Study Of The Stability Of The Vegetation Matrix Mainly Using Iron Tailings

Open-air mining slope ecological reconstruction is one of the major technical problems faced by mineral resource development and environmental protection as well as restoration. The systematic study of the Plant Growing Medium Spraying Technology has important scientific significance and practical significance on the systematic explanation of the rock- matrix- plant ’s protective effects and engineering applications.Focused on the interaction mechanical effects of slope rock- matrix- plant, and applying the method of combining theoretical analysis and experimental research and numerical simulation, the thesis has conducted ratio-matching of vegetation growing substrate, physical and mechanical tests of root- substrate composite system, water resistance test and numerical simulation research of overall stability of substrate–slope. 1) Conducting selective preference of cement varieties according to influence of different cement varieties after hydration reaction on p H value of vegetation growing substrate; selecting sulfur aluminate cement as the cementitious material of plant growing medium preparation. 2) Selecting tall fescue, adsurgens as slope-protecting plants; taking diameter, length and quantity of root system as variables for researching the maximum stretching resistance and tensile strength, and researching tensile performance of root system through measuring tensile force and cross-sectional area. The maximum tensile strength of adsurgens Root is greater than that of the festuca chine department of the same length. 3) Taking the cement, PH adjusting agents and straw as the variables of studying the compressive strength and the shear strength of the root- matrix composite body; analyzing the influence of those variables on the root- matrix composite body strength through orthogonal test and finally making conclusion that the amount of cement admixture has the greatest impact on the strength. 4) Taking the rainfall intensity and the rainfall duration as variables, measuring the erosion amount and runoff volume of each time, and researching rain anti-erosion performance of vegetation growing substrate from the two aspects of rainfall infiltration and rainfall erosion. With the increase of the amount of iron tailings in preparation plant growing medium, the erosion of plant growing medium will gradually decrease and its runoff will gradually increase. 5) Conducting numerical simulation of the above data using PLAXIS software, and researching influential rules of vegetation and non-vegetation, vegetation density, slope and saturation on displacement and variation of stresses of vegetation growing substrate. With the decrease of the root’s density, the increase of the slope and the saturation, the entire stability of the matrix- slope will be reduced.This study has shown that spraying plant growing medium composed by the iron tailings, cement, p H adjusting agent, straw and other materials as raw materials on the bare rock slope can achieve the effect of ecological management.