基于岩层参数贡献率分析的大岗山坝肩边坡模糊评判方法研究

STUDY OF FUZZY EVALUATION METHOD OF DAGANGSHAN ROCK SLOPE STABILITY BASED ON CONTRIBUTION RATE OF ROCK PARAMETERS ANALYSIS

以大岗山坝肩边坡为算例,对不同岩层的变形模量、黏聚力和内摩擦角进行整体和局部折减计算其安全系数,得出不同参数在不同位置下对特定边坡稳定性的贡献率。该贡献率量化处理后应用到评价系统中,定量标定了不同岩层参数的权重分配,确定坡体综合力学参数的隶属度。根据规范要求,以安全系数1.30,1.175和1.05为界,通过线性回归分析有针对性的给出具体工程不同参数分级标准;确定不同岩层内参数所在稳定级别基础上,结合所占分析区域的面积比值,采用不同岩层的安全系数综合贡献率进行修正得出不同参数的隶属度矩阵。该方法对综合评价体系中部分模糊的成分进行了基于有限元计算的精确化处理,在权重分配、隶属度确定、分级标准确定及坡体综合力学参数确定等4个评判主要环节上以消弱主观因素带来的不确定性影响,与经验法相比工程针对性更强,结果得出更科学合理。

Taking abutment slope of the Dagangshan as an example,the safety factor of the slope is calculated by overall and local reduction deformation modulus,cohesion and internal friction angle of different rocks,and the contribution for the specific slope stability at different parameters in different locations are obtained,which applied to evaluating system after the quantization process. The weight distribution is scientifically calibrated for parameters of the different rocks and on this basis the membership of the slope body comprehensive mechanical parameters is determined. According to the requirements of the Code,with safety factors of 1.30,1.175 and 1.05 for boundary,the grading standards of the different parameters of the specific projects are given;on that basis,the stable levels within different parameters in different rocks are determined. Combined with area ratio among the analysis area,the membership grade matrix revised by the comprehensive contribution of different rocks and the different parameters are obtained. The method precisely deals with the fuzzy parts of the comprehensive evaluation system based on the finite element method(FEM) calculation,weakens the uncertain effects caused by subjective factors in the four major evaluation segments of weight distribution,determine the membership grade,grading standards,and comprehensive mechanical parameters of slope,which is more targeted to engineering and results are more scientific and reasonable compared to experience.