黏弹性岩体中圆形巷道位移反分析的唯一性研究

Study on uniqueness of displacement back analysis of circular roadway in viscoelastic rock mass

为了研究黏弹性岩体位移反分析的唯一性问题,本文根据弹性岩体径向位移推导了黏弹性岩体中符合Maxwell模型的圆形巷道位移解析解,并根据参数可辨识性条件对黏弹性岩体中圆形巷道位移反分析的唯一性进行了研究。结果表明,无论布置多少个测点都不能唯一地反分析出所有的5个参数,至少已知2个参数才有可能唯一地反分析出其他参数;侧压力系数是否为1和地应力是否为0对反分析唯一性有明显的影响;随着已知参数的增多,参数的可辨识性增强;地应力和侧压力系数的可辨识性最好,弹性模量、泊松比和黏滞系数次之。研究结果对于岩体参数的反演计算具有一定的指导意义。

In order to study the uniqueness of the displacement back analysis of viscoelastic rock mass,an analytical solution of circular tunnel displacement in viscoelastic rock mass conforming to Maxwell model is derived according to the radial displacement of elastic rock mass,and displacement back analysis of circular tunnel displacement in viscoelastic rock mass is studied according to the parameter identification condition.The results show that no matter how many measuring points are arranged,all the five parameters cannot be uniquely analyzed.At least two parameters must be known before other parameters can be uniquely back-analyzed.Whether the lateral pressure coefficient is 1 and the ground stress is 0 has obvious influence on the displacement back analysis.With the increase of known parameters,the discernibility of parameters increases.The coefficient of ground stress and lateral pressure is the best,followed by elastic modulus,Poisson s ratio and viscosity coefficient.The research results have certain guiding significance for the inversion calculation of rock mass parameters.