Study On Mechanism And Early Warning System Of Water Inrush Disaster In Marl Tunnel

With the rapid development of the western economy,the construction of highways,tunnels and infrastructure in Northwest my country is in full swing.During the construction of the tunnel,engineering problems such as water inrush,soft rock deformation,and collapse frequently occurred.The flood inrush disasters of tunnels have the characteristics of being catastrophic,sudden and unpredictable,which have attracted wide attention.Based on the YK347+840～YK347+865 engineering section of Qinyu Tunnel of Lanzhou-Haikou National Expressway(G75),this thesis launches related research on the mechanism of marl tunnel water inrush disaster and the evolution of precursor information.The main research contents are as follows:(1)Based on the orthogonal design theory test method,red clay,barite powder,cement,river sand and gypsum powder were used as raw materials to carry out the ratio test of similar materials for marl,and the sensitivity law of each characteristic parameter was analyzed.Finally,the optimal ratio of similar materials was obtained.This similar material can not only better simulate the mechanical and hydraulic characteristics of marl,but also simulate the characteristics of cement softening of marl.(2)A three-dimensional geomechanical model test system with large scale and dynamic loading was developed.The model box size of the three-dimensional geomechanical model test system is 2300mm×1300mm×2000mm,which can not only realize five-dimensional loading simulation,but also realize low cycle loading and unloading.In terms of loading mode,the electro-hydraulic servo loading system is used for loading,which has high loading accuracy and good pressure stabilization effect.The initial stress state of the tunnel is restored to the maximum extent,and it is convenient to study the mechanism of tunnel water inrush disaster and the evolution law of precursor information.(3)Multi-functional hydraulic pressure stabilizer loading device was independently designed.The device can provide 0～10MPa water pressure loading,which can meet the needs of most test water pressure simulation.The hydraulic loading device can regulate the flow velocity,p H value and temperature in the water inrush structure.Device interface using standard NPT interface,easy to connect with other equipment.(4)Based on Python programming language and Internet of Things technology,a multiinformation tunnel water inrush disaster warning system is built.The system adopts modular design,mainly including data remote wireless transmission,automatic acquisition,data visualization,IA-BP intelligent algorithm back analysis and comprehensive early warning function modules,in order to realize the purpose of comprehensive early warning and prediction of tunnel inrush water disasters.(5)With the self-developed three-dimensional geomechanical model test system of tunnel gushing water,the engineering geological structure and water-bearing structure of Qinyu Tunnel are simulated by using the developed similar material of marlstone.When the tunnel is excavated by the bench method,the information changes of surrounding rock pressure,displacement and seepage water pressure are collected to study the gushing water mechanism and information evolution law during the excavation of marlstone tunnel.It shows that the similar materials of marl can better meet the test requirements and the stability and reliability of the three-dimensional geomechanical model test system of tunnel inrush water.