| With the continuous development of engineering construction in China, more and more areas will be in the construction of railway and highway tunnels. The karst is widely distributed in Southwest China, it will inevitably encounter the problem of the safety of tunnel construction under the influence of karst cavity. The variability of the cavity and rock parameters are important factors affecting the safety of karst tunnel. The cavity of different location and distance have different effects on tunnel, the measures are also different. At present, there are less research on effect of spatial variability of the surrounding rock on tunnel, the regularity of the effect is not clear and complete. Therefore, considering the effect of the variability of karst cavity and surrounding rock on tunnel safety has important guiding significance to the construction of karst tunnel.Based on the theory of random field, this paper studies the safety of tunnel construction in karst area under the influence of the cavity. Considering the effect of the spatial variability of karst cavity and surrounding rock on tunnel and combined with the engineering example of Jianzhong Tunnel, the conclusions are as follows:(1) Study on the influence of karst cavity variability on tunnel safety, its variability is mainly reflected the different position and distance. And considering on the surrounding rock grouting reinforcement, the influence of cavity position and distance on the deformation and internal force of tunnel lining is obtained. And analyzing the influence of the cavity to the tunnel safety, thus the most unfavorable cavity position is obtained.(2) Based on random field theory, considering the spatial variability of surrounding rock’s elastic modulus, density, cohesion and internal friction angle, simulation is carried out to the tunnel construction of the most unfavorable cavity position. And the method of considering the influence of the surrounding rock vertical and horizontal correlation distance on the tunnel respectively is realized. Comparing the simulation results under the condition of grouting and non-grouting, the effect of the variability of mechanical parameters of surrounding rock and the correlation distance of surrounding rock on tunnel deformation and internal force of lining was obtained. And the control effect of grouting reinforcement is also obtained.(3) Combined with the engineering example of Jianzhong Tunnel, using geological prospecting data to simulate actual working conditions, thus the karst cavity effect on tunnel safety and the control effect of grouting reinforcement are verified. The deterministic simulation method and random field simulation method are used to simulate the section with emergence of cavity respectively. Then comparing the results with the measured data, the guiding significance of the method of random field simulation to the practical engineering is obtained. |
PDF Full Text Request