Loess Hidden Holes In The Earthquake Under The Stability Analysis

With the development of base buildings in western loess area, the damages, which induced by the hidden holes, developed in the shallow loess layer on highway engineering facilities become increasingly obvious. The stability of loess hidden holes not only relates to the engineering geology characteristics, but to all kinds of natural conditions and human factors. The great masses of loess areas in our country come within the areas where earthquakes often take place. Considering the influence of earthquake load on loess hidden holes and by using the finite element method, the dynamic response has been analyzed in this paper.Dynamic response of loess hidden holes subject to earthquake can be seen as a hollow hole without any bracing. Firstly, according to the development characteristics of loess hidden holes, the geological models are summarized. And the corresponding geometrical mechanics models are established by integrating to the buried depth of loess hidden holes and the hole's diameter dimension. The bottom of the model is regarded as an imaginary basement rock's surface. Considering the thickness of the loess covering, the model's border is decuple away from it to avoid the summation of the reflected wave. Considering the practical shape of holes, and to seek the regularity of calculation result, the arch with the same width and height is adopted as the cross section of hidden holes. Secondly, by analyzing the dynamic testing results of the primitive loess in Dingxi, the material parameters that used in the dynamic finite element method are given. The sine wave is used in dynamic test. The results evince that the dynamic elastic module become decline but the dynamic stress become rise. The curves of dynamic strain-stress confirm to hyperbola. But the curve of damping ratio is discrete. Finally, using the elastic and plastic dynamic analysis gets the stress, the displacement and the acceleration peak value of the hidden hole's key sections with the influences of earthquake. And then the time interval curves of sectional nodes are given.The two factors, diameter dimension and buried depth of holes, are mainly considered in the course of analysis. The dynamic response of hidden holes with different diameters and buried depths are summarized based on the calculation results. Pursuantly, the collapse mechanism of loess hidden holes with the influence of earthquake can be got. By calculating, we submit the solutions as follows: The soil layers with the same level attitude have the same horizontal peak accelerations, and the hidden holes can make the horizontal peak acceleration bigger. The diameter andburied depth of holes have a minute effect on the sacrificial displacement. When earthquake take place, the stress concentration will appear in the hidden hole's episporium. The stability of hidden holes with small diameter and deep-buried depth is relatively fine. The forfeit of hidden holes subject to earthquake is sporadic.