of compacted snow

世界强国针对南极科技前沿、地缘政治、开发利用权益的争夺日趋激烈。中国建设和运营南极航空基础设施,有利于提升中国在南极的综合影响力、扩大南极科学考察规模、满足人员和物资快速投送需求,因此,南极机场建设的战略发展价值突出,而压实雪层跑道是中国在南极建设大型机场路面的首选形式。采用压实雪的方法制备人工冰样,结合冰雪跑道所承受的飞机载荷特征,在(-10.0±0.3)℃温度条件下,以1.0 MPa为平均加载应力,以0.03 Hz为加载频率,应力幅值为0.2~1.0 MPa,循环次数100~900为循环条件,开展在1.0×10^(-3)~1.0×10^(-1)s^(-1)应变速率下循环载荷压实雪冰的抗压强度试验,以及5.0×10^(-4)~1.0×10^(-1)s^(-1)应变速率下单调载荷压实雪冰的抗压强度试验。结果表明:单调载荷下的压实雪冰抗压强度在韧性区内随着应变速率的增加而增加,在韧性-脆性过渡区达到最大值,然后在脆性区中显著减少;在高应变速率和一定循环次数范围内,循环载荷对压实雪冰的抗压强度具有强化作用;当超过一定循环次数时,循环载荷对压实雪冰的抗压强度会产生弱化作用。以上试验结果可为压实雪层跑道的设计和维护提供理论依据。

The competition among world powers for the frontier of Antarctic science and technology,geopoli⁃tics,development and utilization rights is becoming increasingly fierce.The construction and operation of Ant⁃arctic aviation infrastructure in China is conducive to enhancing China’s comprehensive influence in the Antarc⁃tic,expanding the scale of Antarctic scientific investigation and meeting the needs of rapid delivery of personnel and materials.Therefore,the strategic development value of Antarctic airport construction is prominent,and compacted snow runway is the preferred form of large airport pavement in Antarctic construction in China.Arti⁃ficial ice samples were prepared by the method of compacted snow.Combined with the aircraft load characteris⁃tics of ice and snow runways,under the temperature of−10℃,with 1.0 MPa as the average loading stress,0.03 Hz as the loading frequency,the stress amplitude of 0.2~1.0 MPa,and the cycle number of 100~900 as the cycle conditions,the compressive strength test of compacted snow ice under cyclic loading at the strain rate of 1.0×10^(-3)~1.0×10^(-1)s^(-1),and the compressive strength test of compacted snow ice under monotonic loading at the strain rate of 5.0×10^(-4)~1.0×10^(-1)s^(-1).The results show that the compressive strength of compacted snow ice under monotonic loading increases with the increase of strain rate in the ductile region,reaches the maximum in the ductile-brittle transition region,and then decreases significantly in the brittle region.In the range of high strain rate and a certain number of cycles,the cyclic load has a strengthening effect on the compressive strength of compacted snow ice.When more than a certain number of cycles,the cyclic load will weaken the compres⁃sive strength of compacted snow ice.The test results obtained in this paper can provide a theoretical basis for the design and maintenance of compacted snow track.