| Highway transportation is one of the important ways to promote the continuous development of the national economy and facilitate the people's travel.However,due to the rapid development of China's economy,the roads that have been built and opened at early stage have been unable to meet the needs of national economic development no matter in terms of traffic capacity or service level.It is urgent to improve their road grades through reconstruction and expansion.In the course of the construction and expansion of the highway,it is inevitable to have two disturbances in the original cutting slope.Especially highway expansion in the mountainous area,the road is bound to be two times of the original excavation slope,if there is no excavation of a reasonable construction scheme and corresponding reinforcement measures,the slope is likely to failure in the excavation during construction or after the road opened to traffic,which will affect the construction schedule,increase the construction cost,and result in potential safety hazards in the operation process of highway.In view of this,it is particularly important to analyze the stability of the two excavated slopes and carry out the corresponding slope reinforcement technology in the process of rebuilding and expanding the trunk roads in mountainous areas.This article is based on the reconstruction and extension project of the Huashan section of G316 Zixi in Jiangxi province to the Huang Shi Du road in Nancheng,Fuzhou.And it studies the K433+380 left cutting high rock slope as the main research object.In this paper,the slope stability is the key control index,and stress and strain are the control target in process of slope excavation deformation.Combining with the slope of geological exploration data,indoor soil test data and the actual situation of the project,and with the help of ANSYS,FLAC3 D,Matlab,SPSS,Crystal Ball,Origin and other software,the finite element strength reduction method,multi factor analysis,and Monte Carlo method by means of mathematical theory are used to study the expansion of slope stability.In this paper,the failure mechanism,deformation failure mode and stability factors of cutting rock slope in mountainous highway are introduced in detail.Based on the actual working conditions of the high cut rock slope at K433+380 road in G316 highway,the safety factor is taken as the evaluation index,and the sensitivity factors of slope stability are analyzed by the finite element strength reduction method,the PCA method and the orthogonal test method.The comprehensive safety evaluation model of the sensitive factor analysis is used as the research object by Monte Carlo method.The risk assessment of the slope is carried out,and the probability of the slope instability failure was obtained.Then,using 1:0.75,1:1 and 1:1.25 of three excavation ratio of the establishment of three-dimensional slope in the Flac3 D model,the paper is focused on the influence of different excavation depth and number of steps on safety factor,displacement,stress and strain of slope to determine a reasonable excavation scheme.Then the ANSYS software is used to simulate the excavation slope with or without support.And the influence of the excavation step on the stability of the slope is further sdudied.Finally,this paper summarizes the commonly used reinforcement techniques and protection principles for cutting rock slopes in the mountainous highway reconstruction and expansion.And a reasonable slope supporting scheme,construction process and the matters needing attention in construction are put forward to improve the stability of slope during construction and operation period,which will play a guiding role on the slope construction.It is expected to provide reference for the similar highway slope engineering. |
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