| Soil and water conservation monitoring of slag dump is the focus of soil and water conservation in production and construction projects.In order to improve the comprehensive efficiency of waste residue field monitoring,taking into account the cost and soil and water conservation effect,this study takes Chihuang railway project as an example,obtains digital surface model(DSM)and digital orthophoto map(DOM)data through UAV aerial survey and remote sensing technology,and carries out research and discussion from three aspects of waste residue field monitoring process,data processing after monitoring and construction suggestions.The optimal flight schemes of different types of slag dumps are studied by calculating the accuracy of earthwork variation and the flight time of aerial photography through the two-stage DSM.The DOM image monitoring value was compared with the RTK measured value to explore its applicability in the calculation of disturbance area of waste residue field in Chihuang railway project.Object-oriented classification technology was used to classify the waste dumps and calculate the area of each category,and the method was optimized according to the DOM image characteristics of waste dumps.Based on DSM and DOM images combined with Arc GIS hydrological analysis tool,a method for extracting channels by river network classification for DSM was explored,and then the corresponding temporary measures were laid on DOM,and the effect of measures was tested by soil loss.The application research of UAV remote sensing technology in slag field monitoring has guiding significance for slag field monitoring.The main results of this paper are as follows :(1)There are significant differences in the selection of the optimal flight scheme in different types and sizes of spoil fields.The difference of flight parameters is mainly reflected in the altitude and the pitch angle of the cloud platform.The types of waste slag fields in Chi-Huang railway project are flat type,slope type and channel type.According to the specific conditions of the project,they are subdivided into large and small waste slag fields in flat area,0-15°large and small waste slag fields in slope area,15-30°large and small waste slag fields in slope area,large and small waste slag fields in channel-shun ditch and large and small waste slag fields in channel-blocking ditch,with a total of 10 types of waste slag fields.In terms of the selection of overlap degree,in addition to 70 %of the course overlap and 60 % of the side overlap of the large slag field of the channel-gully,the other nine types of slag field are 80 % / 60 %;at the altitude,the slag fields of small flat,small slope 15-30°,small gully-shun gully and small gully-blocking gully are 80 m,the slag fields of large slope 0-15°and large gully-shun gully are 120 m,and the slag fields of large flat,large slope 0-15 °,large slope 15-30 ° and large gully-blocking gully are 160 m;in the elevation angle of the cloud platform,in addition to the large flat,15-30°small ditch-shun ditch small slag field of 45°,the other seven types are 60°.(2)The accuracy of calculating the disturbed area of waste residue field based on DOM image is high,and the classification effect of random forest classification method is the best,which is suitable for the classification and area calculation of waste residue field.According to the calculation results of the disturbance area of JC4 #,YT3 # and HC7 #slag abandonment fields of Chi-Huang Railway,the errors between the disturbance area values monitored by DOM images and the RTK measured values are-2.11%,-15.6% and1.81%,respectively,with small errors.It is feasible to calculate the disturbance area of slag abandonment fields based on DOM images.Select the typical waste residue field XD16 #,use KNN,SVM and random forest object-oriented classification in e Cognition software platform.The overall accuracy was 85.15%,85.80% and 87.46%,and Kappa coefficients were 0.80,0.81 and 0.84,respectively.Among them,the random forest classification method had the best classification effect.(3)Temporary measures based on DSM and DOM images are designed to reduce the amount of cover and drainage ditches,increase the amount of blocking measures,and effectively reduce soil loss.The main difference between the soil slag field and the stone slag field is that the cover and the drainage ditch can be laid inside the soil slag field,while the cover and the drainage ditch are generally not laid inside the stone slag field.According to the DSM and DOM river network classification method,the design of temporary measures is compared with the soil and water conservation scheme,the maximum reduction of 92.35% of the cover,the maximum reduction of 57.54% of the drainage ditch,according to the specific situation of the project,blocking measures than soil and water conservation scheme design quantity increased by 3-10 times.Taking the completed slag field as the experimental site,the corresponding temporary measures were laid,and the calculated soil loss was reduced by 29.81 % compared with the predicted value of the ’ Guidelines for the calculation of soil loss in production and construction projects ’(SL773-2018).It is feasible to control soil erosion. |
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