Design And Benefit Analysis Of Soil And Water Conservation Measures For Long Distance Natural Gas Pipeline Project In Southwest Shanxi

China is one of the countries with the most serious soil erosion in the world.With the development of economy,the human-made soil erosion induced by development and construction projects is becoming more and more serious,which directly threatens the national ecological security,and restricts the development of social economy.Therefore,the prevention and control of soil erosion induced by development and construction projects is an important problem to be solved urgently.This study systematically expounds the research status of soil erosion prediction and prevention at home and abroad.Taking gas transmission pipeline project in southwestern Shanxi as an example,according to the requirements of"Standards for Soil and Water Loss Prevention and Control of Development and Construction Projects","Law of the People’s Republic of China on Soil and Water Conservation","Technical Specification for Soil and Water Conservation of Development and Construction Projects"(GB50433-2008),the construction procedure and process of gas transmission pipeline and the site conditions of pipeline laying area,the influence of geomorphological disturbance and different construction techniques on soil erosion is analyzed,and the area of soil erosion prevention and control is divided.On this basis,the types and periods of disturbed land in the process of development and construction of long-distance pipeline project are analyzed,and the prediction of soil and water loss is carried out.The comprehensive design of soil and water conservation measures was carried out.Finally,the comprehensive benefits were analyzed.The main conclusions are as follows:(1)According to the construction procedure and process of gas pipeline,as well as the influence of geomorphological disturbance and different construction techniques on soil and water loss,the prevention and control of soil and water loss is divided into four areas,namely,the prevention and control zone of pipeline operation zone,the prevention and control zone of crossing engineering,the prevention and control zone of waste disposal area and the prevention and control zone of road engineering.(2)In the gas pipeline project in Southwest Shanxi,the area of soil erosion caused by disturbance and damage of original landform is 128.51 hm~2,and the total amount of soil erosion is predicted to be 41400 tons.Among them,the total amount of soil erosion predicted by original landform is 31900 tons,and the total amount of newly increased soil erosion is predicted to be 9500 tons.The total amount of newly increased soil erosion in the construction period and in the natural recovery period is predicted to be 4500 tons and 5000tons.(3)For gas pipeline construction characteristics of soil and water loss,according to the regulation of"Standards for Soil and Water Loss Prevention and Control of Development and Construction Projects",the soil and water loss prevention and control standards for the design level year of soil and water conservation of this project are determined as follows:the treatment percentage of disturbed land is 96%,the general control degree of soil erosion is96%,the control ratio of soil erosion is 0.7,the stopped slag rate is 90%,the vegetation restoration rate of forest and grass is 97%,and the coverage rate of forest and grass is 25%.(4)After adopting engineering measures,biological measures and temporary measures for soil and water conservation,the treatment percentage of disturbed land achieved 99.00%,the general control degree of soil erosion will reach 97.02%,the stopped slag rate will reach96.00%,the soil erosion modulus of this project area can reach about 1250t/km~2·a,and the control ratio of soil erosion can reach 0.80.Within the scope of project prevention and control responsibilities,the project construction area is 128.51hm~2,the plant measure area was 72.13hm~2,the vegetation restoration rate of forest and grass was 96.58%and the vegetation coverage rate of soil erosion control was 58.11%.Therefore,the soil and water conservation measures of this project can meet the requirements of the Standards for Soil and Water Loss Prevention and Control of Development and Construction Projects.