基于PLS法岩体边坡抗剪参数确定及稳定性分析

Determination of Shear Parameters of Rock Slope and Its Stability Analysis based on PLS method

对于岩体抗剪强度的确定,采用偏最小二乘(PLS)法,以岩体基本参数点荷载强度、孔隙率、天然密度为基础,进行主元相关性提取分析。然后将自变量和因变量高维数据空间投影到相应低维特征空间,并将多元回归问题转化为若干一元回归问题,可更好地适用于样本数较少而因变量数较多的参数回归分析。针对实际边坡分析,通过PLS法确定的岩体抗剪强度参数,以弹塑性破坏为准则计算边坡的破裂形态,FLAC3D强度折减法计算边坡的安全系数。并与原勘察报告提供的岩体抗剪强度参数计算边坡破裂形态和安全系数相比较,不管从剪切破裂面分布特征,还是安全系数大小,PLS法确定的岩体抗剪参数,都能更好地反映实际岩体边坡的破裂形态和安全状态。因此PLS法确定岩体抗剪强度参数可直接用于评价边坡的稳定状态,可以作为岩体力学参数拟合的一种有效方法。

For the determination of shear strength of rock mass,the partial least squares（PLS）method is adopted. With the basis of basic parameters of rock mass,point load strength,porosity and natural density,the correlative analysis on principal component was carried out. Then,high dimensional data space with dependent and independent variables are projected into the corresponding lower dimensional feature space,and the multiple regression is converted into a number of monadic regression process,which can better be applicable to the parameters regression analysis with less samples and more dependant variables. In view of the actual slope analysis,and with the use of the shear strength parameters of rock mass determined by the PLS method,the fracture morphology of the slope is calculated with the elastic-plastic failure as criteria,and the safety factor of the slope is calculated by FLAC^（3D） strength reduction method. Comparing with the shear strength parameters of rock mass slope provided by the original survey report,PLS method of determining the shear parameters of rock mass can better reflect the real fracture morphology and safety coefficient of slope rock mass,no matter from the distribution characteristics of shear fracture plane or the safety coefficient. Therefore,the PLS method of determining the shear strength parameters of rock mass can be directly applied to evaluate the stable state of slope,and be used as an effective method for fitting the mechanical parameters of rock mass.