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干湿交替环境下,膨胀土强度具有明显的“变动”特性。结合Palmgren-Miner线性疲劳累积损伤理论,进行了室内不同循环幅度组合的干湿循环强度试验,初步探讨了膨胀土在一定干湿循环条件下的累积损伤规律。研究结果表明:(1)高、低幅度干湿循环的施加顺序对膨胀土的累积损伤有较大影响,膨胀土强度衰减主要受高幅度干湿循环的控制;(2)Palmgren-Miner线性疲劳累积损伤准则可基本反映干湿循环下膨胀土的损伤累积过程,稳定时损伤分数D值接近于1。
Wet and dry alternating environment, the expansive soil strength has obvious “change ” characteristics. Combined with the Palmgren-Miner theory of linear fatigue cumulative damage, the cyclic wetting and drying cycles of different cyclic amplitudes were tested, and the cumulative damage of expansive soils under a certain wet-dry cycle was discussed. The results show that: (1) The order of application of high and low amplitude wet-dry cycles has a significant impact on the cumulative damage of expansive soils, and the strength attenuation of expansive soils is mainly controlled by the high-amplitude wet-dry cycle; (2) Palmgren-Miner linear fatigue The cumulative damage criterion basically reflects the damage accumulation process of expansive soils under the wet-dry cycle. The value of the damage fraction D is close to 1 at steady state.