Study On The Durability Of Vegetation Restoration Of High And Steep Rock Slopes In Cold Regions

In recent years,in the construction of mountain road projects in cold regions of China,the original mountain structure has been damaged due to the excavation of different degrees of mountains.Change the original ecological vegetation growth system;there are a large number of high and steep slopes that are difficult to restore vegetation.In the process of road construction,a large number of excavation slopes and high filled road base slopes are formed,resulting in prominent problems such as slope protection,vegetation restoration,soil and water conservation and landscape.At present,the main methods of slope protection in highway construction in China are engineering protection and vegetation protection.The engineering protection effect is remarkable,the construction is convenient,the overall slope structure is stable,and there are shortcomings such as poor ecological environment and short service life.Vegetation protection has the advantages of improving greening in the short term,but in the case of high and steep slopes,it cannot meet the environment required for plant growth and is difficult to grow under natural conditions.Based on the field environment,soil,topography,rock sampling and investigation in Yanqing area,the temperature and vegetation damage are analyzed.Combined with the above conditions and the factors that meet the needs of plant growth environment,porous ecological concrete is proposed to be used as a stable substrate for vegetation restoration of high and steep slopes.The vegetation restoration base material for high and steep rock slope in cold region is composed of plant base material and stable base material.Plant base material refers to the soil-ecological binder improved soil for plant growth of high and steep rock slope.Stable base material refers to the concrete material attached to the rock slope-porous ecological concrete.This paper mainly studies the durability of stable base materials.Porous eco-concrete is a new type of eco-concrete which is made of inorganic coarse aggregate with particle size of 20mm-30 mm as skeleton,cement,mineral admixtures,additives and other materials.In this paper,the porous ecological concrete porosity can reach30 %-40 %,28 d compressive strength can reach25 MPa,p H value is stable in9.2-9.8,fully meet the needs of plant growth of acid and alkali environment.In this paper,the mechanical and durability tests of vegetation restoration substrate for high and steep rock slopes in cold regions were carried out.Under low temperature conditions,the influence of porous ecological concrete on oxalic acid resistance,sulfate resistance,freezing and thawing,and carbonation was far greater than that under normal temperature conditions.Moreover,the incorporation of different mineral admixtures had no obvious effect on the durability of porous ecological concrete,but had little effect on the durability of the whole structure of porous ecological concrete.Relatively speaking,by adding different mineral admixtures to ensure the applicable strength range of porous ecological concrete,it can reduce the amount of cement.The effect of adding silica fume is stronger than that of adding mineral powder and fly ash,and the effect is best when the dosage is controlled at about 20 %.The effect of adding fly ash with sulfate resistance,frost resistance and carbonation resistance is stronger than that of adding mineral powder and silica powder,and the effect is the best when the dosage is controlled at about 20 %.Through the study of durability,it provides some theoretical basis and reference samples for the engineering application of porous ecological concrete in cold regions.