Research on Harms and Prevention Treatments of Permafrost for Petroleum Pipeline

摘要

By means of analysis of distributing features of frozen soil in high and cold region in northeast of our country, the frozen soil along the line from north to south can be divided into discontinuous permafrost, large pieces of segregated frozen ground, odd pieces of segregated frozen ground and seasonally frozen ground. The relationship between larch woods and frozen soil is intimate and the ill larches distribute in flowage or swap section of permafrost region. The great challenges of permafrost for petroleum pipeline are frost heaving and thaw collapse. Frost heaving and thaw collapse may cause piping bending, fracturing, offsetting and lead piping losing effectiveness. On the basic of now available data of geology, hydrogeology and engineering geology, distribution range, type, scale and destructiveness of harmful geology phenomenon were found out. Referring to ubiquitous and harmful geology phenomenon along China Russia petroleum pipeline project, prevention treatment for piping construction in permafrost district was proposed and science criteria for pipe construction in high and cold region was provided. Firstly, the rout selection rule of pipeline in frozen soil include avoiding going through frozen soil with adverse geologic phenomena, locating at upper part of gentle slope in mountain area and optimizing pipeline means in river crossing or intermont. Secondly, the pipeline means were selected from conventional underground laying, particular underground laying and overhead laying or pipe embankment. It was necessary to pay attention to heat preservation, padding, pipe wall upsetting and stabilizing backbone. Thirdly, it was important to abate the damage of ground vegetation and protects ecologic environment of the line along petroleum pipe line.