Experimental Study On Fault Activity Exploration Based On Distributed Optical Fiber Method

In the research process of geological disasters,it is often found that it is closely related to the activity of faults,such as the occurrence of earthquakes and the formation of ground fissures.The geomorphological features of the linear changes(steep ridges,subsidence pits and ground fissures)are also associated with the reactivation of ancient faults.A series of geological disasters caused by fault activities not only caused huge economic losses,but also threatened the lives of people.At present,geological researchers have paid extensive attention to the activity research of faults,and used various technical means to observe and study the law of fault activity.Based on the singularity of the current research on fault activity technology,the research on fault activity is not comprehensive.Therefore,it is necessary to conduct comprehensive research on fault activity by combining new technical means and some physical experiments,so as to show its activity rules more intuitively.In this paper,the distributed optical fiber sensing technology is used as the research method.Through the indoor uniaxial fracturing experiment,similar physical simulation experiment and field engineering measurement,the activity of the fault is fully studied and analyzed.Mainly get the following conclusions:(1)Through the uniaxial fracturing experiment of rock pressure progressively in the room: during the continuous pressurization process,the rock deforms and deforms until it breaks,and the distributed fiber can completely observe the whole process and at the rupture position.The largest change in strain can be found.This indicates that the distributed fiber has good applicability in the study of deformation and damage of rocks.(2)Constructing similar fault physical simulation experiments indoors to simulate the sliding process of normal faults.Through the distributed optical fiber test system arranged in the model body,the strain response characteristics near the interruption level of the normal fault sliding process are obtained.The results show that: When the normal fault occurs,the optical fiber that crosses the fault transversely has the most obvious response to the fault,and the fiber that passes vertically through the fault responds slightly weakly and changes regularly.(3)Distributed fiber test method On-site in-situ test shows that the rock stratum near the fault plane is more prone to displacement deformation than the rock stratum at other locations.The results show that the strain change near the fault plane is the largest,reaching 85??,and the fault plane 9 m,8 m range would be affected by fault and showed more apparent strain characteristics.(4)The application of distributed optical fiber testing technology is beneficial to accurately and comprehensively grasp the displacement characteristics of rock strata during fault occurrence activities,and can evaluate the stability of some geological bodies,which is of great significance in the prevention and treatment of geological disasters.Figure 39 Table 7 Reference 76...