高海拔严寒地区石马公路边坡植被防护研究

发布时间：2019-01-01 09:50

【摘要】：近年来,随着我国西部大开发战略的实施,在公路、铁路、水电等工程建设中,往往需要开挖大量的边坡,边坡的开挖不仅破坏了原有的植被和浅表部覆盖层,而且导致大量的次生裸地和严重的水土流失,尤其在高海拔严寒地区更加剧了植被生态系统的退化。对于高海拔严寒地区边坡的植被恢复,国内还研究较少。因此,如何快速恢复高海拔严寒地区公路开挖边坡的植被生态环境并实现坡面保护是一个亟需研究和解决的课题。本文以石渠至马尼干戈公路开挖边坡为研究对象,以岩土工程、植被学、土壤学、环境工程等学科为指导,采用现场调研和室内试验的方法,对高海拔严寒地区的土壤特性和适应基材进行研究,通过种植试验选取适宜草种,利用数值软件模拟植物根系与岩土体相互作用关系,并从工程地质、边坡稳定、环境工程三个方面对高海拔严寒地区的公路边坡进行植被恢复设计,主要获得了以下研究成果： 1)通过现场调研和室内试验,阐明了石马公路的土壤特性,并由种植试验提出了高海拔严寒地区边坡植被防护的“草-灌”结合的建植模式,为该公路的植被恢复提供了科学依据。 2)通过植被护坡理论分析得出：植物对边坡稳定性有影响,通过茎叶降雨截留,通过根系对土体进行加固。草本植物主要是通过根系对土体进行加筋作用,土体的含根量越多,土的抗剪强度越大,承载能力越高；木本植物主要通过垂直根系与水平根系对土体进行锚固、摩擦作用,主根类似全长粘结型锚杆,将土体下滑推力传递到深层,并将所受的力传递到侧根,通过侧根与土体的摩擦阻力,平衡下滑土体的推力,进而对边坡稳定性起作用。 3)通过建立4种计算模型,采用数值模拟方法探讨了植被护坡的机理和效果。模拟结果表明,草本植物的根系与岩土体的相互作用是由于土壤中存在植物根系,边坡表土层与根系成为根-土复合体,增加了土体的粘聚力和周边应力,改变了浅层土体的应力应变状态,土体中的应力水平降低,限制了浅层土体的侧向位移,草本植物根系能明显增大边坡表层土体的抗剪强度,增加边坡的安全系数,边坡稳定性得到提高。木本根系的固土作用主要通过主根系将表层土体的应力传递到土体深层,并对深层土体进行锚固,与锚固理论一致,将锚固理论运用到根系的固土机理分析中是可行的。 4)植物根系的固土效应主要体现在对边坡浅层产生作用,对深层的土体效果不明显。“草-灌”结合的护坡方式对提高边坡稳定性最强,草本植物护坡的方式次之,只有木本植物护坡的效果最差。 5)通过对石马路典型的土质边坡和岩质边坡进行植被恢复设计,提出相应的施工方法。湿式喷播技术和绿化基材喷射技术能够对石马公路的土质边坡及岩质边坡起到较好的防护作用,是适用于高海拔严寒地区公路边坡的植被防护技术。
[Abstract]:In recent years, with the implementation of the strategy of western development in our country, in the construction of highway, railway, hydropower and other projects, a large number of slopes are often required to be excavated. The excavation of the slope not only destroys the original vegetation and shallow overburden. It also leads to a large number of secondary bare land and serious soil erosion, especially in high altitude cold areas, which aggravate the degradation of vegetation ecosystem. There are few researches on vegetation restoration of slope in high altitude cold area. Therefore, how to quickly restore the vegetation ecological environment of highway excavation slope in high altitude cold area and realize slope protection is an urgent task to be studied and solved. In this paper, the excavation slope of the Shiqu to Manigango highway is taken as the research object, the geotechnical engineering, vegetation science, soil science, environmental engineering and other disciplines are taken as the guidance, and the methods of field investigation and indoor test are adopted. The soil characteristics and adaptive substrates in high altitude cold area were studied. The suitable grass species were selected through planting experiment. The interaction between plant root system and rock and soil was simulated by numerical software, and the slope was stable from engineering geology. The vegetation restoration design of highway slope in high altitude cold area is carried out in three aspects of environmental engineering. The main research results are as follows: 1) through field investigation and indoor test, the soil characteristics of Shima highway are expounded. Based on the planting experiment, the "grass irrigation" combined planting model of slope vegetation protection in high altitude cold area is put forward, which provides a scientific basis for the vegetation restoration of the highway. 2) through the theoretical analysis of vegetation slope protection, it is concluded that plants have an effect on slope stability, and the soil is strengthened by stem and leaf rainfall, and soil is strengthened by root system. Herbaceous plants mainly strengthen the soil through the root system, the more the soil root content, the greater the shear strength of the soil, the higher the bearing capacity; Woody plants anchor and rub the soil through vertical root and horizontal root. The main root is similar to the full-length bonded anchor, which transfers the sliding thrust of the soil to the deep layer and the force to the lateral root. Through the friction resistance between the lateral root and the soil, the thrust of the sliding soil can be balanced, and then the stability of the slope will be affected. 3) the mechanism and effect of vegetation slope protection are discussed by establishing four kinds of calculation models and using numerical simulation method. The simulation results show that the interaction between herbaceous roots and rock soil is due to the presence of plant roots in the soil, and the slope topsoil and root system become root-soil complex, which increases the cohesion of soil and the surrounding stress. The stress and strain state of the shallow soil is changed, the stress level in the soil is reduced, and the lateral displacement of the shallow soil is limited. The herbaceous root system can obviously increase the shear strength of the surface soil of the slope and increase the safety factor of the slope. The slope stability has been improved. The soil consolidation function of woody root system mainly transfers the stress of the surface soil to the deep soil through the main root system, and anchors the deep soil mass, which is consistent with the anchoring theory. It is feasible to apply the anchoring theory to the analysis of the soil consolidation mechanism of the root system. 4) the soil consolidation effect of plant roots is mainly reflected in the effect on the shallow layer of the slope, but the effect on the deep soil is not obvious. The slope protection combined with "grass and irrigation" is the most effective way to improve slope stability, the herbaceous slope protection is the second, only woody plant is the worst. 5) through the vegetation restoration design of typical soil slope and rock slope of stone road, the corresponding construction method is put forward. The wet spraying technology and the greening base material spraying technology can protect the soil slope and the rock slope of Shima highway, and are suitable for the vegetation protection technology of highway slope in high altitude and severe cold area.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.14;U417.1

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