取甘肃临洮黄土不同深度土层4 ~ 16 m样品,分别研究微观结构类型差异及震陷性、剪切波速和元素比值等指标的关系。由于不同深度土层样品形成年代不同,气候条件变化很大,同一场地不同深度剖面所形成的黄土微观结构也存在较大差异,各深度(4 m,8 m, 12 m, 16 m)土层样品的微结构类型依次为弱剪切结构,易压密结构,密实结构,中强胶结结构; 同时震陷系数依次降低,剪切波速依次增大,其中的弱剪切结构的剪切波速仅为142 m/s。研究表明通过土层样品的微观结构类型特征及指标参数分析,可较为全面地判断土层场地,找到震害分析和土层处理的有效指标和参数,并据此进行合理的工程设计,可为黄土地区震害的成因和预防提供理论依据。
英文摘要:
Different climate region of the loess with different microstructure characteristics,characteristics of microstructure can reaction dynamic performance strength difference. Test research shows that the microstructure characteristics decide the loess pore structure and the strength of the skeleton structure etc. The influence of microstructure characteristics of the engineering properties of loess is very important. By means of electron microscope (SEM) method at high magnification test of undisturbed loess samples,then extract the microstructure parameters,more microscopic parameters in different depth of loess layer,can also response its mechanical. Here,in Gansu loess soil sample of different depth about,for example,4 ~ 16 meters loess microstructure analysis type differences and settlement ratio,shear wave velocity and the element such as index. According to the microstructure of loess type characteristics and parameters,can be more research. Results show that different depth of loess layers,climate change is very big,the depth (4 meters,8 meters,12 meters,16 meters) sample's microstructure types. In turn, the weak shear structure,the easy compaction structure,the compact structure,and the strong cementation structure, the settlement coefficient and shear wave velocity,in turn,increases,the weak shear structure of shear wave velocity is only 142 m/s. Comprehensively judge the loess ground,and the engineering design of the loess layer is a reasonable manner. Due to the different climate and weathering degree field formed by the different depth profile of the loess had different microstructure. The microstructure of loess samples by research can also be found seismic damage analysis and effective index and parameters of the loess treatment and shock in loess area. According to the microstructure of loess type parameters and indicators,we can make a comprehensive judgment to loess site,and also can get a reasonable response to loess site engineering design.