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在实际工程中,滑坡经常呈现出多级破坏的特征,而一般计算和设计中仅关注最危险的滑动面及对应的最小安全系数,这往往遗留安全隐患。在考虑岩土材料软化特性的基础上,借助FLAC3D和Matlab软件平台构建了无需人工干预便可有效模拟与评价滑坡多级破坏的理论框架。以旬阳县党家坝廉租房小区滑坡为例,通过对塑性剪应变、塑性拉应变、剪切应变增量等特征变量的渐进发展规律分析发现:滑坡多级滑动面的形成,其时间和空间顺序并不一定相对应。各级滑动面在时间上按产生的先后顺序依次为第1级主滑面、第2级主滑面、次级滑面;而在空间上按照从前到后的顺序依次为第1级主滑面、次级滑面、第2级主滑面。从计算所得的滑坡最终破坏形态中发现,坡体内部出现的滑动面条数与现场采集的拉裂缝数基本保持一致;第1级主滑面的入口位置与滑坡前缘拉裂缝位置基本吻合;而第2级主滑面及次级滑面的位置与现场勘查到的拉裂缝位置出现偏差。从材料参数的渐进发展规律中发现,滑面上强度参数的分布及大小均随着滑面的产生、发展而逐渐变化,其变化区间为峰值强度到残余强度,这是此方法可以有效模拟多级滑动面形成过程与各级滑动面之间相互影响的核心所在。借助矢量和法成功地实现了基于滑面上强度参数渐进发展规律的安全系数演化过程的确定。通过对安全系数演化过程的分析发现,在滑坡多级滑动面的形成过程中安全系数大小顺序呈现出3种不同的状态,这很好地揭示了各级滑动面在形成过程中的主、被动关系。
In practical engineering, landslides often show the characteristics of multi-level damage, while the general calculation and design focus only on the most dangerous sliding surface and the corresponding minimum safety factor, which often left behind potential safety problems. Based on the softening characteristics of geomaterials, a theoretical framework that can effectively simulate and evaluate multi-stage landslide damage without human intervention is constructed by using FLAC3D and Matlab software platform. Taking the example of Dangjiaba low-rent housing plot in Xunyang County, this paper analyzes the gradual development of the characteristic variables such as plastic shear strain, plastic tensile strain, shear strain increment and so on. The results show that the formation of multi- And the spatial order does not necessarily correspond. The slip surfaces at all levels are, in order of priority, the first main slip surface, the second main slip surface, and the second slip surface. The first slip surface is the main slip surface Surface, secondary slip surface, Level 2 primary slip surface. From the calculated ultimate landslide failure state, the number of sliding noodles appearing in the slope body is basically the same as the number of the pulling cracks collected in the field. The position of the entrance of the primary slip surface is basically consistent with the location of the front of the landslide; The location of the 2nd grade main slip surface and the secondary slip surface deviated from the location of the tensile cracks found on site. From the progressive development of material parameters, it is found that the distribution and size of the strength parameters on the sliding surface both change gradually with the generation and development of the sliding surface, and the variation range is the peak intensity to the residual strength. This method can effectively simulate more The formation of level slip surface and the interaction between the sliding surface at all levels of the core. With vector sum method, the evolution of safety factor based on gradual development of strength parameters on sliding surface was successfully determined. Through the analysis of evolutionary process of safety factor, it is found that there are three different states of safety factor in the formation process of multi-stage landslide, which reveals well the main and passive relationship.