Root Distribution Of Five Typical Plants In South Sichuan And Their Influence On Gas Pipeline 3PE Coating

The petroleum piping have been connecting the resources at upstream and users of downstream as a carrier for oil and gas.There are already millions of kilometers of piping in working all around the world until now.However,the oil pipeline is buried in the soil black box medium,so that the plants root have damaged effets on soil piping3PE coating such as penetration and extrusion,especially the growth of perennial arbor roots with strong penetrating and squeezing forces.Pinus massoniana,Cinnamomum camphora,Cunninghamia lanceolata,Ficus virens Ait.var.sublanceolata,and Phyllostachys pubescens will be the research objects which are widely distributed in southern Sichuan in this study.The distribution of five typical plant roots in southern Sichuan was investigated with the method that typical sample selection.The root vertical distribution model,horizontal root distribution model,and root penetration of five typical plants in south Sichuan were fitted by the micro root canal method,earth pressure gauge method.And comprehensive evaluation of the impact of five kinds of plant roots on the oil pipeline 3PE anti-corrosion layer at the same time.The main ideas are as follows:(1)According to the vertical distribution characteristics of root biomass of five typical plants in South Sichuan,the vertical distribution model Y=1-?d constructed by Gale et al.A vertical distribution model of five typical plant roots was constructed:Toon:Y=1-0.9846d(R~2=0.9843)Huang Geshu:Y=1-0.8013d(R~2=0.9310)Fir:Y=1-0.9473d(R~2=0.9669)Masson pine:Y=1-0.9562d(R~2=0.8572)Bamboo:Y=1-0.9794d(R~2=0.9503)(2)Based on the horizontal distribution characteristics of root biomass of five typical plants in southern Sichuan,the root biomass-horizontal distance models of five typical horizontal root systems were constructed:y=ax~2+bx+cThe fitting accuracy is above 0.8,indicating that the quadratic function model is well fitted and can be used as a prediction of the horizontal distribution of the five plant root systems.(3)Fit the Root Penetration-Root Apex Diameter Regression Model of Five Typical Plants in Southern Sichuan:y=-ax~2+bxThe fitting accuracy is above 0.9,indicating that the quadratic function model is well-fitted and can be used to predict the maximum penetration force of five typical plant root systems.(4)Fit the root squeeze-force-time model,root compression force-root biomass model,root compression force-root diameter model of five typical plants in southern Sichuan,and the root compression force-time model fits The highest degree,all greater than 0.97,can be used to predict the month when the root compression force reaches its maximum value.We have investigated the root distribution of five typical plants in southern Sichuan,and constructed root penetration models and root compression models for five typical plants,predicted the month that maximum root penetration and maximum root extrusion in five typical plants..However,the phenomenon that five typical plant roots penetrated the 3PE anticorrosion layer of the oil pipeline not be observed.five kinds of typical plants have squeezed 3PE anticorrosion layer of oil pipelineand,but there was no occurrence of deformation of the 3PE anticorrosion layer.The growth of plant roots will be rotational bending after they touched the 3PE material.The relationship between the root biomass of five plants and the vertical/horizontal distance(y=1-?~d?y=ax~2+bx+c)and the relationship between plant crown and root level distribution(y=ax+b)were obtained by field investigation and laboratory simulation.The main effect is the mechanical destruction mainly by extrusion and penetration in the process of root growth.The penetration is at least 9.67 MPa(the model is 13.28 MPa,the bamboo is 22.72 MPa),the maximum pressure is 9.44 kPa,and the maximum pressure of the surrounding soil to the pipe is 896.69 kPa.Therefore,it is suggested that the deep root plants of Cunninghamia lanceolata,Cinnamomum camphora and Pinus massoniana have potential threats in the 5m range on both sides of the central line of the gas pipeline.In addition,the root level of the plants of Huang Geshu and Nan bamboo is more than 5m,which should be considered as a potential threat to the gas pipeline.