In the process of side slope deformation from initial buckling to post-buckling, only if canonical factor changes its plus-minus, does the system jump from one state to the other state.

• 边坡从初始屈曲到后屈曲的变形过程中，只有当正则因子改变正负号时，系统才会从一个状态突跳至另一个状态；