The invention relates to the field of
tunnel engineering geology and
support design, and discloses a weak surrounding
rock tunnel deformation risk discrimination method based on shear expansion-shear constitutive, which comprises the following steps: constructing a
nonlinear coupling model between a shear expansion angle and
shear stress, normal stress and joint parameters, and obtaining the shear expansion angle; establishing a volumetric
strain rate discrimination formula; inverting an initial
crustal stress tensor field; reconstructing an irregular tunnel boundary; constructing a
risk level discrimination model, and outputting a
risk level; supporting schemes such as supporting rigidity, anchor rod parameters and spraying
layer thickness are matched according to the risk grades; establishing a model to predict a risk trend; a support adjustment suggestion is generated; collecting
monitoring data to dynamically correct
model parameters; and all the modules are integrated in a deployment
system. According to the method, the
coupling relation between the shear expansion angle and the
shear strength is introduced, the
coupling type constitutive discrimination model is established, the risk grading
system and the support correction strategy associated with the support response are constructed, and active early warning of the high-risk section and dynamic adjustment of the support rigidity are achieved.