路基石灰稳定土的强度特征与干湿循环损伤效应

为研究干湿循环作用对路基石灰稳定土填料的力学性能的影响及机理，首先开展石灰稳定土的击实试验以确定最优石灰掺量，然后对不同含量的石灰稳定土试样进行无侧限抗压强度试验，结合扫描电镜试验分析强度改性的微观机理。结果表明:石灰掺量为6 %的土样最大干密度达到峰值，密实度最优；干湿循环作用造成石灰稳定土力学特性的显著下降，随着干湿循环从零增至10次的过程中，石灰稳定土的无侧限抗压强度、弹性模量逐渐衰减，且养护28天的强度指标明显高于养护7天的试样；随着干湿循环次数增加，石灰稳定土内部孔隙的数量不断增加，尺度不断扩大；由微观图像发现石灰稳定土中的孔隙在干湿循环中逐渐扩大，密实度逐渐下降。

Strength Characteristics of Lime-stabilized Soil and Damage Effect of Dry-wet Cycle in Roadbed

In order to study the influence of dry-wet circulation effects on the mechanical property of lime stabilized soil subgrade filler and its mechanism, firstly, compaction tests on the lime stabilized soil have been carried out to determine the optimal lime content. then, the unconfined compressive strength tests were carried out on lime stabilized soil samples with different contents. In combination with scanning electron microscopy (SEM) test, the microscopic mechanism of strength modification was analyze. The results show that the maximum dry density of soil samples with lime content of 8 % reaches the peak and the compactness is the best. The mechanical properties of lime-stabilized soil decreased significantly due to the drying and wetting cycles. With the drying and wetting cycles increasing from 0 to 10 times, the unconfined compressive strength and elastic modulus of lime-stabilized soil decreased gradually, and the strength index of the sample cured for 28 days was significantly higher than that of the sample cured for 7 days. With the increase of drying and wetting cycles, the number of internal pores in lime-stabilized soil increases and the scale expands. It is found from the microscopic images that the pores in the lime-stabilized soil gradually expand, and the compactness decreases during the dry-wet cycle.