Study On Landslide Disaster Warning Standard Of Oil And Gas Long Distance Pipeline Engineering Between China And Myanmar

With the rapid development of oil and gas pipeline construction, the influences of geological hazards on construction and operations of pipeline become increasingly serious. Due to the characteristics of multi stations, line length, and wide ranges of engineering, long distance oil and gas transmission pipeline almost cross the region which includes almost all types of geological disasters, including mountains, hills, loess, karst developing area. China and Myanmar oil and gas pipelines cross Southwest area, such as Yunnan, Guizhou and Sichuan. The geological and geographical conditions are complex and varied along pipelines. These areas are high-occurrence disaster zone for landslides. During the construction, there are inevitable disasters and harm. Therefore, this paper makes a study on stability of the long distance pipelines along the typical high slope, this study is very meaningful.The common characteristics of the slope in the study are:lateral excavation of high slope, big impact of heavy rain and earthquake. In this paper, the finite element software GTS based on the strength reduction method is chosen to do the reasonable analysis. It gives the general rules of the stability of the slope along the pipelines and plays an auxiliary role in the field monitoring and early warning system. The main contents of the study include:(1) It make the study of the natural and geographical conditions, topography, stratum and lithology, geological structure characteristics of slopes of the China-Myanmar pipelines, analyze of the slope types, distribution, sizes and other characteristics. According to the rock and soil composition, the slopes can be divided into soil slopes and rock-soil mixed slopes; According to the grades of slopes, slopes can be divided into first class slope (15°～19°), second slope (20°～29°) and third slope (30°～35°)。(2) Due to the numerical simulation, this paper makes the research of the stability characteristics of the slope under three kinds of construction conditions, which are nature, excavation and support. Research shows that under the condition of the excavation of horizontal slope is maximum displacement position when the high slope stability changes; Under natural state, the maximum displacement is at the front of the slope whose slope is larger; After excavation, the maximum displacement point transfer to critical surface.(3) Combined with the finite element numerical simulation, this paper analyze the relationship between the control factors of slope deformation damage and the amount of slope deformation. The study found that when the stability coefficient of the rock and soil mixed slope is 1.2, the average value of the corresponding deformation is 5.66mm; When the stability coefficient is 1.0 boundary value, the average value of the deformation is 8.88cm. It can be regarded as the advanced warning discriminant value of ground displacement monitoring system, if the monitoring to the ground surface displacement is more than 8.88cm, the slope should be judged to be nearly damaged, should be timely treatment.(4) Through the analysis of the heavy rain and earthquake conditions characteristic of the slope stability, it indicates that, when first slope K=1, the withstand earthquake acceleration average value is 0.3g:When second slope K=2, the withstand earthquake acceleration average value is 0.08g; When second slope K=3, the withstand earthquake acceleration average value is 0.038g. The safety factor is calculated under different water level, and the field can be monitored by the water level line to determine the stability of the slope.