堆积层斜坡震后变形发展规律的离心模型试验

Centrifugal Model Tests for Post-earthquake Deformation Behaviors of a Slope Covered by Deposits

地震作用后堆积层斜坡的变形规律与稳定特性是我国西南山区防灾减灾工程中关注的重要问题之一。为深入研究震后堆积层斜坡变形发展规律,将坡体概化为花岗岩强风化土与砂土配制而成的匀质土模型,采用土工离心模型试验的方法,探讨地震影响深度为10 m时不同震松程度（震松坡体压实系数分别为0.90、0.85、0.80）对边坡震后时效变形与长期稳定特性的影响,并进一步将离心模型试验结果与原型现场实测数据进行对比分析。研究发现,随震松坡体损伤程度增大,其应力与位移场于震后短期的调整幅度将相应提高;地震震松坡体密实程度以压实系数表征于0.90-0.80间变化时,其位移场于震后的主要调整时间为0.7-1.1 a;由于物理试验中边坡坡度较缓（约35.7°）,地震震松坡体时效位移以竖向固结为主;离心模型坡面水平位移与原型斜坡代表性测孔顺坡向位移随时间的演进规律具有较好的相似性。

Deformation laws and stability characteristics of the slopes covered by deposits after the earthquake actions is one of the important problems for disaster prevention and reduction in China＇s south-western mountainous areas. Three groups of geotechnical centrifugal model tests were conducted to further study the deformation development laws of slope covered by deposits after earthquake actions. Slope bodies were generalized into fabricated soil（ mixed with weathered granite soil and sandy soil） models,and influence depth of earthquake to the slope was taken as 10 m,then,effects of loose degrees of the earthquake loosed slope body on aging deformation and longterm stability of the slope were investigated,furthermore,the relevant results of centrifugal model tests were also compared with the field monitoring data of the archetype slope. The following conclusions could be drawn from analyses： 1. With development of damage extents of the earthquake loosed slope body,adjustment extents of the stress / strain fields in the short term after the earthquake increased accordingly; 2. As compaction coefficients of the earthquake loosed slope body vary from 0. 90 to 0. 80,the main adjusting time of the slope＇s displacement field after the earthquake lies within 0. 7 - 1. 1 years; 3. In the tests,because of the gentle gradient of the slope（ 35. 7°）,aging displacments of the slope bodies are dominated with the vertical consolidation; 4. There is quite good similarity between evolution rules of both the horizontal displacements of the slope surface in the centrifugal model tests and the longitudinal displacements of the archetype slope body near the typical inclinometer borehole.