Modeling of the influence road vibrations on movements in the slide zone under impact waves

In the paper, modeling of the effect of road vibrations on displacements in the slide zone, taking into account impulse waves is presented. The analysis was carried out for an area in which landslide movements occurred in 2010. The analysis concerning the influence of the vibration source’s speed was carried out. The influence of the generated load on the values of vertical displacements created in the slide zone was analyzed. Loads from moving trucks have been included in the form of kinematic impact. Numerical simulations were carried out using a program based on the Finite Element Method.

The Text Analysis on the Relationship between Slide-Zone Loess Porosity Microstructure and Dynamic Parameters

Through analyzing slide-zone loess porosity microstructure and quantitative analysis, the article can obtain the relation between variational characteristics of slide-zone loess porosity micro-structure and dynamic stress. Experimental results show that slide-zone loess microstructural parameters with load increasing appears a certain laws, and we can use simple linear equation to stand for the relation between porosity quantity or porosity area or porosity morphology ratio and dynamic stress. There is a negative correlation between porosity quantity and dynamic stress, but to other microstructural parameters and dynamic stress, it is a positive correlation. All of these laws are closely related to porosity transformation that forming under axial dynamic stress. It is worth mentioning that porosity fractal dimension with increasing dynamic stress increases, appearing linear correlation. When the confidence coefficient is 0.05, their correlation is well. Synthesizing above study, there is some guiding significance for establishing loess microstructure mechanical model and soil mass microstructural mechanics.

A Study on the Effects of Water Content on Strength Parameters of Landslide Soil

Soil samples of slide body and slide zone are obtained to study the strength parameters from a landslide in Yunnan Province, China. Firstly, the basic physical properties of the two soil samples are measured. Then geotechnical tests are performed to study the variation law of strength parameters under different water content by using the automatic KTG triaxial shear apparatus. The results show that the cohesion of soils rapidly reduces with water content increasing, and slowly reduces when plastic limit attains, and it seems that a turning point appears at the location of plastic limit.The relation of cohesion with water content approximately conforms to the exponential function, and the relation of internal friction angle  with water content approximately conforms to the linear relation.

Shear Test on Mixed Slide-Zone Soils of Landslide under Different Water Content

This study is based on a typical residual soil landslide adjacent to Daxishan Reservior in Dalian city of China. By drilling the original samples in the field and remodeling the copy samples in the laboratory, a series of geotechnical experiments are carried out by the improved direct shear apparatus to obtain the changing law between the shear strength and water content of the mixed slide-zone soils. Emphasis is given on the shear stress-strain behavior and the corresponding constitutive model under different water content for the soils. Especially, the typical fitting equation is achieved to reflect the state of shear stress-normal stress-water content, some strain softening and hardening behavior on the mixed slide-zone soils of landslide is also discussed in detail. The results indicate that the shear strength is significantly related to water content of mixed slide-zone soils of landslide. The bigger water content of slide-zone soil is, the smaller the shear strength of soils is. When water content of mixed slide-zone soils approaches to certain value (i.e., 15%), the curve of shear stress and displacement shows a remarkable softening behavior, and the shear strength has marked a peak value.

Crack Arrest Model for Transversely Cracked Piezoceramic Strip under Mechanical and Electrical Yielding

Crack arrest model is proposed for a poled piezoceramic strip under four different mechanical and electrical yield conditions. It is assumed that developed slide zone is bigger than that of developed saturation zone. Expressions are derived for energy release rate and load required to arrest developed zones. Results obtained are applied to predict the crack arrest of strip made of PZT-4, PZT-5H and BaTiO3. Results are presented graphically.