The Research Of Buried Depth And Protective Measures Of Pipeline That Passes Through The Debris Flow

With the rapid development of China's oil and gas pipelines,the situation of pipeline crossing debris flow is unavoidable.However,there are no specifications for pipeline design in debris flow areas in China at present and the design process is always based on experience.In view of this,aimed at the special situation of the oil and gas pipeline passing through the diluted debris flow area,the calculation method of the critical buried depth of the pipeline in the debris flow area has been obtained through the theoretical analysis and field test methods.The research results of this paper have certain reference significance for practical projects.The main contents of this paper included that:the determination method of buried depth of pipeline when the pipeline passes through the diluted debris flow;and the protective measures for pipeline crossing debris flow ditch.The main conclusions of this paper are as follows:(1)The debris flow gully bank belongs to cohesive soil or two element structure gully bank.Due to the special structure of the channel and bank,the lateral erosion process of the debris flow gully mainly includes four processes:shore foot digging;the formation of the internal tensile fracture surface;the instability of the gully and the transportation of instable soil;(2)The formation and development of the fracture surface of the soil in the ditch determine the instability model of the bank and the ditch.If the cracks fully developed,it will lead to ditch bank dumping type instability;if the fissure is fully developed,it will lead to the collapse of the soil on the bank of the ditch;if the upper and lower fissures are well connected and form a slip surface,the slump of the soil on the slope will be unstable.