Law Of Reclaimed Soil Moisture Movement Under Backfilling Of Massive Waste Rocks In The Northern Foot Of Tianshan Mountains

The northern foot of the Tianshan Mountains in Xinjiang is one of the key development and construction areas under the national “One Belt,One Road”initiative.This area is rich in mineral resources and has a fragile ecological environment.The relatively barren ecological environment is even worse.The ecological governance after mining-mine geological environmental protection and land reclamation research has been mostly aimed at coal mines in recent years.For open-pit metal and non-metallic mines There is research.Therefore,during the implementation of the 13 th Five-Year Plan,the green water and green mountains are the golden mountains and the silver mountains.Most of the mine reclamation is implemented based on experience,which obviously wastes the corresponding water and land resources,and the quality of the reclamation And the effect is relatively general,it is particularly important to study the thickness of the reclaimed soil layer and the amount of irrigation water.To this end,this paper takes the northern foot of the Tianshan Mountains as the experimental research area,and specifically selects a representative site—Changji as the experimental research area.Through the mine sampling in this area,under the simulation research of field in-situ experiments and indoor soil column experiments,The changes in the physical properties of the reconstituted soil before and after compaction and one-year management and protection period were analyzed,and the law of water movement in the reclaimed soil was studied.In 4 sets of control experiments,the water movement under different conditions was explained.The relationship between water migration in the soil and the thickness of the overburden and the amount of irrigation was compared and analyzed.The main conclusions of this thesis are:(1)The soil change rate of the reconstructed soil before and after compaction is the largest at the surface 10 cm.As the depth of the soil layer deepens,the effect of compaction is attenuated.The greater the thickness of the overlying soil,the weaker the compaction effect at the depth of 10 cm.This is because the 30 cm thick soil layer is relatively thin.During compaction,the underlying waste rock has a reaction force on the soil layer.After one year of maintenance,the 10 cm area of the soil changes the most,due to watering and Evaporation makes the surface soil harden,the soil density becomes larger,and the porosity becomes lower.The soil layer at a depth of 30 cm has a small change rate.The porosity change in the soil after 50 cm compaction is only 0.01,which can explain Compaction and uncompaction mainly affect the relatively thin soil layer,and the depth of the soil layer that is mainly affected is 10 cm.The effect on the surface layer is more obvious after pipe protection.(2)On the basis of indoor experiments,the relevant laws of water migration are summarized.After the first irrigation,the soil moisture infiltration depth only reaches10 cm.After the second and third irrigations,the moisture can infiltrate to 30 cm.,The depth changes at 40 cm and 50 cm have a slight impact.After watering,the overall water content in the soil first increases to reach the peak,and then decreases slowly and tends to be gentle.After watering,the soil water holding capacity is 30 cm.It is not good,it is easy to lose water,and the water seeps in the underlying waste rock;the larger watering volume at a depth of 30 cm is better than the less watering volume,and it has a better effect on mine reclamation and planting vegetation.(3)Use the Hydrus-1D software to establish a numerical simulation model of the soil moisture migration.Based on the 40-day data of actual monitoring,the soil hydraulic parameters module of different depths is used to adjust the soil hydraulic parameters to establish different buried The curve of the change of deep water content and the number of days,the results show that the model simulated by the software can better complete the curve fitting,and the fitted curve has a high degree of consistency with the actual value.The overall response of the soil moisture content is relatively good,but it is consistent with the actual monitoring There is a certain gap between the values,which is normal.(4)After the simulation is established,carry out the forecast of the plan.It can be seen that when the amount of irrigation is small,the water can only penetrate into the soil layer with the thickness of 30 cm,but as the amount of irrigation increases,the moisture of 30 cm of the soil is easy to be covered.Continue to infiltrate the waste rock,causing water loss.On the contrary,when the thickness of the overburden is50 cm,the water content in the soil is stable when the amount of irrigation is 4-5 times,and the water is mainly stored at 30-40 cm.Vegetation vegetation with a root depth of40-50 cm grows well.