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Potential Hazard Assessment Of Dam Failure Mudflow In Land Creation Projects In The Lanzhou

Posted on:2021-01-06Degree:MasterType:Thesis
Country:ChinaCandidate:B B YanFull Text:PDF
GTID:2370330611952048Subject:Geological Resources and Geological Engineering
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The development of the country is inseparable from urbanization,but for mountainous and valley cities,they lack urbanized land resources.China 's Lanzhou is such a valley city,and its shortage of urban land resources has limited economic development.Since 2000,the land creation campaign started in Lanzhou.At the same time,hidden dangers of geological and geological disasters have also appeared.The history of the land creation project in the world is very short,and there is little research in this area.Therefore,it is very meaningful that scientific research on the land creation project helps to ensure urban safety,and these studies can provide references for similar projects.This article studies the land creation project in Lanzhou.In order to study the type,distribution,regularity and scale of the land creation project in Lanzhou,many research methods are used in this research,such as data collection,field investigation,laboratory testing,remote sensing imaging technology and numerical simulation analysis.In this process,we discovered and studied a rapid loess mudflow triggered by the check dam failure in a land creation project.Finally,the LAHARZ program was used and modified based on previous research results.This study used the LAHARZ program to simulate 93 mudslides in Lanzhou and obtained the research results,it can be used to analyze the impact of the land creation project in Lanzhou.The construction methods of land creation projects have produced different project types.These types can be divided into three types,removing the mountain top,cutting one side slope,and cutting both side slopes.They have different proportions in different scales of land creation projects,but they can evolve and change.The development of the land creation project in Lanzhou has gone through four stages so far.For the land creation project in Lanzhou,between 2000 and 2005 was the initial stage,between 2005 and 2010 was the rising stage,between 2010 and 2015 was the heyday,and between 2015 and 2020 is the declining phase.At the same time,the changes in the area and the volume of excavation and filling of the Lanzhou construction project over time also showed the same law.A rapid loess mudflow triggered by the check dam failure in in Lanzhou City is caused by comprehensive reasons such as construction measures,dam construction technology,and inherent geological weaknesses.The VS2 DI simulation of the check dam showed that the use of high-pressure water guns in the project and the underlying strata of impervious granite have caused groundwater in the fill area to stagnate.At the same time,the loess dam,which is susceptible to erosion by water flow,has not been designed with drainage facilities,which eventually led to the collapse of the dam and resulted in mudflow chain disasters.Therefore,in this type of project,some highly plastic materials should be used for waterproofing the dam core,and drainage measures should also be designed.In addition,the width of the gully and the slope of the terrain have a significant effect on the movement and sedimentation of the mudflow.Land creation projects can already be seen everywhere on the Loess Plateau,landfill dams or check dams had helped these projects to solve some difficult problems,and also brought urban geological disaster risks.Dams failure can cause landslides and mudslides.In this article,the potential mudflow hazards area of 93 projects in Lanzhou were simulated using the modified LAHARZ program.The simulation results show that Lanzhou and Gaolan County are greatly threatened by mudslides because they are lower-lying river valley cities.Lanzhou New District produced different results because of its higher terrain.There are also certain construction projects in other areas,but there are fewer people and buildings in the area,so there is less threat to the life and property of the population.In addition,the analysis results of the movement distance characteristics of the landfill dam breaks can provide a reference for the corresponding disaster hazard analysis.
Keywords/Search Tags:Land Creation Project, Landfill Dam, Dam Failure, Mudflow, Mudflow Deposition Range, Potential Hazard Assessment
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