城市岩质边坡生态防护机理及试验

Bio-engineering protection mechanism of city rock slope and its laboratory test

针对边坡生态防护工程特点,探讨城市岩质边坡的生态防护机理、植物与边坡的力学效应、植物根系加固边坡作用机理,并由此建立相应的力学模型,提出根系-土复合抗剪强度公式。研究植物对边坡降雨截留、径流延滞、土壤防渗、土层固结等效应,并探讨生态防护对边坡的抗冲刷机理。在此基础上,设计并完成城市岩质边坡生态防护室内模型试验,研究不同草种、不同坡度、不同固土方式等情况下的工作特性。将本文方法应用于某城市岩质边坡生态防护工程,获得百喜草、高羊茅和百慕达3种草在不同坡角(38°,48°和58°)与固土结构(菱形铁丝网、土工格室、三维网垫)时的抗冲刷特性。研究结果表明:土工格室的固土效果最优,其次是三维网垫和菱形铁丝网;单位面积的冲刷强度存在一个临界角度值,为25°左右;百慕达的固土效果优于百喜草和高羊茅的固土效果。

Based on the features of rock slope bio-engineering protection, the ecology protection mechanism of the urban rock slope was discussed with the mechanics effect of plants and rock slope, and the reinforcement action mechanism of rock slope by plant root system was analyzed as well. Then, the corresponding mechanical model was proposed, from which the formula to calculate the increased shearing strength of the root system-earth compound body was derived. And the side slope rainfall interception, the runoff lagging, the soil anti-seepage and soil layer consolidating effect were studied respectively. Furthermore, the indoor model experiment of urban crag rock slope ecology protection was designed and completed, in which various grasses to plant in slope with different angles, solid earth form. s, and the different strengthening earth mechanisms were studied. Finally, the present method was applied in an engineering projects, from which the anti-washing behavior of three kind of grasses （i.e., the Bahiagrass, the tall fescue and the Bermudagrass） planted in the slope with an angle of 38°, 48° and 58° respectively and different strengthening structures （i.e., the diamond wire netting, the geocell and the three-dimensional network） were obtained. The application results also show that, the effect of geocell structure is the best one followed by the three-dimensional net and the diamond wire net. The anti-washing capability per unit area exists a critical slope angle of about 25°. The reinforcing effect of Bermudagrass is better than those of the Bahiagrass and tall fescue.