摘要
为了科学划分碎屑斜坡类别和准确评价国道G318藏东段碎屑斜坡的稳定性。本研究历时3年,详细调查了该区段公路沿线所有碎屑斜坡,根据斜坡碎屑物质成分、颗粒大小及运动特征等进行类型划分,分析了各类碎屑斜坡的基本特征和失稳模式。利用信息熵和FLAC数值模拟分析了影响因素与斜坡稳定的相关关系,并建立了基于支持向量机的碎屑斜坡稳定性评判模型。研究表明:(1)碎屑斜坡可细分为溜砂坡、滚石坡和碎石坡3类。(2)碎屑斜坡影响因素从大到小依次为降雨融雪、平均坡度、碎屑物、平均坡高、植被覆盖率、工程建设、地震、风化等级、振动和河水侵蚀。(3)主要影响因素作用下,碎屑斜坡安全系数斜率大小为:降雨融雪(0.8)>平均坡度(0.66)>平均坡高(0.52)>植被覆盖率(0.46)>工程建设(0.43),其斜率越大则影响作用越显著。(4)选取前6个主要影响因素用于碎屑稳定性评判模型,通过模型训练、回判和检验,模型准确率分别达到了89.29%和93.75%,可用于碎屑斜坡的稳定性评判和整治维修参考。
This paper attempts to accurately evaluate the stability of debris slopes located in the eastern Tibet section of the G318 highway. It can provide a reference for the highway public sector to carry out maintenance,with a view to thoroughly solve the serious damage of debris slopes to this section. We investigated all the debris slopes along the section of the district 1277 km in the past 3 years. According to the composition of the debris,the size of the particles and the characteristics of the movement,the basic characteristics and failure mode of all kinds of debris slopes are described. The correlation between the main factors and the slope stability is analyzed with the information entropy and FLAC numerical simulation. The stability evaluation model of the debris slope based on support vector machine is established using the analysis results of the influence factors. The results show that:( 1)Debris slopes can be subdivided into 3 types of sliding sand slopes,rolling rock slopes and gravel slopes. The characteristics of the 3 types of debris slopes are as follows: The sand slipping is of small cale,but happens suddenly and often in groups;The rolling stone slope is mainly composed of spalling or partially slipping of alluvial and diluvial deposits,with a large number and great harm. The gravel slopes are sudden burst with large energy,high speed,a certain scale and great harm.( 2) Information entropy theory is used to analyze the correlation degree of 10 factors on the stability of the debris slope. The effective factors in turn are rainfall snow melting,average slope,debris, average slope height, vegetation coverage, engineering construction, earthquake, weathering degree,ground shaking and river erosion.( 3) Numerical simulation shows the main influencing factors. The slope safety coefficients are compared after normalization with its curve slope relationship: rainfall snow melting( 0. 8) >average slope( 0. 66) >average slope height( 0. 52) >vegetation coverage( 0. 46) >construction( 0. 43). The greater the gradient of the curve,the greater the correlation between the factor and the stability of the debris slope. The conclusion is consistent with the field investigation and analysis.( 4) Combining the information entropy and the results of numerical simulation using FLAC analysis,six of the main factors are selected for the stability evaluation model of the debris slope. The model accuracy rate is 89. 29% and 93. 75%respectively through the model training,back estimation and test,which can be used for the stability evaluation of debris slope to give some advises and reference for maintenance.
作者
叶唐进
谢强
王鹰
YE Tangjin;XIE Qiang;WANG Ying(Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 610031;School of Engineering,Tibet University,Lhasa 850000)
出处
《工程地质学报》
CSCD
北大核心
2019年第4期914-922,共9页
Journal of Engineering Geology
基金
国家自然科学基金项目(41662020,41462012)资助~~
关键词
碎屑斜坡
分类
稳定性评判
影响因素
Debris slope
Classification
Stability evaluation
Influencing factors
