Slope Stability Evaluation And Reinforcement Method For Mountainous Roads With Complex Geological Conditions

There are lots of mountains in most parts of Guangxi Autonomous Region, withso many slopes along the whole line of express ways, and a large proportion of highslopes. Varying degrees and operation of collapse, landslides and other disasters occurin the construction process of slopes. With the heavy task, short construction periodand hidden geological phenomena of highway construction at present stage in China,the geological characteristics of the slope after excavation are very difficult toaccurately predict before slope excavation. Limited by the above characteristics ofsurvey and design, geological problems of high slopes in mountain high-gradehighways in the investigation and design phase are difficult to completely acquire,which often results in inconsistent of the design scheme and geological conditions.This research is supported by High and Steep Slope Stability Evaluation andgeological Disaster Warning System of Road S223from Bingcun of Meixian toMeicheng, Guangdong, supported by High Cutting Slope Survey and reinforcementScheme of Expressway from Liujing to Qingzhou, Guangxi, and supported by HighCutting Slope Survey and Reinforcement Scheme of Expressway from Qingzhou toChongzuo, Guangxi.Based on statistics obtained by a number of field investigation, sufficient data inthe research areas such as engineering geology, geotechnical physical mechanicsparameters and so on were obtained, with focus on the slope rock mass structure.Based on the conditions of geological environment, geochemical testing methods andgeological structure phase matching methods are used to study the causes of the rockmass structure of the high slope and to sum up the formation mechanism of highwayrock slope. Field investigation of the surface of the rock mass structure and stabilityevaluation method are the key of analysis, and the typical high slope of the QinchongRoad in GuangXi is treated as engineering example to carry out the thesis work, Thespecific research contents and the achievements are as follows:(1)The rock mass structure surface is formed during a long geological history ofevolution, it has gone through the process from the digenetic construction to structuralalteration and epigenetic transformation. The research methods of slope rock massstructure's formation mechanism of mountain road are summed up, and the process ofdeformation and fracture of slope by numerical simulation is studied as well.(2) Risk evaluation methods of slope in the design phase are established, whichare on-site investigation, prediction of failure extent, division of evaluation unit, theevaluation value, and then risk evaluation'.(3) Idea of systematic integration of slope engineering is proposed, on-siteinvestigation, stability evaluation, control design, deformation monitoring, information feedback and then design optimization'. The on-site fast method fordescribing slope rock mass structure of mountain road during construction phase issummarized and established, as well as the rupture deformation mode, classificationof rock mass structure plane, and rock mass classification methods of highway sloperock mass.(4) Slope stability analysis method of highway during construction phase can bemay include evaluation methods based on block theory and deformation theory, andthen the feasibility of the methods is analyzed by a case study.(5) The on-site fast method for describing slope rock mass structure of mountainroad during the construction phase is summarized and established, as well as therupture deformation mode, classification of rock mass structure surface, and rockmass classification methods of highway slope rock mass structure.(6)Landslides of highway from Qingzhou to Chongzuo are taken as an example.It shows that engineering measures should be taken in high cutting slopes accordingto specific circumstances. Timely supports after the excavation are used for the tallslope or the slope of adverse geological conditions, and anti-slide piles withprestressed cable are effective for large-scale landslides with deep slip surface,because anti-slide piles with prestressed cable reduce the force of pile body, therebyreduce the cross-sectional area of the pile, steel consumption and buried depth of thepile, which is a reinforcement measure that should be promoted. The geologicalmodel of excavation slope and qualitative evaluation of the process is the key forstability evaluation and the quantitative evaluation of the mechanical mechanism is animportant auxiliary means, which can provide an important basis for remediationdesign at the same time. The calculation means of numerical simulation analysis caneffectively reproduce the failure process and mechanism of the excavation slope, andit can predict the future stable degree and failure mode.