Research on Deformation Control of Surrounding Rock Considering the Bearing Characteristics of Supporting Elements

To explore the characteristics of support bearing and deformation control, a mechanical model for the coupling effect of support and surrounding rock was constructed based on comprehensive consideration of support bearing characteristics such as steel arch frame, sprayed concrete, and advanced reinforcement. A total of 35 working conditions were constructed for 5 calculation types, and the influence of different support forms, support stiffness, and support timing on the deformation of surrounding rock was detailed analyzed based on a certain engineering example. The results showed tunnel support has a good control effect on the deformation of the surrounding rock in front of and behind the palm, and the combined support effect of advanced support and initial support is better, and this control has a spatial effect. A single support or a coordinated combination of multiple supports can achieve the same deformation control effect, depending on the stiffness matching of each support element. Steel arch frame, as a rigid support structure that can immediately and actively bear loads, has more advantages than sprayed concrete in bearing loads and controlling deformation. The combined support efficiency of advanced support and steel arch frame is higher. The earlier the support is applied, the earlier the deformation of the surrounding rock enters a controllable state, and the better the effect. With advanced support, the sensitivity of surrounding rock deformation to support timing is relatively low. Therefore, for complex tunnel projects, early implementation of advanced support is an important measure to compensate for inadequate initial support and reduce construction risks. This study theoretically clarified that reasonable stiffness matching between supporting structures is the key to achieve stress coordination and tunnel structure stability.