| The research on the relationship between the surrounding rock and the supporting structure and the deformation control of the weak surrounding rock tunnel has always been one of the important research contents in the tunnel engineering,and it is also the decisive factor in the safety construction and construction period of the tunnel.This article combines the actual project of Jie(Yang)Hui(Lai)Expressway Xiaobeishan 1# tunnel,and adopts comprehensive analysis methods such as theoretical analysis,on-site monitoring,indoor testing,and numerical simulation for soft rock sections of F3 faults.The deformation of the surrounding rock,the initial support structure and the grouting ratio were systematically analyzed.The main research contents and achievements of the paper are as follows:(1)The system collated and elaborated the definition,classification and mechanical characteristics of soft rock,the relationship between the soft rock and support structure,and the supporting mechanism of each component in the initial support structure.Based on the theory of elasto-plastic mechanics and material mechanics,the theoretical analysis of the relation between the supporting force of surrounding rock and the deformation of the surrounding wall of tunnel No.1 in Xiaobeishan was carried out.(2)According to the Xiaobeishan No.1 tunnel monitoring program,the on-site monitoring and results analysis of the surrounding rock deformation and initial branch internal forces of the soft rock segment of the tunnel are performed.The weak surrounding rock has the characteristics of large deformation,fast deformation rate,and not easy to converge.It is easy to cause stress concentration at the arches,etc.It is necessary to strengthen the support to ensure the stability of the surrounding rock structure.(3)In view of the fact that the soft rock section of the Xiaobeishan No.1 tunnel islocated at the F3 rich-water fault,the indoor grouting ratio test was used to study the permeability and gelation time of the slurry under the conditions of different proportioning schemes and different mixing ratios.,Compressive strength and other performance indicators,select the best grouting reinforcement slurry ratio program.(4)Using GTX NX numerical simulation software,the water-rich soft rock section was simulated and analyzed.The deformation and force characteristics of the surrounding rock under different construction support schemes were studied,and a better construction support program was selected,and it was practical.The comparative analysis of the monitoring results provides some guidance and reference for the construction and analysis of the water-rich soft rock tunnel under similar conditions. |
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