Optimization And Establishment Of Soil And Water Conservation Measures System For An Expressway Slag Dump In Jinshajiang Dry-hot Valley

The serious soil and water loss caused by expressway slag dump is one of the causes of ecological environment deterioration in the dry-hot valley of Jinsha River.Although there have been a lot of studies on the water conservation measures of the slag dump site,there are few reports on the optimization of water conservation measures for the slag dump site in the dry and hot valley of jinsha River where rain and heat coincide,spot rainstorm is concentrated and vegetation is scarce.Based on this,a highway in southern sichuan jinsha river dry-hot valleys abandon slag field as the research object,to the local climate,soil,vegetation and terrain conditions,such as the foundation,choosing slope type and channel type two kinds of typical abandon slag field in two aspects of measures(the actual construction measures,soil conservation scheme design measures)of the comparison and analysis,the control effect and economic benefit of soil and water loss,Optimize and establish the soil and water conservation measure system of the expressway slag dump.It provides theoretical basis and technical support for soil and water conservation design of slag disposal site in dry-hot valley of Jinsha River.The main research results are as follows:(1)optimization and establishment of the expressway slag dump measures system:(1)for slope type slag dump,in terms of engineering measures,the slag retaining wall was optimized,a vertical gravity concrete slag retaining wall was redesigned,and the stone cage slope protection was added to prevent and control soil erosion;In the aspect of temporary measures,added topsoil protection measures,and calculated the required amount of work;In terms of plant measures,the soil and water conservation plants suitable for the slag disposal site in the dry-hot valley of the Jinsha River were determined through a comprehensive study of their native properties,adaptability,stress resistance and biological characteristics,and their seeding methods were designed in detail.(2)For ditch-type slag disposal site,water conservation measures of slope type slag disposal site are applicable to ditch-type slag disposal site.In addition,ditch-type slag disposal site needs more water conservation measures.In terms of engineering measures,ditch-type slag disposal site also needs to set up blind ditches.Temporary measures,ditch type slag dump site also need to add construction access road;In terms of plant measures,the planted plants are slightly different from the sloping slag disposal site.(2)Compared with the water conservation measure system designed by water conservation scheme,the amount of soil and water loss is reduced by 25.3%;Soil erosion control increased by 3%;Soil loss control ratio increased by 0.15.The rate of soil protection increased by 2%;Topsoil protection increased by 4%;The recovery rate of forest and grass vegetation increased by 4%;Forest and grass coverage increased by 12.5%.Compared with the water conservation measure system of the slag disposal site after optimization,the amount of soil and water loss decreased by 37.3%.Soil erosion control increased by 8%;Soil loss control ratio increased by 0.38;The rate of soil protection increased by 2%;The rate of topsoil protection increased by 42%;The vegetation restoration rate of forest and grass increased by 11% and the coverage rate of forest and grass increased by 23.7%.(3)Compared with the water conservation measure system designed by water conservation scheme,the economic benefit of the optimized water conservation measure system is increased by 20.5%;Compared with the actual construction,the economic benefit increased by 83.9%.