考虑土体性质的黄土震陷灾害区域性特征

本研究在通渭、兰州、西吉、宝鸡、西安等多个西北典型黄土震陷灾害场地获取原状土样，通过对密度、含水率、孔隙比、塑液限等物理指标的测试，分析其与土体震陷性的关系；通过动弹性模量和阻尼比、动强度、震陷等室内动力特性试验，并结合大量前人研究资料，分析土体性质对岩土震陷灾害的区域性影响。结果表明：1）震陷系数与单一土体物性参数呈正相关或负相关关系，六盘山以西和以东的黄土震陷特性反映了明显的地区变化规律，在相同地震荷载作用下震害东轻西重；2）随着时间的推移，人类的活动增加，改变了土的含水率，导致土体上覆压力增大，在上覆压力的作用下，土体的初始孔隙数量有所减少，其固结程度越来越好，宏观表现为土体的易损性即震陷性减小。

Regional Characteristics of the Earthquake Subsidence Disaster in Loess Area Based on Soil Properties

Based on physical indexes such as density, moisture content, pore ratio, and plastic limit, the relationship between each physical index and soil vulnerability was analyzed. Undisturbed soil samples in Tongwei, Lanzhou, Baoji, Xiji, Xi''an, and other typical loess disaster sites were used as the research object. Through an indoor dynamic characteristics test and based on the findings of numerous previous studies, the regional effects of soil properties on geotechnical subsidence disasters were quantitatively analyzed. The results showed the following: (1) A positive or negative correlation exists between the seismic subsidence coefficient and individual soil physical property. The seismic subsidence characteristics in the west and east of the Liupan Mountain present a regional law: the disaster distribution is characterized as light in the south and heavy in the east under the same seismic load. (2) Over time, the increase in the number of human activities changes the soil moisture, increasing the overburden pressure of soil. Under the action of the overburden pressure of soil, the number of initial soil pores decreases, and the consolidation degree increasingly improves. Macroscopically, this result shows that the soil vulnerability is reduced, and thus, the seismic subsidence is reduced.