纸坊隧道初始地应力场线性回归分析

Linear Regression Analysis of Initial Geostress Field of Zhifang Tunnel

影响初始地应力场的主要因素有自重应力场和构造应力场。首先,假定研究区域的岩性为弹性;然后,利用各测点的水压致裂地应力测量资料和4个模拟构造应力场的三维有限元计算结果,用最小二乘法多元回归分析,得到了与4个自变量(分别对应自重应力、隧道轴线方向构造应力、垂直轴线方向构造应力和水平面内剪切应力)相对应的回归系数L1、L2、L3、L4,再计算复相关系数r及偏相关系数,判断回归效果;最后回归计算出初始地应力场。

The main factors of influencing the initial geostress field are the self weight stress field and tectonic stress field. Firstly the lithology of the studied area is assumed as the elasticity, and then the hydraulic fracturing in-situ stress measured data every test point and three-dimensional finite element calculation results of four imitated tectonic stress fields are used, the least squares multiple regression analysis is carried out. The regression coefficients L1, L2, L3 and L4 correspondent to four independent variables(separately correspondent to the self weight stress, the tunnel axis direction of tectonic stress, the vertical axis direction of tectonic stress and the horizontal plane shear stress) are achieved. Again the multiple correlation coefficient r and the partial correlation coefficient vi are computed. The regression effect is decided. Finally the initial geostress field is regressed and computed.