Numerical Simulation Of Crustal Stress Field In The Engineering Area Of Yantai Underground Water-Sealed Storage Cavern

Initial geostress field is an important factor in excavation and design of underground engineering,which is mainly superimposed by the gravity field caused by the gravity of rock mass and the tectonic stress field and can be regarded as a relatively stable stress field.The underground water-sealed cavern project is located in Yantai City,Shandong Province.During the preliminary exploration stage,only two boreholes have been surveyed for in-situ stress,and the magnitude of in-situ stress varies with space.In order to understand the characteristics of in-situ stress in engineering area,this paper simulates the in-situ stress field in engineering area by using numerical simulation ANSYS combined with engineering geophysical prospecting,in-situ stress measurement results,rock mechanics test results and field geological survey results.The simulation results show that:(1)Three-dimensional in-situ stress field simulation shows that F7,F8 and F9 faults in the engineering area are all stress concentration areas under the action of NE78 tectonic compressive stress and NW12° tectonic tension stress,while F1 faults hinder and restrict the distribution of stress intensity and the third principal stress.(2)According to the simulation results,the third principal stress value near F9 fault is 32.1?41.1 MPa,which belongs to the extremely high geostress area.During the excavation of caverns,attention should be paid to the phenomena of rock burst,rock ejection and rock mass peeling caused by stress release of granite with more energy stored;away from the fracture,the compressive stress value gradually decreases and transits to the general stress area.(3)According to the characteristics of stress distribution in the simulated area and the occurrence of five groups of structural planes developed in the cavern area,the stability of structural planes with occurrences of 92°?78° and 190°?65° is poor under the current ground stress.The sliding phenomenon of rock mass caused by excavation disturbance should be paid attention to.