南宁膨胀土边坡植被加强系统的试验研究

发布时间：2018-05-24 06:25

本文选题：膨胀土 + 土壤学　；参考：《广西大学》2014年硕士论文

【摘要】：近年来,广西公路建设发展迅速,公路大量穿过膨胀土地区。同时随着人们环境意识的提高,迫切要求膨胀土边坡在稳定的前提下加强边坡植被恢复。本文的工作为“高性能植被保护垫治理膨胀岩边坡的机理研究”项目的前期工作。主要研究膨胀土边坡上高性能植被保护垫(High Performance Turf Reinforcement Mats, HPTRM)系统下植被的恢复。通过膨胀土的养分测试和膨胀土以及膨胀土覆土上的植被的研究,为膨胀土边坡的植被种植做指导。研究的主要结论如下： (1)从土壤学的角度看,膨胀土属于粘质土,有机质、全氮、速效氮含量低,极度缺乏速效磷,并且都低于广西耕地的平均水平,但是不缺钾；其pH值区别广西大多数的酸性土壤,呈中性或者弱碱性；结构性差,与一般的粘土相比,膨胀土的干容重大,孔隙率小且孔隙中非活性孔多,毛管孔少,透气孔的差异性大,且不利于植被扎根也不能解决土壤的水气矛盾；膨胀土不宜直接种植植被,种植之前应该适当的改良,并且选择抗逆性强的植被混播。 (2) HPTRM强度高,耐久性好,其中绿-HPTRM与三维土工网垫EM5相比同为三维结构且单位面积质量接近,但是其抗拉强度高是EM5抗拉强度10倍以上,抗辐照能力强可以使用超过50年。 (3)在水肥光热等条件相同下得前提下,黑麦草的发芽率不受坡度的影响,但会受到埋藏深度会有影响。在相同的条件下,与EM5相比绿-HPTRM中种植黑麦草的生物量略低,但是基本接近。 (4)将初始含水量为30%四盆相同的膨胀土置于露天48日,盆中中心区域膨胀土的含水量变化：覆土5cm+HPTRM+黑麦草的增加量仅为0.8%,其次是覆土10cm的为4.4%和5cm的为5%,不覆盖土增加最大为6.3%,说明覆土种植能有效抑制膨胀土水分增加。 (5)HPTRM所受的径流剪切力是可以计算,本文提出径流剪切力的计算公式,为冲刷试验提供依据。
[Abstract]:In recent years, the highway construction in Guangxi has been developing rapidly, and the highway has passed through the expansion of the expansive area. At the same time, with the improvement of people's environmental awareness, the expansive soil slope is urgently required to strengthen the restoration of the slope vegetation under the premise of stability. The restoration of vegetation under the high performance vegetation protection pad (High Performance Turf Reinforcement Mats, HPTRM) on expansive soil slope is studied. The vegetation of expansive soil and expansive soil and the vegetation on expansive soil are studied to guide the vegetation planting of expansive soil slope.
The main conclusions of the study are as follows:
(1) from the point of view of soil science, expansive soil belongs to clay soil, organic matter, total nitrogen, low available nitrogen content, extreme lack of available phosphorus, and all lower than the average level of Guangxi arable land, but no potassium deficiency; its pH value is different from most of Guangxi's acid soil, which is neutral or weak alkaline; structural difference, compared with ordinary clay, expansive soil dry It has a large capacity, small porosity and many non active pores in the pores, little holes in the capillary tube and large difference in air permeable holes. It is not good for vegetation to take root and can not solve the contradiction of water and gas in the soil; the expansive soil should not be planted directly, and it should be properly improved before planting, and it should choose the mixed sowing of strong resistance.
(2) HPTRM has high strength and good durability, in which the green -HPTRM is three dimensional structure and the mass of the unit area is close compared with the three-dimensional geotextile EM5, but its tensile strength is more than 10 times more than the tensile strength of EM5, and the strong resistance to radiation can be used for more than 50 years.
(3) under the condition of the same conditions, the germination rate of ryegrass is not affected by the slope, but it will be affected by the depth of the burial. Under the same condition, the biomass of ryegrass growing in green -HPTRM is slightly lower than that of EM5, but it is basically close.
(4) the expansive soil with the same initial water content of 30% four basins was placed in the open air for 48 days, and the water content of the expansive soil in the central region of the basin was changed: the increase of 5cm+HPTRM+ ryegrass was only 0.8%, followed by soil 10cm and 5cm was 5%, and the maximum of no cover soil was 6.3%, indicating that soil planting could effectively inhibit the water increase of expansive soil.
(5) the runoff shear force of HPTRM can be calculated. In this paper, the formula of runoff shear force is put forward to provide basis for scouring test.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.14;U417.1

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