Study On Action Of Experimental Of Loess Slope Instability Mechanism Under Rig Vibration

Serials landside has taken place in the sandy-loess area of Shanbei oil fields during drilling the oil well in recent years, and it aroused huge loses. The next investigation indicates that the long-time vibration of the oil rig is one of the most important factors. According to this application, the vibration parameters of the rig and the corresponding response over the slope will be carried out at first. Then the dynamic experiments of sandy-loess will be developed on the loess and dynamic stress-strain relationship is expected to be got. Meanwhile, a simulation model considering the vibration of the drilling is to be set up with FLAC3 D software. Next, the model will be used to do simulated calculation of one or two typical landslides of such type. Influence factor analysis and parameter susceptibility will be done as well. The achievement of this project will be good to remedy the dynamic study of loess, especially for the study of loess dynamic characteristic under manmade vibration and the formation mechanism of loess landslide, and it also can be used for selecting oil well site and guiding its construction.The main research results are as follows:1、The loess slope under the action of the oil field drilling rig vibration instability mechanism has been deeply studied, what’s more the paper made a simple summary of the characteristics of the work area of the loess landslide of Shanbei oil field. It shows oilfield drilling machine vibration is also an important factor that contributed to the well work area of the loess landslide,downhill body vibration displacement and pore pressure and liquefaction as its main form under long time and high frequency of the vibration of the rig substructure work.2、The author used dynamic triaxial test of undisturbed loess samples under different confining pressure and different frequency of dynamic loads to research the dynamic strength of loess and the variation regularity of dynamic strain in different depth, different frequencies of vibration under the action of drill. The research shows that the well work area of the loess under the condition of certain dynamic stress dynamic strength and dynamic strain changed regularity as the changing of consolidation stress and vibration frequency.3、Using the finite difference software FLAC3 D numerical simulation of oil field drilling vibration under the action of the mechanism of slope instability. In drilling rig vibration, the action of the slope dynamic responses with the relative position of soil depth and drills a certain regular changes. Saturation loess vibration increases with time, and the increase of pore water pressure is obviously, but it proves the existence of work area of the loess dynamic without "liquefaction" problem.4、The conclusion of rig vibration mechanism of landslide is as follows: under the effect of vibration drilling rig, it causes the damage of unsaturated loess structure and leads to the decrease of the strength, along with the increase of vibration frequency, and the strength of the unsaturated loess decreases gradually. At the same time, the saturated loess area is mainly increase the vibration pore water pressure with time gradually, resulting in a decline of effective stress and leading to the reducing of the soil shear strength. Even in extreme case, the liquefaction and the intensity are completely lose.