| The Dujiangyan to Siguniangshan Mountain Rail Transit Project is a major project in our province.The route passes through Dujiangyan City in Chengdu and Wenchuan County,Wolong Special Administrative Region and Xiaojin County of Aba Tibetan and Qiang Autonomous Prefecture.The social and economic development along the line is weak.The whole route has Dujiangyan(Qingcheng Mountain),Yingxiu Ancient Town,Wolong Nature Reserve,Siguniang Mountain and many other scenic spots.The ecological environment along the route is easily affected.The construction of the track line will inevitably carry out slope excavation,affect the stability of the slope,and destroy the ecological environment of the slope.Therefore,it is necessary to carry out research on the integration technology of slope ecology and geotechnical engineering protection.Aiming at the slopes in the study area,carry out field surveys of slope characteristics and plant resources,and conduct slope vegetation selection and configuration research based on analytic hierarchy process;On the basis of existing geotechnical engineering protection technology and ecological protection technology,carry out research on slope ecological-geotechnical fusion technology;A comprehensive ecological-geotechnical protection system for slopes in ecologically sensitive areas is proposed to provide a reference for slope protection along the Dujiangyan-Siguniangshan Railway.Through research,the main achievements and understanding of the following aspects are obtained:(1)The author investigated the plant resources of the slope along the Dujiangyan-Siguniangshan Railway,analyzed the composition and structure of vegetation communities along the line,and provided a basis for the selection and configuration of vegetation in the study area.Then we conducted a detailed investigation of the slopes along the line,and analyzed the characteristics of different types of slopes(soily slope,rocky slope,and soil-rock mixed slope)in the study area.It has laid the foundation for the study of the slope-eco-engineering comprehensive protection system.(2)This paper establishes the vegetation selection database and vegetation configuration model of the slope vegetation along the Dujiangyan-Siguniangshan Railway.Based on the investigation of native plants,we consider geographic and climatic zoning,add plant types with good performance indicators,and establish a preliminary selection library of vegetation.We use analytic hierarchy process to select vegetation types,taking into account vegetation protection index(plant growth rate,root soil fixing ability),adaptability index(native,barren,drought tolerance,heat resistance,cold resistance and Resistance to diseases and insect pests),ecological indicators(length of green period,beauty of branches and leaves,and coverage of branches and leaves)and economic indicators(unit price of plants and cultivation costs),a judgment matrix was established to comprehensively sort the vegetation types in the primary vegetation selection library,And finally selected the top ranked suitable plants.Then,based on the results of AHP vegetation selection,the vegetation allocation model in the study area was proposed.The model includes the combination of trees,shrubs,herbs,and vines,the target plant and pioneer plant collocation mode,and the Gramineae and legume plant collocation mode.(3)On the basis of the existing slope geotechnical engineering protection technology and ecological protection technology,a study on the slope ecological-geotechnical engineering fusion technology.It can not only ensure the stability of the slope,but also achieve ecological restoration.1)A technology of ecological geocell slope protection is proposed.Through the indoor slope erosion test,the influence of geocell shape on its erosion resistance was analyzed.The results show that in the shape of diamond,square and hexagonal cells,the hexagonal cells have the best anti-erosion performance.Combining hexagonal geocells,wavy geocell sheets,geotextiles and expenditure inserts to form an ecological geocell,it increases the erosion resistance of slopes,is beneficial to plant growth and is suitable for general soil slopes.2)A technology of reinforcing the slope with ecological anchor retaining wall is proposed.This article uses Geo-Studio finite element software to establish a model of ecological anchor retaining wall slope protection,The software simulation compares the characteristics of stability coefficient,displacement,stress and other characteristics of the unsupported slope and the ecological anchor retaining wall supporting slope.The results show that the ecological anchor retaining wall can effectively reinforce the slope.3)A technology of ecological active net reinforcement slope is proposed.Combining the active slope protection net and JYC ecological base material to form an ecological active net,the feasibility analysis shows that this technology can not only ensure the stability of the slope,but also solve the problem that the vegetation is difficult to attach to the rock slope,The protection technology is suitable for high and steep rock slopes and collapsed rock slopes.(4)Based on the above research results on vegetation selection,vegetation configuration,and ecological and geotechnical engineering integration technology,this paper discusses the design principles and technical points of slope ecological-geotechnical protection.Then this paper proposes the corresponding slope ecological-geotechnical engineering comprehensive protection system for the soil slope,rock slope,soil-rock mixed slope and special road section slope in the study area.Finally,this paper selected the typical slope of the third section of Dujiangyan-Siguniangshan Railway for detailed ecological-geotechnical comprehensive protection design.It provides suggestions for the slope protection along the Dujiangyan to Siguniang Mountain Railway,and also provides some scientific basis for the combination of ecological protection and engineering protection in ecologically sensitive areas. |
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