NUMERICAL SIMULATION OF TECTONIC STRESS FIELD OF THE XIAOKUAN FAULT ZONE DURING THE FAULT DEPRESSION PERIOD OF THE LISHU FAULT DEPRESSION

Based on the structural analysis of the Xiaokuan fault zone, a two-dimensional geological model for the Lishu fault depression area was established on available geological data and petrophysical parameters. The numerical simulation of tectonic stress field was carried out taking the Lishu fault as a case. Studied are the characteristics of tectonic stress field in the Shahezi period (K₁sh), the Yingcheng period (K₁yc), and the Denglouku period (K₁d) during the fault depression period of the Xiaokuan fault zone. The simulation results show that: ①Under the left-lateral strike-slip stress state of K₁sh, the Xiaokuan fault zone was in a tensile stress state in NE-SW direction, and the Coulomb shear stress gradually decreased along the SW-NE direction; ② Under the stress state of K₁yc right-lateral strike-slip, the Xiaokuan fault zone was in a tensional state near NW-SE direction, the maximum Coulomb shear stress was located in the middle part of the fault zone; ③ the left-lateral strike-slip in K₁d was under a tensile stress state of SWW-NEE direction, and the maximum Coulomb shear stress is located in the southwestern section of the fault zone.