## 1 Introduction  
The support structure of soft rock tunnels can ensure the smooth excavation and safe operation of the tunnel [1], and an inverted arch structure plays an important role in improving the bearing capacity and stability of the whole support system. The inverted arch is connected to the side wall to form a stable annular structure with an upper lining so as to make full use of the high compressive strength of concrete and improve the strength and stability of the whole tunnel support system [2]. An inverted arch can also change the stress state of the rock around the tunnel, changing its stress state from only horizontal and vertical two-way forces to a multi-directional uniform force, thus avoiding or reducing the phenomenon of stress concentration in the surrounding rock. This reduces the plastic deformation of the surrounding rock and improves the strength and stability of the surrounding rock. At the same time, an inverted arch can effectively support the side wall and vault support, thus reducing the vertical deformation of the upper support structure. It can also guide the horizontal stress to the lower surrounding rock, reduce the load and deformation of the surrounding rock in the horizontal direction, and improve the stability of the side wall. The stress of inverted arch structures is complex. They not only bear the stratum pressure brought about by the upper support structure, but also resist the rebound force of the surrounding rock at the tunnel bottom. During operation, it also bears the vibration load of trains. Therefore, the uplift deformation of inverted arches at the tunnel bottom will affect the stability of the whole support system of the tunnel, leading to the deformation and destruction of the entire lining structure. In serious cases, it may damage the train running track. This affects the driving safety of vehicles. The invert uplift deformation of soft rock tunnels is a very complex engineering problem which is not only related to the physical and mechanical properties of the tunnel's surrounding rock, the initial stress state, and groundwater development, but is also closely related to the regional geological structure, tunnel excavation and support methods, inverted arch support timing, and other factors. Soft rock is prone to large deformation under the condition of high ground stress due to the low strength of the surrounding rock, easy softening by water, poor self-stability, and other characteristics. Tunnel inverted arch structures are also prone to uplift deformations. Therefore, studying the monitoring methods for arch deformation in soft rock tunnels is of great significance for guiding tunnel engineering, analyzing the causes of arch deformation, selecting control measures, and implementing preventive control measures during construction and operation in the future. [PERSON] et al. [3] studied the Shuiqing Tunnel of the Bijie to Zhenxiong Expressway in Guizhou Province and adopted the New Austrian Tunnel Method to ensure tunnel construction safety in water rich strata. However, this method does not take into account the possible differences in geological conditions in other regions, and its universality is not high. [PERSON] et al. [4] established a hybrid model that combines chaos theory, support vector machine, and an improved Gray Wolf optimization algorithm for deformation prediction in the early stages of dam operation. However, the data quality in this method is poor, which affects the accuracy of the model. [PERSON] et al. [5] modeled the centroid deformation of arch dams through measurement data and determined the spatiotemporal distribution characteristics of arch dam deformations. However, this method cannot obtain real-time dam deformation information and is inefficient. In work by [PERSON] et al. [6], firstly, a pressure sensor was used to collect the pressure disturbance data.